Packard Forum Index » Pre-War (1899-1942)

You think I have a dim view of poured babbit in Packard connecting rods? If you want to see a dim view of poured babbit in Packard connecting rods, suggest you read the engineering reports on them. Plenty of reproductions of these reports floating around. My favorite is one that GMC did, comparing the early 1930's Buicks to pre "insert" Packards.

Interesting story behind this - General Motors was smart enough to figure out they could get by with the cheaper "poured babbit" ( and did so clear into the early 1950's on Chevies and Buicks !) IF they kept the babbit layer VERY VERY thin. The thinner the babbit, the less likely it is to start pounding out (and, of course, the less likely the crank-shaft will survive once the babbit starts to come un-glued).

Packard engineers tried VERY hard to make poured babbit rod bearings work as highways improved and cruising speeds rapidly rose. They went to all kinds of expensive "fixes" that didn't solve the problem. Ever seen the beautifully machined "finned" rods on the early 1930's Eights and Super Eights ? The full flow oil filters ? The full flow oil coolers ? NOTHING worked to save poured babbit rod bearings.

The "sintered copper lead" precision insert type rod bearing on all senior Packards from 1935 production on (until "senior" production ended with the destruction of "senior" production facilities in 1939) was the correct answer then, and remains so today.

As bad as poured babbit bearings were, once road speeds started increasing (reflecting the vastly suprior highways of the early 1930's) poured babbit in 1935 or later Packard con rods is a DISASTER. Again, the thicker the babbit bearing layer, the faster it will "pound out", destroying the crank-shaft.

So - the answer to your post is - don't blame me. I was never a Pacakrd or GMC or Federal Mogul bearing engineer. Blame THEM for the various technical papers that confirm why NO automotive motor ANYWHERE on the planet today (and that includes cars, trucks, boats, piston aircraft, etc.) would think of using this fragile form of rod bearing.

I have to agree with Packard 12 Fan. My 34 Packard had only done 2500 miles before the babbit in the rods gave way. I'm now getting the engine rebuilt. I was amazed to find out that the engine was from a 36 model and yet still had babbit bearings. So the major problem with the later styled bearings is that they are hard to find. Hence this is why I believe when the car was restored 8yrs ago got the babbit treatment.

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...!

Trying to figure out how we got from tires to babbits...lol

Quote:

or to the length of mini skirts!

because YOU weren't paying attention ! ( we were talking about WAY too short micro-mini dresses on cute girls, but some guy distracted us with a discussion on tires.....!)

We went from tires to babbitt bearings because Bedford starts with B, just like abbitt.

Tom

Then shouldn't the conversation have went to bras instead of miniskirts????

34PacRoadst
Great to hear of your satisfaction!

Another Packard is good for thousands of miles.

Enjoy rollin' in Austin.

DanL