Removing Secondary Vacuum System questions.

[bdw18_123]

Originally Posted by xxxscimitarxxx

I dont envy your smog laws in US....but here in UK l think we have tougher general standards, pretty much like all of europe these days

checks for foot brake and park brake efficiency
checks on all lights fitted, operation, alignment etc
chassis and panel corrosion
wind screen conditon
wiper condition
screen wash operation
seat belt securement and operation
seat securement
tyres
brake pipes
bearings
bushes
battery securement
horn operation
door latches
mirrors
exhaust leaks
exhaust securement (if cat required after certain year of manufacture it must be present)
ad finally CO2

you can be pulled over and checked for any of these things and busted

the trick for US car owners in UK is to find a freindly test station.

from my trips to US l have seen some pretty rough cars on the road that might pass smog tests but are a threat to all other vehicles or pedestrians anywhere near them

where l am now in Ukraine.....its much worse...the older cars are death traps..and all the drivers really need is enough cash to bribe the cop that pulls them over...

point in question.....last week l had about 2 shots of cognac at 6-7pm in the evening......8am following morning l go fishing.....drive down road.....pulled over....cop 'says' he smells alcohol.....breath tested.....positive (really....after 13 hours....breath tubes have previously been found to have been dipped in vodka by the police....but on the other hand they do have a zero alcohol tolerance in Ukraine and there could have been a trace left).....so choices?

do the protocol...ukrainian paper work....car taken...3 months later go to court get $500 fine....get car returned etc etc

or

come to an agreement with the cop where he follows me to an ATM and takes $100......

no contest

there is something about corruption here in Ukraine that l like.....its manageable.

Wow, I didn't know the UK required checks of all that non-engine stuff. Sheesh, that would really suck. I guess the moral of the story is, it could always be worse.

[blackjack]

sooooooo.....
is it possible for somebody to sum it up for me? (secondary plates removal)
is there a step by step procedure in the archives?
just want to make sure i dont have to remove the plenum 5 times..
also,is a reworked chip a necessity?
if one is to remove the shafts too,what do you use to block the holes?
car is suffering from vacuum leaks-pump running most of the time-and ive got those nice van deventer heads in the basement
thanks
bj
91/1735

[rkreigh]

for sure the chip changes are needed, and Marc just revised the programming so he can eliminate another sensor. some considerations for those considering this (I took the plunge)

the car will run JUST fine with the right chip programming and no secondaries, the program changes to the memcal are down pat and Marc and others can make it work just fine.

there is NOT a big HP increase as the secondaries when open really don't restrict the flow much. mark showed me the injector housings and the estimates are in the handful of HP range. I did notice improved throttle response but much of that is in Marc's better programming. didn't pick up any top end HP (that was a surprise) but I didn't lose any bottom end and picked up just a bit of mid range torq. to really take advantage of removing the secondaries, it would be best to port the heads to take advantage of it.

emission, yup, there is the problem. but you can probably do OK. Graham confirmed that was of the reasons for the secondaries was to decrease emissions. think about it. it increased the "swirl" and flow veloticy when the engine is just cruising. the LT5 due to the combustion chamber and piston (crevice volume) design is a bit dirty on HC, especially when you just put around all the time.

there is where I'm having troubles. I have a 390 with the big valves and cams, and VA cut the emissions standards from 98 HC to 48.

BEST I could do with the old setup was 98 on a 98. I'm now up around 138 HC and this is with a closed loop chip. not sure what to do next go around. when I talked to marc about an "emissions chip" he stated that if the chip monitors the O2 and calibration is good, not much more can be done.

but I'm not going to pass next time. Marc recommended fresh cats, as I likely poisoned the last set running the car so rich. that's probably what I'll try.

the biggest thing I love about no secondaries is the immediate throttle response and lack of complexity. a few less things to go wrong and worry about and I was able to help out some members with some much needed parts *(that I sold way too cheap!!)*

for a stock displacement car, with the secondaries working well, it's probably much more hassle than it's worth. even on the big strokers it's really not worth much unless you are enlarging the ports in the heads at the same time.

but as said (my fav saying) "parts left out don't break or cost much"

[Aurora40]

Originally Posted by rkreigh

emission, yup, there is the problem. but you can probably do OK. Graham confirmed that was of the reasons for the secondaries was to decrease emissions. think about it. it increased the "swirl" and flow veloticy when the engine is just cruising. the LT5 due to the combustion chamber and piston (crevice volume) design is a bit dirty on HC, especially when you just put around all the time.

I'd *guess* the main problem is that the cam profile on the secondary intake is much more aggressive, and overlaps more with the exhaust.

[billybaloneey]

Originally Posted by Paul Workman

Reliability, simplicity, and more air flow!


Looks tell the story: Simple is a good thing!



FWIW,

P.

Paul - I noticed you removed the secondary shafts...according to the picture. How did you get the bearing out...they are staked (the term used in the FSM), or another way to describe it, a punch was used to dimple the IH in three places around the bearing? What did you use to fill in the holes once occupied by the bearing?

[VetteVet]

I removed my shafts and used 16MM freeze plugs made by Dorman. I got them through Rock Auto.

[billybaloneey]

Originally Posted by VetteVet

I removed my shafts and used 16MM freeze plugs made by Dorman. I got them through Rock Auto.

Ahh...16mm...is the hole size...good to know.

Thanks

[Paul Workman]

Originally Posted by billybaloneey

Paul - I noticed you removed the secondary shafts...according to the picture. How did you get the bearing out...they are staked (the term used in the FSM), or another way to describe it, a punch was used to dimple the IH in three places around the bearing? What did you use to fill in the holes once occupied by the bearing?

Sorry it took so long to get back to ya!

Per Pete's suggestion, I slipped a short socket over the shaft and bearing, and put a fender washer over the shaft. Then I screwed the nut from the throttle plate down on the washer (with some grease under the nut) and the shaft pulls right out!

In my case, there is a machined relief around the bearing. Finding a socket that would stay inside that flat relief circumference and not impede the bearing's coming out, I took my die grinder and ground the inside of the socket down enough to allow the bearing to clear the socket as it was drawn out. Piece o' cake!

Hope this helps.

P.

[billybaloneey]

Originally Posted by Paul Workman

Sorry it took so long to get back to ya!

Per Pete's suggestion, I slipped a short socket over the shaft and bearing, and put a fender washer over the shaft. Then I screwed the nut from the throttle plate down on the washer (with some grease under the nut) and the shaft pulls right out!

In my case, there is a machined relief around the bearing. Finding a socket that would stay inside that flat relief circumference and not impede the bearing's coming out, I took my die grinder and ground the inside of the socket down enough to allow the bearing to clear the socket as it was drawn out. Piece o' cake!

Hope this helps.

P.

What did you use to cover/fill the holes left by the bearing once they were removed? VetteVet posted a reply that he used 16mm freeze plugs.

[billybaloneey]

Originally Posted by VetteVet

I removed my shafts and used 16MM freeze plugs made by Dorman. I got them through Rock Auto.

Is this the one you used?
15.78mm is real close to 16mm




Dorman Cup Type Expansion Plug: Steel; 15.78mm; 10 Per Package 555011

(Dorman - 555011, B001C0F6Z6)



Description:

• Nominal Dia. : 15.78mm
• Metric Dia. : 15.78mm
• Type : Steel
• Height : 0.232"
• Closed End Dia. : 0.615"
• Open End Dia. : 0.630"