When putting one head on my 6.5 rebuild for my truck I lost the threads in the block on two holes. Will it be okay to run a helicoil in this? I've done it on some of the engines for my drag car with no issues. What about the new bolts will it be okay to use them or should I go with another set? Headgasket should be okay also?

Remember to seal the heli-coil and the bolt! There's coolant down below! The gasket should be ok. How did you lose the threads? How did you discover it? Fred

I am assuming that the threads you pulled were in the 2 holes that have the line up sleeves in them. This happened to me 2 years ago when rebuilding my daughters 86 6.2 blazer. My solution was to drill the threads out so that I could tap the hole to 3/4-10. Then I machined a 3/4 bolt to have a hole in the center that was tapped for the 12mm head bolt thread and turned down the portion that would stick out above the deck height to match the diameter of the line up dowels. install the newly made piece into the block with lots of red loctite and then stake it with a sharp center punch to help hold it. Give the loctite 24 hours to set up fully and put it together. This set up has been working for over 30,000 miles with no problems and is stronger than the original threads. :grd:

one of the bolts had the sleeve in it for the head, the other right above it. I'm gonna try the helicoil first. So I guess I should set it in locktite right? I still don't know why they pulled but if another does I will have the parts to fix it this time. Would you try to reuse the head bolts or get another set? The gasket should be fine I believe.

ANy Chance you could post some pictures of the hole you talking about?

A new gasket would be cheap insurance if its already been torqued enough to pull the threads on the bolt hole, better than ripping it down again IMO.

When I had this happen, I re-used the head bolts and the head gaskets. The head gaskets take heat to bond. The new bolts should be fine also as they haven't been subjected to running temps. I have had 0 problems on this engine since. I understand fully why the threads can pull on the holes with the line up sleeves, but I am baffled on how the threads would pull on the full depth hole:confused: The holes with the sleeve in them only have about half of the threads of the other holes. Did you hear a pop when you were torqueing the head bolts?

no pop, just felt it give on the 50ftlb mark, then backed it out checked bolt out and retried it again. When I went to the last 90 mark it gave big. Threads came out with the bolt. Next hole done the same thing. Wish I had a way to get pictures to post not to good on this computer stuff. I'm using the thick head gaskets on this engine, could that be a issue or maybe block been subject to overheating before I got it? Deck and everything checked out good on it. Do you guess think studs would be a benifit on this block now or try the bolts?

I'd always look at using studs but might require more work to use them now.

Wife got the heli coil kit for me, got the inserts put in let the locktite sit up good. Put the head back on that side and everything went the way it should have in the begining. Put the other side on as normal. thanks for the input on this.