Last night at the dyno my crank Pulley fell off. Put it back on and made a few more pulls. The belt was doing some weird stuff after we put it back on, at around 4000rpms the belt tenchioner (sp) would actually move almost a half inch to the right almost like some one was pushing on it. I have no idea what is causing this problem any ideas would be appreciated.

By the way the crank bolt came out again on the ride home

 

use a new bolt. you should never reuse the old one. you should also torque it down to 240 lbs/ft i belive. don't worry about loctite cause a new stock bolt comes coated from the factory.

 

I would also replace the bolt with a new one, although I re-used my old bolt when I got my asp pulley installed, it's been perfect and that was 6 months ago.

 

Service manual has two specs for installing the pulley - one with the new and one with the old bolt. With the new, the pulley is installed with the bolt seat face of the pulley .095"-.175" sticking out from the end of the crank. Then the bolt is torqued to 37 ft. lbs. and then rotated another 140 degrees. With the old bolt the pulley is similarly installed and the old bolt is torqued to 240 ft. lbs.

If your pulley wasn't reinstalled to those specs, that could put the belt out of alignment. If the pulley was damaged and out of balance, that could certainly cause it to behave like it did.

<small>[ November 10, 2002, 03:08 PM: Message edited by: Buckshot ]</small>

 

Nope. All of those steps are part of one process, you use the old bolt and torque as you stated, then take that out insert the new and follow the steps you listed. There are not 2 specs.

 

I agree, old bolt to is used as part of the insallation, new bolt is used to hold part in place. This is an excerpt from the service manual....

Important
The used crankshaft balancer bolt will be used only during the first pass on the balancer installation procedure. Install a NEW crankshaft balancer bolt and tighten as described in the second, third and final passes of the balancer bolt tightening procedure.
The crankshaft balancer installation and bolt tightening involves a four stage tightening process. The first pass ensures that the balancer is installed completely onto the crankshaft. The third, and fourth passes tighten the new bolt to the proper torque.
The balancer should be positioned onto the end of the crankshaft as straight as possible prior to tool installation.

Install the crankshaft balancer onto the end of the crankshaft.

Use the J 41665 in order to install the crankshaft balancer.
Assemble the threaded rod, nut, washer and installer. Insert the smaller end of the installer into the front of the balancer.
Us a wrench and hold the hex end of the threaded rod.
Use a second wrench and rotate the installation tool nut clockwise until the balancer is started onto the crankshaft.
Remove the tool and reverse the installation tool. Position the larger end of the installer against the front of the balancer.
Use a wrench and hold the hex end of the threaded rod.
Use a second wrench and rotate the installation tool nut clockwise until the balancer installed onto the crankshaft.
Remove the balancer installation tool.

Install the used crankshaft balancer bolt. Tighten
Tighten the USED crankshaft balancer bolt to 330 N·m (240 lb ft).

Remove the used crankshaft balancer bolt.

Important
The nose of the crankshaft should be recessed 2.40-4.48 mm (0.094-0.176 in) into the balancer bore.

Measure for a correctly installed balancer. If the balancer is not installed to the proper dimensions, install the J 41665 and repeat the installation procedure.

Install the NEW crankshaft balancer bolt. Tighten
Tighten the NEW crankshaft balancer bolt a first pass to 50 N·m (37 lb ft).
Tighten the crankshaft balancer bolt a final pass to 140 degrees using the J 36660-A .
Remove the J 42386-A and bolts.

<small>[ November 10, 2002, 05:42 PM: Message edited by: JAY4SPEED ]</small>

 

jeeez. what ever happened to...
tighten it till it don't turn no more, then tighten it one more turn..?
<img border="0" title="" alt="[Big Grin]" src="gr_grin.gif" />

 

Wow. Banner Chevrolet is where I bought my 85 Z28 brand new. How long have you worked there?

 

Im with Sixpak. I dont have a torque wrench small enough for all the places i need it.

 

I just did the install tonight.It is a bitch to get 240 ft/lbs.I got as close as I could with 2 1/2 foot torque wrench.Then installed new bolt(put a little red locktight on threads) and could only get about 120 degree after the 37 ft/lbs.I can not see how this with fall off.

 

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by BLKTA:
<strong>Wow. Banner Chevrolet is where I bought my 85 Z28 brand new. How long have you worked there?</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">LOL...... unfortunatly in 1985 is was in the 5th grade. I'm 27. Been at Banner for 3 years. Strange you should mention a '85 Z28, I come to this board for knowlege on my LS1 transplant in my '86 Z28. If your in the area stop to the service dept. and say hi. Ask for Jason.

Jay

 

Man I've been moving ALOT of threads today! Pullys are an EXTERNAL ENGINE mod. Moving there now... <img border="0" alt="[Burnout]" title="" src="graemlins/burnout.gif" />

 

I don't know anyone who's transplanted a LS1 into a 3rd gen, but know of two LT1's into 3rd gens.

I live in MN now and visits are usually on a yearly basis to see my family. Is the dealr still on Chef Menteur HWy?