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How in the world would you fix this stripped thread??? #809667
09/20/10 08:02 PM
09/20/10 08:02 PM
Joined: Jan 2003
Posts: 1,255
Columbus, GA
Michael Ecks Offline OP
pro stock
Michael Ecks  Offline OP
pro stock

Joined: Jan 2003
Posts: 1,255
Columbus, GA
Stripped a bolt hole on my torque converter during install. I DO NOT want to have to take this thing out all the way again. It will tighten to a certain extent and then skip back out at a certain point.

Clearly a heli coil would be best, but is the mounting pad on a toque converter deep enough for one? I'm guessing I would have to cut an insert down in length. Also how far can I drill into it without going into the converter itself. And I'm also guessing I would need to find a bottoming tap to get the threads for the insert deep enough to make a difference. Does any store typically carry bottoming taps?

Also looked at the specs for the permatex thread repair compound. Looks like the recommended torque for a repaired thread is very low.

Any suggestions would be greatly appreciated.


"The happiness of your life depends upon the quality of
your thoughts" ~ Roman Emperor Marcus Aurelius
Re: How in the world would you fix this stripped thread??? [Re: Michael Ecks] #809668
09/20/10 08:12 PM
09/20/10 08:12 PM
Joined: Mar 2007
Posts: 3,275
West Coast, USA
jbc426 Offline
master
jbc426  Offline
master

Joined: Mar 2007
Posts: 3,275
West Coast, USA
Take it out, cut off the little block, weld the hole up, re-drill and tap it, and then weld it back on in the correct location.

Or, look at this as your big chance to get the new torque converter you've always wanted.


1970 Plymouth 'Cuda #'s 440-6(block in storage)currently 493" 6 pack, Shaker, 5 speed Passon, 4.10's
1968 Plymouth Barracuda Convertible 408 Magnum EFI with 4 speed automatic overdrive, 3800 stall lock-up converter and 4.30's (closest thing to an automatic 5 speed going)
Re: How in the world would you fix this stripped thread??? [Re: Michael Ecks] #809669
09/20/10 08:20 PM
09/20/10 08:20 PM
Joined: Dec 2007
Posts: 18,153
Mass
DAYCLONA Offline
I Live Here
DAYCLONA  Offline
I Live Here

Joined: Dec 2007
Posts: 18,153
Mass
Consider using a metric sized bolt that's close to the hole size you have, just slightly oversized...just check out a few tap charts to see what size you can go to,...a metric starter and bottoming tap would do the job, no drilling, just tap, and go

Re: How in the world would you fix this stripped thread??? [Re: DAYCLONA] #809670
09/20/10 08:27 PM
09/20/10 08:27 PM
Joined: Jan 2003
Posts: 1,255
Columbus, GA
Michael Ecks Offline OP
pro stock
Michael Ecks  Offline OP
pro stock

Joined: Jan 2003
Posts: 1,255
Columbus, GA
I'm liking Dayclona's suggestion wayyyy better.


"The happiness of your life depends upon the quality of
your thoughts" ~ Roman Emperor Marcus Aurelius
Re: How in the world would you fix this stripped thread??? [Re: Michael Ecks] #809671
09/20/10 08:31 PM
09/20/10 08:31 PM
Joined: Feb 2005
Posts: 4,309
Prospect, PA
BSB67 Offline
master
BSB67  Offline
master

Joined: Feb 2005
Posts: 4,309
Prospect, PA
Quote:

Clearly a heli coil would be best, but is the mounting pad on a toque converter deep enough for one?




I think that it is, or you can get it to work. If not, it will need to come out for repair IMO.

Re: How in the world would you fix this stripped thread??? [Re: BSB67] #809672
09/20/10 08:39 PM
09/20/10 08:39 PM
Joined: Jan 2003
Posts: 32,884
Grand Prairie,Texas
stumpy Offline
I Win
stumpy  Offline
I Win

Joined: Jan 2003
Posts: 32,884
Grand Prairie,Texas
If you go metric don't forget that the bolt head needs to be ground down thin as the original or it will hit the block.

Re: How in the world would you fix this stripped thread??? [Re: stumpy] #809673
09/20/10 10:09 PM
09/20/10 10:09 PM
Joined: Aug 2003
Posts: 12,291
Kent, Wa
340SHORTY Offline
Truck Nut
340SHORTY  Offline
Truck Nut

Joined: Aug 2003
Posts: 12,291
Kent, Wa
screw a short stud into the hole and tack weld it..


I am truckless..
Re: How in the world would you fix this stripped thread??? [Re: DAYCLONA] #809674
09/20/10 10:53 PM
09/20/10 10:53 PM
Joined: Jan 2003
Posts: 6,591
Canton, Ohio
S
Sport440 Offline
master
Sport440  Offline
master
S

Joined: Jan 2003
Posts: 6,591
Canton, Ohio
Quote:

Consider using a metric sized bolt that's close to the hole size you have, just slightly oversized...just check out a few tap charts to see what size you can go to,...a metric starter and bottoming tap would do the job, no drilling, just tap, and go





Re: How in the world would you fix this stripped thread??? [Re: Sport440] #809675
09/21/10 04:09 AM
09/21/10 04:09 AM
Joined: Sep 2005
Posts: 1,202
California
P
polkat Offline
mopar addict
polkat  Offline
mopar addict
P

Joined: Sep 2005
Posts: 1,202
California
I agree as well. Unless I am mistaken, most mopar converter bolts are 7/16 by 20. This is roughly the equivelant of an 11mm thread size. Measure the depth of the hole and drill it out with a 7/16 drill bit marked with that depth, or a drill size based on the tap size you plan to use. I'd tap it for a 13mm threaded bolt (if you tap it for a 12mm bolt, you may not get deep enough new threads). You will have to dress the new bolt for head size and length as already mentioned.

