Weber Spacer Blocks
 

My 67S with Webers does not have a spacer between the manifold and the head.

But, I have seen many pictures of motors with Webers that have the spacers. What are they for? Is there any advantage to adding them?

Thanks

They reduce heat transfer to the carbs, and, hence, are supposed to minimize fuel percolation in the float bowls and vapor-lock problems when restarting after a heat-soak in hot weather. I'm sure a set cut from 0.040" Titanium sheet would work even better!

Warren,

Thanks. Were the originals some sort of fiber material? When did they first use them?

Bob,

The one's I have seen were about 1/4" thick, and made of a dark-brown phenolic-resin plastic. I believe they became available in late 1967, or early 1968 ... after enough of the Weber-equipped cars had been shipped to Texas and Arizona, and the summer heat caused enough complaints. German engineers have always had a hard time believing what 120-degree temperatures do to the drivability of their cars, compared to the cool weather where they do testing!

I may be mistaken, but I believe that the phenolic insulators were first introduced on the 914-6. They should be used if percolation in the float bowls appears after a thoroughly heated car is allowed to sit, and the condition is not otherwise due to too high float levels or pressure in the gas tank. They are not always required. Since converting from MFI to Webers in 1987, I have never experienced percolation, and thus, have never needed to install the insulators. By the way, it gets pretty hot in Maryland, too.

PMO has them. see their ad in excellence.

One doesn't *need* the insulator blocks.......untill you do.

I saw a post from a fella( 6 mos ago) that never had a problem untill he had a hell of a fire as a result of perculation. It was confined to the carb/aircleaner but it melted his aux venturi and ruined the air cleaner element. Amazingly, the the melted crap didn't hurt his motor.

I can imagine it being worse.
One doesn't realize anything is amiss till you fire (literally)up the motor. An intake port or clyinder can collect a fair amount of fuel
which raises hell when spark is introduced.

They are cheep insurance.