VCCA Home Forums TECHNICAL - 1945 AND EARLIER 1929-1932 Steps involved in babbitting main bearings

Hello all. I took the engine from my '31 Coach to a local machine shop a month ago to be rebuilt. They called me today to say that they won't be able to handle re-babbitting the main bearings after all. So I will have to get that done elsewhere and could use some education on how the re-babbitt process works. I read the relevant articles in the chat archives but want to make sure I have it right and would value the community's opinion. How does this sound: First, I need to remove the upper halves of the main bearings from the block. Do they just pop out? Second, I need to send the upper halves and the bearing caps to a shop that can do babbitting. Any recommendations in Florida or the Southeast? Third, the shop would pour the babbitt a little “fat”; that is, so it is too small for the crankshaft to fit. How do I specify how thick the babbitt should be? Fourth, the babbitt shop would use a jig of some sort to cut oil grooves in the bearings. Fifth, the crankshaft would have any required machining done to establish final diameter of the main journals. Sixth, the upper halves and caps would be replaced in the block and torqued down with some shims. How many? Seventh, the main bearings would then be line bored to match the final crankshaft journal diameter. Does that sound about right? I just want to be able to talk intelligently with the babbitt shop and make sure I get back from them what I need. What have I left out? As always, many thanks for the help. - Tom

You have the process correct. My concern would be with the machine shop not being willing to get it done. I think it's best to have one shop handle all phases of the rebuild whether they do it themselves or sublet it so only one party will be responsible should there be a problem. You don't want to be caught in the middle of a blame game. If it were mine I would look for another shop.

Tom , Kanter Auto products in NJ do exchange rebabbited main bearings for 1929 to 1932 Chevrolet engines. They are semi finished , so need to be installed and line bored in the usual manner to suit the grind of your crankshaft.
clink on the blue underlined link.

https://www.kanter.com/productdetai...2&ProductCode=357&Router=Gallery

Yes, the top inserts just pop out once the crankshaft is removed.
The original inserts were semi-finished ( had extra thick babbitt) so they could be line bored and fitted to the crank shaft size.
The proper bearings will have oil groves cut in.
The line boring is done after the crank is cut.
The original when new h usually had two .001" shims and two .oo2" shims on each side. Necessary for futre adjustments.

Buy and furnish the inserts rather than have that shop "make" them or have them made.

I totally agree! The words: "local machine shop" scares the hell out of me!!!

Tom,

If you can't find a local machine shop close to you, you might try talking to the local Model A club members. They might know of a machine shop that could help out. Those ol' A's are babbit bottom ends also. Just a suggestion.

Jim.

Hello Chev Nut,
To improve my knowledge of the engine's machining process, of which I have little. After the crankshaft main journals are machined to uniformed diameter, and the .006 shims (2-.001 and 2-.002) are considered. What additional diameter/measurement if any would the machinist use to determine the line boring final dimension/diameter? Thanks

Great advice from all of you. Much appreciated! - Tom

Don't forget to use the center of the bell housing as the center for the line boring. Not all of the bell housings were the same and could have a little variation. This is specified in the owners manual. You should not send the actual main bearing caps in case your package gets lost. The bearing shells will pop out of those as well. The top and bottom shells have a different diameter alignment dowel in the center. Take lots of photos and document everything. For instance the champher on the bearing shells where they mate together do not go all the way to the out side so as to not let all the oil drain out when sitting. The top shell has different oil slots cut in it than the bottom so as to distribute oil around better. Herman Kohnke will do a very nice job but is a little spendy.

Can anyone identify three qualified machine shops who specialize in 1929-1932 engines for bearing babbiting. No one has addressed this original request.

Columbia Classic Cars, Inc. Engine Rebuilding
Winthrop, Maine
(207) 377-2107
Ask for Roy Weymouth

I doubt that there are three shops in the whole country that "specialize" in 1929-1932 engines" for bearing babbiting. There are several that have experience and have done work on VCCA member engines. The one I use is a small custom shop that takes his time and does it right on his own schedule. He is currently backed up for over a year. Kanter and Egge sell rebabbited shells. Several other machine shops have been discussed that a search can reveal. Never heard of a shop in Florida but I suspect there are a few that have experience with babbited engines.

Bought a set of rebabbited shells from Egge and they were pure junk! Totally unuseable! Heard from other old car dudes that they had the exact same issue as well.

Dog and Chipper,

What about converting to insert bearings?

Dog, you are so right about Egge. My experience with them was a pure horror story. They combined dishonesty and incompetence at one conveniemnt location.

This is good to know, a few hour drive for me if needed and I can always go see my nephew while I'm at it. Thanks for the info.

The main bearings are already shells with babbit bearing surface. Those are what most call inserts. Not sure anyone makes a modern bearing that will fit the early sixes (194 cu.in.). There are precision bearings for the 216.

I'll also toss in The Babbit Pot, 1693 Rt. 4, Ft. Edward NY. No website but you can find them on Facebook > (518) 747-4277. As mentioned above, like other babbit shops he takes care of all the Model A guys. I had my rods rebabbited there for my '32 about 10 years ago, and they fit perfect.