Insert type bearings

Drive Shaft Dave

Well-known member
I googled How are insert bearings manufactured, didn't get any where with it. Does anyone know? Is the babitt material plated on to the shell or a metal spraying process used?
 
Excuse my ignorance, but once inserts are installed are future inserts drop in or is line boring needed? Also, can you go back to babbit?

John
 
aermotor,

Once the block is properly modified for inserts, by line boring, the replacement of the bearings is "drop in". The interval for replacing insert bearings should be quite long if all machining, assembly and owner use are proper. I have replaced the inserts in two engines with inserts where the ignition timing was over advanced with higher compression heads. In these cases it was "drop-in" to replace them.

You could go back to Babbitt but the thrust area machining may pose problems for the process. With the sharp edges machined into the block to locate and hold the bronze thrusts, I would think the peening process may fracture the fresh Babbitt at these edges.

Herm Konke would likely know the answer to the use of Babbitt after the block modifications for inserts. He may follow with a comment.
Good Day!
 
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Excuse my ignorance, but once inserts are installed are future inserts drop in or is line boring needed? Also, can you go back to babbit?

John

Well John, it goes like this.... it depends! :D

Did the insert bearing spin or roll, -or are you just replacing for some reason? If you are replacing because they are worn out, chances are there are other areas of the engine that are worn too needing attention by a professional. If the bearings worn prematurely, then it and other areas of the engine are likely going to need professional attention also. :o

For example, if the bearing rolled or let's just say if the center main has worn prematurely, then there is much more involved than R&R. I have actually seen a couple of engines that were inserted several years ago that are coming back and the caps need to be line honed due to them walking because the rebuilder did not pin or dowel the caps. I have one in here now where the person that did the insert mod actually linebored to block 0.0015 too large on the center main. The customer & I have debated on this bit and I am going to replace his main caps and set the block up to accept babbitt again.

While I will rebuild with the customer's choice of either inserts or babbitt, my personal opinion is the technology/machinery is better than it was some 3-4 decades ago, --the quality of babbitt is better and the proper mixture is more easily available now than that period, ...and the overall knowledge base of many rebuilders now is better than what was available 30-40 years ago. IMO this has changed the game tremendously where a quality babbitt job can/will rival the quality of an insert conversion on a Model-A engine. The quality of engine rebuilds had dropped during this time period where the use of babbitt had obtained a bad reputation much like the rumors about original Model-A brakes being poor, generators not being adequate, or myths like Model-As steer like a tractor, lacquer paint doesn't hold up, etc. but quality of parts/materials and knowledge has changed the mindset today.

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