trs77

I got another problem. Put on a Performer manifold a couple weeks ago (3701 egr model). Took it out. Runs good. Bring it home. Go out in garage later and hear bubbling sounds coming from the carburetor! Stock q-jet. OMG... gas boiling! Carb is hot. Manifold is HOT. Car then starts running like crap. Last night, I take the carb off. Take air horn off. Gas everywhere! Clean and dry out carb. Check float setting. Right on 15/32". Install new air horn gasket. Put carb back on. Take it out for a spin. Running good again. Bring it home. Go out in garage later and hear bubbling sounds coming from carb, again! OMG... gas boiling! WTH!!!

In this cool weather, temp gauge shows I'm running a little below my normal 200, now around 180, which is the rating on my thermostat. But that manifold and carb sure is getting hot (need to get a good ir temp sensor)

WTH is going on!

I also noticed two HOLES in the intake just below the carb, open to what I think is the exhaust crossover. Are these supposed to be there? Are they letting exhaust gases into the runners bypassing the EGR? I need to call Edelbrock on that one.

Also, I am using stock fel-pro 63482 base gasket (thick one).

Any ideas? thx, tom


[Modified by trs77, 7:38 AM 11/17/2001]

daily_driver

http://forums.corvetteforum.com/zerothread?id=170938

check the above thread...

sounds like this is the problem...

trs77

Yep, I suspect a similar situation, with too much exhaust going through the crossover. I tell ya, that manifold is HOT. I used fel-pro 1256 gaskets with the exhaust port restrictor on the left bank and unrestricted on the right for my hot air choke tube. I would like to block off the cross-over with a new gasket and switch to an electric choke, but retain the egr as I feel that is a beneficial emissions device (lower combustion temps = lower nox with no performance impact to speak of on a mostly stock engine). thx, tom

daily_driver

well if you block the crossover by installing intake gaskets with no crossover hole, then the EGR valve serves no purpose!!!

jegs sells a conversion kit to go from hot air choke to electric choke for the qjet carb...

i have installed it and it is very easy!!

:)

trs77

Doh! (I'm not WITH stupid.... i AM stupid).

daily_driver

heres the part # for the hot air choke to electric choke conversion....
http://www.jegs.com

# 03501932

it works on qjets.....


there is a block off plate for the EGR for that intake, i believe its a holley part #--but itll fit... can someone please post that # for him??

good luck with it!!

:)

Matt Gruber

keep in mind that the egr valve is obsolete.
the c5 does not need it, i think mainly because the cam is big enough to provide enough egr.
it is easy to get rid of the egr and improve emissions and power with a larger cam, if you can legally do that.

MoMo

I don't think you need it. The exhaust gas recirculation valve takes the exhaust gasses from the exhaust crossover ports and reinjects them into the intake for "reburning". However, my own theory on this is that the more efficient you can get an engine to run, the better it will run. Try blocking the port. Sure, it'll make your EGR valve nonfuntional, but so what? If for some reason, it doesn't pass emissions (and I don't think that'll happen), you can ALWAYS open the crossovers back up.

On stock iron manifolds, you probably never had this problem right? Aluminum transmits heat way too efficiently to even have an exhaust crossover. If it needs to be on there to pass a visual inspection, fine. But I don't believe a nonfunctional EGR will prevent you from passing a sniffer test. When you go for the test, use light weight oil, raise the idle speed up to a fast idle, and make sure you have good new spark plugs and your timing is right on. If you have an oil burner, use some Restore...the stuff works. If your cat is questionable, it may need replacing too, but try it first. I'd change a cat before opening up the exhaust crossover ports.

MoMo

Also remember that a lot of states use oxygenated fuels, which basically means alcohol added to crap gas to raise its octane level. The higher alcohol content drastically lowers the gasoline's boiling point. This ethanol is horrible for carburetors. Especially when you have a warm day in the winter.

trs77

Thanks, Everyone!

We don't have visual inspections here in IL, and for old cars like mine, they only test at idle for HC and CO, which are handled mostly by the cat, I believe. And yer right, this did not happen with my stock iron manifold. And, almost all the gas around here contains ethanol. I have been using BP Amoco almost exclusively. I suppose I could try some other brands.

So here's the plan. Reset the mainifold with the fel-pro gaskets that block the cross-over (as would be used on a non-EGR Performer 2101). Convert to electric choke (thx daily_driver). Remove EGR valve and replace with block-off plate. Remove heat riser valve and actuator and replace with spacer. Cap the ports on the carb for those devices. Sound good?
:yesnod: :seeya

Jason Staley

You could try using a wood or plastic carb spacer to reduce the temperature in the carb. Of course this will raise the carb, so you'll have to check your hood clearance. Spacers usually help performance a little also, so there are two benefits in using one. You can find them at most performance shops - I know Jegs & Summit carry a wide variety of them.

daily_driver

make sure you use the right felpro gaskets....

checkout the edelbrock manual... it has a list of some NOT to use....

didnt yah wish you installed a 2101 in the 1st place??

perhaps u can return that manifold still!!

just clean it up a bit...