Help! Stripped Block Thread AND Broken Bolt

[Key]

I first want to say this is my first post to the forum but I have been using the forum for a few months now. Its an amazing tool for information and I hope it can help me again.

Problem: Broken Head bolt in Engine Block AND stripped threads in block for another head bolt.

Engine: 1987 Evinrude 150HP

I was installing a new head gasket and disaster struck TWICE! I was tightening down the head bolts in the proper order and going up in 2.5 ft/lb increments on my torque wrench with hopes of torquing the head bolts down to 20 ft/lbs. What I thought was the "click" from the torque wrench ended up being a broken head bolt that broke at slightly less than 15 ft/lbs within the engine block. I didn't realize it was a broken bolt and on my next head bolt, the bolt stripped the engine block threads at 15 ft/lbs.

When I realized that one head bolt stripped the threads on my engine block I nearly passed out....I decided to back off the other bolts and assess the situation and that's when I realized another bolt had broken off, which I mistakingly thought was the click of the torque wrench. That's when I had a heart attack. My 6 year old son was helping me and that's when he asked, "Dad why are your hands shaking?"

My questions to the forum:

Can I insert a Heli-Coil or equivalent insert into the stripped block threads?
Will a Heli-Coil be able to support 20 ft/lbs?
How do I remove the broken bolt?
Is my engine block a paper weight now?...if not.....
Will a Boat mechanic be able to fix this or should I call a machinist?

Please Help!

 

[ezeke]

Re: Help! Stripped Block Thread AND Broken Bolt

Use a machinist if you are not completely comfortable. I would recommend that you tap to the next size (which would be metric) rather than use any kind of insert.

Be sure to chase the bolt holes before you torque your headbolts or debris at the bottom can prevent the bolt from seating properly.

 

[F_R]

Re: Help! Stripped Block Thread AND Broken Bolt

Since you broke them while going in, we know that they aren't seized and should come out easy. Personally, I despise "easy-outs", but in this case they should take the broken bolt out with no trouble. That's my reccommendation: drill the broken bolt ON CENTER!!, and remove it with an easy-out. No heli coil or tapping necessary.

As for the stripped threads, install a heli-coil. Yes it is a perfectly satisfactory fix.

If you don't feel confident doing it yourself get an outboard shop or automotive machine shop to do it. Shouldn't cost much, especially considering what's at risk.

Get the calibration of that torque wrench checked!!!! Those bolts shouldn't have broken or stripped at 15.

 

[rjezuit]

Re: Help! Stripped Block Thread AND Broken Bolt

I concur. I would do the helicoil before going to a larger bolt.
There is no way 15 ft# should break or strip head bolts. Rick