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Discussion Starter #1
Hi, I had removed my intake/exhaust for access reasons to do some other work and noticed the front and back exhaust (1 & 4?) gasket looks wonky. It doesn’t seem broken through, just like it has eroded on the outside edges.

The head looks like in that area but had the obvious witness marks of blow by, which was easily wiped off. The exhaust flange has not obvious defect but i havent checked flatness yet. Is this an exhaust manifold distortion issue? Or something else?

Obviously I am going to replace the gasket, anything else I should be checking or changing?

Thanks for your help.
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It was definitely leaking. It is fairly common. You need to make sure that you retorque the exhaust studs a few times after running the engine, IME.

Make sure you use a Reinz or Elring gasket.
 
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it was indeed leaking as Johnny said.
We have them milled to make them flat.
Yours has warped and will leak again if it is not machined.
Tightening it up when warped can crack or break the manifold which is also a common problem.
Since the head is aluminum and the exhaust manifold is cast iron the dissimilar metals have a different coefficient of expansion which will cause the torque of the exhaust fasteners to loosen over time.
You should check your manifold fasteners regularly and tighten accordingly to combat the thermodynamics at work to make things loosen.
 

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Discussion Starter #4
Thanks guys for the input. I will take a look locally for a machine shop to take a skim on the head. In your experience is it worth checking the exhaust manifold as well? Or do those break not bend?
 

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You have misunderstood the advice.
It's typically not the side of the head where the manifolds attach that needs to be machined, but the mating surface of the exhaust manifold where it bolts to the head.
 

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Discussion Starter #6
You have misunderstood the advice.
It's typically not the side of the head where the manifolds attach that needs to be machined, but the mating surface of the exhaust manifold where it bolts to the head.
I’m slow... sorry guys. :unsure:

You are suggesting machining the exhaust manifold flat? Leaving the head alone?
 

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Yes that's correct.
 

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Check to see if anything is warped first. It could have been loose bolts.
 

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Discussion Starter #9
Hello again gents. I had a local engine shop surface the manifold for me, he did indicate it and said it was out 0.020”. However upon trying to re-assemble it seems as though one of the pieces has slipped in what appears to be a pressed fit connection to the center part of the manifold. The bolt holes are likely 1/8” off on the two left side bolts. All other holes line up fine with the studs.

This is smelling like I should have bought a new manifold....

Any other suggestions at this point? I am concerned that even if did get the holes lined up the re-surfaced portion would now be out of flat again (assuming i wont get it to move in a perfect linear direction and will get somer rotation). Drilling out the holes seems like as poor idea...

Thanks for the input
 

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Are you meaning one of the side pieces? They are a loose fit in the center piece. They are supposed to move.
 

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It will be fine. They are not a press fit. They are loose when new.
 

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Discussion Starter #13
Thanks. Assume some heat will help me persuade them free again? Any other tips to break them free?
 

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Hammer.
 

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Be careful with the hammer.
Cast iron is brittle and will crack and chip from too heavy a blow.
It is always a good idea to apply indirect blows through a piece of wood that is struck with a hammer or use a rubber or plastic or rawhide mallet or a lead or copper hammer.
Get yourself a factory workshop manual and look up the torque specs for the manifolds.
Do NOT over-tighten the manifolds unless you want to create two problems when trying to fix one.
 
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