babbit tolerance? .000?
 

haggerty is rebuilding a model A engine. He says you start with 0 clearance then bed it in. Is he correct or should there be.0005 or .001 or.0015? link to youtube video. haggerty rebuilding model a engine. https://youtu.be/anDIASMNmCQ?t=39

Re: babbit tolerance? .000?
 

While he admits he doesn't know anything about babbitt, we all need to remember that just because something is posted on YouTube or the internet does NOT make it correct. In this case, he is basically incorrect.

Re: babbit tolerance? .000?
 

I've scraped large babbit bearings. You just keep marking and scraping to 'bed' them.

But I don't do that to adjust a small bearing such as ours. I like ours to end up at .0015"

Re: babbit tolerance? .000?
 

How do you measure 0 clearance?

Dick

Re: babbit tolerance? .000?
 

not with platigauge. but if you wanted to you would mic the crank and use a bore set to measure the main and match them up


I dont have a bore set just a set of those expanders and I dont trust those as far as I can throw them

Re: babbit tolerance? .000?
 

I believe that when babbitt is machined, there is no need to 'bed' it in. I like .0015, more if you are going to race it. I set my Bonneville engine at a minimum of .002".

Re: babbit tolerance? .000?
 

You should watch the video of them pouring that babbit..yikes...Ford spun engines in with an electric motor, they used an ammeter to determine the resistance value. Burnishing the mains,allowing the last step of fitting the bearings to the crankshaft itself through rotation.

Re: babbit tolerance? .000?
 

There has to be clearance to allow for rotation, lubrication, and to prevent galling of the bearing with heat expansion. Folks that do babbitt work prefer to have a crankshaft in hand to fit the bearings to it. They should be set up with standard shims to allow for future service. There are several tools that can be used to check a bore. A T-gauge will work if you know how to use one but a ball gauge can work better. Snap gauges work well too. An inside mike has to be small enough to fit the bore size but they will also work well.

I would talk to someone who does this stuff for a living and find out how they do it successfully. "Bedding In" can mean different things to different people.

Re: babbit tolerance? .000?
 

I've read and watched old video of that. Makes you shake your head.

Re: babbit tolerance? .000?
 

https://www.youtube.com/watch?v=anDIASMNmCQ


Hagerty

Re: babbit tolerance? .000?
 

Cant fit and finish when your building 7500 engines a day..foreman watching you all the time,the stopwatch running..get it close and ship it.if it failed to spin down to the value it went back to the motor building if it could be fixed quick it was,if not it was scrapped.

Ford's assembly line was a cold unforgiving environment..if it works and was installed in time great,if not? scrap it...or fire him..

Re: babbit tolerance? .000?
 

Assembly lines are all hard work jobs no matter what the company or the product. Since Ford developed the assembly lines, they were good at making improvements to keep up both production and quality. If a line inspector was letting too many failing products by, they would have come looking for him so it was not just the line that had to worry about stuff. This type of work would have been better for the younger folks since it's not a sit down job but they paid their workers pretty well.

Some of the first person accounts mention that Ford kept their buildings cleaner than most of the other auto manufacturers did. One thing I felt about the assembly line work, since I worked on one while I was in A&P school, is that the time went by fast and then you were out of there. You just get damn good at putting widgets in the thingamajigs. I helped put glass in a lot of boat windows while I did that type of work. The glass all came from a Ford Motor Company glass plant.

Re: babbit tolerance? .000?
 

I set the clearance at two thousands on the rod and main bearings . I use 20W50 motor oil and have had good results .

Re: babbit tolerance? .000?
 

What he says I think is true for machinery not engines?

Re: babbit tolerance? .000?
 

I fail to see what you guys are calling 'time to ft and finish'. All the components were designed to fit. All crankshaft & rods were poured with identical mandrels, and all crankshafts were machined to the same specs. The Assembler did not need to check clearances of bearing or bores, nor monkey with valve lash clearances as EVERYTHING was the same from engine to engine.

Re: babbit tolerance? .000?
 

That's my point,time wasn't spent with the knife If a crank didn't spin easy,it was assembled and burnished by spinning on the 'break in stand'.They didn't use shim packs much either,as you say there was one spec, and machines were calibrated regularly.

Re: babbit tolerance? .000?
 

That's my take on things as well,modern oils have better load and shear characteristics through additives today then they had back then making a strict .0015 not a critical as before. I use a diesel grade CK-4 15/40 for load/shear/soot and debris entrainment properties,well beyond what was available in '28.

Re: babbit tolerance? .000?
 

In a earlier video he took a tour of rons machine in shandon ohio where they had thier motor rebabited. I looked at there prices pretty reasonable. 240 to have mains poured and cut. I would think he got his info from rons. now there may be a difference between 0 tolerance versus there is no tolerance you need to measure before assembling this engine. if it sticks pull it around the lot till it frees up.



I had stupidly broken a rear main. I got a used one with plan to have the mains rebabited. the used one happened to be worn but for a 10 under crank. So i spent 6-8 hours marking and knifing it. I set to .0015 to match my other mains. Could I have stopped at less as long as it would move? in my cutting it didn't set flat on the block for the first half of the day then it wouldn't move for the longest time.


On shim packs. They were not on every car from the factory but are an aftermarket item? In the catalogs ive seen it stated that the shims are .002 or .003 per leaf? or are the combined shims =.003? how worn would you wait to remove one if they are .003 per leaf? .005? my car has no shims.

Re: babbit tolerance? .000?
 

Some shops pour and line bore to a full pack of shims...030 on the rods,.015 on the mains,the shim packs peel at .001.
Burnishing,the act of running in (or dragging in) a bearing has been done for years,Fit it the way you did and you don't have to wonder if its right,you know its right. Timesaver is a product used to aide fitting as well.

https://www.newmantools.com/lapping/time.htm

Re: babbit tolerance? .000?
 

My engine rebuilder said you want the crank to be able to rotate with minimal drag after line boring and final fitting of the mains. That made sense to me and I've had 1,200 trouble free miles so far.



I believe there is a page in the service bulletins about there being 0.004" of shims on the main bearings from the factory. I might be wrong on that so don't take it as fact.


I think when I pulled some rod shims on my old engine each lamination was 0.001" but it might be different for mains.