Crankshaft pulley missing bolt
Racer
Joined: Oct 2015
Posts: 414
Likes: 407
From: Meadville Pennsylvania
The GM part numbers in my AIM are. 9428643 for the 7/16-20 x 2"-2.5" crank bolt torque is 60-80 ft lbs. and 9423959 for the 3/8-24 x 3/4 pulley bolts torque is 25-35# It would be a good idea to chase the threads on the crank and balance to make sure the threads are straight and true. You should be able to rent the thread chasers from Autozone or Oreilies.
Jerry
Jerry
Thread Starter
Pro
Joined: Dec 2011
Posts: 626
Likes: 15
From: Austin, TX
The GM part numbers in my AIM are. 9428643 for the 7/16-20 x 2"-2.5" crank bolt torque is 60-80 ft lbs. and 9423959 for the 3/8-24 x 3/4 pulley bolts torque is 25-35# It would be a good idea to chase the threads on the crank and balance to make sure the threads are straight and true. You should be able to rent the thread chasers from Autozone or Oreilies.
Jerry
Jerry
Once I finish the paint and everything is back I will post a photo.
Race Director
Joined: Mar 2016
Posts: 14,399
Likes: 8,204
From: Napa Valley California
Thanks for the info, I rented a thread restored set at Autozone, I put some WD-40 just before and they went very soft with no issues, once finished I introduced a magnet to clean up the small metal debris and the new bolts went till the end very well. Everything OK.
Once I finish the paint and everything is back I will post a photo.
Once I finish the paint and everything is back I will post a photo.
I would only use cutting oil that is made specifically for tapping threads. If you use a tap to chase the threads or to tap a new thread in a hole that bottoms out, use a bottoming tap only. Just my .02 cents.
Thread Starter
Pro
Joined: Dec 2011
Posts: 626
Likes: 15
From: Austin, TX
Use extreme caution taping or cleaning up threads with WD-40. it's not designed for that use.
I would only use cutting oil that is made specifically for tapping threads. If you use a tap to chase the threads or to tap a new thread in a hole that bottoms out, use a bottoming tap only. Just my .02 cents.
I would only use cutting oil that is made specifically for tapping threads. If you use a tap to chase the threads or to tap a new thread in a hole that bottoms out, use a bottoming tap only. Just my .02 cents.
I first tried to bolt the new bolt in order to double check how well it was the thread, but it bolted very well. So the problem was the old bolt per se, fortunately.
The metal debris source seemed to be the old bolt thread. I was lucky
Racer
Joined: Nov 2017
Posts: 289
Likes: 32
Use extreme caution taping or cleaning up threads with WD-40. it's not designed for that use.
I would only use cutting oil that is made specifically for tapping threads. If you use a tap to chase the threads or to tap a new thread in a hole that bottoms out, use a bottoming tap only. Just my .02 cents.
I would only use cutting oil that is made specifically for tapping threads. If you use a tap to chase the threads or to tap a new thread in a hole that bottoms out, use a bottoming tap only. Just my .02 cents.
I used ordinary 90 weight gear lube for many years because that's all I had. Then one day I had a LOT of pipe threading to do (using a Harbor Freight hand threader). Every thread I cut ended up damaged so I bought a pint of RIDGID thread cutting oil from the local True Value. WOW, with the RIDGID thread cutting oil it only took 1/4th the effort and every thread came out perfect. Thread cutting oil has a lot of sulfur in it and that's why it was so easy to thread the pipes as sulfur is a terrific lubricant. Now I keep a gallon of RIDGID on hand because I do a lot of threading and tapping as well as lathe and milling machine work.
Racer
Joined: Oct 2015
Posts: 414
Likes: 407
From: Meadville Pennsylvania
Thanks for the info, I rented a thread restored set at Autozone, I put some WD-40 just before and they went very soft with no issues, once finished I introduced a magnet to clean up the small metal debris and the new bolts went till the end very well. Everything OK.
Once I finish the paint and everything is back I will post a photo.
Once I finish the paint and everything is back I will post a photo.
Jerry
Race Director
Joined: May 2003
Posts: 10,956
Likes: 409
From: California
I doubt that is your vibration problem,, but if it is its the harmonic balancer gone bad, if not then its something else.. that pulley with the key will work fine with 1 bolt and the center is so close that off balance vibration just won't be felt.
its:
1. your hormonic balancer
2. you have a center-force clutch
3. your drive shaft is not set up in a "Z" configuration.
4. lots of loose bolts on the transmission, rear-end, u-joints
5. fan and/or fan clutch bent/off balance.
6. bad u-joint
That is 95% stuff
its:
1. your hormonic balancer
2. you have a center-force clutch
3. your drive shaft is not set up in a "Z" configuration.
4. lots of loose bolts on the transmission, rear-end, u-joints
5. fan and/or fan clutch bent/off balance.
6. bad u-joint
That is 95% stuff
Safety Car
Joined: Apr 2006
Posts: 4,057
Likes: 421
From: BC
I doubt that is your vibration problem,, but if it is its the harmonic balancer gone bad, if not then its something else.. that pulley with the key will work fine with 1 bolt and the center is so close that off balance vibration just won't be felt.
its:
1. your hormonic balancer
2. you have a center-force clutch
3. your drive shaft is not set up in a "Z" configuration.
