View Full Version : harmonic balancer bolt

12-20-2001, 05:41 PM
I have a 66 chevy van with a 230 inline six. This may be a dumb question, but is there supposed to be a bolt holding the harmonic balancer on? Thanks

12-20-2001, 05:53 PM
Believe it or not, the harmonic balancer on Chevy inline sixes is called a "drive on" type balancer in the factory manual. Accompanying this statement is a photo of a man in a lab coat using a hammer and a block of wood to "drive" the balancer on the crank!
I just went thru this on my 70 when the balancer disintegrated on the freeway at 75mph on the way to Taz's party. You use a puller to remove it, and a hammer to install it. Just don't hit the outer ring.

12-21-2001, 04:08 PM
interesting question.my 66 was also missing the bolt head.i wound up drilling with a tunsten carbide drill bit(real american made one not a harbor freight special)and taping the crank.still unsure if it ever came with one but now it definitely has one one.mine will definitely not come off.can anyone else substantiate my claim.

12-22-2001, 07:00 AM
You drilled the crank? How long ago did you do this? How many miles ago? I briefly considered doing this to aid installation, but was afraid of weakening the end of the crank. Sounds like a good mod if it doesn't weaken the crank.

12-22-2001, 09:05 AM
still in the process of putting my 66 back together and have not ran the engine yet.all i can tell you is that if you don't use a professional grade "cobalt tip" you won't do anything besides round out your bits.the one i used cut like a knife thru butter.as far as working i'll keep you posted.

solid side 65
12-22-2001, 06:10 PM
I had my crank nose drilled and tapped 7/16"-20 while the machine work and balancing was being done, it was a very minimal charge. Most of the V8 cranks started coming with the nose tapped in 68-69, I don't know about the sixes. After measuring and setting all the clearances especially crank-main bearing end play it seemed silly to beat it on with a hammer. A friend had his balancer come loose and go into his custom radiator, this was my inspiration.

12-22-2001, 08:08 PM
I tried using a porta-power to press mine on the 70, clamped a piece of 3"x3"x1/4" angle to the frame rails, worked up to the last 1/4", then I had to wield the mighty Sledge-O-Matic. Actually, as soon as I find a suitable donor car I'm swapping in a V8/TH700 so I'm not real concerned about the six...

12-23-2001, 01:10 AM
Over ten years ago (when I built my current engine) I drilled and tapped my (cast) 327 crank using an ordinary HS bit. But it's only 5/16-18, so I can't use it to pull on a balancer.
Inspired by having a balancer fall off and roll down the street. --- TV

12-23-2001, 04:49 PM
Being that my job entails dealing with press fit tolerances (I do repair on stamping presses) in my opinion if you have press fit balancers falling off then someone at some time installed the balancer incorrectly, i.e. got it started at an angle, and stretched the hub out of shape. I've rebuilt 1000 ton presses where the only thing locating the clutch/brake assembly is a key and a .001 per inch press fit. (on a 3" shaft, hub is .003" smaller than shaft diameter). If you start them on crooked, it will either gouge out material or stretch it oblong, either way, you no longer have a press fit. Also, on an engine that is more than 15 yrs old and is going to see high rpm's, you should replace the balancer anyway because the rubber ring disintegrates with time. Trust me, I know. I saw the outer ring of my balancer skitter of down the hiway at 75mph....

12-24-2001, 11:41 PM
Actually, I think the hub cracked along the keyway, causing the loss of press fit. --- TV

12-26-2001, 07:38 PM
consistent with what I said below- I've learned the hard way on many things....ask what it feels like to grab a 2nd anode lead on a tv that's on..... http://www.vcvc.org/ubb/eek.gif