Screwed up the crankshaft threads...

[R055]

Hey guys, I didn't have my good compressor and used my neighbors weak one, after about an hour of driving the harmonic balancer with bolt in about 30 seconds every 3 minutes I finally reached the point it was at before. I thought all was well until I took the screw off the next day, looks like I stripped the first inch of thread on the crankshaft.

What's my best option?

 

[Bt Doctur]

sounds like you didnt use the tool to install a balancer and buggered up the crank nose bolt threads
Remove the bolt, retap the threads, install the threaded rod in the crank and install the balancer with the nut, remove the threaded rod and install the nose bolt

 

[R055]

sounds like you didnt use the tool to install a balancer and buggered up the crank nose bolt threads
Remove the bolt, retap the threads, install the threaded rod in the crank and install the balancer with the nut, remove the threaded rod and install the nose bolt

Yeah I was going to rent the tool at autozone but the guy told me to just use the bolt, it worked the first 2 times with a good compressor. Would buying a bolt same with same thread but longer work to install it so it gets more thread before pulling the harmonic balancer or do I need the tool?

By retap, is that where you try to fix the old threads or does that make a bigger hole and make new threads?

 

[boatman37]

never use the bolt to drive the balancer on. and never listen to auto zone employees. i used to work at an auto parts store years ago and i was amazed at the people they hired and their lack of knowledge. i think there were a few that couldn't even change a flat tire

 

[Bt Doctur]

a tap of the same size just cleans up the existing threads.
Get a new nose bolt, get the correct tap 7/16 x 20 RH, get a threaded rod that's threaded and thread the rod in until it bottoms out. Install the balancer using spacers and the nut to draw the balancer until fully seated. Remove the rod and install the new nose bolt.

 

[NHGuy]

So that way you have the bolt stationary in the crank and you use the bolt threads to draw the damper onto the crank.
Don't use the bolt threads turning in the crank, that puts too much force on them.

 

[jimmbo]

You said you chewed up the threads in the crank. In that case you are going to have use a thread repair kit, Heli-coil is one.

 

[funk6294]

As stated before, I would clean up the threads in the crank with a tap and use a new bolt. You might also add a little blue loctite (medium strength) to help keep the bolt there. You should be ok otherwise.

 

[R055]

a tap of the same size just cleans up the existing threads.
Get a new nose bolt, get the correct tap 7/16 x 20 RH, get a threaded rod that's threaded and thread the rod in until it bottoms out. Install the balancer using spacers and the nut to draw the balancer until fully seated. Remove the rod and install the new nose bolt.

Wouldn't I need 9/16? I think the stock bolt is 7/16 so wouldn't I have to go up in size?

 

[Bt Doctur]

No because you can still repair whats left with the tap. bolt is over 2 1/2 inches with plenty of thread.
Besides to go to a larger bolt the crank should be removed and indexed so it goes in perfectly straight

 

[R055]

No because you can still repair whats left with the tap. bolt is over 2 1/2 inches with plenty of thread.
Besides to go to a larger bolt the crank should be removed and indexed so it goes in perfectly straight

I screwed up a good inch of thread so looks like about half inch of good thread left, I'll give the 7/16 tap a chance.

 

[R055]

No because you can still repair whats left with the tap. bolt is over 2 1/2 inches with plenty of thread.
Besides to go to a larger bolt the crank should be removed and indexed so it goes in perfectly straight

Okay thanks

 

[R055]

I'm going to buy a 7/16-20 tap and fix the old threads as much as possible, then buy a longer bolt to catch the good threads in the back.

 

[R055]

Update: I first used the 7/16 tap but it seemed to be extremely loose and weak, I was able to screw the bolt on with my hand.

So I got a 7/16 drill bit and drilled the hole and then used a 1/2-20 tap, the new screw is now really tight and feels right. Now I just need to find a new washer that the 1/2 bolt will fit into.

 

[Rick Stephens]

Drill out your old washer.

 

[R055]

Drill out your old washer.

Seams easier to buy a new one assuming they size is avaliable at the hardware stores and don't half a half inch metal drill bit, if not I'll buy a drill bit and drill the old one.

Thanks for the help guys.

 

[flipbro]

Like Rick said drill the old washer. Not likely find a washer that thick and heavy at your local hardware..

 

[R055]

Will do then, thank you