The Stovebolt Site Forums The Shop Area Engine Shop GMC 302 carb spacer question

51 GMC 1-ton

I finally have my 302 running but not yet on the road. I haven't had any luck finding a carb spacer for the 2 bbl. From previous inquiries on the forum I am convinced that I will have problems without the spacer.

My question is whether asbestos plate will work. I recently picked up some scrap asbestos that apparently came from a brake shop. I have a 1/8 and a 1/2" piece. I'm wondering if the asbestos would be too porous or cause other problems. It also has minute metallic particles in it, I guess for heat dissipation. Does anyone know whether the metallic partices are iron? Could I use the material if the particles turn out to be aluminum or brass?

Thanks again for your help

I'd go with aluminum i have no problems with mine. I put a paper gasket on the top of the insulator and one at the bottom to insure it is sealed good. No leaks and problems with heat at all for 3 or more years. The original one (made out of some hard weird material) was junk! It never sealed any good and broke in 5 pieces when i accidently dropped it on the floor. :mad:

Oh ya mine was for a 1 barrel carb though. Which is about 1/2 the size or smaller of a 2 barrel carb.

Bakelite, phenolic plastic, teflon, acrylic, or maple are good materials to make carb spacers out of. They can all take the heat of the intake manifold just fine. I wouldn't use aluminum because the whole point of the spacer is to keep the carb from getting heat from the manifold. I wouldn't use asbestos because of the health hazard. It may also decide to flake and ruin your engine.

I have a bad habit of posting questions before I have exhausted my options. I found a local plastics shop today with phenolic plate scraps which will be perfect for the spacer. I got varying thicknesses to experiment with; more than I need for $5. Phenolic plate looks just like brown curcuit board but thicker and without the holes. It comes in various thicknesses, probably 1/16 - 1" or more. Looks easy to work with, although I'm not sure how I'll cut the large port holes for my 2 bbl.

The shop assured me it would stand up to the heat and fuel.

Thanks for all the input.

Phenolic is a good material to use, but you must know the hazards. It produces a dust that causes inflammation in the lungs, so were a good dust mask. If you have the right tools, cut it on a table saw, drill the big holes with a hole saw, then sand the inner surfaces smooth. You need very smooth surfaces for the air flow.

We used to use it in aircraft all the time, not much any more.

Fred

Thanks for the verification on the material. I was wondering if I it could be cut with a hole saw.

Kind of funny,. Since I hadn't been able to find something here I was sure I would find the right material at "The Yard" in Wichita the next time I visited Mom.

Stovebolters: "The Yard" is a great military surplus store and also has literally tons of materials. Nuts, bolts, plastics, aluminum and steel billets, diamond plate, sheet and all kinds of gadgets. Stuff apparently comes from the Boeing, Beech, and Cessna factorys and the Air Force Base nearby.

Fred, I'm looking forward to visiting your vintage chevy shop the next time I'm there.

Iz