Note: I have not done this myself, but it makes sense if you plan the tap and drill sizes well. Only possible problem I see is getting a dill in the right position with the oil pan so close! I'd use a mm bolt equalling grade 8, but grade 5 might also work.

Re: How in the world would you fix this stripped thread??? [Re: polkat] #809676
09/21/10 04:29 AM
09/21/10 04:29 AM
Joined: Jan 2007
Posts: 10,115
A Red State
SNK-EYZ Offline
I Live Here
SNK-EYZ  Offline
I Live Here

Joined: Jan 2007
Posts: 10,115
A Red State
Quote:

I agree as well. Unless I am mistaken, most mopar converter bolts are 7/16 by 20. This is roughly the equivelant of an 11mm thread size. Measure the depth of the hole and drill it out with a 7/16 drill bit marked with that depth, or a drill size based on the tap size you plan to use. I'd tap it for a 13mm threaded bolt (if you tap it for a 12mm bolt, you may not get deep enough new threads). You will have to dress the new bolt for head size and length as already mentioned.

Note: I have not done this myself, but it makes sense if you plan the tap and drill sizes well. Only possible problem I see is getting a dill in the right position with the oil pan so close! I'd use a mm bolt equalling grade 8, but grade 5 might also work.




Most standard converter bolts are 5/16th-24NF thread.
It's what they still use currently on the 5.7 Hemi's.
From the factory I thought only Hemi's got the 7/16th bolts.

Aftermarket converters give you the choice I believe.


Kayse can't keep up at all now. lol
Re: How in the world would you fix this stripped thread??? [Re: Michael Ecks] #809677
09/21/10 05:00 AM
09/21/10 05:00 AM
Joined: Feb 2007
Posts: 2,315
MOPAR HEADQUARTERS IN ALDEN NY
H
hemigod426 Offline
top fuel
hemigod426  Offline
top fuel
H

Joined: Feb 2007
Posts: 2,315
MOPAR HEADQUARTERS IN ALDEN NY
put bolt back in just tight enough to hold flex plate to lug. start welding on side of lug and go right to bolt head. did that to all my flex plate bolts on my race car. did not notice they lossened up until it boogered/stripped all of them out. finished the season like that no problem with all lugs welded. pulled motor/trans still coupled them slid trans off converter snout carefully(guys hanging in my shop were laughing what the hell you welded the converter) yep like mid season...cut of bolt head with 4 inch grinder took converter to trans shop they welded all new lugs on and rebalanced it,looked mint


MOPAR OR NO CAR
Re: How in the world would you fix this stripped thread??? [Re: hemigod426] #809678
09/21/10 08:41 AM
09/21/10 08:41 AM
Joined: Jan 2003
Posts: 145
Australia
D
dodgy Offline
member
dodgy  Offline
member
D

Joined: Jan 2003
Posts: 145
Australia
the helicoil will work, i've done it on a small block that i did'nt want to remove the box, just went with the kit that has the coil's and tap in it,used a air powered drillgun and a short bit, to get it square in the hole, screwed it in till it bottomed out on the converter with the some thread's floting in thin air. Just as long as the main threads are seated in the block it will hold.

Re: How in the world would you fix this stripped thread??? [Re: dodgy] #809679
09/21/10 09:13 AM
09/21/10 09:13 AM
Joined: Sep 2003
Posts: 1,465
Carson City, NV
B
babarracuda Offline
pro stock
babarracuda  Offline
pro stock
B

Joined: Sep 2003
Posts: 1,465
Carson City, NV
Be careful, a shortcut is the quickest way to someplace that you don't want to go!

Re: How in the world would you fix this stripped thread??? [Re: 340SHORTY] #809680
09/22/10 10:55 AM
09/22/10 10:55 AM
Joined: Dec 2006
Posts: 3,533
Indiana
F
Fury Fan Offline
master
Fury Fan  Offline
master
F

Joined: Dec 2006
Posts: 3,533
Indiana
Quote:

screw a short stud into the hole and tack weld it..




but I'll go further.

Use an allen-head setscrew and put it in with blue locktite or maybe some epoxy. Spin the converter 360° to ensure the setscrew doesn't hit the block. Then put a locknut on it - make sure locknut is below the surface of the setscrew and/or spin it again.

Use an allen-head so that you can positively hold the setscrew whilst tightening the nut and thereby avoid jumping the threads. Should probably use a distorted-thread locknut as those have a smaller profile than a nylon-insert nut.

Last edited by Fury Fan; 09/22/10 10:55 AM.
Re: How in the world would you fix this stripped thread [Re: Michael Ecks] #809681
09/22/10 01:58 PM
09/22/10 01:58 PM
Joined: Apr 2005
Posts: 1,322
Michigan
C
crlush Offline
pro stock
crlush  Offline
pro stock
C

Joined: Apr 2005
Posts: 1,322
Michigan
You can buy short helicoils, the helicoil taps are made with a few threds for lead in, after taping you can grind most of the lead off the tap and carefully tap threds to the bottom of hole, dont forget to use some taping fluid. Helicoils are considered to be stronger than a regular taped hole, so it is a good fix. Otherwise drill stripped thred out with a bigger drill, weld hole then redrill and tap with bottoming tap. Hope this helps







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