WhtFast

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

1dirtyZ

iTrader: (1)

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.

m1key99WS6

iTrader: (1)

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.

Buckshot

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>

Dave Carney

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.

JAY4SPEED

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>

SixPak

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" />

DrkPhx

iTrader: (15)

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

sited12

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

Slowhawk

iTrader: (12)

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.

JAY4SPEED

</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

Colonel

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" />

DrkPhx

iTrader: (15)

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?

eallanboggs

iTrader: (1)

That sure is a long drawn out process just to get a crank pulley back on. When I read it in the GM shop manual I couldn't believe there was a 4 step process to installing a bolt. You left out the part about the factory tool needed to keep the crank from turning while applying torque to the crank pulley bolt. I believe that is a special tool only available from a GM dealer IF the will sell it to you. I just got a chain wrench from Boudreau's plumbing in Gretna and told my crank pulley it was a piece of cast iron drain pipe and it believed me. Why not just get an ASP Pulley set and then you don't need that special GM factory pusher tool. You can go to Francis hardware on 4th st in Harvey, La. to get a 120mm stainless bolt to "PUSH" the ASP Pulley onto the crank. The factory bolt is only 103mm so you get 17mm of extra thread bite to get the pulley started. Forget that factory pusher tool. The ASP pulley is better than the GM part anyday.

WJ SOM SS

iTrader: (11)

You need the GM tool to correctly install a ASP, also, I believe. WJ. <img border="0" title="" alt="[Wink]" src="gr_images/icons/wink.gif" />

MIGHTYMOUSE

iTrader: (59)

heres the cut to the chase..

for good measure dont re-use and old bolt, get one from a dealership ahead of time

to unbolt put in gear if stick or jam up the flexplate if auto with a screwdriver.

unscrew bolt, use short 3 prong puller to remove pulley.

to put back on lubricate crank nose and iside of stock balancer set balancer on crank nose (should be a very very tight fit, NOT slide on.

tap around the pulley with a hammer turning the engine over to keep it even until you can get some threads started on the old bolt

using the old bolt, pul the pulley on with it and torque to 37# then 140*

after that remove the old bolt and put in new one with red locktite (for good measure, why not?, works for mine) and tighten to 240#

not complicated, just go step by step

when installing underdrive, all else is the same, other than it will go on and get threads without having to hammer around it.

WJ SOM SS

iTrader: (11)

WhtFast: Was it your stock crankpulley that fell off, or a aftermarket underdrive pulley, and which brand? Please respond. I have never heard of a stock LS-1 pulley falling off, unless it had been removed previously. Let's clear this up for everyone. Best wishes. WJ. <img border="0" title="" alt="[Wink]" src="gr_images/icons/wink.gif" />