368 LT5 Drinking oil

[Mitsumark]

Ahh..As if I haven't had enough problems this week with a busted pipe in my house,my wife falling,,now my Z is drinking oil..Literally..Here's what's going on.Hopefully one of you LT5 pros could shed some light on what may be happening..My car is a 91 and has a Vette Doctors built 368 with all the other goodies(headers,flywheel,gears,Marc H tune,ect)The car has also had a very recent service including coils,FIC stainless injectors,plugs,fuel filter,and Jerry's new PCV hose assembly along with new PCV valves..About 2 weeks ago I noticed a trail of Blue taillight smoke under medium/moderate acceleration..Yesterday I'm warming up the car and noticed it is smoking lightly out of the tailpipes just idling.It seems to come and go..However the car has drank 2 qrts of Mobil 1 in the last 300 miles..It is absolutely oil as the oil light came on,the smoke is clearly Blue and it stinks to high heaven.If I blip the gas quickly 3-4 times back to back the smoke becomes heavier and heavier until I stop..I haven't checked compression but I am suspecting a burnt exhaust valve..It idles a bit rough, although it always did..If I hammer it in any gear it doesn't miss a beat.It pulls very strong..There are no CEL light on and the secondaries seem to be working fine..The car also starts without smoke cold..This progresses as it gets hot.So far I've checked for vac leaks and found nothing..I also double checked the PCV valves and there is plenty of suction present while idling.I removed the oil cap and oil dipstick to see if there was any blowby present and there was non that I can see..There are also no external oil leaks as I've checked thourally..This is definitely tailpipe smoke..So what I have is an LT5 with a working PCV system and it's dumping oil into the combustion chamber..Is there any specific entry points I can check before I start suspecting valves or rings?I did drive through a few heavy misfires a few weeks ago when it had a suspect bad coil..Maybe I hurt it then?Help me guys..

[Kevin]

the fact that it's a vette docs car makes me think you're in for a rebuild.

[Mitsumark]

Thats encouraging lol..I forgot to mention it has new 02 sensors and there is no oil visible anywhere around the header flanges..

[USAZR1]

the fact that it's a vette docs car makes me think you're in for a rebuild.


I never had any problems with my 90 that Carmen and Dennis built.

[Kevin]

I never had any problems with my 90 that Carmen and Dennis built.

I'm pretty sure Carmen and dennis didn't build your car.

[Mitsumark]

I wouldn't think of blaming or slamming the builder either as this car was built in 02 and has logged plenty of racetrack miles trouble free..Awhile back I was running a cooler plug that resulted in very poor gas mileage..I also had a bad coil.. I full throttled it a few times to see if I can drive it through the hiccup.Im suspecting that's when I hurt it..Probably lots of carbon buildup from idling and too cold a plug,plus the bad coil..Im not an LT5 expert by no means. Haven't even wrenched in years..I'm just thinking its valve related.As I'm typing,I'm remembering more..The car idles terrible when it's ice cold and it smells like raw fuel being dumped into the exhaust..The idle smooths out quite a bit as it warms but that's when the smoke starts..

[LGAFF]

Does your car have bigger cams?

[Mitsumark]

The original Vette Doc build sheet and receipt states "intake cams"..Don't have specifics on lift/duration but the smoke is definitely recent.

[GOLDCYLON]

Rings and guides sounds right. You should not be going through that much oil. Any oild catching on the cross member and the usual places?

[LGAFF]

Sure its oil and not just running rich? At cold temps you need a lot more fuel, especially with big cams......to get the car to run....air and fuel will not bond well. Might check your PCV, etc to make sure its not pressurizing the pan

[LGAFF]

disregard my comment, you said you saw measured loss, not just smoke

[GOLDCYLON]

2 qts in 300 miles Lee, which is why im asking if its leaking out anywhere else as well.

[Mitsumark]

Definitely oil out of the exhaust..There are definitely no external oil leaks..Lee..When you mention the PCV pressurizing the oil pan..How would I check that and what would cause that to happen?As stated,I dont see or feel any pressure coming from the oil cap or dipstick.I took that as a good sign..However shes drinkin oil really quickly..getting so frustrated because this car has been beating me up since Ive got it..Funny thing is it runs through the gears now without any misses for the first time after the recent work I listed before..However I'm putting in more oil than gas now...If I determine that it's a valve problem and not a block issue,,what kind of money am I looking at to have the heads pulled redone and reassembled?Is there anyone near NY/NJ that still works on LT5s? I swear I'm ready to yank this thing and throw a carb'd 396 in this bomb..Don't mind me..I'm just venting:censored:

[A26B]

Read your plugs, look for black & oily, note plug condition for each cylinder.

Run a compression check, analyze for both rings & valves to insure combustion integrity. Although, if you are not noticing blow-by such as vapor blowing from oil fill or dipstick being pushed up. not likely to be rings.

It could be valve stem seals.

In any regard, from your description of raw fuel at startup sure sounds like an injector leaking at minimum.

[LGAFF]

agree with Jerry, go get a compression tester from autozone, rule out rings.....

Wondering if the breather hoses under the plenum could be leaking too...

[Dynomite]

However the car has drank 2 qrts of Mobil 1 in the last 300 miles..It is absolutely oil as the oil light came on

How about oil consumption say the 300 miles before the last 300 miles?
What oil light came on .......Oil Level ?

When you do the compression check....squirt some oil in in spark plug hole after initial compression check and recheck....I think that is what Jerry is suggesting to distinquish between Valves and Rings.

[Mitsumark]

I will do that.. As far as the hoses under the plenum..I just had the plenum off and they looked good..I've also went through 4 bottles of TB cleaner in and around the whole engine while running..Made sure to even spray around the IH bases,Plenum base,and in between all runners..No changes in idle or leaks found..


Dyno- The "low oil" light on the DIC..Confirmed it with an immediate oil check..It was below the cross hatches on the stick.. although it was just running 5 min before.The car shows very high oil pressure on the gauge when cold..Dead center hot..Running Mobil 1 10w40.

[Pete]

Check compression, if your not pushing out the dipstick or fill hole compression should be good.

I think it's in the heads guides/seals, how many miles on the heads/car.

Let us know what you find.
Pete

[Mitsumark]

Pete-Car has 75k..Rebuild has 15k but it has lived on a road racing track and saw 150mph quite often as I have the cars racing circuit history.Ya know Im thinking.Wouldnt a valve problem show smoke on cold startup?Mine starts without smoke and starts to smoke a bit at idle once hot.I also noticed that it does not smoke on decell in gear at high rpm..Only under moderate pedal action and revving it in neutral..Im gonna try to shoot a vid on Thurs after work and I'll post up..I know a compression test is a must but Im driving myself crazy meanwhile..Worse case scenario.If the heads need to be yanked,am I gonna have to drag this thing to Chitown?Can anyone recommend a good LT5 wrench in NY/NJ?..I dont think VDs play with LT5 anymore and ECS only messes with LSX..I dont have the time or resources to attempt a repair like this..

[PhillipsLT5]

I usually wait 24 hr to check oil, you can not get a accurate read immediately

[Pete]

Pete-Car has 75k..Rebuild has 15k but it has lived on a road racing track and saw 150mph quite often as I have the cars racing circuit history.Ya know Im thinking.Wouldnt a valve problem show smoke on cold startup?Mine starts without smoke and starts to smoke a bit at idle once hot.I also noticed that it does not smoke on decell in gear at high rpm..Only under moderate pedal action and revving it in neutral..Im gonna try to shoot a vid on Thurs after work and I'll post up..I know a compression test is a must but Im driving myself crazy meanwhile..Worse case scenario.If the heads need to be yanked,am I gonna have to drag this thing to Chitown?Can anyone recommend a good LT5 wrench in NY/NJ?..I dont think VDs play with LT5 anymore and ECS only messes with LSX..I dont have the time or resources to attempt a repair like this..


