I'm looking for a source or someone who has those tin spacer plates that fit between the manifold and the carb. The one I have is rusted out. The only good one I have is for the Carter carb and manifold. Where can I find one for the Q-jet on a 425 manifold? Will one from a later Buick application fit? (ie. 430, 455, 67-70), if so, where do I find that? Thanks...
I get them (and everything else) from Carmen Faso -716-693-4090 He is not online but he has many Nailhead parts. :beers2:
Is the gasket for the seal between the stainless plate and intake? Or for the seal between stainless plate and carb? my spacer plate looks like it was mounted directly to the intake without a gasket.
Put the plate directly on the intake, no gasket there. If you put a gasket between the intake and plate, the hot exhaust gasses will burn thru the gasket. EDIT: Buick service bulletin states plate should be against carb surface! But I did burn out a gasket on my 2bbl Special when installed that way. Maybe it was a cheap gasket?
what are the tricks to get a good metal to metal seal with old intakes and old exhaust spacer plates?
Better check your service/assembly manual. The assembly manual I have for my '68 El Camino w/ Q-Jet carb shows the gasket on the manifold, and the steel (it is not made of tin) baffle on top of the gasket, directly against the carb. The gasket has a channel cut into it across the front, that lines up with the exhaust gas passage in the manifold. Therefore, the gasket is intended to be in direct contact with the exhaust gas; and is therefore made from heat-resistant material. The original gaskets were probably an asbestos-based composition; God knows what they're making them from today.
I know that is correct. The steel plate goes against the carb to prevent the corrosive exhaust gases from eating up the carb base plate. The gasket has a cut out to allow the exhaust gases to heat up the carb for cold driveability.
How does the steel spacer plate make a good seal with the metal base of the carb? Seems like you would want a gasket between the intake and spacer, and another between the spacer and carb to insure no vacuum leaks. o No: unfortunately, there weren't any diagrams in my 66 shop manual, but i did not read it carefully to see if something about the steel exhaust spacer plate was in the text.
As long as the carb base plate is square there are no leaks. Both my 65 & 67 are like that. I suppose a little gasket sealer between the carb and the spacer won't hurt. Mine are metal to metal.
I did some research, and... Brucer is correct, the plate goes against the carb base. This will allow more exhaust heat to be transferred to the carb. But... a '66 service bulletin described a problem where too much heat can be applied, resulting in fuel vaporizing in the fuel bowls. Their fix was a new thicker base gasket to act as a heat insulator. I would think putting a gasket between the plate and carb (instead) would keep the carb slightly cooler, which might be better for performance applications. This way, there is an air gap between the exhaust gas against the plate, and the carb. Putting the plate directly against the carb base would provide more carb heating. What do you guys think? The original gaskets were terne (tin/lead) coated for corrosion protection, and to improve sealing. A coat of Permatex copper gasket paint would work well for this application.
What I have been doing for years is: I plug the 2 holes in the manifold that go under the carbs. that are aluminum. For the Rochchester 4GC, since it has a cast iron base I leave it alone as the cast iron is not affected by the exhaust, aluminum is. I use a 1/2" fine thread bolt, after tapping the hole, use Red Loctite to help hold them in place, then cut the heads off flush with the manifold. Since many of us don't drive our cars in the dead of winter any longer immediate heat to the base of the carb. is no longer nec. You still have heat in the manifold because nothing has been done to stop that heat. The heat will still help to atomize the fuel/air mixture for better fuel atomization. I don't even run the heat riser valve any longer either. Just what I do & my opinion.
