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heli coil vs drill and retap


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14 replies to this topic

#1 justajester

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Posted 08 November 2013 - 11:01 PM

So I just figured out the previous owner of my brst completly stripped out the threads where the y pipe bolts to the engine. Im just wondering the best option to fix it. Is heli coil stronger or should I just drill and tap from m10 bolt to 7/16?

#2 skishop69

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Posted 09 November 2013 - 03:20 AM

Helicoil. The reason they strip out is the aluminum in the heads is too soft. It'll just strip out again.



#3 jono

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Posted 09 November 2013 - 05:58 AM

I had one where the other diagonal holes in head were employed in this case, they cut the Y pipes and rewelded in place to suit the 90 degree rotation.

 

I also use the helicoil types- stainless ? Hi skishop !! Halo fixer !!



#4 Bantum

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Posted 09 November 2013 - 08:43 AM

+1 for helicoil ... :)

 

I'd also stay with metric ( keep it in the family ) - as you or the next person who has to work on it will be cursing at having to change tools ...

 

Cheers, Bantum ...



#5 Gloyale

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Posted 10 November 2013 - 01:24 PM

Tap for 7/16.  Install new stud with loctite.  Easier and cheaper.  Nut head will be 11/16 so 17mm socket and aftermarket nuts for metric subie studs are all 17mm head anyhow.

 

IF that strips later THEN you can helicoil.  If you do the helicoil first and then it comes out later (happens alot...helicoils aren't ment to be taken apart often) you'll have no meat left for retapping.

 

Leave the option open for another chance.  Just my $.02



#6 skishop69

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Posted 10 November 2013 - 11:44 PM

If you use green Loctite sleeve locker on the helicoils when installing and let them dry overnight, they will never come out unless you use a torch. Guaranteed. I've had to remove parts that had the green on them and it's damn near impossible unless you break out the smoke hatchet.



#7 ARJ

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Posted 11 December 2013 - 01:24 AM

Mate if you mean the exhaust y pipe into the head forget helicoils been there done that the helicoil drills stuffs your chance of the next size drill and tap procedure and they wont last anyway  . Drill and tap is the way to go ,you can drill a further 1/4 to 3/8 deeper no more use plenty of correct lube on tap and only about 1/2 to one turn at a time then clean out  and do another 1/2 to one turn . If you stuff it up your in deep s---t so be slow and careful and make sure the tap angle is spot on .

 You may have to enlarge the y pipe flange holes possibly with a round file and trail and error .  

   

                          Good luck  ARJ


Edited by ARJ, 11 December 2013 - 01:26 AM.


#8 spazomatic

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Posted 11 December 2013 - 09:16 AM

Id use a helicoil. Then in the future you dont have to worry about an oddball size to grab a tool for. The heli-coil will be stronger than the original threads were.

#9 Gloyale

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Posted 11 December 2013 - 12:30 PM

Id use a helicoil. Then in the future you dont have to worry about an oddball size to grab a tool for. The heli-coil will be stronger than the original threads were.

 

7/16 studs use a 11/16 nut.

 

Aftermarket nuts for the M10x1.25 will be 17mm head (subie nuts this size are 14mm head except lower starter nut is 17mm)

 

11/16 and 17mm are so close you could use the same socket for all.



#10 spazomatic

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Posted 11 December 2013 - 07:59 PM

7/16 studs use a 11/16 nut.
 
Aftermarket nuts for the M10x1.25 will be 17mm head (subie nuts this size are 14mm head except lower starter nut is 17mm)
 
11/16 and 17mm are so close you could use the same socket for all.


Well then...6 of one, half dozen of another. Either way, its a drill and tap operation. Ive had real good luck with heli-coils, so thats what id do.

#11 Leeroy

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Posted 12 December 2013 - 06:40 AM

Why heli-coil when you can Timesert?

#12 JTCoyoté

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Posted 13 September 2014 - 12:16 PM

Related only because it involves heli-coils, is the "nest of little metalic worms" I uncovered this morning... while replacing the much worn timing belt, idler, and tensioner bearings on my EJ22... I discovered that all but one of the idler/tensioner bolt bosses had been heli-coiled when half of the internal threads broke loose and were still adhering to the bolt threads as I removed them.

I knew something was up when it took considerable force to loosen them...

Insight, anyone... (Timesert?)

JT


Edited by JTCoyoté, 13 September 2014 - 12:27 PM.


#13 Leeroy

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Posted 13 September 2014 - 12:42 PM

http://www.timesert.com/

#14 Txakura

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Posted 13 September 2014 - 01:04 PM

Seriously? $83 for one exhaust stud?

 

http://www.amazon.co...words=time-sert

 

drill and tap it and be done with it, don't bugger it up



#15 JTCoyoté

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Posted 14 September 2014 - 01:08 AM

The solution to my stripped idler bosses...

 

Drill the idler bolt bosses out to 29/64" and tap the holes to 1/2"x20TPI, 1" deep...

Cut a 4" length of 1/2"X20TPI all-thread and chuck it up in the lathe 3-jaw with 1" or so running free...

Face it, center drill it, then drill it to a depth of 1.15" with a 1/4" drill.

Next, finish out the hole with an S drill, and tap it to M10 -1.25...part the piece at 1" length,

Set it aside and repeat the drilling, tapping, and parting process 2 more times.

 

Blow out the chips from the new threads in the bosses as well as from the sleeves then

give them all a blast with ether to clean and prime the threads for the Locktite...

Place a jam nut on each mounting bolt and run the sleeve on 5 or 6 threads then jam it

fairly tight... screw the jam bolted sleeves into the block to test each for depth and flush

final fit. Now you're ready...

 

Coat the internal block and external sleeve threads with Red Locktite, making sure both surfaces are lightly

yet completely coated. Keeping any excess glue clear of the area where the jam nut will rest, slowly

tighten the bolt until the jam nut is snugged tight against the clean surface of the boss. Let it cure for

24 hours. Using 2 wrenches, release the jam nut and remove the bolt. You now have tight,

forward loaded inserts that are at least as strong as the original threads and fully capable of

taking the 26-32 ft.lbs of torque for secure idler operation.

 

Cost: about 6 bucks. (with the proper equipment of course.)

 

JT


Edited by JTCoyoté, 14 September 2014 - 02:15 AM.





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