View Full Version : Injector Housing to Head Port Match Issue
While addressing an issue regarding injection housing fuel injector seals, Jerry, from Jerry's LT5 Gaskets and Parts pointed out the housing I was describing was not for my 95 ZR-1 but for an earlier model engine. After pulling the intake plenum i noticed a port miss match between the injector housing and the head. Didn't think much of at at the time but given this new information, I thought I would attach a photo that represents the issue. Some ports are a bit better but this was one of the worse cases. Please note that the housing was ported by the previous owner who decided to use a non-stock housing and intake plenum for porting and powder coating. Unfortunately he no longer has the original parts. I guess my question is, is this common, if not, what can be done to fix it or at least improve it?
XfireZ51
08-14-2013, 11:45 PM
A. Not unusual
B. you port match the head
We Gone
08-15-2013, 08:47 AM
Nice to see another GA ZR-1.....We are few.
LGAFF
08-15-2013, 09:14 AM
The mismatch while not ideal is not horrible, there is still a signficant improvement in flow without port matching. Porting matching can be done on the car.
**Use the gaskets to mark the area that needs to be removed
1)Tape off all of the intake ports you are not porting; and cover the motor to catch the aluminum. If you have secondaries only do the primary ports
2)buy tack clotch to put in the primary ports or spray some lint free cloth with WD40 to make it sticky to trap aluminum, push them into the ports. These are the back up layers
3)Put something on top of the cloth as a primary catch for the aluminum....cork, rubber stopper, or I used styrofoam balls from a craft store, cutting them in 1/2 and pushing them into the port on top of the cloth.......then soaking them in WD40, the styro is porous and caught alot of the aluminum splinters. IF using stoppers make sure you have a method of getting them out
4)Have a vacuum handy, stop periodically to vac out the splinters to reduce the mess...be careful not to suck out all of your cloths and stoppers, keep a finder on top of the stopper
5)Using the die grinder slowly start removing material, be sure to follow the angle of the port and not just going straight down
6)You only needs to go in an inch or slightly less to reap the "potential" 5-10hp, others have gone deeper.
To be clear, you are saying to remove material from the head to match the larger injector plenum port? Are there coolant passages in that area? I just am not sure I want to grind on a set of Dunn heads. I have done my fair share of porting intake ports but never a head port.
LGAFF
08-15-2013, 09:40 AM
Correct, you are grinding on the heads, if you do not wish to do so, leave it.....it is not "hurting" you results vs stock. I did a set for a member and he did not port match it and still picked up 37rwhp
LGAFF
08-15-2013, 10:02 AM
Who ported the intake?
How did you get your car to Marc's? That would be a cool thing to do but the logistics of it would be a challenge. Too bad there is no one in the Atlanta area. How long have you had the car?
LGAFF
08-15-2013, 10:08 AM
I believe he shipped it
Not sure who ported it. Was ported by previous owner by some guy named Gregg.
LGAFF
08-15-2013, 10:12 AM
Greg VanDeventer from Mercury Marine????
My bad is name is Mike Ebert.
I may consider it. Blending the head port to the intake would also eliminate the oil/fuel from collecting there working its way through the gasket.
I figure I would use a long scribe and mark the heads while the intake is still on the head.
I wonder what it cost to ship?
My bad is name is Mike Ebert.
I may consider it. Blending the head port to the intake would also eliminate the oil/fuel from collecting there working its way through the gasket.
I figure I would use a long scribe and mark the heads while the intake is still on the head.
Reference: Jerry's Gaskets are port enlarged to 36.5mm and precision die cut to dimensions from original engine drawings, so they make an ideal template to work from. They retain the bifurcation between the primary & secondary ports for stock applications.
You would benefit in the long run by using a set of correct gaskets as a reference for both the injector housing and cylinder head ports to match them up. Then, you can use a new set of gaskets without having to trim to match. At this point, it's not known if the injector ports are correctly located. I have seen significant core shift in early housings. I wouldn't recommend matching your Dunn heads to a set of injector housing that are not ported correctly.
BTW, you also have Aaron Scott, South Georgia Corvettes, in Thomasville, GA. He is closer to you and very well versed in the LT5.
Dynomite
08-15-2013, 12:24 PM
I wouldn't recommend matching your Dunn heads to a set of injector housing that are not ported correctly.
Then there are the Crankcase Ventilation (CV) differences between 90' and 91'-95' Injector Housings as Jerry described :thumbsup:
90' and 91'-95' Injector Housing Differences (http://www.zr1.net/forum/showthread.php?p=102911)
For which a modification exists if you install a 91' IH on a 90' Head for example.
I do not think there is an issue installing 90' IH on later Head as you would only end up with CV double restrictions vice NO restrictions going the other way.
