Original Exhaust System Fitment Problems

[LarryC]

I cannot seem to get my exhaust system lined up properly on my '79. Two years ago I replaced the entire system with new components (down pipe, catalytic convertor, and muffler, along with the slip rings, spring hangers, etc.). My trouble is that the down pipe has to be cocked severely to meet up with the exhaust manifold, and in doing so the down pipe rubs against the opening in the rear of the engine compartment. It is always in a bind, subject to rattling against things, and so after about two months it needs to be re-aligned and tightened into its uncomfortable position. The original system never rattled or needed attention. So I know it is possible.

My question is whether there are variations in the down pipe or something else. The down pipe I sourced from e-bay and I compared it with my original pipe and it appeared similar in all angles and lengths. If everything is in order, is there something that I am missing? Is there a preferred order of fitting the pieces so as to avoid mis-alignment? Is the dogbone too loose and letting the assembly rock back and forth too much? I cannot figure this one out for the life of me. It is a strange one.

Discussion on any similar fitment problems and resolutions are welcome.

 

[bbrown]

I had issues with other down pipes

For some unknown reason, the end of the down pipe didn't line up the same as the original. So I ended up sending out my original to be ceramic coated. (as the second one I bought)

My guess is that these things have to be heated and bent slightly to some degree (when they are bought new) in order to fit the existing hardware.

BTW, nice exhaust hardware you've got there. :headbang:

 

[LarryC]

Thanks Bob.

That sounds about right based on my experience with this down pipe. Nice to know that I am not alone. I guess I will get a new down pipe and start afresh.

 

[Mark Plaia]

Check motor mounts & lower crossmember....<NT>

.

 

[LarryC]

Mark, good idea.

I have new motor mounts top and bottom, but I have not gone over the cross-member for a while. Looking at the geometry of the fit problem, it seems to be more of a lateral alignment than could be accounted for via the (usual) cross-member problems. But you never know unless you look! Sometimes you still don't know after looking, too.