Straight 8 Exhaust Manifold Question

[midman]

I’m working on reinstalling the engine on my 1931 90 Series and I have a question I know you guys can answer.

My original exhaust manifold basically was in pieces when I got it and I have been lucky enough to scrounge up a few spares.

My guestion is, knowing the manifold has to move some, are the intake and exhaust manifolds supposed to be exactly the same thickness(the part where the slightly cone shaped washers go)?

I am assuming yes but my exhaust manifold was surfaced flat and is now about .71 and intake is .75.

Should I have the intake surfaced to match or do you think I am safe?

[Bob Engle]

My first thougtht was that .040" would be an acceptable  difference, but knowing the problem with cracked exhaust manifolds. I would opt to get them the same thikness.  You could take the metal off the  washer side as this will give you a nice smooth surface for movement.  Most of these manifolds show a groove from the washer and his could  prevent the washer from grabbing rather than sliding.

 

Bob Engle

[midman]

Bob,

Thanks for the thoughts. I am going to try your suggestion. 

Much appreciated.

 

Chuck