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.

Re: babbit tolerance? .000?
 

You mentioned burnished on a break in stand. Do you have evidence of a break-in stand? If you are calling what I have pictured below as a break-in stand, I don't believe that is what this unit was.


Burnishing is accomplished by multiple heat cycles of spinning the crankshaft until the babbitt becomes slightly 'fluid-like' or 'plastic' then allowed to cool. The unit pictured below never spun for long due to there not any engine oil or trans lube in the assembly.


Your comment about them not using shim packs much kinda needs some clarification. First, the shims were specified to be 0.002 - 0.0025 in thickness. Ford did not line-bore the blocks and caps together. The babbitt in the blocks was specified to be bored to 1.623" - 1.624". The caps were specified to be bored to 1.618" - 1.620". The crankshaft main journals were to be ground to 1.622" - 1.624". When the three components were assembled, it effectively had 0.000" tolerances when you do the math, so 'one can assume there was indeed 0.000" clearance requiring burnishing however I have never seen pictures that show this process. To clarify my statement about what Damon said in the video, it is true that at one point in the original machining process where the babbitt did have 0.000" clearance however it did not leave the factory with that clearance. That would be like saying the engine cylinder cases (blocks) were bored to 3.8735" in size. While that is accurate statement, that was not the finished bore size after honing.

Re: babbit tolerance? .000?
 

interesting. So assembled with .001-.002 tight on the block mains and .005 tight on the main caps and 3-4 or so shims to give a .001-.002 tolerance on crank from factory?

Re: babbit tolerance? .000?
 

That would be like saying the engine cylinder cases (blocks) were bored to 3.8735" in size. While that is accurate statement, that was not the finished bore size after honing.

Per Ford drawing A-6015 (April 1929), the cylinder bore was specified to be reamed to 3.873 to 3.874 inch diameter, and then rolled to 3.875 to 3.876 inch diameter. There is no mention of boring or honing.

Re: babbit tolerance? .000?
 

Thanks, Terry. Do you have available the official Ford factory method of obtaining correct bearing sizing and clearances? What did they really do?

Re: babbit tolerance? .000?
 

True Terry about the reaming, and maybe I am looking at it in a different manner of terminology (then & now) that boring and reaming can be synonymous in meaning. I guess the way I also look at it is that on the print, it also mentions finish sizes of other bearings or bores but really does not tell you how to get there. I think much of that came from common sense and SOP from the Machine Shop employees who just knew what was necessary, and that knowledge was passed down to the apprentice machinists that came thru the factory. One "other final" thought of mine is while using a reamer will put you to an exact size, it will not produce a surface finish conducive for a cast iron piston ring. Therefore they had to grind (-or hone) to finish size. Am I still missing something??

Re: babbit tolerance? .000?
 

Also Terry, does your print give a minimum spec on Brinell hardness for the bore and a max spec. taken on the pan flange? What do you think is the Engineer's mindset for measuring in two different locations? Why not give a minimum & maximum for both locations??

Re: babbit tolerance? .000?
 

I see evidence of the brinell test on crankshafts, steering arms, front axles, haven't seen it on blocks, rods, main caps, I think it was just done on heat treated parts

Re: babbit tolerance? .000?
 

I think they were more concerned with hardness on rotating assemblies. Brinell testing is mostly used on course stuff like castings but the stationary parts were not all that hard. If cast iron is too hard it gets brittle. Casting techniques then were not what they are now for sure.

Ford used tooling to get the job done as quickly as possible with the best results possible. Honing of cylinders is not something that can be skipped. They may have used ball hones so they could get a quick cross hatch without worrying about set up and stone wear but I don't know for any certainty. Rings won't break in without a proper crosshatch on the cylinder walls. If they were power honed, it would likely have been by a machine that could do all four cylinders at once. Boring would have been done the same way. It can be called reaming if that was how the tooling was designed. Some of the machines Ford had were pretty amazing. They would drill and tap all of the holes on the block at the same time.

Re: babbit tolerance? .000?
 

it appears those model T engines were set in a stand and spun by an electric motor,that large meter behind them I'm sure read amperage,the load on the motor told them if it was spinning at their prescribed load for acceptable resistance of an assembly,in essence a 'break in' stand,in fact Ford did not fire the engines till the car was completed at assembly,so that stand was all the break in the engine got.The same technique was used with the model a engine. I don't know if Ford line bored or not,it would stand to reason that they did,its the only true way to set the main bearings in alignment,just cutting bores on caps to a .005 difference than the bore on the block makes no sense.
Burnishing is the act of polishing metal with metal,ie spinning a crankshaft in a babbit bearing can help set the bearing through polishing..a process that does work with minimal lubrication,which would slow the desired effect.would be interesting to know how ford approached that.

Re: babbit tolerance? .000?
 

