Exhaust Manifold Bolts

[Guest Chrisegg]

My 2.0ltr Pinto original exhaust manifold was fitted using M8 bolts, not studs. Following my fitting of the RH 4into1 stainless manifold I used M8 stainless cap head screws. The engine has never been run since a full rebuild, I'm still building the 2B, but I suddenly have begun to wonder if the cap heads will be OK given the differences in tensile strength of studs.

 

Views and advice gratefully received.

 

Regards

Chris

[Guest GeordieJim]

I was thinking of doing the same myself and couldn't foresee any problems. I guess studs just make lining up the exhaust easier. One problem I have found is that the RH 4-1 exhaust flange must be thinner than the original so you can't get the studs to tighten up enough (though I am sure that washers could soon sort this out).

 

My thoughts are that as long as you use high tensile steel bolts you should be fine (and as long as they're the correct length - which may be an issue, though again, I am sure washers could sort this out).

[Guest paul thompson]

Under the brass nuts that were on my exhaust manifold were large (thick) steel washers which I used on the RHE manifold and had no problems, did anyone else have these thick washers or am I an unusual case? Any way it has run and works fine with no leaks at the manifold.

[Guest TerryBarry]

Mine also had the thick washers on the studs except the front two where the lifting eye was fitted.

Terry

[Big Jim]

I personally wouldn't use bolts into the cylinder head, it's only cast, and keep screwing them in and out will soon wear the threads loose. I personally went to Uncle Henry's and got the genuine studs, nuts, & washers. the nuts & washers are special ones for the job.

[Guest Takumi]

Bolts are a good idea, dont worry about the thread disapearing, how often do you take your manifold of-and put it back on again..

 

just put some acrylate ( same as QuickBond superglue) thread lock onto your bolts, they will work loose much easier than studs, but im sure they wont.

 

 

gd job.

 

 

tak.

[Longboarder]

The thread depth of the exhaust stud holes is only about 14mm and they are not all equal. Add compressed thickness of gasket and manifold flange less thickness of any washers used and wonder if the bolts are the right length, too long or too short. The three lower rear stud holes also go into the holes for the head bolts and too long a bolt may lock or damage a stretch cylinderhead bolt leading to failure when trying to remove the head next time.

Uncle Henry chose studs of specific tensile strength on which he machined the correct length thread to get the right mechanical properties to save us all from having to think it out and get it wrong. If it ain't broke don't fix it.

 

Nigel