brjason

After having to take a break from what has now become a 3-month head gasket replacement (and counting), I felt like I was really on a roll today. I just about had both camshafts back in and was tightening down the bearing bolts and one bolt on each head is completely stripped now.

I definitely did not overtighten them... I was using a torque wrench and it never felt like I was even close to the 12 foot-pounds I needed, but the bolts just kept turning and when I removed them to examine, there were lovely little spirals of aluminum wound around them.

So, my question is: now what? As I'm sure you can imagine, I am particularly interested in solutions that don't require me to take the heads back off...

I've got to get this damn thing finished... my wife is wondering more and more loudly why we didn't take it to a shop (for $4,500).


Jason

89934runr

Heli-coils, and take your time prepping the area for some minor drilling. East fix if you do it right.

GT88Yota

I've had similar problems with aluminum heads, in fact last weekend I was torqueing down the exhaust manifold I pulled 3 studs out so I had to take it all apart and sent it BACK to the machine shop. It turns out, when you're using a torque wrench very close to the limits of its range (I'm assuming you have a standard 0-150ftlbs) it can be inaccurate. Also, torque wrenches can become uncalibrated and give false readings.

As far as fixing it, if you or someone you know is EXTREMELY good with a hand drill you can drill the holes out and heli-coil them but you'd be better of taking it to a machine shop, having the fix the holes and install the cams for you. If that is possible with your engine, I don't know as I only have experience with the 22re as far as 'Yota's go.

Also, $4,500 for head gasket replacement is ludicrous. You can swap in a 350 for that price.

Ron521

If installed properly, heli-coils will provide stronger theads than the original material. Used to be required on all high performance VW engines, otherwise cylinder studs would pull right out of the block. Also very common on motorcycles.

Ganoid

I learned the same lesson using a clicker type Inch/pound TQ wrench on valve cover bolts. I tossed the TQ wrench and just went by experience. The other option is to use an older beam style TQ wrench.


On something like this you may want to skip the helicoil and use whats called a timesert

20005spd

dont mean to but in guys but ganoid what problems did u have with doa. i couldnt help but notice ur sig. i always thought lcengineering was a better company than them, what do u think.

20005spd

oh ya i also had a problem using a tc wrench while tighening exhaust manifold studs on a 22r i had. spec was 33ftlbs if i remember correctly and the head did not want to hear it.
but what i did to fix my problem was of course a heli coil. i also used it in a 22re i had when i put a header on it the same stud stripped the one nearest to the firewall.
after doing both of those i realized aluminum from the 80's dosent need much to be overtightened. with that experience what i would do now is set a newly calibrated tq wrench to less then what is required or even just use my hands, after a while youll seem to know when your about to go to far.

brjason

Thanks guys,

So as far as tightening by hand or whatever... what's the goal? Should they just be snug? Is there any other way to describe how tight they should be?

I used a brand new Craftsman clicker torque wrench 10-80 foot pounds (or was it 10-150? I can't quite remember right now), so it was definitely at the bottom end of its torque range.

So are torque wrenches really useless or "dangerous" to use at such low torque specs? Cause if so, I'm gonna take back the $60 wrench I bought just for the purpose of stripping these threads...

Jason

brjason

Ganoid (and everybody): What advantages/disadvantages do timeserts have compared to helicoils?

Thanks,
Jason

20005spd

ok i used a $100 craftsmen around 20-200 ftlbs. it was the first time i used it and it stripped the head. it is a lil large for that application.
as far as the hand torquing goes, i was only saying once youve done some work on cars and aluminum heads you can tell how tight your getting. this would only work if your tightening things with low torque specs like cams manifolds etc. cuz the torque spec is around 15 or 25 or 30ftlbs higher than that it is tough to tell and you might make things worse with just your hands.
aluminum is very easy to strip, so when your at the factory torque spec on motors 9 10 11 15 yr old its gonna be cutting it close.
you could just set the torque wrench a bit lower like 5ftlbs to be safe.
im sure people will argue against what i say cuz thats what happens everytime someone posts so take this info and do what you will. it works for me at work everyday.

brjason

The spec torque for these was 12 ft lbs, and I set the 10-75 wrench at 12. What I'm hearing is that at the low end the wrench may not be completely accurate... and that was said even for a wrench that would go down to 0.

