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Pilot Bearing Problem on a Poly

Posted: Fri May 14, 2010 4:38 pm
by dspeed
Back from travel, yard work caught up (well, sorta), the DTA headers are here and I'm back to work on the Poly.

Looking through the manual, I could not find a torque value for the flywheel bolts - seems that I'm not the only one with this problem. Anyhow, I settled for 55 ft pounds as appropriate for that size bolt.

After some thought, it seemed to me that I had to remove the clutch/flywheel before getting the bellhousing off. After the discussion here and looking it over, I did not see what an issue. was. Installing the flywheel first was fine.

But now, I'm stuck on a pilot bearing issue. Is there more than one size? I bought a new one from Rock Auto. It fits over the transmission shaft nicely. It is a Dorman pn 14652. After a good cleaning, I cannot see or feel a bearing or shoulder (of an old bearing) inside the crank. I pulled the pilot bearing out of another crank (labeled as 'old' below) one out of another crank (on a -2 block. This bearing was obvious. They are both essentially the same size and match the nominal dimensions on the package as shown below:

new old
package measured measured
dimensions dimension dimension

length 0.873 0.875 0.878
id 0.753 0.750 0.755
od 0.939 0.940 0.938


I can get a Sears 11/16" deep socket (OD 0.920" into the old crank handily. I can't get this into the new (aka 'installed') crank. My calipers don't reach quite that deep, but I'd say it was 0.900 or 0.910 diameter. The new crank was from a -1 block and the old crank was from a -2 block.

Any thoughts?

This has me stopped for the moment. I have another good crank 'old', but would hate to pull this one out. I have a friend w a lathe and could take 0.020 off the bearing. Or use a brake cyl hone on the crank? Or use a bigger hammer?

Dave

Re: Pilot Bearing Problem on a Poly

Posted: Fri May 14, 2010 8:03 pm
by Nuthinbutmopar
Sounds like your "installed" crank was from an automatic transmission engine and wasn't machined for the pilot bearing. Don't know if there's an easy fix at this point...

Re: Pilot Bearing Problem on a Poly

Posted: Sat May 15, 2010 1:23 pm
by dspeed
OK; I have the auto trans crank that wasn't bored the whole way to 0.940 ID on the crank.

Rather than disassemble the whole mess, I made a 'lathe' out of my el cheapo drill press, a long impact socket and some hardware as suggested by Paul on the Poly mailing list. On slow speed, using a mill bastard file, I took the OD of the bushing from 0.940 to 0.915 where it tapped in nicely (I gave the starting end a little bevel for good measure).

The rest of the assembly went OK; just the usual challenges of aligning (to me) heavy parts with various blocks, pry bars etc.

Ready to drop it in now.

Thanks for everybody's help!

Dave