Are the studs for the exhaust manifold installed finger tight, then copper plated lock nuts are torqued to spec.

I would think they should be torqued as any other fastener. They should not be loose.

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Steve Brotherton
Continental Imports
Gainesville FL
Bosch Master, ASE Master, L1
33 years MB technician

Steve is right. I install them double nutted...use plain nuts...and tighten to around 18 lbs ft.

Any that don't take the torque or are obviously stripped, get a SERT installed.

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The motor is out of the car. All studs have been removed, cleaned, have been run thru a die. Holes in heat are cleaned and have had tap run in to hole to clean.

18 ft. lbs seems like way to much. Are you sure? I can not seem to find a torque value for either the studs or the nuts in my workshop manual.

No need to torque the studs to spec, in my humble opinion.

The point of the torque specification is to ensure that the manifold is snugly held to the head, compressing the gasket properly, and so the nuts won't come loose. None of these factors come into play until the manifold is on. When you torque the nuts, you are also applying force to the threads in the head. In effect, torquing the nuts loads up the threads on both ends of the studs, at the nuts and at the head.

So, there is no need to torque the studs into the head. All it does is bottom out the studs into the hole, forcefully. All you need to do is make sure that the studs are fully engaged in the head.

If you want to fix the studs in place, then locktite them, after snugging them up reasonably, not to torque specs. But consider that you may need to get the studs out at some point. If clearance is a problem with the engine in the car, then you may want to remove them with the manifold in place. I would not use loctite. I think that finger-tight is good, as long as the studs go in all the way.

Andrew

That how I handled the install. Torquing each nut to 18 ft. lbs.