Heli-Coil Help
Thread Starter
Safety Car
Joined: Aug 2000
Posts: 3,909
Likes: 26
From: Clymer PA
Heli-Coil Help
While bolting my flywheel to my crank I discovered a stripped out bolt hole. Is it alright to put a heli-coil in the crank for this application or is this a no-no? I really see only a few alternatives:
A. Drill the hole out and heli-coil it
B. Drill the hole out, tap it and use a larger bolt
C. Buy a new crank.
Surely I don't have to buy a new crank because of one stripped out bolt hole :(. I had plans of setting up my clutch and bellhousing and dropping the motor in tonight...but it appears as though it will be another day or so.
P.S. I stripped down my engine bay and painted it....boy does it look purdy :).
A. Drill the hole out and heli-coil it
B. Drill the hole out, tap it and use a larger bolt
C. Buy a new crank.
Surely I don't have to buy a new crank because of one stripped out bolt hole :(. I had plans of setting up my clutch and bellhousing and dropping the motor in tonight...but it appears as though it will be another day or so.
P.S. I stripped down my engine bay and painted it....boy does it look purdy :).
Le Mans Master
Joined: Aug 2000
Posts: 9,662
Likes: 7
From: Semper ubi, sub ubi
Cruise-In VI Veteran
Cruise-In VII Veteran
Re: Heli-Coil Help (bence13_33)
I'm not an expert by any means, but I'm not sure I'd use a heli-coil on a flywheel bolt. I think I'd drill out the hole and retap it to a slightly larger size.
Drifting
Joined: Mar 2001
Posts: 1,514
Likes: 1
Re: Heli-Coil Help (bence13_33)
Thats a tough one. I've used heli-coils in lots of situations but never on a crank. If done right I'd have no problems trusting the strength. Another is to weld it up and redrill and tap. Bigger bolt :nono: , I'd be interested to hear how someone else has fixed theres.
Scott
Scott
Drifting
Joined: Oct 2000
Posts: 1,825
Likes: 56
From: Shawano WI
Re: Heli-Coil Help (bence13_33)
I would not drill it out and use a larger bolt. There is the possibility that the couple of extra ounce of weight of a larger bolt could cause a vibration.
As long as the other bolts and thread are in good shape to except being torqued I would put in a heli-coil. Be sure there is a dowel pin in the crank to align the flywheel. Between the dowel pin and the other bolts I don't think you would have a problem with the one that is heli-coiled.
As long as the other bolts and thread are in good shape to except being torqued I would put in a heli-coil. Be sure there is a dowel pin in the crank to align the flywheel. Between the dowel pin and the other bolts I don't think you would have a problem with the one that is heli-coiled.
Thread Starter
Safety Car
Joined: Aug 2000
Posts: 3,909
Likes: 26
From: Clymer PA
Re: Heli-Coil Help (bence13_33)
I think ddn had a similar problem with his crank. ddn are you out there, how did you fix your stripped out thread on your crank?
Pete:
The crank has a dowel and the flywheel is externally balanced and can only be placed on one way. I agree, I don't see why a heli-coil wouldn't work on one bolt.
[Modified by bence13_33, 9:42 PM 4/14/2002]
Pete:
The crank has a dowel and the flywheel is externally balanced and can only be placed on one way. I agree, I don't see why a heli-coil wouldn't work on one bolt.
[Modified by bence13_33, 9:42 PM 4/14/2002]
Drifting
Joined: Oct 2000
Posts: 1,825
Likes: 56
From: Shawano WI
Re: Heli-Coil Help (bence13_33)
Bence;
When i put aluminum blocks together all the head bolt holes and main cap bolts holes are heli-coiled so I really don't think that one for the flywheel would be a problem. I would use loctite on the heli-coil and all the flywheel bolts.
If you tried drilling it out you would also have to drill the flywheel and I think that could cause you problems.
