12-08-2014, 09:51 PM
Trust me, done it enough times to know, you have about 2-3 chances with bolts before the head is either scrap or requires helicoiling.
The threads are not designed to have the manifolds hang off them whilst you tighten against the threads in the ally head. This is precisely why early XUD9s have bolts and later ones have studs. You cannot tighten the allen bolts to the point the gasket is well sealed without damaging the threads - the turning and tightening action just destroys the incredibly soft aluminium.
Think about putting a self tapper into a soft wall - once it's tight, it's fine - you can actually put a serious amount of force on it - try tightening that little bit more, you'll just pull everything out of the wall and be left with a hole because the wall is weak.
The threads are not designed to have the manifolds hang off them whilst you tighten against the threads in the ally head. This is precisely why early XUD9s have bolts and later ones have studs. You cannot tighten the allen bolts to the point the gasket is well sealed without damaging the threads - the turning and tightening action just destroys the incredibly soft aluminium.
Think about putting a self tapper into a soft wall - once it's tight, it's fine - you can actually put a serious amount of force on it - try tightening that little bit more, you'll just pull everything out of the wall and be left with a hole because the wall is weak.
