Author Topic: torque problems (Read 1093 times)

Jsmitty42 · « **on:** October 26, 2013, 08:03:54 pm »

ok so i torked all the head nuts down after a rebuild and then i started it a few times and went threw the heat cycles and one of the nuts just keeps spining and going down but wont tighten and i dont know what to do?

Dangerouspower · « **Reply #1 on:** October 26, 2013, 08:58:44 pm »

Look at the threads on the stud also look at the threads inside the nut. Something is stripped out.

Jsmitty42 · « **Reply #2 on:** October 26, 2013, 09:08:56 pm »

no every thing is good but when i am trying to tighten it the bolt is getting higher i think the bolt that is on the cylender for the head bolts is double sided threads

Dangerouspower · « **Reply #3 on:** October 26, 2013, 09:12:34 pm »

If the bolt is getting higher as you try tightening that means its stripped out in the cylinder, no worries. Easy fix just need to get it heli-coiled. Happened when I rebuilt my kx125.

Jsmitty42 · « **Reply #4 on:** October 26, 2013, 09:23:32 pm »

so do i need to take the head back off because i already had it torqued down and if i take it off wont i need a new gasket

Dangerouspower · « **Reply #5 on:** October 26, 2013, 10:24:49 pm »

Head definitely has to come off. Probably need to take cylinder off as well to get the tools in there to do it and when you blow the shaving out after retapping it I wouldn't trust just a rag covering things up and would want to do it way from the rest of the engine. Did you use OEM head gasket? Should be fine putting it back on..

Jsmitty42 · « **Reply #6 on:** October 27, 2013, 07:29:27 am »

yes i used oem head gasket so i can reuse it ?

Jsmitty42 · « **Reply #7 on:** October 27, 2013, 08:41:13 am »

no it was actually a moose gasket kit

Stpltn250r · « **Reply #8 on:** October 27, 2013, 08:50:50 am »

your going to need to remove the cylinder to heli-coil the head stud. and will need to get another head and base gasket.

Chuckie25 · « **Reply #9 on:** October 27, 2013, 09:47:27 am »

I had this problem with 2 of my studs. 1 some epoxy fixed it up. The other was too bad off an I had to heli-cool it

Now I'm having this problem with one of my pipe studs....

Jsmitty42 · « **Reply #10 on:** October 27, 2013, 10:36:07 am »

ok so i took the stud out with the head and cylinder still on and it has already been heli coiled so cant i just get a new insert heli coil piece and insert it with locktight without takeing the head off ?

Stpltn250r · « **Reply #11 on:** October 27, 2013, 06:19:32 pm »

I read a builder used to remove the stud and helicoil. Machine the hole out and press in new material and drill and tap a new hole.

13.robb · « **Reply #12 on:** October 27, 2013, 06:30:29 pm »

The better repair is a time-sert. Thats what gm uses to repair aluminum engines that strip threads. Helicoil is not that strong. Time-sert is way better, Costs more, but worth it.

SBLT500R · « **Reply #13 on:** October 27, 2013, 08:08:25 pm »

why do people use heli coils in cylinder studs. they never hold for long.

Chuckie25 · « **Reply #14 on:** October 27, 2013, 08:49:30 pm »

Well I'm a cheap mofo and plus I don't plan on my engine opening up that many times.
Put it this way, I beat the crap out of my bike for a year and a half. I looked up through the exhaust port last week and still saw cross hatching. I think a heli coil will do fine for me lol

But there are definitely better ways to do it, that's for sure.

MotorGeek - Jerry Hall · « **Reply #15 on:** October 28, 2013, 07:52:37 am »

Quote from: SBLT500R on October 27, 2013, 08:08:25 pm

why do people use heli coils in cylinder studs. they never hold for long.

I have used time-serts and heli-coils. I prefer the hel-coils in aluminum. The majority of the failed heli-ciol repairs we find are because shops use heli-coils that come with the repair kits. The helicoils that come in the kits are typically 1.0 or 1.5 D heli-coils which are too short. A 1.5 D heli-coil only has a length of 1 1/2 diameters of the bolt that screws into the new insert That is ok for repair of a hole in steel as long as it is not something that has extra high loads like head bolts, main bearing caps etc.

We use heli-coils that engage the full length of the head stud. The length of the head studs threads are usually about 2.5 times the diameter of the thread.

We repair a lot of time-serts that are loose in the hole and back out even though they have been "staked" or flared. We also repair stripped time-serts. None of the time-serts or heil-coil repairs are idiot proof. Novice mechanics think it is better to over torque a bolt to just make sure it does not get loose.

Most of the time when the threads pull in the original casting, it is because someone over torqued the head nuts. Mechanics over-torque the head nuts because they do not use a torque wrench or they think that putting a little extra torque will fix a leaking head gasket. If you have a leaking head gasket replace the gasket and machine the gasket surface if it has blemishes or is not flat.

MotorGeek - Jerry Hall · « **Reply #16 on:** October 28, 2013, 07:59:29 am »

Quote from: Stpltn250r on October 27, 2013, 06:19:32 pm

I read a builder used to remove the stud and helicoil. Machine the hole out and press in new material and drill and tap a new hole.

Pressing in new material will pull out.

We often have to make a over-sized aluminum insert that is threaded on it's outside diameter and drilled and tapped for the head stud to repair failed time-serts or heli-coils.