MTFCA Forum

Quick question….. recently got my T engine back from a Babbitt shop…. I pulled a brain cramp and neglected to tell the shop to remove the old crank gear…. getting the gear pulled was quite the project….. the crank is in the block so obviously I didn’t wanna get any heat near the front main Babbitt so I just increased the pressure on my impact gun and removed it. It took about 160 pounds…. So the question is, should I heat the new crank gear at all before trying to press this back on to a 100-year-old crankshaft?…. My gracious that gear was tight coming off. I can only imagine the new one will be just as tight, pressing it back on…. I figured I would just heat the gear in the oven rather than risk getting too much open flame heat on it. ….as always chums, thanks for the input!

Cheers!

Ed

I think you should remove the crank, rather than put your new babbitt, or even the block itself, at risk. Yes, it's a pain, but it's not difficult and you'll have it out in under an hour.

Agreed. Much better to use a press than beat it back on.

If your crankshaft was installed in a newly babbitted block and you used an air hammer at 160psi from the backside of the gear to drive the gear off, you may have damaged the the babbitt work and crankshaft alignment. The 3rd main thrust surface may be opened up beyond service limit and the 1st main bearing clearance could be enlarged too. If either of those two has changed, it is likely to have bent the crank too. It should come all apart and all the parts should be verified now.

If heated, don't go beyond 300 F. degrees. This would increase the bore by about. 002 in. which would significantly reduce the installing pressing force. Can't give exact numbers without knowing the geometry.

Art Mirtes

I assume you used a puller to get the old one off and not a hammer? The last thing you want to do is assault the rear main thrust bearings with a hammer. I always press new gears on before I install the crank but I can’t do that with counterbalanced crank like Scat so I heat the gear to 450 degrees and it will slide right on and shrink. No reason you can’t do that with the crank in the block.

Eric Barnett…..exactly….thats what I came up with…worked like a charm

And yes Eric….used a 2 arm puller and impact wrench