stripped head bolt hole!!

[sc2dave]

while starting to disassemble the engine, i noticed that one of the head bolts came off with probably 10 lbs of twist. All others were hard. and i also noticed that this one screw had course threads and looked like it came from a hardware store!! Anyways, can i heli-coil the block threads and be alright? 86 22r .Also, are the bolts m12 x1.25mm? can i reuse bolts?

[dopeassjackson]

find a new block or get on helicoils web site and see if you can tq them to the correct pressure for a head bolt. not sure what size the bolts are but dont reuse them.

[kustomyoung]

I heli-coiled the head bolts on an old flat bottom boat engine after using a friends screwed up torque wrench that pulled 3 threads out of the block. This was a 350 Chev that was putting out decent power and it held. Like a lot of things we deal with, maybe not the best idea and probably a little bit of a gamble, but it worked fine until I sold the boat. If it's just one, I'd probably feel comfortable doing it. Those bolts are only torqued to like 60lbs anyway if I remember right.

[Erick561]

Be extra precise the first time or else you need a new block. I used a bolt for my water pump that was 1 thread too long in my timing chain cover (aluminum), didn't realize it and went to torque it, stripped it, so drilled and tapped it, held up fine. I've heard of people heli coiling these blocks, as long as you get the proper torque you're good to go

[BRreddog]

I have an '86 that I built up as a stroker with LCE parts. The head bolt holes are heli-coiled and I went back with ARP studs. Just be sure to use a square or have a machine shop drill out the holes. They must be perfectly straight or you will have trouble getting the head on the block. Don't ask how I know. I have over 50k on the motor with no head gasket issues. And yes the holes are 12x1.25m

[Myanarchy]

its a low compression tractor motor, helicoil it and forget it

[forbergler]

Heli-coils are typically stronger than the original thread. The have more surface area.

[C Luna Tech]

Dude I bought a heli coil kit it was $90 that was 12 X 1.25 and drilled and taped myself it was easy. You don't need a machine shop to do it as long as you can drill pretty straight. If you never done one before just read the instructions on the box.

[techman]

If you are at the beginning of your build and have not had any work done to your block, I would just go find a new one. For the $90 that the heli coil will cost I think you could come up with two good blocks to rebuild. Expessialy knowing that somone previously put a course thread hardware store bolt in there.

[Erick561]

Originally Posted by techman

If you are at the beginning of your build and have not had any work done to your block, I would just go find a new one. For the $90 that the heli coil will cost I think you could come up with two good blocks to rebuild. Expessialy knowing that somone previously put a course thread hardware store bolt in there.

Hmm yeah who knows what else was done by that backyard mechanic...pretty shotty if you ask me. Although heli coil's are good, why bother rebuilding that engine when you could find one with lower miles and just throw it in lol

[mauidogg]

I vote time-sert over heli coil..........just my .02

[C Luna Tech]

Whatever is the cheapest.

[sc2dave]

I find heli-coils everywhere for 30. fr the kit. where did you buy them for 90.00??? I'm preferring to go with a timesert,but no one's heard of them around her. A shop will timesert it for 40.00, but i have to find a way to get the truck over there. I'm not rebuilding the engine, just the head.

[trkklr77]

ive used heils on a 22block before, held up fine, just dont puthe heil at the bottom of the hole. leave it up just below the head surface, other wise the insert tool will allow you to go in all the way but the bolt wont fit because of the tapper in the thread tap.

[C Luna Tech]

I've heard of keenserts. They say they are stronger than heli coils but I don't know the difference. My kit came with a lot of coils and the tool and 2 taps. Hayward tool was the only place I could find it at the time. Where are you at I could heli coil it for you if you are close for $60. You can leave your truck at your house. No tow charge.

[subliminaltrips]

Originally Posted by BRreddog

I have an '86 that I built up as a stroker with LCE parts. The head bolt holes are heli-coiled and I went back with ARP studs. Just be sure to use a square or have a machine shop drill out the holes. They must be perfectly straight or you will have trouble getting the head on the block. Don't ask how I know. I have over 50k on the motor with no head gasket issues. And yes the holes are 12x1.25m

i used stock bolts with helicoils , never had a problem after 45k all of the holes are heli coiled.and i drilled them out myself with an 18v ryobi, no problem getiing the head on and no torque issues.

[YOUNG BEN]

As to re-using your head bolts, if they are in good shape, no rust/ corrosion, and the threads are good you can re-use them as many times as you want. Thats per the advice from a guy who own a reputable shop building toyota motors for 20+ years.

[boggerunner]

i did the helicoil fix on my block also. ive got the kit minus 1 helicoil if u want to save some$$

[sc2dave]

Originally Posted by boggerunner

i did the helicoil fix on my block also. ive got the kit minus 1 helicoil if u want to save some$$

how much? also, what is the drill size to use for m12 x 1.25?