Insulating Against Heat on the Carb

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I would not recommend using those thin plates and gaskets that you stack up under the carb base. If you don't run the nuts down evenly, you can crack the ear off the carb mounting base... Been there done that.

Now I only will go with the thick gasket, not the stack of thin gaskets and plates...
 
this. Firm believer in just the simple large aluminum plate. Spacers did nothing for hot soak fuel percolation, but an 1/8" thick plate nearly cured it.
jbc426 said:
I've cured similar hot carb issues in the past by both making and installing a semi-ridged, sheet-aluminum plate to shield and dissipate heat transfer from the engine to the carb, and installing a 1/2" phenolic spacer on top of that. Using this combination requires 3 gaskets and longer studs. Be sure that the aluminum plate does not interfere with any linkages or throttle blades etc.. Also, depending on your intake design, you can use an open plenum or 4-hole style spacer. I sourced a one foot by one foot piece of aluminum sheeting from my local hardware store and cut it to fit. It was pretty thin, but still thick enough to be somewhat rigid.

Another successful addition I made was to use a gas filter with the return nipple to circulate the fuel back to the tank. I had to add the return line to the back of the car and a fitting on the sending unit to make this happen.

Having your ignition timing properly tuned helps too.
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krazykuda said:
I would not recommend using those thin plates and gaskets that you stack up under the carb base. If you don't run the nuts down evenly, you can crack the ear off the carb mounting base... Been there done that.

Now I only will go with the thick gasket, not the stack of thin gaskets and plates...
Click to expand...

This, my next move, Holley 108-18 for dual plane / 108-12 for single..

The 108-70 heat shield kit looks cool too.
 
So I will revisit my question one more time from previously, is the thinner Edelbrock heat insulator gasket (0.32" or 5/16", whichever) better than a slightly thicker (1/2") wooden or phenolic spacer? I see a lot of good ideas, but didn't really get an answer to this question. I appreciate all of the input to this discussion.
 
Do both. It's not either or; it's plus or minus, each part plays a role in the total temperature reduction. Together your going to get better results than each on their own.

Should be CLEAR as **** set glass by now.
 
1969VADart said:
So I will revisit my question one more time from previously, is the thinner Edelbrock heat insulator gasket (0.32" or 5/16", whichever) better than a slightly thicker (1/2") wooden or phenolic spacer? I see a lot of good ideas, but didn't really get an answer to this question. I appreciate all of the input to this discussion.
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If you have room, use the 1/2". If you don't go to the thinner .32. It just prevents (insulates, blocks, etc) heat transfer from the intake to the carb. I don't think between the fiber, Phenolic or wood/laminate ones you'll see a huge difference between and i believe you will hit a diminishing return with even thicker spacers. Use what fits.

On my car with a Weiand Stealth I need all the room I can get and age and type of mount and intake air cleaner can vary. It just prevents (insulates, blocks, etc) heat transfer from the intake to the carb.
 
Another thing that we haven't addressed is what about the make up of the fuel is causing it to evaporate out of the bowls. At least around here, it is made up of 10% ethanol. If I run the expensive premium with NO ethanol, the situation improves.
 
BrianT said:
Another thing that we haven't addressed is what about the make up of the fuel is causing it to evaporate out of the bowls. At least around here, it is made up of 10% ethanol. If I run the expensive premium with NO ethanol, the situation improves.
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Yes, I have. The insulating spacers address the conducted heat only. The large plate type insulator that I've suggested several times address' the heat radiated off the engine below the carb. A spacer won't do a lot for the radiated heat, and a plate can only do so much for the conducted heat (acts as a heat sink). A combo of both is the best route forward. Plate on the intake, then the spacer.

FWIW I looked up some thermal conductances:
Phenolic (linen filled): 3.75-4.03 BTU-in/hr-ft^2-°F
Birch: 1.20 BTU-in/hr-ft^2-°F
A356 (Cast Aluminum): 1050 BTU-in/hr-ft^2-°F

Note that the wood spacers aren't pure wood, they have some sort of resin put into them under high pressure so a wood spacer is likely closer to the phenolic number than the straight Birch number. Could not find a number for paper, suspect that it is similar to wood.
 
I run the eddy gasket 5/16 i think with the steel sleeves for the studs,my fuel line in the engine bay has a heat sleeve and stops 3 inches short into the Carb,running the Moroso valley Baffle and a small 5 psi electric fuel pump solid state which lives along the chassis in the engine bay covered via a heat shield. Since running this combo ive had zero issues,mild build 318.Ran the car even in 42 degrees thats 107 Fahrenheit in your neck of the woods! not pleasant with out aircon. 650 AVS
 
Yes, I know. My comments still apply, though while avoiding the corn lobby's foolishness is preferred it's nearly unavoidable here. Shielding the fuel bowls from heat with "gasohol" as the fuel is even more important.
 
I have 12 inch aluminum spacers and nether one of my edelbrocks gets in the ballpark of hot ! lol
triple-R in post #25 I think you're talking about a composite material like what the Milodon oil pan gasket is made out of?
 
j par said:
I have 12 inch aluminum spacers and nether one of my edelbrocks gets in the ballpark of hot ! lol
triple-R in post #25 I think you're talking about a composite material like what the Milodon oil pan gasket is made out of?
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12 inch was that a typo?
 
1969VADart said:
So I will revisit my question one more time from previously, is the thinner Edelbrock heat insulator gasket (0.32" or 5/16", whichever) better than a slightly thicker (1/2") wooden or phenolic spacer? I see a lot of good ideas, but didn't really get an answer to this question. I appreciate all of the input to this discussion.
Click to expand...

What did you end up going with? I just bought the Edelbrock thick gasket https://www.summitracing.com/parts/edl-9266 and will be getting it running hopefully tonight. I also am going to use header wrap around my fuel line above the intake manifold leading up to the carb. We'll see how it goes. Thing all but died off the line against a Monte Carlo a couple weeks back and I don't like to misrepresent Mopar.
 
The #1 thing you can do is block the heat crossover if your intake manifold has it.

I use the adapter and spacer from CoolCarb but they recommend highly that the heat crossover be blocked off prior to using it.

An electric pump and fuel return system would be great too.
 
jrc4y4 said:
What did you end up going with? I just bought the Edelbrock thick gasket https://www.summitracing.com/parts/edl-9266 and will be getting it running hopefully tonight. I also am going to use header wrap around my fuel line above the intake manifold leading up to the carb. We'll see how it goes. Thing all but died off the line against a Monte Carlo a couple weeks back and I don't like to misrepresent Mopar.
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I ended up ditching the Edelbrock carburetor and installed a Holley. I kept the 1/2" phenolic spacer on the car for good measure. I did not block off the heat crossover at all on my intake. I have not had a single problem since switching to the Holley carb.
 
Ok thanks for the info guys. If I take the intake off I'll look further into blocking the heat crossover. Just want to get it running without tinkering further if possible lol.
 
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