Yes,your right about start up.
You mention it starts to smoke when she gets up to temp which I'm thinking oil thins out with hot temps.

Did this just start?
Basicly what was the last thing you did when this started.

Pete

[USAZR1]

I'm pretty sure Carmen and dennis didn't build your car.

Post edited by the Administrator.

[Kevin]

Post edited by the Forum Administrator.

[Dynomite]

If I blip the gas quickly 3-4 times back to back the smoke becomes heavier and heavier until I stop

As Jerry and Pete suggests...........Most likely its your Intake Valve Guide Seals or your valve guides. It will smoke during deceleration because the engine is pulling a higher vacuum (each blip) with the TB closed allowing minimal air going in to the cylinder while the cylinder vacuum is still able to pull your crankcase/oil through your intake valve guide seals. Seems to me I recall the 90' to 91' was the change to Valve Guide Seals (exhaust) with the Intake Valve Guide Seals available on both the 90' and 91'.

flyin ryan says 90' did not have exhaust valve guide seals but they can be installed (http://www.zr1.net/forum/showthread.php?p=87067)

Description: 1990 Red/Red 21K - $ (AZ)
Very clean & original looking on the outside, cylinder heads & plenum (upper & lower) ported, new valve seals installed on the intakes & added to the exhausts (90's never came with exhaust valve seals), competition valve job, cams degree'd with ARP cam bolt's used, Accel injectors installed, 4.10 Mopar 'Viper' gears installed with a Ratech deluxe install kit & Dexron gear oil, Haibeck speedo calibration gears installed to compliment the gear change, C-4 beam plates, Doctor Don rebuilt & upgraded stereo, speakers & amps, Goodyear GS-D3 F-1 tires, Very strong but subtle running car, original paint with no touch up's, rims never seen a curb etc. Very well cared for no nonsense car, everything works, no issues.
Contact: Ryan Bell

Did this just start?
Basicly what was the last thing you did when this started.

Pete
I was wondering the same thing ........when I asked if the 300 miles just before the last 300 miles was the same issue?

Another Idea.......to diagnose if the smoking is related in any way to the PCV System.
Disconnect your PCV system on Camshaft covers and Injector Housing (plug the associated vacuum ports on Air Horn and Plenum) and rev it up to see if it smokes. If the smoking stops you are getting oil through your PCV system into the plenum (Then we are back to rings gone bad or something peculiar with your PCV System).

If the compression is good you do not have a burnt valve or bad rings and then we are back to Intake Valve Guide Seals. I have no clue how bad Intake Valve Guides or Bad Rings would start smoking ALL OF A SUDDEN.

[USAZR1]

As Pete suggests...........Most likely its your valve guide seals or your valve guides. It will smoke during deceleration because the engine is pulling vacuum with the TB closed allowing minimal air going in to the cylinder while the cylinder vacuum is still able to pull your crankcase/oil through your valve guide seals.


I agree with this,too.

[edram454]

As Pete suggests...........Most likely its your Intake Valve Guide Seals or your valve guides. It will smoke during deceleration because the engine is pulling a higher vacuum (each blip) with the TB closed allowing minimal air going in to the cylinder while the cylinder vacuum is still able to pull your crankcase/oil through your intake valve guide seals. Seems to me I recall the 90' to 91' was the change to Exhaust Valve Guide Seals.

flyin ryan says 90' did not have exhaust valve guide seals but they can be installed (http://www.zr1.net/forum/showthread.php?p=87067) This being a 91' with 91' heads makes this information not relevant but just informative for others viewing.


I was wondering the same thing ........when I asked if the 300 miles just before the last 300 miles was the same issue?



my two cents. yes Lee the 1990 did not have exhaust valve seals. the difference is the 1990 will smoke a little at the initial start up.. once you drive around and gets warm... no more smoke.. at all. His is smoking at deceleration, idling.. I would think he would need some type of valve work on his heads. Hope I am wrong.

[XfireZ51]

my two cents. yes Lee the 1990 did not have exhaust valve seals. the difference is the 1990 will smoke a little at the initial start up.. once you drive around and gets warm... no more smoke.. at all. His is smoking at deceleration, idling.. I would think he would need some type of valve work on his heads. Hope I am wrong.

Smoke at idle and decel means it's sucking at the highest vacuum conditions.

[USAZR1]

Post edited by the Forum Administrator.

[A26B]

.........
When you do the compression check....squirt some oil in in spark plug hole after initial compression check and recheck....I think that is what Jerry is suggesting to distinquish between Valves and Rings.

You would be correct in your thinking.:handshak:

[alnukem]

After the compression check, wouldn't the next check be a vacuum gauge?

Steady idle Fast fluctuation between 14 to 19 points Worn intake valve stem guides. Excessive pointer vibration at all speeds indicates a leaky head gasket.

[Mitsumark]

Just to address a few of the statements above..When I picked up this car in Virginia last July,it ran strong to the point that it actually scared me.I've owned some quick high powered Mitsu's that made power on boost.However I wasn't used to the instant power just tapping the gas like in this car.It was a fun ride back to NJ..The car had a rock steady idle,pulled hard,and just ran great.The one thing I noticed that I hated the most was a 1100rpm idle.The previous owner had all the documentation on the car.The build sheet stated that idle was set high to quite the inheritant noise that comes with a light flywheel..I hated the high idle as it was very loud,I was putting a ton of gas in it,, and getting out of 1st sometimes was a pain with the CC stage 3 clutch..So I contact Marc H for one of his tunes.I told him what I had and he burned me a chip for a 368 with my bolt ons..After speaking with him,I also relocated my IAT sensor from the airhorn to under the front bumper..while waiting for the chip to arrive I also installed plugs that were a step colder than stock..Once the chip arrived, I followed the directions and started it up..I don't know which of the things I did that did it,but the car hated it..Although the idle was where I wanted,the car hunted for idle, ran very rough,and developed misfires.I even listened to it ping many times under light throttle on premium fuel.I drove it for a month thinking the computer would relearn and things would get better..They didn't..The misfires and hunting idle were driving me nuts so I started replacing everything..Coils,back to correct HR plugs,new IAC valve,new MAP sensor and hose,Jerry's PCV rig with new valves,new Delco 02 sensors,and I checked high and low for vac leaks under and around the whole engine..Non found..Installed new 2ndary vac pump and turned the key.. Worked like it should..Ran 3 sec and shut..Would continue to run when I pulled a vac hose the way it should..The car now ran again without any misfires.The idle still does hunt from 800-1200 rpm while rolling in neutral until I completely stop where it settles around 700..The smoke started a few weeks ago.. I hammered it a bit getting onto a highway and held on..It took off but I noticed a nice cloud behind me..Didn't think nothing of it.I had it idling in my driveway a few days later and I noticed after running for about 10 min it started smoking faintly out of the tailpipes..It has smoked everyday since then..Currently,sometimes I can be sitting in traffic for 10 min and there is no smoke at all..Then all of a sudden,even without throttle,I'll get the smell,look behind me and theres the smoke..It comes and goes at random..Again, I don't know jack about these cars..But I did drive through a few bad misfires before I discovered I had a bad coil.. I honestly think I burnt a valve up with the dead cylinder being dumped with fuel,the plugs being to cold and loading up(they were covered sooty Black when removed)..Just a bad combination of things..For the record,the build sheet says the car dynoed 459 WHP and it stated 'recommend customer returns after break in for more tuning'..The chip I removed and sent to Marc did say B Kirchoffer on it..

