head bolt threads

[odee]

While putting the first head on my new 6.5 I have run into a problem. I pulled the threads on two of the head bolts from the block. I have a helicoil kit on the way, will this be a good way to repair the block? Will the bolts and head gasket be okay to reuse since the engine was never fired?

[More Power]

Do you have any idea why the threads pulled?

I'd use new bolts/gaskets, especially if this problem occurred during the final torque to yield tightening of the bolts.

I'w probably use a threaded insert instead of heli-coils. However, GM uses them in the aluminum bellhousing adapter on the Duramax. Haven't heard of a big problem, but the bellhousing bolt torque and starter bolt torque is quite a bit less than head bolts.

MP

[rjschoolcraft]

If properly installed, a helicoil insert should work fine. The advantage of these over other threaded inserts is less material removal is required to install them, so you don't weaken the damaged part as much. However, they can be screwed up. Be sure you follow the instructions carefully and adhere to their specifications for oversize of the original hole.

[odee]

thanks guys the helicoil kit should be here tommorow. I don't have a clue to why the threads pulled I used the same tap to clean the threads that I had used before. Should I get another tap? I'm gonna get another set of bolts tommorow so I can try to get the heads on this engine.

[More Power]

Yes, double-check the tap thread size....

Should be 12mm x 1.75

MP

[odee]

tap was m12x1.75 same tap I had used before got tape marking it for that purpose. Wife just picked up my drill bit and the inserts and threadlocker for me today. Was gonna try it tonite but my friend is gone to church. Guess I will try it tommorow if I can get ahold of him to help. Do you guys think a set of studs will help out any?

[tom.mcinerney]

Not to be retarded, & second-guess , but was the tapped-hole/threaded-bore for the head bolts CLEAN to the bottom? The service manuals always stipulate to remove debris and fluid in the holes. Good Luck.