Hi,

When I was fitting a replacement head to my B18 last year, I found after fitting it that one of the threads for the manifold studs had been enlarged at one stage to the point that a normal stud wouldn't fit. It seemed to be threaded and I found that a piece of 3/8" (I think) threaded bar would fit and grip, so being in a hurry, I left it like that. It's the exhaust manifold stud nearest the firewall and for one reason or another the threaded bar has decided not to grip any more so it looks like its time to fix it properly. I'd fitted a four branch manifold which seems to generate a lot more heat in the engine bay than the standard one and I think that the piece of threaded bar was heating more than was good for it.

I'd prefer not to have to take the head off again so I'm looking for a solution that can be applied in the small space available. I've had a look around and I think that a helicoil insert might be the answer. I'm hoping that the existing hole is large enough for the insert without drilling which would save taking off the head. Is it the way to go or is there a better solution? If its the right solution, does anyone know the size (width) of a standard manifold stud and whether its AF or metric so that I can be sure of buying the right kit?


Thanks,

Aidan
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1967 131, 1969 131, 1973 Triumph GT6