Ya know I was thinking maybe the oil got so thinned out from dumping fuel with the dead cylinder and cold plugs that maybe it thinned out enough to get past valves and rings.. I'm gonna try changing the oil again but I did not smell any fuel in the crankcase with the cap removed..

[bradley]

is there a place you can run her on the dyno to get what the air fuel is ????kinda sounds like she is pig rich . you can pull the plenum the pull the injectors out while still attached to the fuel rails . have a friend turn the key on while you look at the injector sand see if you have a leaker . oh put a towel under the injectors before doing the test

[scottfab]

As you mention in the original post your oil light came on so I agree, it's smoke from oil. What you did not mention (or maybe you implied it) is that the oil comes from both sides? If it does not have a crossover or H pipe and smoke is from both sides then you'd be burning oil on both sides. If it's a burnt valve then there are burnt valves on both sides. (less likely) If the oil burning is due to lack of valve guide seals then it would come from both sides.

FWIW
I know for sure what is in my engine.
I have an almost bone stock 90 with >90k on it. It has no valve seals. It burns a bit of oil at each WOT. It burns hell of a lot more on the track when I use the wrong oil. (1qt of 0w30 in 20mi). It burns more when I inadvertently overfill it. (don't let the oil settle)
When I let it sit overnight and top it off it burns about 1qt per tank full with lots of WOT.

Now here is the interesting part.
When I use a 20% mix of 10w40
AND
only fill the oil to the bottom of the dip stick line I get very little oil burn.

Just food for thought.
Hope your wife's fall was not serious. We're all pulling for ya.
We all have weeks like that.

PS unrelated but 3sec between secondary pump cycles is not good. That is too much leak down. When you're below 10sec cycling then you're on the slippery slope toward 1sec cycles and failure of the secondary to hold in.

[Schrade]

...

It burns more when I inadvertently overfill it. (don't let the oil settle).
...


This is a good point Scott:

Some engines, when you put too much oil in the crankcase, the crankshaft spins IN THE OIL, and makes a foamy, frothy, jammy mess.

It will make the oil light come on, when the system pickup tube starts suckin' up the froth.

I can't imagine WHAT goes through the PCV plumbing when this happens.

And who knows what would go through the cylinders. And the exhaust...

I don't know how LT5 dynamics would handle too much oil...



(good job Admin on editing - some people don't know a tactful way of telling another that they THINK another MIGHT be wrong. Even if they KNOW they're wrong. 'Cause they might NOT be wrong)

Like so:
That's what it ALL ABOUT - learning. No one knows it all.

I would NOT have mentioned 2 Ohm if just "anything close would work"!OK. I didn't know the igniters in the bag were that close in tolerance. I learn something new every day.

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;

Slightly more tactful ways exist of telling someone they might be wrong too...


ed.:
That's a good attitude there Franke. And good restraint. Responses like that start arguments. Right or wrong...

[GOLDCYLON]

I usually wait 24 hr to check oil, you can not get a accurate read immediately


A true statement, I always pull the dipstick in the morining however 2 qts is telling I think the guide/seals are the key

[geezer]

Just to throw in my 2 cents worth here - the PCV valves are new but as we know each has very different characteristics to deal with 'no load' plus WOT conditions. A lot of blowby at 'no load/ low load ' Could the PCV 's be reversed? LH is AC 913. GM info. has this reversed.
???

[GOLDCYLON]

Just to throw in my 2 cents worth here - the PCV valves are new but as we know each has very different characteristics to deal with 'no load' plus WOT conditions. A lot of blowby at 'no load/ low load ' Could the PCV 's be reversed? LH is AC 913. GM info. has this reversed.
???

I doubt it as the Stock PCV 2 piece hose is stepped as are each of the PCV valves with a body stop to avoid reversal. To reverse it would be rather odd and look of it would be Odd as well. In the non stock Samco replacment that could be done however I would tend to say no as the stock one was designed to give the mechanic a clue. In the correct position both PCV valve will be flush in the hose as intended. Actually a neat little bit of engineering by GM if I must say so

[Mitsumark]

PS unrelated but 3sec between secondary pump cycles is not good. That is too much leak down. When you're below 10sec cycling then you're on the slippery slope toward 1sec cycles and failure of the secondary to hold in.

Maybe I was mis understood..The 2ndary vac pump is brand new and cycles on for only 3 sec when the key is turned..It does NOT cycle on at any time during running unless I pull off the vac hose that controls secondaries..Then it will run nonstop.Although its irrelevant to my issues,I've already established the complete secondary system is fully functional.

Re: 368 LT5 Drinking oil
Just to throw in my 2 cents worth here - the PCV valves are new but as we know each has very different characteristics to deal with 'no load' plus WOT conditions. A lot of blowby at 'no load/ low load ' Could the PCV 's be reversed? LH is AC 913. GM info. has this reversed.
???


Good guess..However as stated above they really only fit one way correctly.I second guessed myself with that and double checked it yesterday..I really appreciate all the ideas and advice on what to do..I have about 2 hrs to play with tomorrow so I'm gonna change the oil with M1 15W50..I will also do a compression check..Standbye fellas..

[Pete]

Can you try using the old PCV valves, of course clean them first.

Let us know how the thicker oil works out.

Pete

[LGAFF]

I run 15-50 all the time and ran it in the car prior to installing the new engine with valve seals; reduced smoking at idle

[Paul Workman]

...However the car has drank 2 qrts of Mobil 1 in the last 300 miles..It is absolutely oil as the oil light came on,the smoke is clearly Blue and it stinks to high heaven.If I blip the gas quickly 3-4 times back to back the smoke becomes heavier and heavier until I stop....

All these ideas...

Following along, but this happened more or less suddenly. And the tail pipe stinks... Does it smell like gasoline or smell rich, or does it if fact smell like oil? Does the oil on the dipstick smell of gasoline??

Reason i ask, you made some comments about it running poorly and hunting, etc. With the smell - especially if it were fuel smell - I'd be wanting to do a leak down test. If you have a leaking injector, then some fuel may be washing down into the crankcase diluting/thinning the oil considerably, AND it would likely cause some rough running AND some stinking exhaust...

Just a thought.

[Mitsumark]

Compression test results..Don't know if these are good #s on an LT5..It was done with engine hot, all plugs removed,TB wide open..Each # represents that cylinder..

1.261
2.258
3.265
4.265
5.260
6.261
7.258
8.255

Check was done at a local performance shop..They have no LT5 experience and the techs were all intrigued with the car and how the engine looked..I was speaking with the head tech and told him the history and what I did..He said it may be possible that I may have a stuck oil control ring or valve that is not.seating properly due to carbon buildup from the cold plugs,bad coil,and excessive idling..He said I would probably never talk to him again after this next statement..He suggested when it gets low on oil again to run a qt of Rislone through it for a few hundred miles..He swore up and down that he has witnessed it free sticky valves and rings..Driving around awhile after that today she is still faintly smoking at idle..Mostly on medium/hard gas..I also took notice that the smoke comes from both sides..The car is running Watson headers into a dual chamber resonator,then into a B&B Triflow exhaust..No X or H pipe..Tomorrow I'm changing oil and gonna pull every PCV related hose/pipe to look for blockages..I have heard someone here mention some kind of sponges in the PVC system that can become brittle,break, and even clog passages..If that is true, where are they?Also forgot to mention even the stock plugs were very carboned up after just being in for 800 miles..No wet oil seen on plugs.