Kind of like trying to mix 90' Plenums with 91' and later Plenums which look/fit the same but have differences in Charcoal Canister Vacuum connections. The charcoal canister for 91' being located by gas tank and the charcoal canister for 90' located under drivers side head light ;)
We Gone
08-15-2013, 12:42 PM
How did you get your car to Marc's? That would be a cool thing to do but the logistics of it would be a challenge. Too bad there is no one in the Atlanta area. How long have you had the car?
KJL,
Drove it up on Sunday nite, I got old Blue in 2002 also had a 1990 Black/Gray for many years. I only know of about 3-4 others in this area. We need to meet up sometime.
Steve
Locobob
08-15-2013, 01:34 PM
I don't see anything really wrong here, just looks like a ported injector housing on top of an unported head. In my experience plenums, injector housings and heads all exhibit some degree of port "skew" from the factory. You'll pick up some power if you port match the top of the head ports to the injector housings but I don't see where what you have now is hurting anything.
Kevin
08-15-2013, 02:00 PM
How did you get your car to Marc's? That would be a cool thing to do but the logistics of it would be a challenge. Too bad there is no one in the Atlanta area. How long have you had the car?
dunno how close you are to aaron but check out http://www.southgeorgiacorvette.com/
I have attached a picture showing the top side of the FI housing. It appears they were Siamese ported. Is this typical? Also, the secondary ports line up perfectly with the heads. The primary ports on the FI housing seem to all be oversize and they all line up perfectly with the head port side that is adjacent to the secondary port. After I remove the FI housing I am sure I will learn more including why the mysterious oil leak.
The previous owner said the car dyno'd at 389 rwhp.
Locobob
08-15-2013, 04:07 PM
What you have there is a partial siamese or figure 8 porting job. Typically you'll find this style on more aggressively modified engines i.e. 368's, strokers, it is probably not doing much extra given your engines relatively low state of tune - doesn't hurt anything though.
LGAFF
08-15-2013, 04:28 PM
Ya gotta go all in....
These are from when I was still working on the port match!
http://i134.photobucket.com/albums/q115/lgaff/DSCN3847.jpg (http://s134.photobucket.com/user/lgaff/media/DSCN3847.jpg.html)
http://i134.photobucket.com/albums/q115/lgaff/DSCN3832.jpg (http://s134.photobucket.com/user/lgaff/media/DSCN3832.jpg.html)
Wow! you removed all of the material between the ports then cut back on the head ports. Looks like a lot of work! What tools would you recommend? I have a dremel and air powered die grinder as well.
I just receive the dyno info from where he had it tested, 392 max rwhp and 356 rwtq. There is also a chip that I need to look at. Not sure what brand. I hope I can tell. My plan is to get her back together, and stick her on a dyno to get the air/fuel ratio data. Send data to Marc Haibeck and have a chip setup for me. Hopefully this will also take of the backfire issue.
We Gone
08-15-2013, 06:04 PM
Marc will be able to add the anti-backfire to the chip for ya for sure. Good luck.
Here is a picture of the intake plenum porting.
Paul Workman
08-17-2013, 08:22 AM
Several of the "FBI" gang have aluminum chips in their fingers!
By the time I went from the intake plenum, progressing to the IHs and onto the heads, I wore out a couple cheap pneumatic die grinders, and ended up with these two work horses - a Snap-On PT200L (actually about a foot long, tho the picture makes is look small) and a the small one (purchased at the same tool and die supplier where I bought my bits).
http://i185.photobucket.com/albums/x220/6PPC_bucket/tech%20files/diegrinder003Large.jpg (http://s185.photobucket.com/user/6PPC_bucket/media/tech%20files/diegrinder003Large.jpg.html)
I also tried the Makita GD800C. It is a powerful, variable speed control with constant speed feature. It is an excellent, durable tool, if one prefers electric. (Pete liked it so much that he's offered to keep it at his place for safe keeping - now that I'm done with it;)) (Oh! BTW, they're on sale at Amazon right now for $219, if you're interested!)
http://i185.photobucket.com/albums/x220/6PPC_bucket/tech%20files/diegrinder2001Large.jpg (http://s185.photobucket.com/user/6PPC_bucket/media/tech%20files/diegrinder2001Large.jpg.html)
The bits that worked best for a relative novice like me were the fine, single cut fluted carbide burr (pictured). However, Marc Haibeck uses the very aggressive aluminum burr that has maybe a dozen flutes. I don't recommend them for anyone except the very experienced person, as I can attest that those big fluted SOBs cut like crazy, and are difficult to control; a two-handed, locked elbow, both fists around the grinder, with position controlled by swiveling one's hips...seriously!