So what can I do if
a) there is no torque wrench that I can trust to be accurate at that low of torque
and
b) hand tightening isn't safe?

I know these different opinions have come from different people, and perhaps the people who believe a) disagree with b) and vice versa. Does anyone have any good overall suggestions considering the difference of opinions about this?

(and btw, for the record, it was a $75 wrench on sale for $60... slightly higher quality than it might have seemed.)

Would I be better of exchanging this click type for a beam type that goes down to 0?

Thanks,
Jason

Trumpfan

the top and bottom 15% of the torque wrenches scale is not that accurate. I'm a aircraft mechanic and use snap on wrenches that cost far more than 60 bucks and those can't be trusted in those ranges. When choosing a wrench for 12 ft lbs try to find one that has the range your looking for in the middle of the scale, for 12 ft lbs you might have to go to a inch lb wrench. IE 12 ft lbs = 144 in lbs. a 50 to 250 in lb wrench would be perfect for your application. I'm almost positive you could find one cheap at NAPA or Sears.

Trumpfan

x2 on the helicoils, most of the threaded castings on magnesium housings on Pratt and GE engines are Helicoils from the factory or O/H shop, way strong if installed properly.

benwahballs

I had similar experience when tightening my bearing cap bolts. I was using a 1/2 " drive torque wrench to tighten them little ass bolts. Stupid, I know, but did not really expect to strip threads. Anyways, same thing happened to me, just kept turning and turning, removed bolt and seen aluminum threads on bolt. The kicker is it is one of the bearing cap bolt holes that have that metal "seat" above it, making heli-coil impossible (???). So, i put more washers on bolt, found that there the bolt would still catch the last threads in the hole that were not destroyed, and tightened it down as much as I dared to go. For remaining bolts, i just used a 3/8 drive ratchet and tightened them down good and snug. My recommendation to you is to remove heads and heli-coil. A pain in the ass, i know, but better than having major problems down the road. Good luck.

brjason

crap, I didn't even think of that... I haven't taken these back off since I discovered that I had stripped the holes, but I'm pretty sure at least one of the two is on one of the holes that have the seats.

What can I do, assuming that is true? What exactly are those seats for? Can I just remove the one or two I might need to if I have to?

Jason

benwahballs

The seats are on the two holes on either end of both heads (so four seats total for each head) if i remember correctly. I think they are just there so that the bearing caps sit properly on head and cam, but i could be wrong. I would suggest drilling right through them when you go to heli-coil, that way you might be left with the outside of the seats still, but they might just come off anyway. Im thinking your best bet would be to take the heads off, sorry to say, and send em to a machine shop. good luck, and let me know what u end up doing.

94 blkrunner

The same thing happened to me. I put a longer bolt in and got some to some good threads.

MonsterMaxx

I find helicoils (or any generic brand) to be quite easy to install. No reason whatsoever to take the head off and send it to a machine ship.
If you've pulled the threads out you probably don't even need to drill, just get the helicoil tap w/ a little cutting lube and have at it.
This is an easy fix with the right tap, some helicoils and an install tool.

I suggest a Recoil set from Travers Tool. It'll be about 35 bucks and will have everything you need. Recoil isn't the quality of install tool that helicoil is, but for the kind of use you'll put it to it'll be fine. I can't tell the difference between the two brands of insert other than the price.

brjason

Well, I tried 94 blkrunner's method, and it seems to have worked. I measured the depth of the hole with an awl, ran a tap down the holes to clean out the threads and confirm how far down the threads went, and found that the length of the untouched threads was about as far as the upper portion that had originally been engaged with the bolts.
So I got some long bolts and cut them to fit all the way down with some bolt cutters, then cleaned up those threads and put it all together.

I also got a hold of an inch-pound torque wrench and VERY CAREFULLY tightened everything down, with no problems.

Thanks for all the input everyone. At this point it looks like disaster has been averted, though we'll see what other threads I have to start here before the job is finished.

Jason

thook

Yeah, I ran into the same problem redoing my heads. Longer bolt with spacers...worked like a charm. I just didn't cut them.