99pewterc5

has any one had this problem? it was fine before cam swap. now I can not keep it tight. I replaced the bolt and went with the torqe specs .

dave777

I had the same problem after cam swap. Got a new GM bolt and had the same problem still. Somehow the bolt stretches. I bought an ARP bolt, no problems since.

Patches

I've seen this happen when re-using the crank pulley. It seems that the looser fit the pulley has upon reinstall (it's a non-keyed light press fit) could allow it to more easily push against the bolt flange causing the bolt to loosen up. The ARP bolt is a good solution also.

IFLUBYU

I used a stock crank bolt, did everything to spec, but with a new asp ud pulley, did not pin the crank either. No problems after 4k miles, and around 30 runs at the strip. I have changed the oil twice and check it each time I change the oil.

Good Luck!

rwj383

pin the crank and be done with it. Magnuson sells a slick kit that comes with everything you need to do it except the drill itself, for about $90. I pin every pulley when I do anything that involves taking the stock pulley off.

Robert
www.gen3motorsports.com

SideStep

My buddies and I have made part our stand cam install procedure....

corvettebob1

Here's a littlle known secret, if you pin the crank there can be no relative motion between the balancer and the crankshaft.
And for this reason there really is no reason to fight to torque the bolt beyond 150 ft lbs.
For added insurance I would use an ARP bolt (they don't strech) and some high strength loctite.
Just a little info passed on to me from a fastener engineer friend.

Jackal

I agree with corvettebob1, there is no reason to go to 250 ft lb if you pin the grank. Just use some high strength high temp locktite and it will be just fine.

kromberg

With my crank being keyed for the ASP Harmonic Balancer from the F-1R kit, I torque the ARP crank bolt to about 150#.

Keith

530hp_zo6

same thing happed to me after heads &cam install. i bought a new balancer and bolt. so far no problems!!! im suprised nobody mentioned that you HAVE to use lock tight when installing the new bolt.

99pewterc5

thanks to all I will try that .Larry

530hp_zo6

look at this , might help :: http://forums.corvetteforum.com/showthread.php?t=884180

dddz06

i am having that same problem right now. This is my second time my pulley came loose. My pulley went on very tight going top try the arp bolt an some high strenth lock tight an see how that work

IFLUBYU

I'm not surprised at this, because neither the GM service manual nor jmX's www.ls1howto.com say to use lock-tite on the crank bolt. I didn't, I used a stock bolt, torque/stretched it to specs, and it's tight as a rat's ....



Remembering how hard it was to get the stock bolt off without lock-tite on it, you should pray you never have to take that one off.