Crank Nose Threads & Thick Washer Question

[PurpleBeeper]

A shop worked on my car and the large crank bolt at the harmonic balancer fell out! The bolt is stripped. The shop said they ran a tap in the hole (but re-used the stripped bolt?) Anyway, the shop is talking about a VERY expensive “key-cert” (sp?) insert. I want to try a new bolt first. I’m wondering if I should use a thinner washer instead of the mega-thick factory washer to get a couple more threads inside the crank nose (since the shop said they tapped the hole already)
Thoughts?

 

[PurpleBeeper]

Here is the bolt that fell out

 

[Fran Blacker]

A 6cyl and a Hemi bolts are much longer, maybe too long. Might have to use to many washers. You could figure out how deep the threads are and cut the bolt. They may have to large of a shoulder. Do you have a Fastenal near by and buy a bolt 1/4? longer?

 

[69Bee]

A phone call should have been made when the damage was found to ask for your approval for what is the best to fix the issue. Well, that ship has sailed, and their attempt to get by the problem failed, and here you are again... Before anyone says "Heli-Coil", that won't work effectively here because the bolt torque is too high. I assume that the repair they want to use is called a "Key-Sert" where the hole is drilled over, and a solid threaded insert is installed, then 4 wedge shaped keys are hit with a hammer to lock the insert in place. I use a "Time-Sert" to make my thread repairs and they use an expander to lock the insert in place, same result by two different methods.

Key-Sert:

Time-Sert:

 

[pnora]

If they re-threaded the hole and the bolt and it will torque to specs it most likely would be ok. My self I would of tapped the hole as deep as possible and then found a bolt that would go as deep with the factory washer. As tight as the balancer fits I doubt it will go anywhere. Old Chevrolets had a press on hub/balancer and they did not have a bolt.

 

[Don Frelier]

I would certainly toss the bolt that part is a no brainer.
There's a reason why I work on my own stuff.
No-one to be angry with except the guy in the mirror.

There are ways to install a balancer without an installation tool.
I just take a soft faced deadblow hammer, oil the balancer and crank snout and knock it on a little at a time staying close to the crank.
You could cut a piece of heavy PVC pipe and use it as a drift as well.
Once the bolt goes on far enough to allow about 6 or more full turns on the balancer bolt it should pull the balancer all the way on.

 

[dvw]

I find it hard to believe that there is any way overtighten a crank bolt and strip the threads without breaking the rachet first.
Doug

 

[493 Mike]

You could likely use a stud w/nut setup too.
Mike

 

[PurpleBeeper]

A phone call should have been made when the damage was found to ask for your approval for what is the best to fix the issue. Well, that ship has sailed, and their attempt to get by the problem failed, and here you are again... Before anyone says "Heli-Coil", that won't work effectively here because the bolt torque is too high. I assume that the repair they want to use is called a "Key-Sert" where the hole is drilled over, and a solid threaded insert is installed, then 4 wedge shaped keys are hit with a hammer to lock the insert in place. I use a "Time-Sert" to make my thread repairs and they use an expander to lock the insert in place, same result by two different methods.

Key-Sert:
View attachment 1674385

Time-Sert:

View attachment 1674386

A 6cyl and a Hemi bolts are much longer, maybe too long. Might have to use to many washers. You could figure out how deep the threads are and cut the bolt. They may have to large of a shoulder. Do you have a Fastenal near by and buy a bolt 1/4? longer?

This is good advice. I will try to see how deep the threads go, get a die to clean the threads and cut to length.
What about that OEM fat washer??? Does it NEED to be that thick?

 

[PurpleBeeper]

I find it hard to believe that there is any way overtighten a crank bolt and strip the threads without breaking the rachet first.
Doug

I swapped the cam 3 yrs ago and tightened it with an impact. The shop says that caused the damage

 

[RemCharger]

Yes to needing the thick washer.

 

[dvw]

I swapped the cam 3 yrs ago and tightened it with an impact. The shop says that caused the damage

No way unless you just layed on it for a few minutes.
Doug

 

[Don Frelier]

More likely they either cross threaded or tried to pull the balancer on without enough thread engagement.
Not a good place to make a mistake.

 

[Bird 426]

This is why we should not install the harmonic balancer with the bolt.

 

[68HemiRR]

Check this out Crankshaft Damper Bolt/Washer 64-74 Small Block and 426 Hemi | Roseville Moparts

 

[Fran Blacker]

Check this out Crankshaft Damper Bolt/Washer 64-74 Small Block and 426 Hemi | Roseville Moparts

He'd need to space out with more washers but would work unless threads are chewed up.

 

[oldkimmer]

I have had to use a small block crank bolt b4. Kim

 

[PurpleBeeper]

No way unless you just layed on it for a few minutes.
Doug

That was my thought. It “looks” like someone got in a hurry and put the impact to it while it was cross threaded.
Any idea how deep that hole is vs the bolt? Which metal is harder, the crank or the bolt?
I ordered a small block bolt (1” longer, same thread) and a tap/die. I want to at least “try” to clean the threads, cut deeper if possible and use a custom-cut longer bolt (screw the die into the bolt, cut to length and remove due to clean the threads)
Will this work?

 

[68HemiRR]

That was my thought. It “looks” like someone got in a hurry and put the impact to it while it was cross threaded.
Any idea how deep that hole is vs the bolt? Which metal is harder, the crank or the bolt?
I ordered a small block bolt (1” longer, same thread) and a tap/die. I want to at least “try” to clean the threads, cut deeper if possible and use a custom-cut longer bolt (screw the die into the bolt, cut to length and remove due to clean the threads)
Will this work?

I measured a 440 crank I have here. It is 1 3/4" deep. The threaded part of a stock bolt is 1 1/4". So it looks like you should have a 1/2" extra depth to play with. Good luck with your repair .

 

[hofferwood]

That was my thought. It “looks” like someone got in a hurry and put the impact to it while it was cross threaded.
Any idea how deep that hole is vs the bolt? Which metal is harder, the crank or the bolt?
I ordered a small block bolt (1” longer, same thread) and a tap/die. I want to at least “try” to clean the threads, cut deeper if possible and use a custom-cut longer bolt (screw the die into the bolt, cut to length and remove due to clean the threads)
Will this work?

If you ordered a tap, hopefully you ordered a "bottom tap" it will run threads all the way down, verses a "starting tap" witch will not.