I have been experiencing the typical hard start after the engine has warmed up problem. I have a rebuilt 292 with a 4 barrel Autolite carb and after a drive, if I shut it off and try to restart after a few minutes, it takes quite a few cranks to get it running again. I've read alot of posts on this problem and one solution is to use a phenolic spacer under the carb to decrease heat transfer to the carb. I currently use a 1/2" aluminum spacer with a vacuum port to the PCV valve. Does anyone know of a similar phenolic spacer compatible with my carb that has that vacuum port?
Going to be tough finding a 1/2" phenolic spacer with a pcv port. A 1/4" pipe fitting with a barbed end must be close a 1/2". If you have room for 3/4" under the hood that could work or a more drastic approach would be to install a small electric fuel pump to prime the carb before you crank it over.
You might be able to drill and tap the spacer if it's thick enough. I was experiencing a similar problem on hot starts.
I wrapped my fuel line in a heat shied insulation material and minimal improvement, I installed a phenolic spacer, no improvement, I replaced my fuel pump too.
I spoke with Edelbrach to see if I could get some tech support since I had a Edelbrach carb, I got nowhere since everything I was experiencing was a heat or fuel problem as per the techs I spoke with.
I finally replaced my carb with a Holly and I no longer have any starting issues hot or cold, it sits for a couple of months and I just hit the key and pump the accelerator pedal a couple of times and it fires right up. Going on a year now and I honestly think looking back I had a carburetor issue but chased all of the vapor lock, to close to manifold heat issues, etc.
I feel your pain hopefully you can resolve it without chasing rabbits as I did.
I put an aftermarket carb insulator kit on mine, it solved my hot start problem. No other changes were made.
I'm pretty sure I have a couple. I'll take a look.
If I were to use a heat insulator gasket, should I install it between the carb and the spacer or the spacer and the manifold?
If it's just a gasket, couldn't you use them in both places?
The gasket I think he's referring to is slightly over 1/4", so if you go that route of you may as well use one 1/2" phenolic spacer. I would put the insulator gasket between the carburetor and your aluminum spacer.