Exhaust Manifold Nut size

Brendan_91XJ said:

Does any one know the size and thread pitch of the exhaust manifold nut.
There is one up front and another in the rear. Just found one missing.
'91 4.0

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5-90 said:

3/8"-24. The bowl-shaped washer isn't a "spring" washer per se - it's too thick. It is, however, a load-spreading washer to help with clamping forces, so you do want to keep it.

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RichP said:

I thought the same thing, it does both I think.
Next time you put one on and torque to I think 27ftlbs watch it 'compress', or maybe 'deflect' would be a better word. I would like to find a cheaper source though, those bastards are pricey.

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5-90 said:

It does deflect a bit, but not overmuch.

Next time I do a manifold job, I've got a bagful of 3/8" Belleville spring washers and some more silicon bronze screws to use. I know the cuprous alloys work well (I used them before,) but I didn't have the Bellevilles to try then.

I'd think the Bellevilles will work a bit better, since there is more "spring" to them than to the heavy OEM washers. I'd have to stack a few - probably in parallel - to get good clamping, but that's doable. I've got plenty...

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RichP said:

What about heat ?

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