We freshened up my buddy's 528 Hemi. It had 170 passes on it. 20 since he had bought it. All we did was replace the rings and bearings and removed the roller cam and put in a flat tappet. We installed the ATI balancer with the proper tool, used an ARP bolt and torqued the balancer to the 135 ft lb stock spec. After one pass the harmonic balancer bolt was not tight, maybe had 30 ft lbs on it. We retorqued it made another pass and some idling around. Checked it again and it had around 30 ft lbs on it. Any ideas? Thank you.

When I had an ARP bolt in the damper on my 500" 69 Dart it would NOT stay tight. I don't know what I was doing wrong.

Are you SURE the balancer is bottomed out on the crank..
in a lot of cases 135# wont move the balancer if your
trying to pull it on... I cant say why its coming
loose.. I've never had that issue on my SB stuff

Clean the threads and put it on with red loctite ???

The pulley system they had on the 499 had a front one with a 3/4" square hole in front so the engine could be turned over by hand. When I pulled them of fthe bolt was rattling around loose inside the cavity between the rear and front pulley. Haha, that is what that noise was (among other issues). My guess is they didn't have the dampener on all the way and you can't get the right torque otherwise.

The new ATI balancer we installed at the beginning of this year would not go on all the way unless it was honed out. On some aftermarket cranks the tolerances are a little on the high side making the fit too tight.

I had an engine that the bolt came loose after each run and after 5 runs 2 aluminum rods broke blowing a big hole in the block. I hope that is not your problem. I have never used any locktite on a dampner bolt. Should not be necessary. I think maybe your dampner is not seated on the crank yet.

I tighten, especially Hemi motors , to at least 250 lbs, the bolt is a 3/4x16 so it will take a lot more Did you use any antiseize on the inner hub and crankshaft snout? If not try that also

Make sure the damper is fully seated with the tool, then run the bolt down to spec. Then a short burst with the impact. If you don't do the impact, you can't roll the engine over by hand.

I will try your suggestions. Thank you.

Do you guys heat up the balancer in boiling water before putting it on, making sure to lube the ID first?

I can honestly say the only harmonic balancer bolt that I've used lock-tite on has been the small 7/16 bolts that Chevy uses and never had one come loose. Those chevy bolts SCARE me.

Mine kept acting like it was coming loose - but it was because I never actually had it all the in to the stop. The last time I had it apart - I honed the inside of the balancer some and now it goes on nice and stays tight. No locktite required.

i use a bolt long enough to engage about all the threads in the crank with the balancer fully seated.

A balancer bolt should not need Loctite to stay tight. The dampner, if done correctly is a press fit, on a straight shaft. There shouldnt be much load trying to " push" it off the crankshaft.Although belts and drive accessories could contribute, especially if out of balance) The press fit holds the dampner on, not the bolt. The bolt is a safety precaution more than anything. Its a massive 3/4" bolt, it takes a lot to hurt one, and a lot to torque one.

The only things that SHOULD loosen a dampner bolt by itself are:

A bad dampner, or a bad balance job ( or components)

A dampner that is not fitted properly or pressed on all the way.

Sometimes the hard finish of the ARP type bolts need a burnishing with a wire wheel etc as they tend to be slick as finished, or covered in protetcive oils. Make sure to spray some brake clean etc in the damper hole fo the crank. to make it grease free and dry.

My