Gary's '66

I fully understand the concept (heat riser deleted) just asking exactly how it's done.
Do I just loosen the intake bolts then slip the shim in behind, and by behind can I assume you mean between the gasket and "head", and re-torque? Should a sealer be used? Like I said before this sounds like a great idea and an easy fix. My main concern would be an intake leak.

Gary

MOXIE62

This shim thing sounds like a good fast idea but you will get LEAKS. You can not loosen the bolts, slip a shim under and retourque and think that will fix it. The intake gaskets compress when first installed and any loosen of bolts and you loose that seal. Do it right the first time and you want have any grief. Fel-pro makes a gasket Fel-Pro #1204 that has the exhaust ports with the metal shim already in place.

MikeM

I doubt you could loosen a manifold that's already been heat cycled without tearing the intake gaskets so you'd want to start out with new gaskets. But, sometimes, you get lucky.

But yes, you have the process figured right. No, they won't leak as the gasket will absorb the extra thickness and conform to it.

Never mind the nay sayers that have never done it and see the need to criticize something they know nothing about. As an example, the restrictors the gasket makers put in their gasket kit actually DO OVERLAP the intake gasket so if leaking is a problem, they would also leak. But they don't.

Faslane

I installed the EDL 8723 spacer today, i also put 7/16 freeze plugs in the exhaust passage holes, I know it will still heat the intake up but easy and probably worth a few degrees? Put everything back together, went and drove it for 30 minutes, the gauge stayed at 180, it is about 80 degrees here.
I parked it and waited about 1/2 hour before opening the hood. It went from the intake valleys having puddles of fuel on the left side, to the linkage being wet, I think it may have dripped after a while longer, but not puddles you could scoop out with a spoon. it is alot better. But when it gets in the 90s, I think it will show itself again.
The heat under the hood and the way that air cleaner covers the carb, there is no where for the heat to go, closing the hood is like closing a oven door.
I will try running some mixed C16 VP fuel with it, at least if it pours out at a show or cruise in it will smell good!

MikeM

I thought there was a commercially made gasket that had the crossover blocked as I described. Just didn't know who made it or where to get it. I looked at the Fel pro 1204 and it does exactly what I described in the same manner. So, if you have to buy new gaskets anyway, that would be the way to travel.

My original response was to the post about somebody saying something about a "crappy little piece of metal" as opposed to his idea of spending $39.95 including the Corvette tax for something that does the same thing. I think that post has been deleted from this thread.

Anyway, Fel-Pro has stuck a "crappy little piece of metal" on their gasket and are selling it for a reasonable price.

Gary's '66

Thanks for the clarification (both posts) Mike. Might try my luck and see if I can slip in a couple of shims but will have a set of gaskets handy as I usually don't get out the easy way.

Gary

Faslane

I drove my car again today, it is about 88 degrees here today, i drove for about a hour, i pulled into the garage left it running, with my fluke meter, the exhaust manifolds 550ish, the front of the head 190, the intake runners (all 8) 156-166, the fuel bowl of the carb 125 degrees. Last the center of the intake right above the exhaust passages 265! Bingo!. After shut off the fuel bowl went to 140, the exhaust passages were still at 200+. the fuel was just pulling the heat out.
I think mine will do ok with the spacer. I am confident that I know what to do to mine at least if it get out of hand again. Intake gaskets.
Hope this helps someone else.
Lane

Frankie the Fink

There is a reason to block off those exhaust runner passages...every iron manifold I've seen on driven cars that have many miles on them look like mine did

TJefferson2020

My 64 roadster has a 1970 LT1 with a heat-shield (don't remember if it was a stock feature for that motor) and a drop down air cleaner (stock 1970), stock aluminum high rise manifold and it BARELY clears the hood with stock motor mounts.

I can't imagine how I'd ever fit a spacer in there.

I've had a few hot starting issues here in Texas - but I think it was more of a timing issue. I just kept the heat shield for good measure.

