I think you will find that the contact area on modern engine bearings is an alloy of aluminum. Ron W
Did you know that there is no contact surface in a Model A main bearing?If factory poured babbit were still an option, this would be a no brainer, BUT it's not and it never will be. My understanding is that the technology of getting a durable product is not trivial; some guy's garage operation--no matter how well intentioned and researched--may or may not be OK--it's a crap shoot. I've replaced enough bad rebuilds that I'm not interesting in unnecessary gambles.
Did you know that the actual bearing contact surface in inserts is Babbitt?
Did you know that there is no contact surface in a Model A main bearing?
Nothing here has anything to do with "contact Surface". The crank and bearing don't have any contact with each other except perhaps when the engine is at rest. Once the crank begins to turn immediately a hydraulic wedge is formed by the oil and any metal to metal contact is eliminated. Well kept bearings and oiling systems should last indefinitely.Jim,
I don't know what you mean.
Steve
Everyone,
Here's a segment from what Wikipedia has to say about Babbitt that may be of interest:
Modern Babbitt bearings[edit]
Until the mid-1950s, poured Babbitt bearings were common in automotive applications. The Babbitt was poured into the block or caps using a form. Tin-based Babbitts were used as they could stand up to the impact loads found on the connecting rods and crankshaft. The poured Babbitt bearings were kept thin. The rods and caps would have shims that could be peeled off as the Babbitt wore. Ford was known to use two .002" on each cap and Babbitt that was 86% tin, 7% copper, 7% antimony (see the KRW catalogs for the Model T). Steel shims were used as the brass shims used today tend to compress over time contributing to shorter bearing life. The poured Babbitt bearings commonly get over 50,000 miles of use before needing replacement. Poured Babbitt bearings are also known to fail gracefully allowing the car to be driven for extended periods of time. The failed bearing is not likely to damage the crankshaft.
In more modern practice, the crankshaft and connecting rod big end bearings in a modern automobile engine are made of a replaceable steel shell, keyed to the bearing caps. The inner surface of the steel shell is plated with a coating of bronze which is in turn coated with a thin layer of Babbitt metal as the bearing surface.
We use J and M Machine up in Mass exclusively for all our work, new and old alike. They are one of very few shops in the country that do metal stiching of cracks and do it properly. They have saved castings that no one else would have a chance at and I have seen several of them, wow!
They have done several Model A and T engines for us of which were Babbitt and one of these has almost 50 thousand miles on it and going strong. We check the clearances usually every 10-15k or so.
State of the art machinery that you won't find anywhere else in the entire country! Every time I visit them I never want to leave!
Take a look at their website, you will be impressed!
www.jandm-machine.com
Meskhov
Nothing here has anything to do with "contact Surface". The crank and bearing don't have any contact with each other except perhaps when the engine is at rest. Once the crank begins to turn immediately a hydraulic wedge is formed by the oil and any metal to metal contact is eliminated. Well kept bearings and oiling systems should last indefinitely.
BTW, Wikipedia is not the end all, be all. It is simply a place for people with opinions to have a voice and sometimes contains wrong or incomplete information.