[LGAFF]

That's pretty damn high....looks good to me

[Dynomite]

Compression test results..Don't know if these are good #s on an LT5..It was done with engine hot, all plugs removed,TB wide open..Each # represents that cylinder..

1.261
2.258
3.265
4.265
5.260
6.261
7.258
8.255

Check was done at a local performance shop..They have no LT5 experience and the techs were all intrigued with the car and how the engine looked..I was speaking with the head tech and told him the history and what I did..He said it may be possible that I may have a stuck oil control ring or valve that is not.seating properly due to carbon buildup from the cold plugs,bad coil,and excessive idling..He said I would probably never talk to him again after this next statement..He suggested when it gets low on oil again to run a qt of Rislone through it for a few hundred miles..He swore up and down that he has witnessed it free sticky valves and rings..Driving around awhile after that today she is still faintly smoking at idle..Mostly on medium/hard gas..I also took notice that the smoke comes from both sides..The car is running Watson headers into a dual chamber resonator,then into a B&B Triflow exhaust..No X or H pipe..Tomorrow I'm changing oil and gonna pull every PCV related hose/pipe to look for blockages..I have heard someone here mention some kind of sponges in the PVC system that can become brittle,break, and even clog passages..If that is true, where are they?Also forgot to mention even the stock plugs were very carboned up after just being in for 800 miles..No wet oil seen on plugs.

Your compression is nice and even and high :D
Must have plained the heads......;)

The sponges are in the cam cover breathers which vent through the Air Horn...Marc Haibeck has them.

Cam Covers (Filters and Wear Strips) (http://forums.corvetteforum.com/c4-zr-1-discussion/3005470-tech-info-lt5-modifications-rebuild-tricks-500-hp-5.html#post1581825192)

Cam Cover Filters (http://www.zr1specialist.com/HAT%20Web/products/cam%20cover%20filter.htm)

http://i287.photobucket.com/albums/ll142/dynomite007/Dynomite3/5507ecfb-7c0a-4330-8ba9-278d953a3d45.jpg

[Mitsumark]

Dyno-Forgive my ignorance..Cam cover?Are you referring to the valve cover?If I'm looking at a valve cover above,you say that the filter goes where your pointing..Is that the part of the valve cover that faces the rear( closest to PCV)? If so, do these filters prevent large amounts of oil from entering the PCV system?If Im understanding this right,maybe mine are either missing or deteriorated enough to pull excessive amounts of oil through that area..Also,this car sat for the last 8 yrs before it was recently being used regularly again..

[Jagdpanzer]

Compression test results..Don't know if these are good #s on an LT5..It was done with engine hot, all plugs removed,TB wide open..Each # represents that cylinder..

1.261
2.258
3.265
4.265
5.260
6.261
7.258
8.255



Numbers look right for a 12:1 compression ratio motor.

[Kevin]

Dyno-Forgive my ignorance..Cam cover?Are you referring to the valve cover?If I'm looking at a valve cover above,you say that the filter goes where your pointing..Is that the part of the valve cover that faces the rear( closest to PCV)? If so, do these filters prevent large amounts of oil from entering the PCV system?If Im understanding this right,maybe mine are either missing or deteriorated enough to pull excessive amounts of oil through that area..Also,this car sat for the last 8 yrs before it was recently being used regularly again..

being as this is an OHC engine it doesn't have valve covers, but yes the covers that sit over the heads

[Schrade]

What's the spec squeeze ratio on stock mill? (I'm couchin' ATM )

[Mitsumark]

Kevin-I see your from PA..I bet you call those big sandwiches with the meat on them hoagies right? Lol.. Where Im from they're called subs..I was thrown off by Dynos "cam cover" reference as here in NJ,it's always referred to as valve cover regardless of it being pushrods,OHC,or whatever..Different states have different terms I guess..

[Dynomite]

Dyno-Forgive my ignorance..Cam cover?Are you referring to the valve cover?If I'm looking at a valve cover above,you say that the filter goes where your pointing..Is that the part of the valve cover that faces the rear( closest to PCV)? If so, do these filters prevent large amounts of oil from entering the PCV system?If Im understanding this right,maybe mine are either missing or deteriorated enough to pull excessive amounts of oil through that area..Also,this car sat for the last 8 yrs before it was recently being used regularly again..

Yes....as Kevin described.....the Cam Cover is what I show.
That filter goes inside the end of the Cam Cover towards the front.
You will see a Vent Tube inserted in the front top of the Cam Cover that directs vapors to the Air Horn which is what is connected to the Air Bellows (usually Black and corrugated). The other end of that Bellows is attached to the Air Filter Intake.

The Vent Tube is located on each side one in each Cam Cover. The Vent Tube extends up and under the Injector Housing Coolant Manifolds where it connects to a rubber hose...that rubber hose then connects to a port located on each side of the Air Horn.

These filters do get brittle and when removing them (there is a wire keeper) sometimes they will just crumble. Whenever you remove a Cam Cover ALWAYS replace the Cam Cover Filters. Also check the Chain guide located just in front of those filters located in the tops of Each Cam Cover.

http://i287.photobucket.com/albums/ll142/dynomite007/D%20Engine%20LT5/f6da30fd-c4c0-4c81-9e31-f7510aaf14f2.jpg

[Mitsumark]

Thanks for clarifying..I will check that out tomorrow..I promise not to ask anything else as this thread is already 5 pages long..But if that filter is compromised in any way, can it contribute to my smoking/ oil burning issue?

[Dynomite]

Thanks for clarifying..I will check that out tomorrow..I promise not to ask anything else as this thread is already 5 pages long..But if that filter is compromised in any way, can it contribute to my smoking/ oil burning issue?

I would say yes.......but the bulk of the oil would come from the PCV system (the two PCV valves) and some of us mount Oil Catch Cans to catch some of that oil (The Red Canister on the drivers side inside fender well). I think the Cam Cover Vents are primarily to keep condensation from forming in the Cam Covers.

Do NOT stop with the questions in this thread....your questions are informative for EVERYONE :thumbsup:

http://i287.photobucket.com/albums/ll142/dynomite007/Dynomite3/e432a450-3b35-4a8e-9c8c-75b433b4ac6f.jpg

[Kevin]

Kevin-I see your from PA..I bet you call those big sandwiches with the meat on them hoagies right? Lol.. Where Im from they're called subs..I was thrown off by Dynos "cam cover" reference as here in NJ,it's always referred to as valve cover regardless of it being pushrods,OHC,or whatever..Different states have different terms I guess..

when I make them myself it's usually "hey where'd the tip of my finger go?'

[bradley]

most 368 builds end up with 12 to 1 compression pistons on them which may acct for the higher readings . if he had bigger cams in it would most likely bleed of someof the cranking compression

[Mitsumark]

Ok so I had a a few hrs to tinker with the car today..I would of went further but it's freezing here in NJ..Ok so I started with warming up the car fully and going for a nice 40 mile trip with a few romps occasionally..I noticed right away that the car was way down on power since the last time I drove it.As I posted compression tests a few days ago, a few of you have told me the readings were good.So onto the next.Once home I hooked up a vac gauge to a port on the plenum with the car running..The car is pulling a steady 18" with no fluctuations..It this normal vac for a 368 LT5?It seemed low to me but I was happy to see it wasn't jumping around..Im having fun with my new vac gauge/pump and also decide to pull the secondary hose on the passenger side of the plenum..I tried to apply 12-15' vac to it and it bled down instantly.Bad secondary parts?So I shut the car and proceed to start pulling the plenum..Once removed,I'm surprised as there is plenty of oil inside..I also noticed the bases of the injector housings looked damp with oil so I pulled them too..They to had a good supply of oil in them..No wonder this thing is smoking..Can anyone tell me what would cause this much oil to be in the intake & IHs?This can't be normal..I'm going to clean these things out and reinstall everything..But first I'm gonna have to order some gaskets from Jerry..Also,,Where can I find all new parts to rebuild my secondary system(actuators,selonoid,resovoir)?This car hates me..

