Are L26 exhaust manifolds prone to warping.

[Rusty1]

Hi guys, I recently bought a 260z 2+2 (the +2 is because I have +2 children). The car is original and the engine has been reconditioned.

There is a slight exhaust leak at the rear of the manifold and the rear stud is missing from the head. My mechanic thinks that a previous owner may have removed the stud to fit the manifold back on as it is possibly warped out of shape.

Before I pull everything apart does anybody know if this is a common fault with the L26?

Also can any Oz members adivse, is $150 au too much to pay for a set of second hand extractors.

[LanceM]

I think the broken rear stud is a common problem on many L series engines, my is broke, gone, but no leak.

[2ManyZs]

More likely the previous owner overtightened it and broke the stud.

The studs have a bad habit of breaking like that if they are overtightened one time to many.

It could be a difficult job getting the stud out depending on how much is protruding from the head. You have to be very careful if you have to drill it out of the aluminum head, one slip and you may end up putting a heli-coil in it to repair it properly.

Most people never replace the manifold studs over their time of owning the car, so they are very susceptible to breaking off.

[Zedrally]

Common problem, I've got the same on the 260.

Reason being the manifold developes a warp [very slight] but enough to cause a leak.

The solution is to use silicone gasket stuff [it's orange, can't remember the name].

This should be applied on the gasket faces.

You could try applying it around the offending area without undoing the manifold.

Let me know how you go as it might be an easy fix for a problem that I have.

[Rusty1]

Thanks Mike,

I will try it and see how it goes, although I will probably try to replace the broken stud at some stage.