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I have a couple of thread holes stripped on my gearbox AND timing cover. (fuck previous owners!) Leaking like a faucet. I have never used a helicoil (which seems like a $$$ rip-off in my opinion for what you get). The bike was set up for brit threads originally (66 T100), so I got the "set" that does 1/4-20. Pretty close. A couple of the holes I need to tap and heli are deep. Let's just say that a helicoil insert is roughly 3/8". The hole that I need to put it in needs about 2 and 1/2 inserts in to make it all the way to the bottom. How do I do this? It's a blind hole. The inserts have the "tang" on the bottom that the "key" fits in and turns it. How do I put the other coils in when there is a "tang" in the way? I know I can break it off as per the shitty instructions, but how do I get the broken piece out? I know this may seem like an idiotic question, but my feeble brain can't think of the answer.

Thanks,
Erron
 

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ratwagon said:
I have a couple of thread holes stripped on my gearbox AND timing cover. (fuck previous owners!) Leaking like a faucet. I have never used a helicoil (which seems like a $$$ rip-off in my opinion for what you get). The bike was set up for brit threads originally (66 T100), so I got the "set" that does 1/4-20. Pretty close. A couple of the holes I need to tap and heli are deep. Let's just say that a helicoil insert is roughly 3/8". The hole that I need to put it in needs about 2 and 1/2 inserts in to make it all the way to the bottom. How do I do this? It's a blind hole. The inserts have the "tang" on the bottom that the "key" fits in and turns it. How do I put the other coils in when there is a "tang" in the way? I know I can break it off as per the shitty instructions, but how do I get the broken piece out? I know this may seem like an idiotic question, but my feeble brain can't think of the answer.

Thanks,
Erron
you can blow the tang out with compressed air. you can also stack helicoils on top of each other if need be but most deep holes aren't threaded their whole length. just at the bottom. also 1/4-20 is pretty course. 1/4-28 would hold better.
 

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Don't be too worried over the length of the threaded holes, maximum holding power for threaded fasteners is 1.5 x diameter of bolt so if you have a 1/4 inch screw 3/8 is perfect.
 

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you can also stack helicoils on top of each other if need be
I wouldn't advise that.

It'd be real tough to get them to align such that the screw wouldn't bind up when installing. There'd also be no way to prevent them from turning independent of each other even if you could ensure alignment.

One coil is plenty, as was mentioned.

Respectfully,
Jason
 

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Something I always tell myself, length doesnt really matter. The thread depth that one provides is all you need.
 

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JasonMcElroy said:
I wouldn't advise that.

It'd be real tough to get them to align such that the screw wouldn't bind up when installing. There'd also be no way to prevent them from turning independent of each other even if you could ensure alignment.

One coil is plenty, as was mentioned.

Respectfully,
Jason
i guess i better go track down all the ones i've doubled in the last 30 years and take one out. ;)
 

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JasonMcElroy said:
Bill,

No disrespect intended. I also wasn't saying it couldn't, or hadn't ever, been done.

Just that there is little benefit and a potential for more problems than it's worth.

Jason
i know, i'm just jerkin yer chain. speaking of proper installation of helicoils i just went thru a ratfuck with a local automotive machine shop over misinstalled helicoils. i took them a rear head off a shovel to have a "threaded insert" not helicoil installed in the sparkplug hole. i would have done it myself but i was out of inserts and feeling lazy. anyway they say "no problem". the owner picks the head up a week later and brings it to me to install. i check the work on the plug hole and discover a 1/2" reach 14mm helicoil installed INSIDE a 3/4" reach helicoil. WTF ?!?!
i storm back to the machine shop totally pissed and i'm told "we do that all the time"..."no problem, just run it" etc etc. bottom line they weren't going to replace the now fucked head and i was welcome to sue them. :mad:
so i had to figure out a way to repair this head myself. did a little homework and found out the time zert company has an oversize 14mm threaded insert that would fit in the wallowed out hole that was left after i knocked the fuckin helicoils out.
if you are in the central arkansas area stay far away from "Auto Parts and Bearing" in hot springs.
sorry for the long winded rant
 
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