The small grinder got the majority of the flap wheel work on the ports, and a Dremel with its tiny flap wheels came in handy to polish the curves in the valve bowl area.
Also pictured are "Pete's balls" - made of steel (what else?) - one a 36mm diameter, and one a 35mm diameter. One of those magnetic wands holds the ball nicely for taking measurements. A snap gauge is essential tooling and a precision caliper (dial is fine, but digitals are available for a little more $$).
Pictured is another of Pete's balls - a bit larger than 36mm; threaded to accept a threaded bolt shank (or the like) as a handle.
http://i185.photobucket.com/albums/x220/6PPC_bucket/tech%20files/Headporting002Large.jpg (http://s185.photobucket.com/user/6PPC_bucket/media/tech%20files/Headporting002Large.jpg.html)
This wasn't my first rodeo, far as porting goes, but it was my first aluminum project, and first LT5. So, I'm not portending to be an expert here - just passing on what I experienced and what I learned from the masters: Pete and Marc Haibeck and Bob G and "Flyin Ryan", and a couple things I picked up along the way. Runner length, size, Siamese'ed or not ...lots of ideas and different ways to 'skin a cat"; opportunities for "Carbide Cowboys" (as Ryan call 'em) to experiment with an LT5!;) Intrigued??
P.
Paul-
Thanks for all that great info!! I have a snap gauge set and several types of calipers. I could see if one was going to do full Siemens porting that an aggressive bit in experienced hands would be the way to go. That is a lot of aluminum! Luckily, all I am looking to do is some port matching. I don't want to go crazy on the heads, just enough. I plan on following Jerry's advice and use one of his gaskets as the guide. I will also mark the actual IH foot print on the heads to see how much they differ from the gaskets.
The Makita is slick, but for what I want to do, I am hoping to find one similar in features for less money. I will also try to stay away from using any "grit" based bits. I am afraid bits of grit may make it into the the cylinder. I plan on plugging the ports but you know how that goes. If a couple of small flecks of aluminum get in there probably wont damage anything but small bits of carbide grit?....
My existing port job is fairly smooth but could use a bit more polishing, maybe with ultra fine 500-600 grit wet sand paper? How smooth does a port job need to be?
LGAFF
08-17-2013, 12:48 PM
Smooth is bad for airflow, as it creates a boundry layer next to the wall were air speed slows, 60 grit flap wheels are a perfect finish
Bob Eyres
08-17-2013, 01:31 PM
Does someone have CNC capability to do the porting? It would seem impossible to match the flow exactly, by hand.
Are there any coolant passages in the Dunn heads near the ports that I should be concerned about?
Paul Workman
08-18-2013, 07:10 AM
Does someone have CNC capability to do the porting? It would seem impossible to match the flow exactly, by hand.
Yes. Pete has access to a CNC program based on his heads, at least. I've not heard of anyone that has CNC for the IHs or the plenum, but wouldn't be too surprised if someone like Lingenfelter has a CNC program for them as well.
P.
Paul Workman
08-18-2013, 08:14 AM
** I will also try to stay away from using any "grit" based bits. I am afraid bits of grit may make it into the the cylinder. I plan on plugging the ports but you know how that goes. If a couple of small flecks of aluminum get in there probably wont damage anything but small bits of carbide grit?....
My existing port job is fairly smooth but could use a bit more polishing, maybe with ultra fine 500-600 grit wet sand paper? How smooth does a port job need to be?
Couple things:
No worries about grit, if you pack the bores tight with (I used) WD40 sprayed paper (shop) towels (the thick, heavy blue ones). Paranoid, I packed each runner twice; one primary plug, and one secondary. When finished, I used a vacuum cleaner with a tube small enough to reach into the ports and pick up the bulk of the loose debris and grit. Then with a super-long set of hemostats, the packing can be retrieved, while vacuuming again before removing the second plug. Then I used fresh towels, sprayed lightly with WD40 and wiped the bore surfaces; changing towels until they came out clean. No grit! No worries!
Like an surgical theater, the entire top of the engine bay is covered with a (I used a shower curtain), and everything but the port being modified is masked off...
http://i185.photobucket.com/albums/x220/6PPC_bucket/tech%20files/IH5Large.jpg (http://s185.photobucket.com/user/6PPC_bucket/media/tech%20files/IH5Large.jpg.html)
Port "matching" in LT5 heads - in progress (note plug)
http://i185.photobucket.com/albums/x220/6PPC_bucket/tech%20files/IH8Large.jpg (http://s185.photobucket.com/user/6PPC_bucket/media/tech%20files/IH8Large.jpg.html)
Surface left by carbide bit before sanding
http://i185.photobucket.com/albums/x220/6PPC_bucket/tech%20files/IH6Large.jpg (http://s185.photobucket.com/user/6PPC_bucket/media/tech%20files/IH6Large.jpg.html)
Note finish imparted by the 60-grit flapwheel...
