Brass washers/nuts on exhaust manifold studs

[frmhrt]

Have seen several posts with recommendations to use brass nuts and/or brass flat washers on exhaust manifold studs.

No indications given for the reason to do this. Is this to reduce leaks or to reduce corrosion or? Any input?

Also, if I use hi strength bolts for the exhaust manifolds, shall I use flat washers/brass flat washers and why?

thx

alan

[texas webb]

Brass tends to not corrode like ferrus metal.

[J Franklin]

You will be able to remove them without snapping the studs off! I always use washers where they are called for I don't know about your car. I always use Locktite blue even with all washers.

[cas3]

i have to disagree with J franklin, exhaust manifolds are like head gaskets, they must be retorqued after some heat and cool cycles. brass is old school, plain steel works fine, just use high temp antiseize and you're done

[J Franklin]

I agree with the use of anti-seize. no matter which nuts are used on the exhaust manifold. brassl nuts can be re-torqued as well as steel. The Locktite reference is for standard fastener applications. Sorry for any confusion.

[flatheadmurre]

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The studs still corrode so most of the time its just to break the nut and clean up the thread.
The ideal would be a stainless stud and a brass nut no risk the nut seize on the stud that way and no corrosion.

[Mac VP]

We stock the steel studs and the brass hex nuts. Because of the heat and moisture conditions, you’ll never have to worry about the brass rusting to the steel studs. Never seize with steel nuts would be the next best option but I’m not sure how long this combination will work over a long time span.

[JM 35 Sedan]

I picked up a complete '37 engine ~ 20 yrs ago that was removed from a sedan being hotroded. The exhaust manifold nuts and washers were all brass. I always wondered if this was factory installed hardware or if a previous owned had added these

[blucar]

Brass nuts on the manifold head pipes minimizes the possibility that the head pipe nut (s) will come loose. The brass nuts expand/contract at a different rate than steel, therefore they are more stable. Regular brass exhaust nuts are thicker than steel, by approximately 1/8", therefore they get a better purchase on the stud.
Good brass exhaust nuts are very hard to find, I know that Dorman use to stock them in their nut/bolt assortment cabinet.
Steel flat washers work just fine, in lieu of brass.

[19Fordy]

Over time due to the extreme heat and and cooling lock washers can crack and break resulting in an exhaust leak. Use flat washers, brass nuts and anti-seize to ensure easier removal. No problems since installed in 1999.

[frmhrt]

thank you all, great information!