Exhaust leak between manifold and head - best way to fix?

[Matt Innocenzi]

Hello all.  As indicated in the title, I have a nasty exhaust leak between my manifold and head on the left bank of my engine.  When I rebuilt the engine, I foolishly did not have the exhaust manifold planed, and the slight warpage is leaving a gap between the manifold and the head on exhaust valves for cylinders 1, 3, and 5.

Of course, the simple approach is to replace the exhaust manifold with a spare one that I have that I just had planed.  But then again, there is nothing ever simply...ever.  The front most bolt connecting the manifold to the head is about 1/8" too long.  What is happening is the bolt is topping out on the upper control arm spacer, so I cannot back it all the way out before it gets wedged.  There is probably about 1/2 thread still connecting it to the head.

I see this as having three options:

1.  Notch a spare set of exhaust manifold gaskets, butter them with copper RTV sealant and slide them in the gap between the warped manifold and the head.
2.  Cut off the bolt with a metal cutting wheel and when I put the new manifold on, scrounge around for a bolt that is 1/4" shorter so I can insert it
3.  Undo the bolts from the motor mount and hoist the engine up to provide clearance from the control arm and slide the bolt out.

Of course, #1 is the easiest, but probably the least effective.

Any other ideas, suggestions, or tips?

Matt

[Philippe M. Ruel]

Your #3 was my answer even before reading it in your post.

[Scot Minesinger]

Agree, # 3 was what I was going to type.  Like you write nothing is ever ever ever easy.  Maybe you can reduce the bolt length an 1/8" on the grinding wheel that way this repair will never be required again, otherwise it may take tow or three tries.  On the other hand that 1/8" of threads may be needed.

[russ austin]

The bolt may be too long to remove, but it should be out of the threads in the head. Can you lift the manifold out? 

Don't know what year car, but if you left the engine, be sure to remove the front tranny yaw mounts.

[Matt Innocenzi]

Thank you all for the reply.  I was afraid of that *sigh*

Russ, this is for a '62 Cadillac Fleetwood.  I never paid attention to the length of the bolts, because I installed the exhaust manifolds on an engine stand and then dropped it in the car before the entire front end was re-assembled.  Who would have thought...

I am going to try to lift the manifold out, but of course, Murphy's law has that bolt just about hanging on so I don't think I can do.  Believe me, I am going to try like the devil though to wiggle that manifold out as I really do not want to go unbolting the motor mount bolts.

The best lessons are indeed the most costly ones.

[dadscad]

Instead of removing the bolts holding the mount to the block, could you not loosen the stud going through the frame a little and put a bottle jack under a pan bolt head close to the mount? Lift the engine on that side just enough to clear the obstacle. If you had to lift much to clear, it would be wise to loosen both mount studs and be cautious about the yaw mounts, as Russ mentioned.