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Gasket, Inlet Manifold to Exhaust Manifold BJ8

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AUSMHLY

AUSMHLY

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What is the purpose of having a gasket between the Inlet Manifold and the Exhaust Manifold on the BJ8, being both manifolds have sealed surfaces?
IMG_2851.jpg
 
Not certain but I think it's to allow for the slight movement caused by the different expansion rates of cast iron and aluminum, same reason there is a metal side to the manifold to head gasket.
 
red57 said:
Not certain but I think it's to allow for the slight movement caused by the different expansion rates of cast iron and aluminum, same reason there is a metal side to the manifold to head gasket.
Click to expand...

The engine gasket has fiber sandwiched between metal. I'll assume metal exterior for heat and the purpose of the gasket is to seal any air leakage.
The gasket that's between the Inlet/Exhaust manifolds has metal sandwiched between fiber. Why is it the reverse of the engine gasket?
Interesting that both the Inlet and Exhaust manifolds have a square impression (where the gasket goes) that seems to serve no purpose.
 
I think it provides some controlled heat transfer from the exhaust to intake to keep the fuel from condensing in the intake manifold.
 
John Turney said:
I think it provides some controlled heat transfer from the exhaust to intake to keep the fuel from condensing in the intake manifold.
Click to expand...

This (at least, it's the best explanation). The gasket in the OP's photo is too thin, they used to be about a quarter inch think and appeared to be made of a material that would moderate heat transfer. No idea why they now sell a thin one that won't fill the gap (unless you stack a few). At any rate, you can probably get away without them, they usually degrade and disappear eventually anyway. Don't torque the through-bolts until you've torqued the manifolds down, and then just enough to keep the bolts from working loose; I think the only reason they're there is to keep the gaskets in place.
 
Bob_Spidell said:
This (at least, it's the best explanation). The gasket in the OP's photo is too thin, they used to be about a quarter inch think and appeared to be made of a material that would moderate heat transfer. No idea why they now sell a thin one that won't fill the gap (unless you stack a few). At any rate, you can probably get away without them, they usually degrade and disappear eventually anyway. Don't torque the through-bolts until you've torqued the manifolds down, and then just enough to keep the bolts from working loose; I think the only reason they're there is to keep the gaskets in place.
Click to expand...

New Gasket in photo is from Moss. Are there torque setting for both manifolds?
 
Below are the required torques from the manual. Divide lb in by 12 for lb ft.

If one insists on torquing everything, suggest downloading a torque values chart from google images and using the standard values for that size thread.

IMO using a torque wrench where not needed is overkill - exception: captive nuts such as front shocks and anti-roll bar mounts.

FWIW, the manifold studs are 3/8"-24

screenshot.2021.jpg


Wrench sizes and their bolt sizes:
7/16" - 1/4"
1/2" - 5/16"
9/16" - 3/8"
5/8" - 7/16"
 
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