why did my exhaust studs snap?

[peteinjp]

I posted about a possible rod knock a while back. The noise occured only at certain rpms under full load. Well it turned out to be 2 broken exhaust studs ( think.) I have a supersprint header and the fit is so so but seems ok after a bunch of work here and there. I wonder if snapped studs is a non occurance with the stock manifold? The nuts may have just come loose with vibration and then snapped? The header is well supported at the rear of the tranny. Ideas and prior experience welcome don't want to be stranded again anytime soon (i.e. every 15,000 miles.)

[monkeystripe]

are you running a resonator? Because if you aren't you may have picked up a harmonic resonance in the exhaust sytem, which can shatter just about anything in the exhaust system. However if the nuts were loose it could have very possibly just rattled around enough to snap the bolts.

[c.d.iesel]

because.....the header mounting holes were not fitting over the 8 studs

tension free. The holes on the header flange needed to be filed so the header fit over ALL the studs with no contact to any of the flange holes.

Custom fitting is required for trouble free service.

New studs installed in dry/clean holes secured with blue thread locker, and using 'correct' self-locking copper exhaust nuts with flanges (no washer is needed if the nut has a flange). If the studs are under side stress because the header was 'forced on" - then you will have the failure you describe.

good luck