Exhaust Maniford Issues

Richard Vyse

Richard Vyse

On the trip the right exhaust manifold developed an exhaust leak even after replacing the gaskets. I'm told the exhaust manifold is somewhat out of kilder so, it is coming off and heading to the machine shop to have milled flat again.
Anyone got an extra right exhaust manifold if by chance I need one?
 
They are machined flat when new, however, if they are not properly installed by torquing them in small increments to the final torque setting, they will warp. I have seen even recently "corrected" manifolds start to leak as a result of improper installation. I suggest that once they are installed, torqued to the final setting, etc. that you "paint" the remaining part of the stud that is protruding with a high temperature anti seize compound. You don't want to do this prior to the torquing, since the bare threads are needed to keep the nuts from loosening. I would suggest stainless steel nuts and heavy flat washers be used. Makes it easier to get it off later on.
 
It's been a few years since I have done this (like 15), Cadillacs' of Richard's vintage use bolts. The best one to use is a case hardened stainless bolt, make sure this is used or the process of that manifold heating and cooling will pop the head right off a lesser quality bolt and you are back to square one. Been there done that. Using the case hardened SS bolts took care of future problems.
I learned this trick from an old school Caddy Master Mechanic who was in his late 70's and was still working on the older Cadillacs that came in for repairs at Dew Cadillac in St Pete Fl in the early 90's.;)
 
As a last resort, I've had good luck getting rid of leaks with "dead soft" aluminum manifold gaskets. They're obviously not period-correct, but they do a good job of compressing and conforming to irregularities.

They are found most commonly in speed shops like Jegs or Summit, but sometimes the local auto parts megastore can order them for you. Not sure if they are made for Caddy engines though. They make them for all of the "common" engines like small and big-block Chevys and Fords.
 
And it is done...

Just picked it up and it is almost as quiet as Chief Ron's Pontiac Combo, almost. Had it milled so it fits great. Good to go for now!.
 
Headers?

As I await the return of me engine, I was looking into the parts I'll need for the engine reinstall. My manifolds cracked into pieces and it appears they are a bit hard to find.

Has anyone put Summitt Headers on their 455? Will they fit in the engine compartment? (OK, I know it won't be stock, but I hate to shell out the bucks on cast iron again....) Nothing real racy, just their stock headers for the 455. Looks like they are less expensive than the cast iron I located on line elsewhere.

Thoughts, advice, and other comments always appreciated!
 
bolts poped off

Richard did your bolts come off or did they break? my back two are snapped off in the head, we are planing to pull the head this weekend and send them out I probley wont even try to pull the exhast manifold off the head just give it to the shop to drill out the old bolts
 
Have both the head and the manifold plained / milled. That is the only way to get a truly flat surface. Then they need to be installed with a torque wrench and tightened evenly and uniformly.
 
Michael Lee said:
Richard did your bolts come off or did they break? my back two are snapped off in the head, we are planing to pull the head this weekend and send them out I probley wont even try to pull the exhast manifold off the head just give it to the shop to drill out the old bolts
Click to expand...

Actually only one bolt broke off so it had to be drilled out. My mechanic used a lot of heat to free them up and thank goodness the broken one was accessible or I would be doing what you're doing.
I hear if you plain both the head and the exhaust manifold you will not have to use a gasket. That's what I heard anyways.
 
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