Harmonic Balancer - bolt stripped.

ParadiseXJ · Feb 21, 2011

Last week I finished my harmonic balancer install and it went fairly well. I had not torqued it down because it started raining and I figured I'd just finish it the next day.

So my problem is it WON'T torque down. It just spins. I noticed that the end of the bolt is chewed up. Can I use a shorter bolt or should I re-tap the crank snout...and if so should tap it 1/2" x 20 or??

Any answers? I wanna drive the mutha'.

PaulJ · Feb 21, 2011

Sounds like you tried to use the bolt to pull the harmonic balancer on. I would try installing the balancer properly and then a new bolt might reach far enough in to capture threads that aren't stripped out.

PhotographerMike · Feb 21, 2011

In short, here's what I ended up doing after the previous owner stripped out most of the crank threads. Much easier job with bumper removed.
1) buy 2 (just in case) long grade 8 bolts from http://mcmaster.com
2) buy bottom tap to open up some threads in crank
3) J.B. Weld long bolt in crank shaft hole, let J.B. cure, cut off end leaving 4+ inches of bolt shaft sticking out
4) Install new harmonic balancer using stacked, greased washers, and proper nut , leave end of bolt sticking out of crank, you will need it it you ever want to remove the H.B. again

Good luck,
Mike

lawsoncl · Feb 21, 2011

PhotographerMike said:
In short, here's what I ended up doing after the previous owner stripped out most of the crank threads. Much easier job with bumper removed.
1) buy 2 (just in case) long grade 8 bolts from http://mcmaster.com
2) buy bottom tap to open up some threads in crank
3) J.B. Weld long bolt in crank shaft hole, let J.B. cure, cut off end leaving 4+ inches of bolt shaft sticking out
4) Install new harmonic balancer using stacked, greased washers, and proper nut , leave end of bolt sticking out of crank, you will need it it you ever want to remove the H.B. again

Good luck,
Mike

Put a nut or a die on the long bolt before you epoxy it into place. Then after you cut the head off to make it a stud, you cut run the nut/die off the end to help reform the threads. Little trick I've learned along the way.

PhotographerMike · Feb 21, 2011

You are right! Here's the LONG version; http://www.naxja.org/forum/showthread.php?t=921771

lawsoncl said:
Put a nut or a die on the long bolt before you epoxy it into place. Then after you cut the head off to make it a stud, you cut run the nut/die off the end to help reform the threads. Little trick I've learned along the way.

old_man · Feb 22, 2011

Being a machinist, I say you drill out the snout and insert a helicoil. If you are going to fix it, you might as well do is right.

lawsoncl · Feb 22, 2011

old_man said:
Being a machinist, I say you drill out the snout and insert a helicoil. If you are going to fix it, you might as well do is right.

True, but that is a much more daunting task for the non-machinist. In all likelyhood, it's just the end 2-3 threads that got ripped out and once the balancer is on there is probably at least 1-dia worth of threads engaged. Epoxying in a stud is a quick fix.

joe_peters · Feb 22, 2011

Pull the HB--yeah, sucks right.

Inspect the damage.

Run a tap--clean up what remains of the threads.

THEN decide what you want to do.

I do, however, lean towards Heli-Coil.

ParadiseXJ · Feb 22, 2011

Actually, pulling the HB is what I had in mind even if I was going to either tap it or if I had to drill it. The threads are fine for the first 1" to 3/4". The HB is flush with the snout. Then the one big washer, then the bolt.

Not being a machinst, and never having done a helicoil 1.) how much would I have to drill and 2.) does that change the size of the bolt? and 3.) how the fritz did I screw this up.

joe_peters · Feb 22, 2011

3--not a clue, if you had short-started the bolt the outer threads would be toast.

2--you purchase a Heli-Coil kit for the original size bolt, it comes with the correct tap and the correct drill size is indicated.

1--as deep as the hole for the bolt is, no deeper.

87manche · Feb 22, 2011

joe_peters said:
3--not a clue, if you had short-started the bolt the outer threads would be toast.

2--you purchase a Heli-Coil kit for the original size bolt, it comes with the correct tap and the correct drill size is indicated.

1--as deep as the hole for the bolt is, no deeper.

make sure it comes with the drill bit.

http://naxja.org/forum/showpost.php?p=245248634&postcount=22913

ParadiseXJ · Feb 23, 2011

old_man said:
Being a machinist, I say you drill out the snout and insert a helicoil. If you are going to fix it, you might as well do is right.

I think I got out easy, read on.

joe_peters said:
Inspect the damage.

Run a tap--clean up what remains of the threads.

THEN decide what you want to do.

This is good advice because this is what I did. I just ran the same thread tap. I think there were just a few crinkled threads at the end. I had worried that I may have cracked the crank snout, but there's no evidence of that.

Ran tap, bought new bolt, torqued down to 80 fp. Went for a drive.

87manche said:
make sure it comes with the drill bit.

http://naxja.org/forum/showpost.php?p=245248634&postcount=22913

None of the ones I looked at did...at NAPA.

Harmonic Balancer - bolt stripped.

ParadiseXJ

NAXJA Forum User

PaulJ

NAXJA Forum User

PhotographerMike

NAXJA Forum User

lawsoncl

NAXJA Forum User

PhotographerMike

NAXJA Forum User

old_man

NAXJA Forum User

lawsoncl

NAXJA Forum User

joe_peters

NAXJA Forum User

ParadiseXJ

NAXJA Forum User

joe_peters

NAXJA Forum User

87manche

NAXJA Forum User

ParadiseXJ

NAXJA Forum User

Similar threads