[Schrade]

Ok so I had a a few hrs to tinker with the car today..I would of went further but it's freezing here in NJ..Ok so I started with warming up the car fully and going for a nice 40 mile trip with a few romps occasionally..I noticed right away that the car was way down on power since the last time I drove it.As I posted compression tests a few days ago, a few of you have told me the readings were good.So onto the next.Once home I hooked up a vac gauge to a port on the plenum with the car running..The car is pulling a steady 18" with no fluctuations..It this normal vac for a 368 LT5?It seemed low to me but I was happy to see it wasn't jumping around..Im having fun with my new vac gauge/pump and also decide to pull the secondary hose on the passenger side of the plenum..I tried to apply 12-15' vac to it and it bled down instantly.Bad secondary parts?So I shut the car and proceed to start pulling the plenum..Once removed,I'm surprised as there is plenty of oil inside..I also noticed the bases of the injector housings looked damp with oil so I pulled them too..They to had a good supply of oil in them..No wonder this thing is smoking..Can anyone tell me what would cause this much oil to be in the intake & IHs?This can't be normal..I'm going to clean these things out and reinstall everything..But first I'm gonna have to order some gaskets from Jerry..Also,,Where can I find all new parts to rebuild my secondary system(actuators,selonoid,resovoir)?This car hates me..

Good job testing...

I've got 2 actuators that I pulled when I deleted the sec vac system; both held vacuum, as did the reservoir and lines from the pump to the reservoir, and you're welcome to them for postage + a couple $ for lunch.

(from a '90; 32k)

[A26B]

Oil in the valley and around the injector housings is not uncommon for the LT5.
Cause & Cure
1. PCV Crankcase Ventilation Baffle Cover ("the box") bolts loosen over time. During WOT, crankcase pressure exceeds what the PCV system can normally handle and crankcase oily vapor seeps out past the gasket. Over time, creates an oily mess under the plenum in the valley.

Shortcut Fix: Remove ea of the 13, 8mm hex head bolts & clean the oil from the bolts with brake or carb cleaner spray. Apply Loctite 243 http://jerrysgaskets.com/store2/root/index.php?main_page=product_info&cPath=28&products_id=591 to the bolt threads and reinstall. Loctite 243 performs better than 242 when the surfaces are contaminated with oil & there will still be oil in the bolt threads in the block.

Tighten the bolts in an alternating, crossing pattern from the center of the box sides outward.

Long Fix: Same job, just add removing the box, cleaning out the threads in the block & replacing the gasket. What makes it long is the secondary port throttle covers & linkage has to be removed to get it out. Not a bad job, just more work.

2. Injector Housings: Injector housing bolts also are prone to loosen over time. In this case, not only does crankcase pressure leak from the PCV ports in the injector housings, but can also allow coolant to leak.

Fix: Like the crankcase vent baffle cover (the box), clean the bolts & threads of oil & use Loctite 243 http://jerrysgaskets.com/store2/root/index.php?main_page=product_info&cPath=28&products_id=591 during reinstallation of the injector housings. Clean all gasket mating surfaces thoroughly to remove all foreign material and wipe down surfaces with brake cleaner or carb spray to remove any oily residue. Some builders prefer to use a light smear of non-hardening Permatex on both sides of the injector housing, around the coolant ports. In the case of your modifications which likely include porting this is a good recommendation as there is not much surface to isolate the coolant port from the intake runners when they have been ported.

Regarding replacement of actuators & such. I don't advocate replacing arbitrarily. You have a new toy, the vacuum tester. Use it on those components. Replacing a tested good part with a new part isn't going to accomplish anything except to cost $'s.

You still have a leaking injector issue to resolve. If you don't have one, get a fuel pressure test gauge. perform a Key on-Engine off test to build max fuel pressure, then turn the key off & observe the fuel pressure bleed-down (seconds & pressure). based on your earlier comments, I would expect the test to confirm the leaking injector. Then, pull the plugs, one at a time, note the condition & smell the plug well for fuel odor. That should identify the leaking injector location.

Since you have the injector rails removed, you could also reconnect the rail assy to the fuel feed & return block & turn the key on for a sec to spot the leaker. Just be cautious of fuel & ignition sources before attempting this type of test.

[Dynomite]

Perfect Jerry.......In -Solutions- (http://www.zr1.net/forum/showthread.php?p=148376) Under Engine Issues :thumbsup:

I must say also....Jerry has all the gaskets and bolts you will need including various components....and his delivery is usually two days at most to my mail box :cheers:
Jerry's Gaskets (http://jerrysgaskets.com/store/index.php?main_page=index&cPath=0)



Oil in the valley and around the injector housings is not uncommon for the LT5.
Cause & Cure
1. PCV Crankcase Ventilation Baffle Cover ("the box") bolts loosen over time. During WOT, crankcase pressure exceeds what the PCV system can normally handle and crankcase oily vapor seeps out past the gasket. Over time, creates an oily mess under the plenum in the valley.

Shortcut Fix: Remove ea of the 13, 8mm hex head bolts & clean the oil from the bolts with brake or carb cleaner spray. Apply Loctite 243 http://jerrysgaskets.com/store2/root/index.php?main_page=product_info&cPath=28&products_id=591 to the bolt threads and reinstall. Loctite 243 performs better than 242 when the surfaces are contaminated with oil & there will still be oil in the bolt threads in the block.

Tighten the bolts in an alternating, crossing pattern from the center of the box sides outward.

Long Fix: Same job, just add removing the box, cleaning out the threads in the block & replacing the gasket. What makes it long is the secondary port throttle covers & linkage has to be removed to get it out. Not a bad job, just more work.

2. Injector Housings: Injector housing bolts also are prone to loosen over time. In this case, not only does crankcase pressure leak from the PCV ports in the injector housings, but can also allow coolant to leak.

Fix: Like the crankcase vent baffle cover (the box), clean the bolts & threads of oil & use Loctite 243 http://jerrysgaskets.com/store2/root/index.php?main_page=product_info&cPath=28&products_id=591 during reinstallation of the injector housings. Clean all gasket mating surfaces thoroughly to remove all foreign material and wipe down surfaces with brake cleaner or carb spray to remove any oily residue. Some builders prefer to use a light smear of non-hardening Permatex on both sides of the injector housing, around the coolant ports. In the case of your modifications which likely include porting this is a good recommendation as there is not much surface to isolate the coolant port from the intake runners when they have been ported.

Regarding replacement of actuators & such. I don't advocate replacing arbitrarily. You have a new toy, the vacuum tester. Use it on those components. Replacing a tested good part with a new part isn't going to accomplish anything except to cost $'s.

You still have a leaking injector issue to resolve. If you don't have one, get a fuel pressure test gauge. perform a Key on-Engine off test to build max fuel pressure, then turn the key off & observe the fuel pressure bleed-down (seconds & pressure). based on your earlier comments, I would expect the test to confirm the leaking injector. Then, pull the plugs, one at a time, note the condition & smell the plug well for fuel odor. That should identify the leaking injector location.

Since you have the injector rails removed, you could also reconnect the rail assy to the fuel feed & return block & turn the key on for a sec to spot the leaker. Just be cautious of fuel & ignition sources before attempting this type of test.

