Cracked Rear Main
 

A friend with an engine that was totally rebuilt 17,000 miles ago as part of a frame-off restoration has been trying to figure out the cause of an oil leak. This past weekend he removed a section of the rear Main and discovered that the Babbitt was compromised. He is not on the forums and asked me to post these images hoping that someone might have some insight to offer.

The first pic is showing the problem found just a few minutes after removing the 2 mounting nuts.

The second pic is showing the piece of babbitt stuck in one of the two passageways which feed the oil return tube. The tube was otherwise clear.

The third pic is showing the piece of babbitt once removed from the passageway after using a screw drive to pry it out. When It was lifted it out it made a snapping sound to dislodge from the bearing passageway where it was sitting.

Simply put, the questions are:

1. What would cause the condition found in pic #1?

2. Would a piece of babbitt this large covering one of half of the oil return tube oil entry port contribute to the shorter life of the main?

This gentleman is meticulous about caring for his engine to a degree that borders on obsession. He is in the process of pulling the engine.

Thank you.

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Re: Cracked Rear Main
 

Looks to me if the damage has been done by the crank journal pounding in the babbit, balance problem ??? The oil groove is mostly worn away which would allow the crank to drop which means for sure the other two main bearings are shot as well ,certainly the centre one . It looks like that loose bit of babbit is from a thrust face ,in practise a partially blocked return tube will not affect lubrication but will contribute to a leaking rear main seal .In this case by the state of that rear cap it must of had a spectacular leak anyway . Pull the motor and send it off for a bottom end rebuild sad to say .After 17000 miles it should not be in this condition does it have any form of guarantee ???

John in very windy Suffolk County England .

Re: Cracked Rear Main
 

If you take one of the pieces and try to bend it what happens---another piece and hit with hammer on anvil of vice ----I suspect it will not bend,just break, and hit with hammer it more explodes than just flattens

Re: Cracked Rear Main
 

I would NOT invest any more money with this "rebuilder".

EVEN IF HE FIXED IT FOR FREE IT IS NOT WORTH THE RISK THAT SAME THING WILL NOT HAPPEN AGAIN.

Find someone who knows how to pour babbit.

Properly done babbitt will last at least 60,000 miles or more.

Re: Cracked Rear Main
 

I agree, we have a 29 that has never been rebuilt, has 70,000 mile on it. Good compression, all in 60's. Does not use oil or make any funny sounds. Runs great. Has had valve job. These are great little engines. Just change oil, do not lug, and keep well tuned.

Re: Cracked Rear Main
 

In "stickies" at top on main webpage are recommended vendors ... not everyone does Babbit though

https://www.fordbarn.com/forum/showthread.php?t=17518

Listed under "ENGINE RESTORATION" in list.

Listings 1 through 4

AND do not overlook.

Herm Kohnke rebabbiting. (not on list)
http://www.kohnkerebabbittingservice.com/our-story.html

#10

#14

#18 on list

Re: Cracked Rear Main
 

Take out a piece, clean the oil off and take a picture of the edge.

I am curious what the crystal structure looks like.

Re: Cracked Rear Main
 

FWIW, Repeated descriptions of: "an engine that was totally rebuilt 17,000 miles ago" should read,

"an engine that was improperly reassembled 17,000 miles ago"

Over the past 20 years, one can hear and/or read on Model A Forums about these same "typical" sad stories over and over, (saying that an engine was "rebuilt" vs. an engine was "improperly reassembled").

It is most educational to see where Model A owners continue to relate to other Model A owners what can happen when one chooses to have Model A engines "reassembled" by anyone who never was qualified to perform such a simple task of "rebuilding" a Model A engine.

Re: Cracked Rear Main
 

I ALWAYS take the words Restored or Rebuilt with "a grain of salt".


True story ...

My friend went to visit a "restorer" to buy some parts.

He bragged that: "I have restored over 25 cars in the last 50 years!"

