Idler Pulley stripped threads - HeliCoil?

[musthave]

At the very end of my HG job, battery tray in, ready to go. Remembered that I hadn't tightened the 14mm bolt for the idler pulley. Reached down, tightened it with a stubby ratchet but felt like I needed more. Not thinking, I hit it with a 1/2" ratchet, went for a tiny snug and it went soft. Turned a few more times and knew it was stripped. Backed it out, no problem, little pieces of aluminum were in the threads so it was obvious what I had done.

Took things apart thinking that I might take off the timing chain cover and get a new one. But with valve cover off and the two front head bolts out. The FSM states that you have to take off the head (which I just put on), and you need to take off the upper pan, which I didn't want to do. I saw @cruiserdan thread from back in 03 and it sounds like you can take off the timing cover without taking off the head or the upper pan, but I'm not sure how. Would like any feedback on that...

Messaged a few people and one person suggested using a helicoil. I hadn't used one previously so I researched it and it seems like a very plausible solution given that this bolt once in, with a new pulley shouldn't need to come out for a long time. The hold is supposedly better than original (but I'm not sure I fully believe that).

I bought the helicoil kit for M10X1.25 . It comes with helicoils that are 15mm, but the hole is truly 24mm or so deep. So, do I use a single one and put it all the way in? Or put it in to just past the metal, or do I stack them? I have read that stacking isn't recommended. And, I don't see anywhere that has an option for a longer helicoil in the M10X1.25.

What have others done (besides using a torque wrench and making sure that you don't rely on your own judgement on how tight it should be)?

 

[LC4LIFE]

If this is the idler pulley on the drivers side and not the A/C idler pulley, lots of people just run without it. My previous 80 ran without it for 75K miles and never an issue.

 

[cruiserdan]

The upper oil pan does have to come off to remove the timing cover.

 

[musthave]

If this is the idler pulley on the drivers side and not the A/C idler pulley, lots of people just run without it. My previous 80 rand without it for 75K miles and never an issue.

I thought about that, and still am thinking about it. I figure if the helicoil doesn't work, I would consider going without. No issues though, that's promising.

 

[musthave]

And to confirm, yes, it's the idler pulley under the starter on DS.

 

[fjbj40]

Doesn’t it thread into the oil pump cover? Remove oil pump cover and do it that way.

 

[musthave]

Doesn’t it thread into the oil pump cover? Remove oil pump cover and do it that way.

Yes, I have the oil pump cover removed, ready to helicoil. Just not sure if I use two helicoils or 1, and if 1 to what depth? If helicoil doesn't work then I need to either run without it, or decide to do the timing cover and oil pans. With the oil pump cover removed I should be able to drill, tap, and helicoil I think.

 

[hotdiggitydamn]

Not an 80 guy as you know but I’ve used helicoils extensively in Aluminum. They are truly great provided you clean throughly both surfaces (acetone or proper loctite two part clean and prime) and then red loctite in place. Let that fully cure and you are good to go! I have never tried stacking two but would imagine getting proper internal thread alignment between the two might be problematic if slightly off. Just 1 is good well past 300 inch pounds in my experience.

 

[musthave]

 

[musthave]

Not an 80 guy as you know but I’ve used helicoils extensively in Aluminum. They are truly great provided you clean throughly both surfaces (acetone or proper loctite two part clean and prime) and then red loctite in place. Let that fully cure and you are good to go! I have never tried stacking two but would imagine getting proper internal thread alignment between the two might be problematic if slightly off. Just 1 is good well past 300 inch pounds in my experience.

That's great to hear! I've never used them. I can clean with acetone, then blow it out. Then use red loctite. So would you run 1 15mm helicoil all the way in, or would you just run it until it clears the outer metal edge?

 

[Rifleman]

Not to disagree with hotdiggitydamn above me, but I've never liked Helicoils. For a permanent repair I'd go with a metric thin wall EZ LOC insert instead of relying on a thin coiled of wire. Below is a link to EZ LOC inserts.