[Mitsumark]

So I guess it's safe to assume with the compression & vaccume test results I can say the engine is healthy and the smoke is coming from a less vital source..

Regarding replacement of actuators & such. I don't advocate replacing arbitrarily. You have a new toy, the vacuum tester. Use it on those components. Replacing a tested good part with a new part isn't going to accomplish anything except to cost $'s.

I just figured since the components look original and there is a faulty part in the system that I would have piece of mind knowing it is all new..Years ago I enjoyed working on my car.. However with a very hectic work schedule I'd much rather enjoy driving the car than working on it on my off time.Once it goes back together, I'd hate to have to pull it apart again soon later..

You still have a leaking injector issue to resolve. If you don't have one, get a fuel pressure test gauge. perform a Key on-Engine off test to build max fuel pressure, then turn the key off & observe the fuel pressure bleed-down (seconds & pressure). based on your earlier comments, I would expect the test to confirm the leaking injector. Then, pull the plugs, one at a time, note the condition & smell the plug well for fuel odor. That should identify the leaking injector locat

The injectors are the stainless units from FIC and they are exactly 14 months old..I'm hoping they are not leaking but I will check that the next time I go out to mess with the car..Although the exhaust does smell like raw fuel(only when cold)..I came to the conclusion it was probably from not having any cats.I have also tried smelling the oil a few times and I can't smell the slightest bit of fuel..Now that you mentioned it I'm gonna check anyway.

[scottfab]

,....snip....
Im having fun with my new vac gauge/pump and also decide to pull the secondary hose on the passenger side of the plenum..I tried to apply 12-15' vac to it and it bled down instantly.Bad secondary parts?

There is a check valve in there that is notorious for getting stuck especially if you life is a dust/dirt filled environment.


So I shut the car and proceed to start pulling the plenum..Once removed,I'm surprised as there is plenty of oil inside..I also noticed the bases of the injector housings looked damp with oil so I pulled them too..They to had a good supply of oil in them..No wonder this thing is smoking..Can anyone tell me what would cause this much oil to be in the intake & IHs?This can't be normal..I'm going to clean these things out and reinstall everything..But first I'm gonna have to order some gaskets from Jerry..Also,,Where can I find all new parts to rebuild my secondary system(actuators,selonoid,resovoir)?This car hates me..

If you work on oil leaks in the "V" I'd advocate for the use of this type of SERRATED LOCK WASHER over loctite on all fasteners. They are oil proof. ;)
http://www.tracepartsonline.net/PartsDefs/Production/EMILE_MAURIN_BV/10-22122011-067464/pictures/10-22122011-067464L.gif

[Schrade]

Before I pulled the secondaries, I started vac integrity tests in sec vac system here, starting post #362 http://www.zr1.net/forum/showthread.php?t=21439&page=37

Yup - seen THAT before...

... and for NOW:

Re-assembled, with gear oil on the eccentric, and grease on the end of the armature shaft WATCH FOR A WASHER ON THE END OF THE ARMATURE SHAFT.

(AND THIS IS THE GOOD STUFF)

Pump lid NOT sealed yet...

bench (tire http://www.zr1.net/forum/images/icons/icon10.gif ) test dialed in (jumped straight from battery - more on that momentarily here)

vac nipple blocked; switch killed pump right away

https://lh3.googleusercontent.com/-7fqBC1uZ6UU/Uogn9iWAD5I/AAAAAAAAC1M/-qQtWlnxsEw/s1280/HPIM7535.JPG

and this question, about vac test without plenum re-installed, is answered



cables run to P side fenderwell, jumpers on vac pump (never mind the Guinny Stoudt - NONE for you! )

https://lh6.googleusercontent.com/-G--CfZ1E4dI/UogpehqvzCI/AAAAAAAAC1c/zupzTzvQdQQ/s1280/HPIM7536.JPG

This juncture shut off right away, and held

https://lh5.googleusercontent.com/-_XpFXrDTKVI/Uogp5ERUr5I/AAAAAAAAC1o/GJc5Am_14rA/s1280/HPIM7537.JPG

reservoir evacuated in 3 seconds and held

https://lh5.googleusercontent.com/-5_LGuG1CO_0/UogqXy0R5JI/AAAAAAAAC1w/mx8WNuSLVKM/s1280/HPIM7538.JPG

[PhillipsLT5]

Jerry has you going in the right direction, were the injectors new or rebuilt units from FIC, I do think they will warranty any bad units, I did here of trouble with rebuilds, I would suggest to yank secondary's and have Marc burn you a working chip for that

[Mitsumark]

Ok fellas an update..I changed the oil and switched to Mobil 1 15w50..Ive driven 2200 miles since my last post..I have also replaced all the plugs at that time so the plug pictured below only has 2200 miles on it..Oil consumption has been cut down since the last oil change..Probably cut in half..However it is still burning oil at an alarming rate(1qt 600miles) as seen by the plug below and it still smokes faintly at idle,and under moderate heavy accelaration..It does NOT smoke at all on decel in gear..Now remember earlier I ran compression test and it came back with great numbers..Since then on top of the plugs and oil change,I replaced both 02s,and both PCVs again just for good measure..My PCVs and piping were loaded with oil after 2200 miles again also..I have checked high and low for vac leaks and have found none..Car still pulls hard in every gear with no misfires..Idle is stable when sitting still however she hunts from 900-1500 when rolling in neutral until dead stop where she evens out at 900..I know from reading the plugs it is running pig rich as they are loaded with carbon,but its looks like oil is present also.All plugs look similar with 3 looking a bit worse than the others.Hunting idle,pig rich,burning oil..Is it possible I have a leaky plenum gasket that is undetectable?Ive triple checked spraying carb cleaner around the base of the entire plenum,inbetween runners,underneath..No change in idle..Can I be pulling oil into the injector housing somehow?What other way can oil be making it in to the combustion chamber?Im at a loss and Im extremely close to selling this car..Pic coming in 5..

[scottfab]

I'm not really sure which problem you're after, oil or possible plenum leak? I don't thing a plenum leak will cause higher oil consumption.

Staying with the oil for a bit. What happens if you drive for a bit and keep the rpms low? Does it still consume 1qt per 600mi?

[Mitsumark]

All plugs are ugly..Oil comsumption is bad regardless of how Im driving as proven by smoking at idle.

[Polo-1]

I'm no Vette Doc. But looks to me your I need of a tune bad. Your washing down your oil with way too much fuel and drinking it.

See if you can get help with a stock chip and drive it. Yes, you will leave power out. It will still run fine for testing.

[Mitsumark]

That is what I wish I can do..This all started with the installation of a canned tune installation..The car had a chip burned specifically for this build and I had it flashed over like an idiot with the new tune..I don't know if a stock tune would help me as this car is pretty modded and also has intake cams..I don't have access to a stock chip either.Theres nobody in NJ that wants to touch it.. Seems all the LT5 know how's are in Chi-town.I'm definitely in over my head..

[Karl]

I am no expert but why not just get another chip or have yours flashed again and see if that fixes the problem. After all you said it started when you changed the chip so there seems to be your problem.

Good luck!

[Mitsumark]

Very good point..Reason is I never would have imagined a tune to be so out of whack that it would cause oil consumption issues..I also didn't want to write over the existing tune as it was expensive and I'd hate to do it if it turns out it wasn't the problem..I know it's a lot to ask but if any of you would be kind enough to loan me a stock 91 chip for testing for about 2 weeks I would be extremely great full..Ofcourse I would cover shipping both ways..Sorry to come off hard faced but I'm desperate as I love the car and I want to get to the bottom of it before its to late..

