hey all! i have a 63 buick special with the 215 2 barrel. i pulled my intake to clean/inspect underneath. i put the intake back on with a new valley pan/oil gasket. i properly torqued to specs. the car ran fine. the next day i re-torqued and the bolt torque had dropped from 30 lb to 15 lb. i tightened them again to 30 and the next day they were once again at 15 lbs! i have done this 4 times. when i torque these bolts and spray carb cleaner around manifold it is sealed tight. the car then runs fine for a while then it starts to stumble. i then spray around manifold to find it is once again sucking air! what is this problem? do i need new bolts? should i use lock-tight? could i have other issues? thanks for any help. keith
My guess is that with the aluminum heads, the threads are about to strip out in the head where the intake bolts go in. The 215 and 300 heads are famous for threads stripping out.
I know that You're probably not going to want to hear this, but it might be time to put heli-coils in the heads. Check 1st with someone who knows the motor better than I to see if there are any thin wall areas in the head where a threaded insert is NOT a good idea. I wouldn't think that it would be a problem on such an early head with ample "meat", but check 1st. Jeff
It can be done. You might as well head down to the parts store and buy a box of 3/8 coarse thread heli-coils, the heli-coil tap, and the insert tool. Go on and do all of them while you are at it--I made the mistake of just fixing the stripped ones before and had to go back and do the rest a few weeks later. Unless you find some of the extra long heli-coils, it will take two per threaded hole since the aluminum heads have a deep hole so the bolts have lots of thread engagement.