The restorer asked him to help take some greasy grimy parts ... (Trans, engine, differential) to the car wash. He had hurt his back and needed help.

After they were back at the guy's shop he asked where should he put the parts?

"Oh put them in the paint booth ... after the water dries I will paint them and install in restored car ... tomorrow !".

Really!!! ??

'If you can't dazzle them with brilliance, baffle them with bulls$$t WC Fields

Re: Cracked Rear Main
 

It may well have been improperly assembled while being rebuilt. What about the images makes you think that it was done improperly? Are you in agreement that the babbitt was improperly poured/cast/machined? That is what the owner believes as well as a local club member, and a few people that have responded here. Thank you.

Re: Cracked Rear Main
 

In reply to above #10, a hands on forensic evaluation would be the the most prudent way to determine the probable cause(s) as opposed to trying to guess at looking at photographs from miles away.

As hinted above, it could be a lack of engine balance, bent crankshaft, Babbitt problems, or whatever.

Model A engine rebuilds were done very often in years past, e.g., in the 1940's, Sears rebuilt and traded thousands of Model A engines with no problems because of having trained individuals and proper tools & equipment.

I have personally experienced at both U. S. Army Depots in Utah and Alabama thousands of military engines for tanks, jeeps, etc., that were professionally totally rebuilt with no problems because of having trained civilians rebuilding same with the most modern expensive equipment available ...... they even successfully grind the valve type faces of the revolving tank turrets that get beat up after firing rounds ..... the whole tank body, with tracks, is turned 90 degrees sideways and rotated on a fixed cutter ...... a rebuild sight to see.

I just find it sad to see so many Model A owners experiencing engine reassembly failures ...... but many should be commended for humbly reporting such problems because Model A owners can help other Model A owners to be cautious.

Never a bad idea to call Mr. Kohnke and others for Model A rebuilding advice.

Re: Cracked Rear Main
 

I don't know anything about babbet but it looks to me like it didint bond to the cap like a bad solder joint that was not fluxed or heated enough

Re: Cracked Rear Main
 

http://i68.tinypic.com/2z4ms9c.jpg


you are not alone..this cap came off a 'fresh' engine too..

Re: Cracked Rear Main
 

Cast rear main is peened, not tinned.

Re: Cracked Rear Main
 

Find a good engine builder, looks like a poor job to me.

Re: Cracked Rear Main
 

One of these is original Babbitt, the other imposter is out of my rebabbited engine that I paid good money to have done,,,,never even bothered to put it together,it just didn't look right,,lots of other stupid sloppy work.

I mean seriously, why bother?
It will have inserts.

Re: Cracked Rear Main
 

Wrong alloys or improper prep of the heated babbitt or both.

Re: Cracked Rear Main
 

In my opinion, Mr. 30, both samples are made of lead. The right picture does not have factory oil grooves, and looks like it was poured with a Jig with grooves already on the Jig.

Herm.

Re: Cracked Rear Main
 

That babbitt looks like it has a high led content and the clearances were not correct allowing the crank to beat it to death. Not a good builder.

Re: Cracked Rear Main
 

FWIW:

After reading 20 years of Model A Forum members' sad engine rebuilding problems & reading sad reported experiences, plus Forum members continuously trying to deal with these cheap, fake Model A engine rebuilders is not much different in my opinion than trying to deal with one of these supposedly Nigerians rogues sending us a fax and asking for our bank account number(s) so they can deposit the millions that they recently inherited.

Doctors know good doctors; lawyers know good lawyers; engineers know good engineers; Model A engine rebuilders know good Model A engine rebuilders.

Fakes & crooks are in every profession and business.

When too far from a known Model A engine rebuilder, please call him anyway ...... he usually knows who to trust ...... and if he says he never heard of someone ..... please, please buy a lottery ticket prior to bringing him your Model A engine ...... chances of lottery/engine success might be equal.

Hope this can help any Model A owner in the future with such an investment.