[Polo-1]

[QUOTE=Mitsumark;197786]I don't know if a stock tune would help me as this car is pretty modded and also has intake cams..QUOTE]

My 402 cube with both stage ll cams ran fine with a stock chip. I would think we have a brother somewhere near by that cam help with that.

[RICHARD TILL]

Will a 90 model chip work? I have two extras. One is stock, (AUAH 8555) idled high but otherwise fine. The other one has Super Chip written on top and have never tried it. Bought it here on the forum. Wanna try either or both?

[Mitsumark]

Ok well my inbox awaits:)..I know I'm kinda new here but I have spoke to some of the forum members by phone..I promise anyone who can float me a chip a few weeks that I will not pull anything shady..I'd be ecstatic if I find it's the tune as I'm suspecting something worse..Atleast if I prove it's the tune it won't be a waste of another $500+ to get it on a dyno with a reputable tuner..

[Mitsumark]

Rich-Don't know if 90 will work..I thought they were yr specific.. Can anyone confirm?

[scottfab]

All plugs are ugly..Oil comsumption is bad regardless of how Im driving as proven by smoking at idle.

Oh, didn't know low rpm generated the ugly plugs. That rules out that.

[Franke]

They (mem cals) are year specific. Check the ZR1 specialist Marc Haibecks web site for info about each year for 90 thru 92. Looks like 93 to 95 are the same.

[XfireZ51]

Will a 90 model chip work? I have two extras. One is stock, (AUAH 8555) idled high but otherwise fine. The other one has Super Chip written on top and have never tried it. Bought it here on the forum. Wanna try either or both?


Rich,

A 90 memcal won't work because it doesn't have the knock sensor circuitry on board. Also, any memcal will work from 91-95 BUT it must have the correct model year Broadcast Code. 90 bin is an AYBK, 91 is a BFXB.
I suspect the 368 w intake cams is idling rich. The additional overlap causes the O2 sensor to think motor is lean and so it keeps increasing the pulsewidth. Like a systemic vacuum leak. Also if the calibration hasn't been modified to deal with the additional displacement, the ECM is trying to feed a 5.7L motor but that turns out to be not enough according to the O2.

OP,
Are you running Closed or Open Loop?

[Mitsumark]

Car is running a Heibeck chip tuned for a 368ci with IAT sensor relocated..I spoke to Marc through e-mail last night and he says that his tune would not cause this overly rich condition at less than 50% throttle.He suggests I check vac readings again and I get a scanner on the car to read the 02 banks.I will try to get access to one in the next few days..He said something about if the vaccume is above 50kpa the map sensor will command so much fuel the 02 sensors won't be able to control it..Now I don't know what that means,but I did put a vac gauge on it and got about 15-18" of vac..As stated I also checked for leaks and none were found..I also blocked the TB inlet while running and the car died immediataly like it should..I know these motors are prone to oil consumption but this is out of control..There is oil in the intake tract along with the PCV piping and on my plugs.The car has not yet thrown a code to point me in the right direction..Anyone have an LT4 car they wanna trade:-({|=

[rkreigh]

it's frustrating but don't give up! the bottom end is likely fine so the really expensive fix is likely ruled out. at some point a trip to haibecks is in order. he's really not that far.

he'll fix you right up! I honestly don't think it's valve guides. they wouldn't drink oil like that. I think something is wrong on the crankcase breathing system and you are pushing oil into the pvc system and sucking it into the intake.

try plumbing in a catch can into the pvc and see how much oil dumps in.

good idea anyway, I need to get off my duff and add one.

[Karl]

I added a oil catch can after reading about them on the forum. So far I have less then 500 miles on it.

[Bob G]

call frank u he probably knows whats wrong !

[Mitsumark]

Who's Frank?..Also this may be nothing,but does our oil caps have a rubber gasket ?Mine doesnt but I dont get any oil seepage.Also when checking my plugs I noticed they had oil on the very top of the threads(opposite of firing end)..Found that strange as the thought the upper threads would be sealed from the combustion chamber..Point is I was suspecting leaky valve covers in the plug tunnels and seeping into the electrodes to be burned...However the tunnels are clean and dry...Still want to try a stock chip..

[icarus-54]

Not sure if this aplys,but I had a similar problem with my built syclone.Went thru many of the same steps as the op.Check the back of the throttle body for oil.I wouldn't be suprised if the so called sponges were letting oil into the pvc's and into intake.On my sy I had to build baffles in the valve covers to correct it.The simptoms were exactly the same.

[Mitsumark]

^Good point.. I was thinking of that also..This motor hasn't been cracked open since 03 so I'd imagine that what's left of those sponges,if anything must be saturated..I'm gonna wind up yanking the covers to see what's going on..Does Jerry carry these sponges?

[Polo-1]

Don't do all that work on the cam covers.. Way too much work for a very small piece of foam.
Better off doing oil separator. Faster, easier, cheaper and way more effective.


http://www.zr1.net/forum/showthread.php?t=21338&highlight=oil+separator+pcv

[Mitsumark]

Wow Polo..Thanks for that..I just read 30+ threads online involving oil burning/fouled plugs and they were mostly all cured with oil/air separators..Can anyone point me in the right direction on where to purchase the best unit that includes all parts ready to go on LT5..If this turns out to be the cure I will be happier than #^£t...Most threads I've read talked about chasing this very problem for months including buying hundreds of dollars in parts that didn't cure it..The Oil/Air separator did..Seems to be More of a problem on modded motors..

[Schrade]

So if the oil separator, that most put in front of the plenum inlet (or SOMEwhere between the twin PCV's and the plenum inlet), allows oil to separate into the separator can, how will it stop oil from being vaporized from the crankcase, and entering into the ... separator?

Seems to me, that the only thing a separator will do, is prevent oil from being pulled INTO the plenum. IF the separator is emptied on a regular basis...

This is why I entertained the idea of running the PCV plumbing FROM into the plenum behind the TB, TO in front of the air filter.

Never mind that vacuum would be insufficient; that's not the question here...........

[Dynomite]

So if the oil separator, that most put in front of the plenum inlet (or SOMEwhere between the twin PCV's and the plenum inlet), allows oil to separate into the separator can, how will it stop oil from being vaporized from the crankcase, and entering into the ... separator?

Seems to me, that the only thing a separator will do, is prevent oil from being pulled INTO the plenum. IF the separator is emptied on a regular basis...



Good point Schrade......;)

I am thinking he intends to dump the oil caught in the oil Catch Can back into the engine when engine is not running :p

Just between you and I Schrade.......I am firing up my 90' tomorrow after a quick Top End...also now have all 4 speakers working perfectly.
Stand by.....:D

[Mitsumark]

Ok I'm gonna try running the unit in the link.Notice the drain valve on the bottom of the unit..Would it work if I installed the unit inline and left the dump valve open full time and running a dump hose back into the oil pan or valve cover?If this is possible I can always tap the pan for a fitting.This would stop the need to constantly drain the separator as the oil would cycle right back into the engine.Or am I pipe dreaming?

http://lightningmotorsports.com/i-408939.aspx?gclid=CKy2uYWcj70CFZLm7Aod3jAASg

[Dynomite]

Ok I'm gonna try running the unit in the link.Notice the drain valve on the bottom of the unit..Would it work if I installed the unit inline and left the dump valve open full time and running a dump hose back into the oil pan or valve cover?If this is possible I can always tap the pan for a fitting.This would stop the need to constantly drain the separator as the oil would cycle right back into the engine.Or am I pipe dreaming?

http://lightningmotorsports.com/i-408939.aspx?gclid=CKy2uYWcj70CFZLm7Aod3jAASg

No....you are now bypassing the function of the PCV valves.

