I got ****ed...durability of helicoils?

[AmoebAssassin]

Long story short, I got ****ed by the dude i got my engine off of. He went impact wrench happy on the flywheel bolts while removing them, and I guess the flywheel cocked when the last bolt was coming out, and the bolt mangled all the threads in the crank.

So here I am with an SR20 with one of the flywheel holes in the crank stripped. Meaning no thread in the crank in one of the flywheel holes.

My question is:

Are helicoils safe in this application? Are there any alternatives?

Thanks,Neel

[virus77]

helicoil should be fine, since there are so many other bolts its not the only load bearing one. Or you can retap slightly bigger and use a new bolt, I dont know if this will throw off the rotating assembly or not though, I doubt it but its something to consider.

Also if the threads are slightly screwed you might get away with using a thread chaser and saving those threads.

[srpowered240sx]

my vote is tapping to the next size and using a bigger bolt. but if your worried about the weight, get creative, weigh both bolts and file off all you can to get closer to even. take into account the missing sections of crank. i dont know, maybe its too early to be thinking.

[nzmoman]

talk to a mechanic first and ask about the reliability of helicoils. I think they may be strong enough because of their design, but you should ask a dealerships master mechanic, they should be able to tell you cause its to risky asking that kind of question on here

[karmakaze]

I would think that a helicoil would hold. however, i would not risk it. retap all the holes to a slightly larger size so that the balance is not messed up.

[ser2102]

you just gotta retap the one directly across from it. if the crank has 6 bolts, you only need to do two of them to be balanced.

[AmoebAssassin]

I went with these, they look a lot beefier than helicoils and are less likely to screw up my balance (replacing solid steel with solid steel rather than coiled spring steel):

http://www.timesert.com

They'll be in on monday. Hopefully everything will go well.

[karmakaze]

i forgot about those. they work pretty damned well too.

[AmoebAssassin]

It's been two months since I time-serted two of the crank bolts, and the car runs great, the crank bolts haven't failed. I'd reccomend the time-serts over the helicoils for high-stress areas.
Modified by AmoebAssassin at 7:47 PM 11/1/2006

[sr20-thoj]

darn if only i new about them timeserts earlier.. i used the helicoils and it didnt work all that great..

[sil8y-X]

Helicoils would be fine. I've used them in camshaft bearing cap threads without any problems. Only thing I would be wary about when using a helicoil is when using a big bolt. Say, a harmonic balancer bolt.

[RyanAwesome]

im a professional technician. i've helicoiled stripped bolts for front brake caliper mounts on a few 996 carreras and one 997. a proper helicoil is just as strong or stronger as the originial thread, and it wont throw off the rotating assembly. my .02 for what its worth