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What is the advice of your engine rebuilder? I'm assuming he's familiar with these engines? I don't know how willing they'd be to giving advice to competitors, but there are shops that make a steady diet of doing these engines who have encountered and solved this other times.

Tom,

One process that I've used with success on worn cam bearings for the early Packard's is to bore the cam bearing oversize and metal spray or hard chrome the cam bearing journals oversize. The oversize journals are then ground down to provide the correct oil clearance to the cam bearings.

Since the cam bearings for the early models are not Babbitt lined, but solid steel or cast iron, boring them oversize is one option. Another option would be to bore and re-bush them, but I don't like this option because you have to make sure the bushings will never loosen up and move.

Some places will weld up the cam journals then grind them back to size but I prefer the metal spray or hard chrome option because these do not distort the cam due to the lower heat generated for hard chrome or metal spraying.

I've had good luck with Delta Camshaft:

http://www.deltacam.com/

A video of the metal spraying process at Delta:

http://www.deltacam.com/services.php?p=2

You may want to contact:

http://www.effinghamregrinding.com/aboutus.htm

or

http://www.elgincams.com/

A good house can take your cam bearings, bore them out and then respray or re-chrome your camshaft. They should also be able to supply written data on the re-ground cam lobes to show that the correct lift has been restored.

One comment on checking the Packard camshaft on these models, a common problem with these camshafts is twist because of their length. Even if the cam lobes look OK and don't look like they need a re-grind, check each came lobe after checking the straightness of the camshaft bearing journals.

The cam lobes can easily be checked by supporting the camshaft between centers in a lathe and then using a dial indicator to measure the base circle of each cam lobe. Slowly rotate the cam and read the run-out on the dial indicator. Stop just before the ramp on each side of the base circle. You want to have the run-out for each cam lobe base circle be .001 or less.

After checking the cam lobe base circles check the cam bearing journals to make sure they have run-out .001 or less. Once again a good cam rebuilding shop will do this for you, this is part of the re-building and quality verification process.

I would HIGHLY recommend you do this if the shop you deal with does not know how to do this. I had a poor running condition with an engine that took me two months to find, the root cause problem was with the camshaft. The shop I brought the cam to to told me the cam was fine, and I believed them.

I later found out a few of the cam lobes were bent off center .010 from the center of the cam journals. This made adjustment of the .006 tappet clearance impossible. After tearing the engine back apart and having the cam straightened and re-ground everything was fine.

Removing the cam on these early model is not an easy job and you want to make sure everything is right before you bolt the block on.

Regards,

Dave

Dave,

Thanks tons for the information. That is a lot to consider. Given that the cam bearing journals themselves are within 0.0005 of spec, I think we will go with adding metal to the bearings.

Thanks again. This is very helpful.

Regards,

Tom