Sagging exhaust manifold

[Geo.T]

The exhaust manifold on my car is leaking. I have a spare one that shows
the rear port sagging about 1/16 inch below the other three ports which are in-line. Is it worthwhile to sandblast, paint and install this unit or should I look somewhere else? Thank you.

 

[Tom Wesenberg]

I'm using an exhaust manifold like that on my 28. I can't install the rear exhaust port steel ring due to about 1/16" droop on the #4 port. The car runs fine with it.

 

[pat in Santa Cruz]

1/16th might be use-able. 1/8th is about all the gripping surface you have with a good one, so with 1/16th, you are close to the bitter end. I would also check if all ports are flat in the same plane. The late 31 copper gaskets seal best with sagging manifolds. I put some RTV or grease on the surface and place it against the block, tighten the bolts slightly, then remove it to see how much of the gasket surface would actually clamp. When in doubt, I always replace it since Snyders makes a good manifold. I do not like spending the bucks, but I dislike leaks even more.

 

[Mike V. Florida]

The model T guys have a jig to heat and bend back the manifold. Has anyone tried it with an A?

 

[Tom Wesenberg]

The model T guys have a jig to heat and bend back the manifold. Has anyone tried it with an A?

Thats exactly what I am going to make sometime. Other jobs need to get finished first.

 

[Ray in La Mesa]

The model T guys have a jig to heat and bend back the manifold. Has anyone tried it with an A?

I tried the Model T method of straightening the maniforl wih heat and a flywheel for weight but it had a memory and rebent. The temperature cycling is what gives it the memory I believe.

 

[Ray in La Mesa]

I tried the heat and upside down weight method and it worked for a while but I believe the temperature cycling of many years gave it the memory and it drooped again.

 

[V4F]

easier to buy a new one ................... steve