1320IN9

going to pin the crank soon. can i take off the bolt with an impact gun? and when i install the new bolt what is the torque spec? thanks

BowlingGreen00

A good impact should do the job for removing the old bolt, that's how I did mine. I forget the torque specs but I do remember that it has to be stretched so it's pretty damn tight. Don't forget to use a new bolt and red loctite.

aquachuck1

If I remember right it comes from the factory at 240 ft/lb. My impact gun couldnt move it. I used a breaker bar with a length of pipe on it to get it off (If you have a manual put it in 4th gear).

Bill Curlee

WRONG INFO!!!!!

If its a stock OEM damper bolt, Its NOT 240 ft/lbs !!!!

FOLLOW THE SERVICE MANUAL instructions. It's seated with the old bolt and then the new bolt is installed and is torqued to 37 ft/lbs and then angled torqued to 140 deg. I can never remember all the steps so I always refer to the installation procedures.

If you dont want to damage the crank or have it come loose, break out that service manual.

BC

timemender

The GM bolt is TTY (Torque To Yield) – procedure listed below.

a. Tighten the crankshaft balancer bolt a first pass to 50 N·m (37 lb ft).
b. Tighten the crankshaft balancer bolt a second pass to 140 degrees

If you use an ARP (aftermarket) bolt, it is NOT TTY and is tightened to a torque value of 240-ft. lbs.


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SDPC

Unless you have a REALLY good impact, it's not going to even try to get the bolt out.

I prefer to go back with an ARP bolt instead of factory. Reusable, and just a straight TQ spec instead of TTY.

Bill Curlee

I agree 100%

1320IN9

thanks guys, the pin kit comes with a factory bolt so i guess i have to do the 37 ft lb then another 140 deg. yes it's a manual so will 4gear hold the motor when doing the 140 deg final turn?

aquachuck1

I was using an aftermarket bolt....so 240 ft/lb was correct for it. Sorry I guessed the same was true of the factory torque. Wondering how many foot pounds is 37 ft/lb plus 140 degree's??

On my manual....I tried first gear and almost rolled it off the jack stands...a fellow forum member advised me to use 4th gear and the car didnt move ....but always block it anyways.

thetaxman

I disagree
If you have an adequate air supply ( pressure and volume) it should come off easily unless your gun is total garbage
Even my 30 year old ( pre china ) CP gun will do that.
My Blue Point or IR guns will knock that off w/o even a thought

navy99vert

I have an OK air gun and it didn't move the bolt. I used a friends Snap-On and it took it right out

SDPC

Depending in which CP you have, you would obviously be an exception to the rule There is Central Pneumatic and there is Chicago Pneumatic. One is Harbor Freight knockoff style, and one is the hardest hitting impact I've ever owned. It owns my Snap-On in every way including hitting WAY harder, and is around 20 years old.