Harmonic Balancer/Crankshaft Disaster (?)

[Mark H.]

Was installing the balancer tonight - after much thought had the machine shop drill and tap the crankshaft for a snout bolt. Decided to pull the crank (new GM replacement) using different length bolts and a variety of washers. Went on about 2/3 fine, then hung up. can't be on all the way because it's still a ways back from the front cover and much to go to get the snout of the crank close to the face of the balancer. Anyway, removed the bolt and found the threads we starting to get a bit messed up. Ran the bolt through a 7/`6 x 20 die, straightened right out. Then I decided to run a tap in the crank to make sure I hadn't cross threaded them. I found a helicoil in there!!! In fact, I wound up with about 1/4 inches of it hanging out the front of the crankshaft before I knew what was going on.

This was quite a surprise, to say the least. Is using a helicoil (at least that's what I think it is - spring like coil in there now hanging out, looks a bit like an over-stretched slinky) normal in this application? If so, can I put a new one in? Any suggestions on how to install the balancer? I always thought pulling them on like that was the safest way to go and better than beating it with a mallet.

I'm pretty discouraged.

[roy braatz]

Re: Harmonic Balancer/Crankshaft Disaster (?)

First the keeper may have moved back or your using the wrong size ,that is probably the trouble your having.
Some times when you remove a bolt the helicoil can come with it.
The machine shop should have not helicoiled the hole but taped it.
Now you need to install a new helicoil.
Yes don't beat the balancer on Drive it on that is the way it's done.

[Craig S.]

Re: Harmonic Balancer/Crankshaft Disaster (?)

Mark - while a helicoil would not be the norm for a crank snout, I should not hurt anything. You will have to replace it based on your comments though. And you are correct that you should not beat on the balancer, but, there is a special puller to remove the balancer, and another tool to install and draw on the balancer. You should not use the bolt itself to draw the balancer on as you observed when the bolt was damaged. The installer threads into the snout, but has a larger diameter threaded shaft with a large ball bearing thrust bearing to pull the balancer on to the crankshaft. These can be obtained from reputable suppliers such as SUMMIT, or local jobbers. RIMAC makes an excellent example of this tool...Craig

[Clem Z.]

damper installer

can be rented at some of the larger auto parts stores. you can install the new heli coil after removing the old one by taking a 7/16" bolt and cutting a notch in the end to grab the tang on the new insert. once you get the new insert what you have to do will be easy to see.

[Pierre J.]

Re: Harmonic Balancer/Crankshaft Disaster (?)

Check on eBay, there is a few harmonic balancer puller/installer kit in the $55/60.00 range.

Good luck,

Pierre G. Joly $34410

[William V.]

Re: Harmonic Balancer/Crankshaft Disaster (?)

also check out COMP CAMS for a balancer instalation tool.

[Joe L.]

Re: Harmonic Balancer/Crankshaft Disaster (?)

Whatever balancer installation tool you obtain, make sure that it's the type that uses a BALL or ROLLER THRUST BEARING between the nut and the balancer. Some of these balancer installers are supplied with only a large, thick flat washer for the "bearing". You DON'T want that type. If you happen to get a good deal on this type, though, you can upgrade it with ball or roller thrust bearing that you can purchase from an industrial bearing supply.

[Rich Benjamin,jr]

Re: Harmonic Balancer/Crankshaft Disaster (?)

Since you already messed up the threads/ coil in the end of the crank I would not use a tool to install the balancer. The early chevys and sixes did not have a tapped crank end. I have installed dozens of these balancers with a block of wood and a 3lb hammer. You can warm the balancer with a heat gun or a propane torch slightly,(This is a good idea with any press fit assembly) make sure it is started squarly and drive it on.Two or three solid shots is all it takes.I have over 25 years as a full time mechanic and put the balancer on this way on every engine I ever worked on , tapped crank or not. Do not over think yourself or get to technical. Good Luck.

[Ronnie Robertson # 36786]

Re: Harmonic Balancer/Crankshaft Disaster (?)

Mark,
You have two options:
1. If you have not reinstalled the engine, take it and the balancer to the shop and have them install it.
2. Take the engine back and have the snout rebored and tapped for a 1/2 " bolt.

The balancer does not go back to the timning cover. Measure before installing to determine the correct position.

Lastly, Make a note: "DO NOT use that machine shop again."

[Mike McKown]

Re: Harmonic Balancer/Crankshaft Disaster (?)

Best thing I've heard all day. That's the way I've done it a hundred times and never had a problem. I don't own a tool to "pull" the balance back on. And, like the man said, don't try to get too technical.

[Theo]

Re: Harmonic Balancer/Crankshaft Disaster (?)

This is interesting, since i'm soon to be pulling my balancer off to replace the front crank seal. The warming up idea sounds good, but am i right in thinking the front seal actually runs on the shaft of the balancer itself? If so, if it got too warm it might melt the lip of the seal when you whack it back on? Not done this yet, so i'm not totally sure.....

[Craig S.]

Re: Harmonic Balancer/Crankshaft Disaster (?)

Theo - the seal does indeed ride on the snout of the balancer. However, the seal can take quite a bit of heat, it obviously does when the engine warms up when running. I think the idea is to warm it up some but the crankshaft is cold, letting the balancer drive on easier. Since I a a tool kind of guy, and I have always have threaded cranks, I have never tried beating one on...Craig

[Theo Law]

Re: Harmonic Balancer/Crankshaft Disaster (?)

I guess my immediate thought was that if the balancer shaft was hot enough to actually make it expand a significant amout, then it might be hot enough to melt or damage the seal. Still, as you say, things must get pretty hot down there normally...
I think you'd need to be careful with your gas torch or whatever, 'cos it would be very easy to make that balancer shaft very hot indeed - need to find a happy medium i guess. I don't have any heating equipment, so i'll be using the thread (carefully!) when i do mine next week!

[Clem Z.]

Re: Harmonic Balancer/Crankshaft Disaster (?)

if you want to heat the balancer use a electric hot plate and set the part that goes onto the crank on the hotplate. the seal should take 250+ degrees as the oil temp will go that high