Stripped head bolt threads!!! Resize or helicoli?

[ClassySoob]

Hey guys,

So I'm in the middle of a re-ring on my 97 2.2L, I was getting ready to reinstall the heads and a couple of my threads spun. I mounted the heads and went through the first step of tightening, which was 22 ft-lbs. When I started the second step of 51 ft-lbs, I barely started on the number one bolt and it spun. This happened on both side same #1 bolt. I was wonder which is a better repair, heli coli, or rethread to a bigger size like M12x1.25. I've searched around and can't really find the M11x1.25 thread repair kit besides pricey ones.

 

[Steptoe]

I called a thread repair guy who charged more than a kit was worth, but restored it to M11 and never had any more trouble. If I had bought a kit, it would have 18 years of dust on it now and likely lost for next time I needed it

[ClassySoob]

43 minutes ago, Steptoe said:

I called a thread repair guy who charged more than a kit was worth, but restored it to M11 and never had any more trouble. If I had bought a kit, it would have 18 years of dust on it now and likely lost for next time I needed it

I've thought about a shop, but like you said that's pretty pricey. I don't have alot of cash and need my car haha. I've done some fix a threads before, but never on a head bolt. I did some more searching and found the right size helicoli set for $40. So I think I might chance it

 

[idosubaru]

35 minutes ago, ClassySoob said:

I've thought about a shop, but like you said that's pretty pricey. I don't have alot of cash and need my car haha. I've done some fix a threads before, but never on a head bolt. I did some more searching and found the right size helicoli set for $40. So I think I might chance it

 

I've done lots of thread repair but never heads. I think timeserts are considered better quality for something as critical as head repair but i get it that $40 talks sometimes. 

https://www.subaruoutback.org/threads/repair-stripped-head-bolts-yourself-diy-timesert-repair.504785/

[DaveT]

I used a helicoil type thread repair on a EA82 head bolt.   Worked fine.  I used 2 inserts to get the length of engagement. 

11mm is a weird size so they were harder to find.

[FerGloyale]

You've got  DOHC head bolts from an EJ20g or EJ25D.  I made this mistake once years ago and it's excactly what happens.

Since the DOHC bolts are deeper in the heads, under the camshafts basically, they are too short and only engage about 4or 5 threads instead nearly 20. when used in the SOHC engines.

I will bet money on it.  Proper length head bolts won't strip that easily.  Unless maybe your Torque Wrench is WAAAY of calibration and you really put 100 lbs on it.

 

Now, you've got 2 striped holes though........And if it indeed is a result of too short bolts, you've still got a good amount of useable threads deeper in the holes.....not enough for the stock bolts.  They would only catch the threads on the very tip.......but, tell you what........7/16th fine thread all thread is so close to M11 that the threads match for about 2"

Cut the 7/16th fine thread (high grade) to length of the entire hole int the block +thickness of head+ an extra 1~1-1/2" and use nuts.  Viola!  redneck head studs.

If you drive those studs ALL the way to the bottom of the striped holes, they will hold.

My 2.2 in my wheeler is running this setup.  Been great for 5 years, probably 25k~35k miles so far.