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A while back, I bought some later model exhaust manifolds. I think they came off an 84-86 Euro motor. Anyhow, it came with a few nice thick washers like the one below.
Are these the factory washers I should be using? If so, any one know where I might buy a new set of these? The local hardware store just has the normal flat ones.
Well, not having the proper washers and in a hurry, I bolted the manifolds on with new gaskets as seen below. The engine is still on an engine stand.
I just used a single grade 8 flat washer and the new copper/brass crush washers that came with the manifolds. I put some never sieze on the studs and tightened it up, but did not torque them or anything.
Is this good enough? Or should I try and find the proper fat washers and start over? I hate the idea of getting an exhaust leak and trying to access these nuts from underneath. I would also have to buy new crush washers, I would assume. What would you guys do? Thanks.
Those are the correct thick factory washers, 928 111 181 00, used 78-95.
I'm not sure what the theory is behind the use of the thick washers, but if you google thick washers exhaust, you pick up plenty of discussions about them.
Mcmaster has really thick M8 washers in SS or black oxide, the latter are inexpensive- 50 cents a pop.
Those are the correct thick factory washers, 928 111 181 00, used 78-95.
I'm not sure what the theory is behind the use of the thick washers, but if you google thick washers exhaust, you pick up plenty of discussions about them.
Mcmaster has really thick M8 washers in SS or black oxide, the latter are inexpensive- 50 cents a pop.
The reason it needs thicker washer is to bridge the slot in the flange without deforming, and retain clamping force on the smaller contact patches even after many heat cycles. If you use standard washers, they'll do the job for a while, but they'll gradually deform over time and you'll lose some clamping force, and be likely to get leaks.
Crush washers are ... washers. They don't have a thread pitch. They have an inner and outer diameter and material.
Your picture shows copper exhaust nuts. They do have a pitch. I wouldn't use those on the engine-side of the manifold. I do use them on the cat-side of the manifold.
The exhaust manifold does have a crush washer that's silver dollar-sized.
Here, I'll stick my neck out too far: Anytime you run into a stud on the outside of a 928 motor, it's M8x1.25. Except for the M6 stud on an L-jet air guide, 80-84.
Crush washers are ... washers. They don't have a thread pitch. They have an inner and outer diameter and material.
Your picture shows copper exhaust nuts. They do have a pitch. I wouldn't use those on the engine-side of the manifold. I do use them on the cat-side of the manifold.
The exhaust manifold does have a crush washer that's silver dollar-sized.
You are correct. I meant to say nuts, not washers. I saw a set for the 928 on Ebay a while back, but now can't find them. Looking elsewhere to try and find same type. btw, good idea, that tool looks handy. Just bought me one, just now!
05-03-2017, 05:44 PM
Exhaust Manifold Bolt Down Question
Gonna redo it with the proper washers.
