1964 429 question

[g27g28]

My nephew has purchased a 1964 4 window series 62 and noticed the harmonic balancer was loose.  As he tore into it the front part of the crankshaft seems to be loose and has him and myself baffled.  Can anyone shed any light on what might be going on with the crankshaft.  Thanks

[The Tassie Devil(le)]

Are you saying that the front snout on the crankshaft is loose?

If so, then I would be suggesting that there is a serious break in there, and the front part is only being turned by some unevenness of the break.

Bruce. 

[russ austin]

Or the outer ring on the balancer is loose, and so is the hub on the shaft.   Now since the balancer is a press fit, with no bolt holding it on, there is a question of if flying off the crank.

[Caddyholic]

I had the same thing with my 61 390. It turned out that when the engine was rebuilt by the PO the shop use a crank timing gear from a 331 which is thinner so the balancer would not bottom out against the gear and the crank.

[g27g28]

He pulled the harmonic balancer off but there is movement in the shaft.  I find it hard to believe that the crank would somehow break forward of where there is little to no stress.  He says it's almost like the crankshaft was built in two pieces and the front part is loose from the back part.  This looseness seems to be before the first journal as it still ran before he pulled the front part off.

[The Tassie Devil(le)]

It is possible for anything to break, and still be retained.   It all depends on how jagged the break is, and where.

I have seen a crank that was broken and still turned.   Some things work out funny in the mechanical world.

It broke at the No. 1 Journal, and the break was within the big end, and it was the width of the big end that kept it together.   Like a circular splint.

Bruce.

[g27g28]

Well he found that the crankshaft was broke right before journal 2 and that journal 1 was worn bad.  Hard to believe a crankshaft would break there but it did.  I think he is leaning towards putting a modern gm engine in vs fixing what he's got.

[The Tassie Devil(le)]

Got to have pictures.

As I said, mechanical things do different and interesting things, more often than one would realise.

Bruce.

[russ austin]

I have a crank if he needs one.