The Stovebolt Site Forums The Shop Area Engine Shop Manifold gasket replacement - 235

Can one leave the exhaust pipe connected, and still have enough "play" to get the manifolds removed from the engine and the new gaskets in place?

Probably a dumb question, and hints at my impatience/laziness...but the flange seems seized up pretty good. And I'm not really wanting to destroy it just yet.

I have successfully done what you describe.

Should I remove the intake from the exhaust first? To get some weight off?

I vote "no".

Keep the intake and exhaust manifolds connected, unless the seal to the head is/was bad/leaky.

I tried it once that way. The second gasket set I bought had the gasket for the heat riser and the manual said to separate the manifolds and not tighten them until they are tightened to the head.

This is one of those..."while I'm at it" jobs. Cheap enough that it's hard to justify not doing it.

I am fairly certain I had an exhaust leak at the head. And I have reason to suspect (from vac gauge and rough running), that there was also an intake leak. Couldn't keep it running long enough to further diagnose the vac leak.

Given that, would you disconnect the two?

Now, after your last post: in order to eliminate leaks, you should take the manifolds apart.

You could leave the exhaust manifold on the exhaust pipe, if you do not have to have the joined manifolds planed in order to sit flat against the head.

You are reading my mind today. I was wondering about that very thing. How will I know if the manifolds need planed? Is it something I can "see", or will I not know until I bolt it up and start it?

Another issue with leaving the exhaust pipe attached is dealing with the intake alignment sleeves. They are easy to deform even without the exhaust pipe attached.
I recommend that you take care of all possible causes for leaks, and take everything apart and put it all back together.
Trust me, you will feel better about it once you are done and have no leaks.
Carl

To check manifolds , take them and lay a straight edge across entire length, use a straight edge or level across entire length of manifold, then use a feeler gauge to see if you can slip it under straight edge anywhere, if you can then it needs to be milled to clean up and true. Pat

The exhaust flange to manifold bolts are seized up tight. I do not have a torch. I soaked with penetrating oil for a few days.

The exhaust needs replaced anyway. But I'm not ready for that until the engine is proven worthy. What if I sawzall the pipe a few inches below the manifold? Then cob job the exhaust back together temporarily?

Nothing wrong with temporary cob jobbing. I like your way of thinking ahead to avoid unnecessary fruitless work.
Carl

Sometimes a propane torch is useful and they do not cost a lot of money. If you can get access, drilling the nuts can weaken them and get them ready for removal by chisel.

dremel tool with a cut off wheel will make quick work of the exhaust studs.

once the manifold is off drill the studs out out and replace them.

Breaking flange bolts is not recommended I have chosen to use a sawzall an cut the tail pipe, replace the gaskets resurface the manifolds,or whatever then weld the exhaust pipe back together or take it to the muffler shop and pay them to do it.