Re: Getting new tires on a 34

Posted by Peter Hartmann On 2008/8/20 9:13:30

wrong - the "later style bearings are hard to find" is wrong wrong wrong. They are not "hard to find"! They are IMPOSSIBLE to find !

That is why a little intelligent and competent machine-work is necessary to fit today's "inserts" to pre-war "senior" Packard rods.

For those who are not familiar with Packard connecting rods, they are BIG and HEAVY. They generate MUCH more severe forces on the "big end" bearing then a modern car.

Unfortunately, Packard motor engineers got it into their head that a provision for "side-play" was important, so that is why the rod bearings look like "thrust-loaded" MAIN bearings, meaning they have a flange. Of course that flange is necessary to take up "end play" on a rotating crankshaft, but a waste of time on con rods.

To fill in the space where the flange used to be, we just brazed some bronze "tits" around where the flange used to be, to take up the end play. In case no-one noticed, there are about twenty billion million thousand trillion cars and trucks running around with insert bearings, that have NO flanges and plenty of oil pressure....!

I hear someone is thinking of re-producing authentic flanged rod bearings just the way Packard and Federal Mogul made them in the 1930's. Sounds great ! I get real nervous when I hear some well-meanig machinist, who wasnt able to find from the bearing charts a modern insert that WILL fit, went ahead and bored a Packard rod out so far that he had to cut into the rod bolts. NOT a good idea. Sets up a stress concentration. Very naughty !

Oh - let me explain - the SAE ASTM tech. standard for the thickness of the insert "shell" changed at some point just before during the 2nd world war. The Packard / Federal Mogul insert shells were THINNER. In theory, good idea, better heat and shock transfer into the rod itself. In practice, leaves us with rods that dont have enough "meat" to go crazy with a Sun rod hone....!

Now, where was I...oh yes...way-too-short mini dresses. Now THERE is a subject that wont bore you guys...!