[6d7gto]

I took off the lower crank pulley and 3 piece harmonic balancer in order to bead blast the pulley then zinc plate it before painting everything the correct engine color. I thought it was painted black but research told me it was engine color from the factory on my application. Power steering, no air conditioning.

Anyway, I noticed that the balancer hub can move slightly independent of the crank. This is the heavy piece (with the timing grooves) that the dampener actually bolts to via 6 small castle head style bolts and that special plate in between. This is the way they did it before going to the one piece dampener system in 1968.

Is this very slight movement normal? Or is the crank bolt supposed to hold this piece on tight and mine is defective? I am assuming the crank bolt is fully tightened as the engine was recently rebuilt by a professional engine builder.

[Kenth]

With 160 lb/ft on crank bolt the hub must NOT move.
If it does, check for too long bolt or too long snout on crank or incorrectly machined hub (too short).
And, if the hub has been loose for some time it may be cracked at crankshaft key.

[6d7gto]

Thanks Kenth. Can you recommend a flywheel locking tool in order to remove the balancer hub bolt? Engine is on frame with no drive train yet.

Robert

[6d7gto]

Just thought of an idea how to remove that 160 lb bolt. The 4 speed trans and clutch have been installed. What if I put the trans into two gears at the same time? Would that work or possibly mess up the transmission?

[6d7gto]

Putting trans in reverse and 2nd worked. Found out what was wrong. Ugh...the crank is longer than the hub! No wonder it was able to move, the washer wasn't even touching the hub. Can't believe the engine builder didn't catch that.

Any help would be greatly appreciated. Did the early hubs come in different thicknesses? Mine is almost 1/8" too short. This is an NOS balancer...supposedly for 1967. If all the hubs are the same thicknesses, could an outside washer be welded on to the hub?

[Kenth]

1959-62 389 damper hubs are aimed for 2.50" long crank snout.
1963 and later crank snouts are 3.00".

http://www.pontiacpower.org/PontiacCranks.htm

Aftermarket new damper hubs are for 1959-67 cranks.

https://aacincdirect-com.3dcartstore...-428_p_75.html

You can get by with a later hub on earlier crank, but not the other way around.
You may have got a 1959-62 NOS hub for your 1967 crank?

[6d7gto]

Turns out I had two NOS sets. Both were supposed to be for 1967 but one hub is deeper where the fat washer secures the hub to the crank. Obviously the wrong year hub was used. The other one looks to be correct.

After removing the wrong hub I found out the oil seal was damaged (probably from not being tight). Will order a new front seal from our sponsor or see if someone has a better one on this forum they'd like to sell.

Not sure why, but the correct hub does not slide easily onto the crank. The wrong one also has trouble getting started so pretty sure the crank is slightly messed up on the outer portion. Is it okay to tap the correct hub on with a rubber mallet after installing a new seal? Or should I file the outer edge of the crank?

Again, any help will be greatly appreciated. Thank you kindly for your great information Kenth! You have saved me more than once before and you are a tremendous asset to this forum.

[Goatracer1]

You can clean it up with some fine wet/dry sand paper. Just don’t get carried away. You can try a rubber mallet but a dead blow hammer would work better. You can also use a hub installer like the Chevy guys do. If you can’t find one that works on a Pontiac you can make your own.

[lust4speed]

I'd stay away from the hammer. First blow pushes crank thrust back on bearing and additional blows go right to the bearing.

Not unusual for either (or both) crank snout and/or hub to be off. Since the crank is in engine and timing cover is on I'd simply work on polishing the ID of the new hub until it can be slid in place. Wouldn't hurt to dress the end of the snout but I'd still concentrate my efforts on the hub.

[6d7gto]

Thanks for all the great advise!