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I replaced the rings on my 1951 300 when I removed the engine and transmission to replace the transmission since I only had reverse and low. I cleaned all the carbon from the piston ring lands, gapped the piston rings. I plastic-gauged the rod bearings and only replace one set of bearings. When I put it back together I cranked the engine without he head. I cranked fine. After I put the head on last night the engine cranks very slowly. I cleaned, tightened, and put dielectric grease on all the cable ends.
Help. And how difficult should it be to turn the engine over by hand? Thanks in advance

Not clear on where you applied the grease but if it is preventing direct metal to metal contact that could be an issue.

The grease is insulating and generally used more as a seal to keep moisture out. Typically between the rubber boot to the ceramic portion of plugs or on other rubber or insulating components of various high voltage applications. The actual terminal connections are clean.

If it is on the battery posts and inside of cables or between cable ends and metal terminals elsewhere I would remove it. Would also make sure the battery is at full charge & hasn't discharged some from sitting. If it is cold it might not be able to produce quite as much output either.

I had slow cranking on my 51 300 and it ended up being the battery cable were defective. Too much resistance I changed them and it made a lot of difference. I still need to do the type of work you did to your engine though.

Thanks guys,
I went out and cleanded the cable ends and connections at the starter and at the block with acetone. I will try to start the car tomorrow. I'll let you know what happens
Casey Rog

Cleaning connections with acetone would only remove oil or grease residues but not corrosion, rust, etc. Best to clean the connections with a wire brush or steel wool or abrasive cloth after any oil or grease has been removed.

What you need to do is a split-half search. Basically, you need to figure out if it's an electrical issue or a mechanical one. The electric tests are easier to do and will permit you to eliminate the easy stuff first. The Tune-Up Training Manual (available under literature and manuals-https://packardinfo.com/xoops/html/modules/article/view.article.php?50 ) goes through all of the electrical tests and most can be done with your average multimeter-- that way you can clear the cables, the battery, the starter, and the ignition switch as possibly causing your issues. High resistance in any of these would cause the issue you describe.

G'day DrewLA,
Somehow I missed your first post, #4 of this thread, back in September. A belated to Packardinfo.

And I invite you to include your '52 Patrician in the Packard Owner's Registry here on PackardInfo!

I cleaned all the cables, with a wire brush etc,I even wire brushed the bell housing where the starter is attached. Still very slow cranking, The starter ran fine until I replaced the rings. I miced the replacement rings vs the original rings and they are almost identical (I got the replacement rings from Kanter so I am assuming they are correct. Any Suggestions?
Thanks,
Casey Rog

Assuming you checked and gapped the new rings so they have the proper clearance and none of the rod inserts slid out of position and are now binding against the crank, then I don't have any

I think the key word there was "gapped".