67 L-36 Carb question

[Lawrence S.]

I recently bought a very nice restored correct carb for the above engine. Eric Jackson is the guy who I bought the carb from and he sent the correct gasket with the carb that allows for the exhaust heat to transfer under the front of the carb. I installed the carb without a heat shield and with the correct gasket. The carb has now developed a front bowl flooding issue similar to when there is trash in the needle and seat. I have had the carb apart cleaned everything and there is no trash in the carb or the needle and seat. While doing this I noticed water in the area behind the power valve and in the bottom of the base of the carb. The water was dirty like carbon was getting in there. While I had the carb apart I noticed that the power valve was rusted...brand new power valve! When I took my incorrect carb off I threw away a thin heat shield that I thought was an aftermarket piece but maybe was a factory piece? I assume I should be using this head shield but can't find one at the auto parts store. Is there a gasket that I can buy that will double for the heat shield and gasket?

The picture below is the base of the carb with carbon on it. Is this normal?

Thanks for the help.

carbon on carb base.JPG

[Joe L.]

Re: 67 L-36 Carb question

I recently bought a very nice restored correct carb for the above engine. Eric Jackson is the guy who I bought the carb from and he sent the correct gasket with the carb that allows for the exhaust heat to transfer under the front of the carb. I installed the carb without a heat shield and with the correct gasket. The carb has now developed a front bowl flooding issue similar to when there is trash in the needle and seat. I have had the carb apart cleaned everything and there is no trash in the carb or the needle and seat. While doing this I noticed water in the area behind the power valve and in the bottom of the base of the carb. The water was dirty like carbon was getting in there. While I had the carb apart I noticed that the power valve was rusted...brand new power valve! When I took my incorrect carb off I threw away a thin heat shield that I thought was an aftermarket piece but maybe was a factory piece? I assume I should be using this head shield but can't find one at the auto parts store. Is there a gasket that I can buy that will double for the heat shield and gasket?

The picture below is the base of the carb with carbon on it. Is this normal?

Thanks for the help.

[ATTACH=CONFIG]41684[/ATTACH]

Lawrence------


If using a stock, unplugged-heat-slot manifold with an original-style slotted gasket the stainless steel heat shield MUST be used between the carburetor and gasket. Otherwise, serious damage to the carburetor WILL result. This may already have occurred in your case.

I strongly recommend plugging the holes in either end of the manifold's heat slot and completely disabling this feature. The holes can be plugged with drive plugs (manifold on-engine) or drilled and tapped for allen head pipe plugs (off-engine).

I would still use the stainless steel heat shield even if the heat slot is disabled.

[Lawrence S.]

Re: 67 L-36 Carb question

Thanks Joe. Any idea where to buy the heat shield?

[Joe L.]

Re: 67 L-36 Carb question

Thanks Joe. Any idea where to buy the heat shield?

Lawrence-----

The GM part number was 3884575 but it's long-since discontinued. Reproductions are available from Dr. Rebuild, Corvette Central and, most likely, most of the other parts vendors.

[Clem Z.]

Re: 67 L-36 Carb question

when GM used cast iron throttle bodies on their carbs the exhaust heat was directly on it but with aluminum throttle body you need to keep the exhaust off of it with the stainless steel shield. rebuilding carbs i saw a lot of what your picture shows.

[Lawrence S.]

Re: 67 L-36 Carb question

I am sending the carb back to Eric for him to check it out. I think the power valve is shot but not positive. I feel stupid for doing this. My other cars are aluminum intake cars and just have not had this experience. I will buy the stainless steel shield tomorrow.