http://i185.photobucket.com/albums/x220/6PPC_bucket/tech%20files/IH9Large.jpg (http://s185.photobucket.com/user/6PPC_bucket/media/tech%20files/IH9Large.jpg.html)
Far as "grit based" bits go, grinding bits load up almost instantly when cutting aluminum. So the cutting is via carbide bits. However, to remove blemishes and nicks left by the burr (and you will have some!), as Lee pointed out, a 60 grit flapwheel (seen in my photos in previous post on this thread) is ideal for cleaning those up and imparting the right amount of surface roughness to avoid boundary layer encumbrances.
But, back to port matching:
Just my 2-cents, but Flyin Ryan suggested to me that when it comes to changing the diameter of a runner, to prevent pulse reversion it is best to not exceed (if I recall him correctly) 4% change in diameter for a given linear distance (along the axis). (Other sources vary - one I read said 7%.)
I went with 4% - less is better, in some cases - which resulted in a long taper extending from the input and narrowing to just above the valve guide.
WOW! I wish like hell I had dyno'ed it at that point, cuz the seat of the pants improvement I got from top end porting alone was way beyond what I expected! There was a big improvement when I ported the heads as well, but not as much a change as I got from the top end phase - ending up at 432 rwhp, w/ stock cams, stock TB, and SW headers + X-pipe. (Someone tell me again how the stock LT5 isn't starving for air!)
Prolly more than you wanted to know, but mebby somebody will be intrigued enough to consider joining the majority of the FBI gang and port their babies too! BE A WARRIOR!:dancing
P.
mike100
08-18-2013, 11:59 AM
^^^ The only thing I would add to Paul's post is that I port matched my primaries pretty much similarly, but I rotated the engine 90 degrees 8 times and did each port separately. This ensured that the intakes were closed on TDC just in case a chip or two got left in the port after removal of the wd-40 soaked rags. The worry wasn't a couple of bits touching the piston and blowing through, but more to keep the seats free of debris.
http://i29.photobucket.com/albums/c265/mschrameck/Cars/makingamess.jpg (http://s29.photobucket.com/user/mschrameck/media/Cars/makingamess.jpg.html)
The shower curtain is a good idea. A lot of time was spent on clean-up the way I did it. It was not difficult, just tedious. I was finished in about 5 hours.
Paul Workman
08-18-2013, 04:07 PM
^^^ The only thing I would add to Paul's post is that I port matched my primaries pretty much similarly...**
Yes, both primary and secondary runners received the long taper to the valve guide on the initial top-end porting; starting at 36mm a the top and tapering to stock diameter at the valve guide...I meant to say.:)
mike100
08-18-2013, 05:01 PM
I saw your pic and you were working on the secondary (hmmm)... anyways, mine are still intact. Also my port job was more modest at 35-ish mm on the bottom of the I/H with just enough port matching to blend the core shift and 2 mm of size change.
I did remove my injector housings for an unrelated leak repair and took the opportunity to take a little more out of them a few months afterwords, but I feel like any more improvement would come from getting back to the plenum for a little more work there. Since I'm finally running headers, I've seen the light on top end power.
Paul Workman
08-21-2013, 10:44 AM
I saw your pic and you were working on the secondary (hmmm)... anyways, mine are still intact. Also my port job was more modest at 35-ish mm on the bottom of the I/H with just enough port matching to blend the core shift and 2 mm of size change.
I did remove my injector housings for an unrelated leak repair and took the opportunity to take a little more out of them a few months afterwords, but I feel like any more improvement would come from getting back to the plenum for a little more work there. Since I'm finally running headers, I've seen the light on top end power.
So as not to confuse, when I made the decision to port the top end, I had also opted to delete the secondaries too, in the name of improved air flow (because the highest velocity in the column of air is in the center...right where that throttle plate and shaft resides...) The stock transition just below the secondary plate is quite abrupt; i.e., not in keeping with my goal of 4% taper, so the runner below the secondary plate got some attention as well.
Anyway... That's what the pix were showing: both primary and secondary ports getting "the business"...And, no steeeeking secondaries!!!
P.
Thanks for all the great feed back. I am looking forward to getting everything done within the next few weeks.
Update: Finally got injector housings off and discovered why I had an oil leak, it appears a steel gasket was used...see pictures. Not sure why? I also discovered that the IH secondary ports have been opened up to just shy of 38mm. The steel gaskets are also 38mm but the head was not matched to the gasket or IH. Question: why was a steel gasket used and should I proceed with opening up the primary port on the heads to 38mm to match the IH? I will have to trim some material off the new gasket as well.
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