Balancer hub slippage
Thread Starter
Burning Brakes
Joined: Feb 2004
Posts: 958
Likes: 1
From: In the Beautiful Shenandoah Valley of VA
Balancer hub slippage
I know that there has been much discussion in the past over balancer hub slippage, and some people haven't been sure how this could happen or what it would look like. Well, my 1974 LS-4 hub had slipped about 20 degrees, so I had to replace it. Once again, a Corvette forum member came to my rescue (forgive me, I can't remember who) and sold me a good used unit that he had.
Anyway, I thought it would be interesting to some to see just how much a hub can rotate, so I placed the new and the old units side by side and took a picture.
Both hubs are placed so that if installed on a crankshaft, TDC would be facing straight at you. As you can see on the one on the left (the original), the timing mark is off significantly. I painted the white dot to represent where the TDC mark should be. So you can guess what one of the reasons was for this engine to be "running rough" when I purchased it. Even if a mechanic had set the timing to specs, with this balancer, it was off by at least 20 degrees.
The moral of this story is to always expect the unexpected and you won't be disappointed. Hopefully, this is a good illustration for those who have never experienced a slipped hub.
Steve
Anyway, I thought it would be interesting to some to see just how much a hub can rotate, so I placed the new and the old units side by side and took a picture.
Both hubs are placed so that if installed on a crankshaft, TDC would be facing straight at you. As you can see on the one on the left (the original), the timing mark is off significantly. I painted the white dot to represent where the TDC mark should be. So you can guess what one of the reasons was for this engine to be "running rough" when I purchased it. Even if a mechanic had set the timing to specs, with this balancer, it was off by at least 20 degrees.
The moral of this story is to always expect the unexpected and you won't be disappointed. Hopefully, this is a good illustration for those who have never experienced a slipped hub.
Steve
Melting Slicks
Joined: Feb 2003
Posts: 3,053
Likes: 4
St. Jude Donor '03,'11
all stock type balancers with outer ring pressed on the rubber are going to slip. There is a procedure in the Chevy Power manual to pin it which allows it to viberate but not slip.
Another alternative is to buy a balancer cover from Jegs or wherever for about 35 bucks. The cover bolts over the whole thing and is held in place by the 3 bolts on the inner portion of the balancer which is keyed to the crank.
Another alternative is to buy a balancer cover from Jegs or wherever for about 35 bucks. The cover bolts over the whole thing and is held in place by the 3 bolts on the inner portion of the balancer which is keyed to the crank.
