Re: Crankshaft Bearings for 34 Standard 8 Engine

Posted by Peter Hartmann On 2008/8/4 9:53:00

I was kicked off the AACA site for discussing the connecting rod bearing failure problem on pre 1935 Packards.

This subject gets people VERY upset. And for good reason. A lot of restorers recognize that MOST people paying big bucks for restorations know what they want. They want a car that looks pretty, and can win prizes at car shows.

Many restorers recognize most people today couldnt care less how the car actually runs, or what its techical capabilities are. They have a good point - would be unethical to add to the costs, to build into the motor technical capabilities the customer couldn't care less about. No restorer or friends of restorers wants to hear the technical facts on this issue - what happens when you try and drive a poured-babbit equipped motor at anything APPROACHING modern speeds.

The sad fact is, pouring babbit into connecting rods, instead of or in place of a proper "slipper" or "insert" type bearing, virtually guarantees eventual bearing failure, which means VERY costly crank-shaft damage. The laws of physics will not respect the desires of ill-educated back-woods type mentalities who are just trying to make a fast buck restoring cars for "show".

Packard and its partner in bearing development (Federal Mogul) put a lot of engineering effort into solving the rod-bearing failure problem. In one test I read, General Motors found that at 75 mph, a non "insert/slipper" Packard would develop rod bearing failure after approx. 2,500 miles.

The "last gasp" of the poured babbet rod bearing was in the 1934 model year, when Packard went to finned connecting rods, full flow oil coolers, and full-flow oil filters.

It didnt work. High speed "runs" on Packard's famous test track made it clear there was only one solution - the "insert" type rod bearing.

In my own personal experience with my own '34 Packard Super Eight, I can assure you I tried EVERYTHING avail. in poured babbit bearing technology. No matter what methodolgy of using poured babbit I tried, (this was in the mid 1950's) I would get rod bearing failure in short order after high speed driving.

In late 1934, Packard took a off-the-shelf production 1935 Packard Standard Eight, and demonstrated with the new "slipper"/insert type rod bearings, the car could be run at over 90 mph for over 25,000 miles, after which, the engine was torn down, and in the words of the engineering report " could have done the test again without replacement of parts'.

Bottom line - "you pays your money and you takes your chances".

I strongly recommend that if you want to actually DRIVE and enjoy your Packard, dont let someone ruin it by pouring babbbit into the con rods. Find someone who KNOWS what they are doing, and have the rods machined to accept modern (meaning 1935 or newer thinking) insert / slipper rod bearings.