Exhaust Manifold Bolts
Exhaust Manifold Bolts
(OP)
I am looking for a different bolt material to secure a guard to an cast iron exhaust manifold. The current grade 8 steel fasteners snap off when you turn them out, or will loosen and fall out. Manifold temps are about 600degF. Any recomendations for something better?
I see 309/310 as well as 316/317 Stainless Steel being recommend.
I see 309/310 as well as 316/317 Stainless Steel being recommend.





RE: Exhaust Manifold Bolts
ISTR that zinc embrittles steel of all kinds at the high temperatures to be expected in exhaust manifolds and abused clutches.
Instead, I use uncoated/black/plain fasteners and completely cover them with Never-Seez.
Mike Halloran
Pembroke Pines, FL, USA
RE: Exhaust Manifold Bolts
RE: Exhaust Manifold Bolts
The best option would be to install A286 cres key-locked studs in your manifold and use silver plated self-locking cres jet nuts to attach the heat shield.
RE: Exhaust Manifold Bolts
Why were the grade 8 fasteners used?
RE: Exhaust Manifold Bolts
This is a stock application. Its a industrial diesel engine on a drill rig.
RE: Exhaust Manifold Bolts
Offshore?
Did the yellow zinc stock bolts fail the same way as the gradeeightz?
Is there room to use longer bolts with spacers so clamp length to diameter gets up around 8 to 1 ?
RE: Exhaust Manifold Bolts
I have used 3.5" long spacers on a 5/16" bolt. That give you an L/D ratio of 11.2:1.
Thanks Tbuelna.