Just install the Oil Catch Can and see how much oil you are catching through the PCV system. You will also notice immediately the oil burning (blue smoke) has stopped if the PCV system was sucking oil into the intake.

[Schrade]

Ok I'm gonna try running the unit in the link.Notice the drain valve on the bottom of the unit..Would it work if I installed the unit inline and left the dump valve open full time and running a dump hose back into the oil pan or valve cover?If this is possible I can always tap the pan for a fitting.This would stop the need to constantly drain the separator as the oil would cycle right back into the engine.Or am I pipe dreaming?

http://lightningmotorsports.com/i-408939.aspx?gclid=CKy2uYWcj70CFZLm7Aod3jAASg

Some sort of dump valve is something I've considered as well. A valve that's CLOSED while vacuum is pulling, and allowing drainage when the motor is off.

I began thinking on this too, when I noticed oil - CLEAN oil, POOLED in the plenum vacuum INLET, after having to pull the plenum after just half a dozen Closed Loop cycles, following the 'Top End Resto', that I just finished after the holidays.

Either cycling the oil BACK to the CC, OR, filtering it up front.

So if the oil separator, that most put in front of the plenum inlet (or SOMEwhere between the twin PCV's and the plenum inlet), allows oil to separate into the separator can, how will it stop oil from being vaporized from the crankcase, and entering into the ... separator?

Seems to me, that the only thing a separator will do, is prevent oil from being pulled INTO the plenum. IF the separator is emptied on a regular basis...

This is why I entertained the idea of running the PCV plumbing FROM into the plenum behind the TB, TO in front of the air filter.

Never mind that vacuum would be insufficient; that's not the question here...........
I'm told (by Dom, I think, or Marc), that not enough vacuum can be had, if routed up to the AF housing. Q: HOW MUCH vacuum IS necessary to keep a purge on the PCV???

------------------------------------------------------------------------------------

Still thinking on it here. Even CLEAN oil will foul the burn...

Another thing I'm thinking on - is some sort of small lawn mower filter in the line. That would require frequent cleaning, based on what I saw after half a dozen CL cycles. I don't know where I'd put it, with new painted PCV plumbing that I prefer to NOT hack.

http://www.zr1.net/forum/attachment.php?attachmentid=3292&stc=1&d=1394712511

But keeping a clean burn is paramount. ESPECIALLY since total new exhaust is about to go in here.........................................

[icarus-54]

You need a baffle or something to keep the oil from being sucked into the pvc,ya want to get on the front end of the problem.

[A26B]

You need a baffle or something to keep the oil from being sucked into the pvc,ya want to get on the front end of the problem.

This is not possible in the LT5 due to the engine design. Simply no place to add any baffles. Here's why.

The LT5 doesn't have a conventional style of PCV system. The majority of the crankcase vapor comes up through a large baffle with cover and 2 large hoses to an isolated chamber in the injector housings (all under the plenum).There are 2 small holes in the cyl head (or inj hsng if 1990 model) that vapor from the cylinder heads passes through, into the same isolated chamber. The pipes with grommets you see on the outside of the injector housings then connect to the PVC hose at the rear of the plenum.

Regarding the pipes from each cam cover to the air horn, in front of the throttle body; Those pipes are for filtered/fresh air purge of the crankcase.


Under normal driving/high vacuum conditions, air flow is INTO the cam covers, through these pipes.
Under WOT/low vacuum conditions, crankcase volume & pressure is greater than the PCV system can handle. Reason is simple, no engine vacuum, no flow through the PCV valves except for positive pressure flow from high to low pressure.

The same principal applies to the cam cover tubes, thus the reason for the cam cover "filters," whose purpose is actually mist extraction. WOT flow would then be from the cam cover to the engine air inlet at the air horn.

So, under WOT, low to no engine vacuum conditions, heavily laden oil vapor can reach the plenum by two different paths, PCV system and the cam cover filtered air purge tubes.

The amount of oil in the crankcase vapor depends on engine condition and will normally accumulate in the plenum through the PCV system, even under normal driving conditions. Not a perfect condition, but not a serious problem either. It is a condition that can be improved upon, but not entirely eliminated, with the installation of an oil catch can. WOT conditions can still result in oil through the air inlet. The more blow-by the more oil.

[Karl]

Check here

http://m.corvetteforum.com/c4-zr-1-discussion/3434788-f-s-lt5-computer-engine-control-ecm.html

[icarus-54]

Got ya,BTW Jerry,thanks for the excellent explanation,really helps my understanding how these things work.

[ZZZZZR1]

Stock 1991 chip?

Do you need one? I can let you borrow it to use.

Want me to ship?

Cheers

David

[FU]

I'd be Frank U.
Wait a second........go back to the original post. Who built the engine ?
The Vette Dr's (Billy Kirchoffer) built the engine ?


call frank u he probably knows whats wrong ! Bob my brother, I miss you guys !

[Mitsumark]

David to the rescue..I would appreciate that immensely..I'm gonna PM you my addy.. 2 weeks tops and I'll have it back to you with shipping for both ways..I really don't think it's the tune but this will allow me to fully rule that out(hunting idle/rich condition)...


I'd be Frank U.
Wait a second........go back to the original post. Who built the engine ?
The Vette Dr's (Billy Kirchoffer) built the engine ?


Quote:
Originally Posted by Bob G
call frank u he probably knows whats wrong !
Bob my brother, I miss you guys !


Oh ok Frank..Yes Vette Docs built the motor.You work there?..Original chip had Kirchoffers name on it..


UPDATE on the oil burning.. I installed the Moroso oil separator inline today and the smoke totally stopped after a good 15 min romping..Upon installation I noticed a fair amount of oil in the PCV tract along with the Map hose and sensor..So don't know for certain but I'm thinking the oil that is making its way to the map is really altering the A/F mixtures being the MAP is being choked on with oil..Thus causing an overly rich condition,fouling of the plugs, and the hunting idle..I'm already happy as I don't have to see that embarrassing smoke cloud behind me when I accelerate..I'll update again soon..

[FU]

Lets start at the base.......
Do a compression test , preferably a leakdown compression test on the engine first.

When was the engine built ?
How many race miles have been logged on the engine since becoming a 368 ?

Are you checking the oil after the car has been sitting for at least an hour ?

VD 368.............

[ZZZZZR1]

David to the rescue..I would appreciate that immensely..I'm gonna PM you my addy.. 2 weeks tops and I'll have it back to you with shipping for both ways..I really don't think it's the tune but this will allow me to fully rule that out(hunting idle/rich condition)...




Oh ok Frank..Yes Vette Docs built the motor.You work there?..Original chip had Kirchoffers name on it..


UPDATE on the oil burning.. I installed the Moroso oil separator inline today and the smoke totally stopped after a good 15 min romping..Upon installation I noticed a fair amount of oil in the PCV tract along with the Map hose and sensor..So don't know for certain but I'm thinking the oil that is making its way to the map is really altering the A/F mixtures being the MAP is being choked on with oil..Thus causing an overly rich condition,fouling of the plugs, and the hunting idle..I'm already happy as I don't have to see that embarrassing smoke cloud behind me when I accelerate..I'll update again soon..

Take your time with it. No worries

Will ship it tomorrow

:cheers:

David

[emmvette]

One more thing to add to the list of potential sources for the issue: My car was running very rich on one side and after some serious trouble shooting, Marc H figured out it had a decent leak through one of the headers. He welded this up, then completed a tune and it was good to go. On my car, it was running very rich on the side with the leak and a little lean on the other side. I think you would need to be connected to the car's OBD system with a scan tool to read this.