VCCA Home Forums TECHNICAL - 1945 AND EARLIER 1937-1945 babbit vs press oiler?

what year was the switch from the babbit bearing spalsh oil system to the pressure oiled systems? i have read that the 53 pass. pg (w/ the 2 stud valve cover and side oil blocking plate) is the first press. oil motor and only one w/ this config. all other press oil motors are 54 and later and have a 4 bolt valve cover and no side plate on the block. have had a couple of sellers tell me 51 and 52 235 were press motors even w/ the plate and 2 stud cover. thanks for any and all help.

please see my parts wnted add for a motor. again thanks

ONLY the dipper engines have the little side plate.
The 1953 Power Glide and all 1954 and up engines are full pressure so will not have the plate.
The 1953 pressure and dipper engines used the same cylinder heads and they had the 2 studs hold the valve cover...all 1954 and up had the 4 side screws.
1951 and 1952 engines do not have full pressure.

The dipper engines have the bearing babbit material on the rod its self. The full pressure oiling engines have rod inserts and the babbit is on the insert. All bearings have babbit on all cars.

ok, so can anyone explain babbitting and inserts to me? i have just come to the realization that i am no where near as smart as a 5th grader. i had a completely different idea than what i am reading about. thanks a newbie w/ A LOT to learn

Babbitt is a softer metal mixture that will tolerate particles with minimum effect. It is used on all rod and main bearings. As engine developments were made over the years the thickness of the babbitt was reduced to the point that it is only a few thousands of an inch thick today.

There are two basic types of crank and rod bearings. The oldest type is the bearing material (babbitt) poured in place in the rod or block and cap. It is then machined to size. Typically shims were installed so that the bearings could be tightened without machine work by removing shims.

Insert type bearings have been used from at least the teens by Chevrolet. They are made using a hard metal shell, typically steel, brass or aluminum alloy. A varying thickness of babbitt was then added to create the bearing surface. As stated before thicker at first and then only a very thin layer today.

Chevrolet began to use "precision" bearings or what is commonly known as inserts with the 1953 Powerglide engines. They were manufactured with enough precision to result in proper gaps when installed in an engine or rod. They are typically available in STD, 0.002", 0.010", 0.020" 0.030" oversize. That is why crankshafts are ground to those undersizes.

With the older (I will call them "non-precision") bearings then the crank can be ground to any undersize and then the bearings fit to that size by boring, scraping and/or shims. The process did not require the precision machines so could be done much more conviently and inexpensively. Once all the shims were removed then more expensive machine work was necessary.
Does that help?

that was an excellent start. thanks for taking the time.