I also ditched the stock 750 Holly and installed a 650 Barry Grant Demon. HUGE improvement in almost every category including hot starts. Not sure if replacing the fuel line with braided stainless helped or not either (but it sure looks nicer...)

C2Racer

Thanks for the reply. I went to great pains to get a date correct 2818 for my car when I got it and it runs okay but the heat soak issue and fuel smells has me thinking about a Demon or Quick Fuel now. I am pretty sure the motor will come out next winter for a freshening and this will be a good time for this.

Steve

65silververt

This caused a bent rod in my fathers 427/390. I pulled the old Holley when this became a problem and changed to a quick fuel, but clearly that did not resolve the problem. I changed to different intake gaskets and an aluminum intake, but it still wants to percolate after shut down. I am convinced it is ethanol related. I have checked temps and everything is in normal operating range. I guess I'm going to install a heat shield next. https://m.youtube.com/watch?v=pKU91tRR7DY

Ironcross

You can try any trick including FI gaskets, but it really wont work.....My experience whether this is a early or late problem is the 62 was bought in Miami and neither the 61 or 62 {both} never experienced any fuel problems.like I do today...Hard starting for lack of fuel hot or cold. The only thing different today is the fuel .......

FI`s have a unique problem that can actually break internal parts....save that for a different day but its in the forums files

Kappa Sigma, Miami

65silververt

Here is the correct link below. I forgot to mention that in addition to the new carburetor, intake gaskets, and aluminum intake, I also removed the heat riser and put in the FI spacer in its place and made sure the fuel pump was working correctly. The cast iron intake did have the crossover holes blocked at the carb pad. I purchased a spacer, but there isn't enough hood clearance with the new aluminum intake.

MOXIE62

If your carb is OK, I believe it's to much fuel pressure.

65silververt

I appreciate the response(if it is directed at me) but as mentioned, the fuel pressure has been checked, along with everything else. Hence why I am convinced it is an ethanol issue as others that are experiencing the same problem are as well.

MOXIE62

I have a similar problem with my carb. The only non-ethanol gas in my area is higher octane. Talked to Dayton and I did not asked about non-ethanol gas but did asked about gas in general and he said never put high octane gas in your car or you will have more problems than a drip of gas into the carb, which is what I'm trying to eliminate.

OLDED

The common thread thru all these posts is the additive "enriched" fuel avaialble today. I would propose that most of our old, restored cars today are actually in as good, or better than, the condition that they were in a couple of years after manufacture. All those suggestions on spacers, blocking the exhaust ports in the intake, etc. are all valid and using 1 or 2 of them will likely resolve the percolation issues.

histoy

I've had problems with percolation in our '64 300 hp engine. I run only 91 octane without any ethanol. I've wired open the heat riser valve, but that didn't help. I removed the carb and drove plugs into both small holes. I made sure to use the proper gasket, spacer, and SS shim upon assembly. Still had the percolation. I checked the fuel pump pressure, and it was 5 psi. I installed an inline fuel pressure regulator and reduced the pressure in .5# increments, testing for percolation each time the car was driven. I found that when I reduced the pressure to 3.5 psi the percolation stopped. I just use the car for cruising and I've had no problems with fuel starvation on the highway, or when going up long, steep hills. Just offering it as a possible way to solve this issue.

MOXIE62

Funny you should mention the fuel pressure as a problem. I too think it is pressure related. I'm so convinced that I purchased a new airtex pump, sent it to a pump shop to have the pump spring replaced with a spring that will put out 3 pounds. Pump is in the mail now and should get it Wednesday and have car running by this weekend. I talked to Don at Dayton and he said cars run better with a low pressure and even at 3 pounds it's putting out more gas then engine would ever need. That is what is wrong with 65silververt's carb. All you have to do is look at his video but like so many others, he believes the pressure the cars had back when they were new is fine today, but it's not with the gas we are burning now. Some can get away with 5 1/2 pound and some cannot.