Solid Wall Threaded Inserts | Shop Solid Wall Threaded Inserts for Metal at E-Z LOK

E-Z LOK thread inserts for metal solid walls are ideal for repairing threaded holes in soft metals. Our threaded inserts for metal are strong, easy to install and seal against liquids and gases to pressures up to 6,000 psi. Purchase yours at E-Z LOK today!

www.ezlok.com

 

[hotdiggitydamn]

Yes, I have the oil pump cover removed, ready to helicoil. Just not sure if I use two helicoils or 1, and if 1 to what depth? If helicoil doesn't work then I need to either run without it, or decide to do the timing cover and oil pans. With the oil pump cover removed I should be able to drill, tap, and helicoil I think.

I ba

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As a quick side note you can drill and tap J&B weld. They even make one formula just for that I think. It’s not at all ideal. Perfect if you had real minimal wall thickness to work with and it were very low torque/load. Also this attached chart help with determining next size up to drill tap if you ever wanted to go that route. Sorry if it’s a bit off topic.

 

[fjbj40]

Just make sure it is at least one full thread below the surface. Otherwise you take the chance of pulling out the heli-coil. If put in with the lock-tite it will be better than the factory threads.

 

[hotdiggitydamn]

Not to disagree with hotdiggitydamn above me, but I've never liked Helicoils. For a permanent repair I'd go with a metric thin wall EZ LOC insert instead of relying on a thin coiled of wire. Below is a link to EZ LOC inserts.

Solid Wall Threaded Inserts | Shop Solid Wall Threaded Inserts for Metal at E-Z LOK

E-Z LOK thread inserts for metal solid walls are ideal for repairing threaded holes in soft metals. Our threaded inserts for metal are strong, easy to install and seal against liquids and gases to pressures up to 6,000 psi. Purchase yours at E-Z LOK today!

www.ezlok.com

These are great but frequent run of the mill helicoils are all you can get when you suddenly much something up and need it fixed now. Either way depending on the bolt I would personally run it just slightly further in than flush.

 

[hotdiggitydamn]

These are great but frequent run of the mill helicoils are all you can get when you suddenly much something up and need it fixed now. Either way depending on the bolt I would personally run it just slightly further in than flush.

And yes I would use just 1 personally.

 

[musthave]

Use loctite 262?

Loctite 262 Threadlocker Red High Strength

Buy Henkel Loctite 262 50ML online at Krayden. Buy Loctite 262 50ML from an Authorized Loctite Distributor. Red Bottle Loctite 262 Threadlocker.

krayden.com

Sounds like I have a plan.

 

[Rusty Marlin]

I've used helicoils fairly extensively, not from being a ham-fisted mechanic but from specing them into alumium designs.
hotdiggydamn is not steering you wrong. One turn below flush, inserted with Red 262 or Green (permatex bearing and sleeve retainer) into a clean hole and you'll be good to go. If you can get the primer that will be even better, but sometimes the primer is hard to get. Make sure to wash the helicoil in acetone too, and try not to touch it with your fingers after its clean. I thread them on the insert tool, then clean them.
The thin-walled units work great too, but they are overkill for this application, in my opinion.

 

[musthave]

I will find the Red 262. I will see if Grainger or Fastenal have the primer. Clean in acetone and don't touch it.

Yea, I wasn't thinking when I tightened it by hand, poor decision after using torque meter on every other fastener there was.

 

[ccslider]

I'd just spray it with brake clean then air and red loctite it in. Call it a day. No big worries there.

I'd be more worried about you taking the two headbolts back out out of torque sequence.

 

[Rifleman]

The thin-walled units work great too, but they are overkill for this application, in my opinion.

I've got to say after working with customers that were capable of breaking an anvil, I've found there is no such thing as overkill when it comes to doing repairs.

musthave after you've installed and loctited your new helicoil in place, Don't forget to break off the drive tang on the end of the helicoil.