Let me shed some light on these questions of machining. It was stated cylinder bores were reamed then rolled to finish size. No mention of boring or honing. Both processes mentioned, "reaming" and "rolling" are still commonly used industrial processes that lend themselves to fast, economical work cycles.
It appears that the rough cast bores were reamed ( think of a large core drill) to near finish size , then a roll finisher used to bring to finished size and required surface finish. Apparently Ford did not hone. Honing in a large scale high production operation is a costly and potentially hazardous operation. Hazardous because of the (typically) used kerosene honing fluid. An industrial honing area in an automotive production plant would require partial enclosure and installed flooding ( CO2 ) fire suppression systems. Apparently Ford found a way to avoid all this by roll finishing that cylinder bores.
My $0.02 opinion based on 40 year experience as engine/ axle automotive manufacturing engineer.

Joe B

Re: babbit tolerance? .000?
 

You are right, Mr. Rotor, on the cylinder reaming, all at once. I have seen it in Ford videos !

Herm.

Re: babbit tolerance? .000?
 

After watching this video a few assumptions can be made..Ford did not line bore assemblies,you are correct.Ford held a strict tolerance through out the process negating the need for line boring the assembly.They basically assembled them and 'spun them in' using an electric motor on a stand,spun them till the engines resistance fell into spec. The honing and cylinder process is covered by the video as well.

https://www.youtube.com/watch?v=Xa0PAg7FfMk

https://i.imgur.com/KWL2COq.jpg?1

Here another photo of Ford spinning engines to a prescribed resistance..the shear size of the Rouge operation is fascinating.

Re: babbit tolerance? .000?
 

A very interesting and informative video for sure. Thanks for posting.
As for the cylinder bore machining process, the short sequence shows no honing operation. In deed, there is a view of an cylinder bore reaming operation and what surly appears to be a roller (burnishing) finishing operation on the bores. So it looks like Ford was still using this process on the V8's

Joe B

Re: babbit tolerance? .000?
 

Mr Kohnke,perhaps you can shed some light on why Ford never showed their babbitting process?

Re: babbit tolerance? .000?
 

Brent,

There are no Brinell hardness requirements on the drawings.

I agree that most dimensions are specified without telling the machinist how to do it. Some dimensions tell the machinist to "Grind" like the crankshaft journals, or to "Ream" and "Roll" like the cylinder bores. We now know that the cylinders should not be rolled, but instead honed like this: https://www.hastingsmfg.com/ServiceT...efinishing.htm

Compared to a modern engine, the tolerances in a Ford Model A engine are very loose and I believe that they needed to be "broken-in" by spinning with an electric motor until the amperes (torque) dropped to a certain level.

The crankshaft connecting rod journals on drawing A-6303 are specified to be ground to 1.497 to 1.499 inch diameter (each of the rod journals could be different), and they could be ground undersize per drawing note on A-6303 which reads "see specification MS 46303 for salvaging crankshaft".

The connecting rod drawing A-6200 specifies 2 different big end diameters. A-6200-A has a big end diameter of 1.4965 to 1.4970 inches, and A-6200-B has a big end diameter that is 1.4865 to 1.4870 inches (which is .010 inches undersize).

If you were to see the big picture, every engine could have connecting rods with 4 different diameters and main bearings with 3 different diameters.

The engine assembly drawings that I have call for a pair of shims at all connecting rod and main bearings.

Regarding engine "break-in", I agree 100% with Vince Falter where he explains it here: http://www.fordgarage.com/pages/bearingshims.htm

Once broken-in, the engine was stamped with the serial number.

Re: babbit tolerance? .000?
 

I have found this very interesting. One of the most interesting and educational in years!!

Re: babbit tolerance? .000?
 

I haven't looked at many V-8 videos, to see any pourings exist, but I have seen the T, and A ones. They were poured babbitt from 1932, to early 1936.

If you want accuracy on measuring all bearings to a 1/10 of a thousandths, every time, use an inside Mic. and an out side Mic to measure that. "Pictures"

As far as the two videos go, every thing is wrong.

Does this look like what you have seen. These mains and rods are ready to bolt together. "Pictures"

Like Jim said, set clearance at .002, when broke in it will be about .003 to .003-25, or -50. Never under .001-60, or you will loose unnecessary bearing surface Babbitt.

NO shim removal, no time saver, no burning in to ruin the first .010, of babbitt. If you have to pull a motor in a car to turn it over, where the starter , and hand crank won't, find a different engine builder.

The engine assembler got fed all useless, Information. I felt sorry for him, as he looks pretty sharp, and a nice clean shop.

When I seen the Babbitting job in progress, I knew what all the rest was going to be like.

My Opinion,

Herm

Re: babbit tolerance? .000?
 

..

Well, if y'all say so..


.


.

Re: babbit tolerance? .000?
 

here are the next two installments on this video series. it is good to see haggerty throwing money at our model A. thank you guys for correcting any bad info.



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


https://www.youtube.com/watch?v=PMU_BqdBI0g

Re: babbit tolerance? .000?
 

it makes sense from Hagerty's perspective..bangers are the future of model a collecting..he doesn't mention the rule of 9's when adjusting the valves either..