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Harmonic Balancer Remove/Install ????

I have a 250 straight six which I am currently restoring. I would like to pull the balancer in order to clean the front of the motor. The question I have is that the center of the balancer is not threaded. I know I can pull it but how do you press it back on with nothing for the puller to grab on to? Any help would be appreciated. Happy Holidays! Billy


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Hmmm. Normally when installing a balancer you would thread the stud into the crank. Then you would use the large "nut" to thread onto the stud pulling the balancer onto the crank.

Normally a crank has a "cone shaped" hole which is actually just the thread hole that has been countersunk. Are you positive there are no threads in the crankshaft? That's where the bolt goes that holds the balancer on the engine.
 

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Early engines didn't have balancer bolts they just pressed on. Everyone and I mean everyone used a BFH to install balancers. Bolts were installed in the later 70s engines. I think you have two options. You can tap the crank hole so you can use a bolt and an installation tool or you can do what everyone did before the bolt. Beat it on with a BFH. RM
 

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Early engines didn't have balancer bolts they just pressed on. Everyone and I mean everyone used a BFH to install balancers. Bolts were installed in the later 70s engines. I think you have two options. You can tap the crank hole so you can use a bolt and an installation tool or you can do what everyone did before the bolt. Beat it on with a BFH. RM

You're kidding right?

What year did they start putting threads in the center hole for the balancer/pulley?

I have a forged GM crank that's threaded, I thought my crank was from an L78 396.....maybe not?

Also wouldn't hitting the balancer on with a BFH hurt the bearings??????
 

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Hi,

I agree that a lot of early engines were not taped. I think all big block cranks are taped (Im not referring to 348-409 style). I think in the 60s only "Special High Performance" and heavy duty style truck engines came with the crank drilled and taped.

If it were me I would "carefully" drill and tap the crank and pull the balancer on. Its a good safety feature as well.

Good luck

Jeff
 

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If you don't drill and tap the crank, make sure the crank nose and the inside of the balancer are clean and smooth and heat the balancer to about 200 degrees before putting it on with the BFH. I don't think that you should get it any hotter or you might ruin the balancer.

John K
 

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When I went in the Army in 1966 there were no bolts in the cranks on any GM cars I saw and worked on. My 62 model 340 HP 327 didn't have one. I lost a balancer once and we drilled it to keep that from happening again. It never hurt the bearings to use a BFH to install the balancer and back then they didn't make cast cranks, all the cranks were steel. They went to the bolt while I was in the Army cause when I got out we installed a cam in my buddies new Z 28 and it had the bolt. My best guess is the bolt came out in the mid to later 60s. Everyone I know pretty much used the BFH method for installing balancer until the 80s when someone made a installer tool that people could afford to buy and advertised it. Now everyone thinks that a BFH is a terrible way to do it. If I didn't have a tool I'd use a BFH in a skinny minute but I don't suggest everyone else does. Tap the predrilled hole and buy a tool. RM
 

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Hello.

I think RM may be right about the 340hp 327 not being threaded, but it seems to me the 350hp -365hp series starting in 65 may may have been the first hp style to threaded. I think the big blocks started and in 65 and I think they were threaded.
As far the any GM cars goes I think a lot of the Buick-olds- pont etc- used bolts in the early 60s as some had "slip" fit style balancers, These generally use a very large bolt (5/8-3/4?).

As far as "hammering" the balancer on that is the way it was done. I have factory Chev service manuals, showing how to do it. If the engine is out, and you have room to swing the hammer, the "bigger" nylon style dead-blow hammers are great. They generally wont damage the balancer at all.

If engine is in the vehicle its a bear no matter what.

A little oil on the surfaces helps and I always add a small amount of silicon in the keyway to help prevent oil seeping through.


Good Luck

Jeff
 

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Leo's Book

In respect to Six's I would read the pages in Leo performance book on proper removal of a Harmonic balancer.
 

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Big f..kin hammer = BFH. Merry Christmas. RM
 

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Checked my crank threads this weekend, they appear fine - thankfully! The keyway area is not so lucky - but something did this to my balancer :eek:
Any ideas? I'm thinking a loose bolt.
M

 
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