1971 250C Exhaust Dampers?

[caviterruptor]

The above car runs well around town with its original twin zenith carbs, but boggs down at highway speed. Rather than mess with further carb adjustments, rebuilds, etc, I bit the bullet & bought JAM Engineering's Weber carb kit.

Upon removing the Zeniths, I noticed two "dampers" on each of the ports in the exhaust manifold. It appears the dampers are supposed to be opened by bi-metalic coils as the engine warms.

Both coils are broken & it appears the forward damper is seized in the open position, while the aft one moves freely & may have been open and/or closed as I drove.

Dos anyone have experience with these things & how they affect performance?

[thorsen]

That's a common problem on these cars. Check out this link.

http://www.peachparts.com/shopforum/vintage-mercedes/237863-1967-250s-exhaust-flaps-frozen.html

On mine, I ended up getting a piece of steel to close off the heat risers.

[Mike D]

Alternatively, post #6.

http://www.peachparts.com/shopforum/vintage-mercedes/238292-m115-t-b-i-conversion.html

[caviterruptor]

Thanks, fellas. I'll leave the forward heat riser sealed shut (San Francisco) & secure the aft in the same position.
Regards, C