[Modified by Pete79L82, 9:53 PM 4/14/2002]
When i put aluminum blocks together all the head bolt holes and main cap bolts holes are heli-coiled so I really don't think that one for the flywheel would be a problem. I would use loctite on the heli-coil and all the flywheel bolts.
If you tried drilling it out you would also have to drill the flywheel and I think that could cause you problems.
[Modified by Pete79L82, 9:53 PM 4/14/2002]
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
Top 10 Most Expensive Corvettes Ever Sold on Bring A Trailer
Brett Foote
10 Things Every Corvette Owner Needs (2026 Edition)
Michael S. Palmer
8 Most "Only Corvette Owners Understand" Quirks and Problems
Pouria Savadkouei
10 Reasons the C6 Z06 is Still A Performance Benchmark After 20 Years
Joe Kucinski
How Much Horsepower Every Corvette Engine "LOST" in 1972
Joe Kucinski
Top 10 DOs and DON'Ts for Protecting Your Convertible Top!
Michael S. Palmer
Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!
Joe Kucinski
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter
Joe Kucinski
8 Coolest Corvette Pace Cars (and Replicas) of All Time
Verdad Gallardo
Thread Starter
Safety Car
Joined: Aug 2000
Posts: 3,909
Likes: 26
From: Clymer PA
Re: Heli-Coil Help (redvetteman)
Thanks for the help guys. I'll stop by my local auto supply shop tomorrow and pick up a(nother) heli-coil kit. Bob I must say that is a very sharp looking '67 you have there!
Advanced
Joined: Mar 2002
Posts: 90
Likes: 0
From: Colorado
Re: Heli-Coil Help (bence13_33)
:yesnod: :yesnod: :yesnod: YES, absolutely, use the helicoil kit that'll allow you to using the originally sized bolt. I had this exact same situation happen to me in the 1980ish timeframe on my '70 and it's still holding strong as ever. You will not have a problem with this approach.
Couple tips: 1) spend the money to buy a brand new drill bit in the exact size recommended in the heli-coil kit. The kit will not come with the bit you need. 2) use what I call a "slow speed" or "geared down" .5" drill and do your best to get the bit square with the crank flange. 3) watch carefully how deep you install the heli-coil...make sure you stop screwing it in as soon as the trailing edge of the coil disappears past the face of the crank flange and is slightly recessed. Then you can break off the coil's installation 'tang'
I was SOOO... nervous when I was doing mine because it was the first time my tranny had been removed, I was under the car in the dark, that was my only transportation at the time and the last thing I wanted to have to do was replace the crank...especially under those circumstances. Just use the regular amount of care and attention to detail and you'll feel GREAT when it's finished! :cheers:
Couple tips: 1) spend the money to buy a brand new drill bit in the exact size recommended in the heli-coil kit. The kit will not come with the bit you need. 2) use what I call a "slow speed" or "geared down" .5" drill and do your best to get the bit square with the crank flange. 3) watch carefully how deep you install the heli-coil...make sure you stop screwing it in as soon as the trailing edge of the coil disappears past the face of the crank flange and is slightly recessed. Then you can break off the coil's installation 'tang'
I was SOOO... nervous when I was doing mine because it was the first time my tranny had been removed, I was under the car in the dark, that was my only transportation at the time and the last thing I wanted to have to do was replace the crank...especially under those circumstances. Just use the regular amount of care and attention to detail and you'll feel GREAT when it's finished! :cheers:
Le Mans Master
Joined: Apr 1999
Posts: 6,134
Likes: 46
From: Raleigh North Carolina
Re: Heli-Coil Help (ORVette)
Don't forget to assess the length of the insert you need... they come in different lengths.
You need the proper thread engagement.
Autoparts stores typically carry a "common" length, which may not be long enough for your application.
FYI
Tom
You need the proper thread engagement.
Autoparts stores typically carry a "common" length, which may not be long enough for your application.
FYI
Tom