4. lots of loose bolts on the transmission, rear-end, u-joints
5. fan and/or fan clutch bent/off balance.
6. bad u-joint
That is 95% stuff
its:
1. your hormonic balancer
2. you have a center-force clutch
3. your drive shaft is not set up in a "Z" configuration.
4. lots of loose bolts on the transmission, rear-end, u-joints
5. fan and/or fan clutch bent/off balance.
6. bad u-joint
That is 95% stuff
Last edited by CanadaGrant; Dec 2, 2017 at 12:38 AM.
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Thread Starter
Pro
Joined: Dec 2011
Posts: 626
Likes: 15
From: Austin, TX
I doubt that is your vibration problem,, but if it is its the harmonic balancer gone bad, if not then its something else.. that pulley with the key will work fine with 1 bolt and the center is so close that off balance vibration just won't be felt.
its:
1. your hormonic balancer
2. you have a center-force clutch
3. your drive shaft is not set up in a "Z" configuration.
4. lots of loose bolts on the transmission, rear-end, u-joints
5. fan and/or fan clutch bent/off balance.
6. bad u-joint
That is 95% stuff
its:
1. your hormonic balancer
2. you have a center-force clutch
3. your drive shaft is not set up in a "Z" configuration.
4. lots of loose bolts on the transmission, rear-end, u-joints
5. fan and/or fan clutch bent/off balance.
6. bad u-joint
That is 95% stuff
2. No idea about the center force clutch
3. This was my first suspect...still to be confirmed.
4. Everything look fine
5. I run electrical fans
6. U-joints with no play. But after intalling 8" bolts on the rear the camber changed, don't know if may affect as well.
Let's see whether I have time tomorrow to install everything back or not, so that I can confirm problem has been fixed.
Last edited by corvetero; Dec 9, 2017 at 05:56 AM.
Thread Starter
Pro
Joined: Dec 2011
Posts: 626
Likes: 15
From: Austin, TX
If you look at the pulley in the original pic it is off center on the balancer. That would create a wobble with the belts and balance along with the missing bolt. You probably would never notice the missing bolt by itself but with the off center pulley, that would be it.
Race Director
Joined: May 2003
Posts: 10,956
Likes: 409
From: California
Hey... hope it solves the problem... but. How can you be off center with a center bolt???
And no, a missing bolt there will not show up in noticeable vibration...
But again.. hope I’m wrong wrong for the op :-)
And no, a missing bolt there will not show up in noticeable vibration...
But again.. hope I’m wrong wrong for the op :-)
Race Director
Joined: May 2003
Posts: 10,956
Likes: 409
From: California
If you look at the pulley in the original pic it is off center on the balancer. You can see it in the bolt holes. That would create a wobble with the belts and balance along with a bit from the missing bolt. You probably would never notice the missing bolt by itself but with the off center pulley, that would be it.
Thus maybe a off balllance HB
Thread Starter
Pro
Joined: Dec 2011
Posts: 626
Likes: 15
From: Austin, TX
I will give a try with new bolts, in case it is not satisfactory, next stop would be HB and front seal.
Race Director
Joined: Jul 2015
Posts: 13,082
Likes: 3,399
From: SW Florida.
is the vibration gone, or dunno yet? if still there, you described it as while sitting still in neutral, with and without clutch pressed. this rules out everythingfrom the middle of the trans back. put it in gear and rev with foot on clutch. this will rule out everything from the clutch disc back. if you still have vibration, it is flywheel, pressure plate, balancer or engine itself. in fact, rev it before you put the fan belts on to rule out fan, water pump, alt, etc...might want to try it before installing the pulleys too.
Last edited by derekderek; Dec 2, 2017 at 07:37 AM.
Thread Starter
Pro
Joined: Dec 2011
Posts: 626
Likes: 15
From: Austin, TX
If you look at the pulley in the original pic it is off center on the balancer. You can see it in the bolt holes. That would create a wobble with the belts and balance along with a bit from the missing bolt. You probably would never notice the missing bolt by itself but with the off center pulley, that would be it.
is the vibration gone, or dunno yet? if still there, you described it as while sitting still in neutral, with and without clutch pressed. this rules out everythingfrom the middle of the trans back. put it in gear and rev with foot on clutch. this will rule out everything from the clutch disc back. if you still have vibration, it is flywheel, pressure plate, balancer or engine itself. in fact, rev it before you put the fan belts on to rule out fan, water pump, alt, etc...might want to try it before installing the pulleys too.
How can a missing fu.... bolt in a certain place affects that much. Engine rev up much more softer...first time I reached out 5k rpm since I own the car...the cam was asking for more, I don't need it though.
Safety Car
Joined: Apr 2006
Posts: 4,057
Likes: 421
From: BC
Glad you found it! The damper, or the center bolt in the damper was not causing your problem. The problem was the pulley was off center on the damper because of the missing pulley bolt. The tension from the belts moved the pulley off the center of the damper without the extra bolt causing a pulley wobble and vibration but the damper itself was fine.
Thread Starter
Pro
Joined: Dec 2011
Posts: 626
Likes: 15
From: Austin, TX
Glad you found it! The damper, or the center bolt in the damper was not causing your problem. The problem was the pulley was off center on the damper because of the missing pulley bolt. The tension from the belts moved the pulley off the center of the damper without the extra bolt causing a pulley wobble and vibration but the damper itself was fine.