Model B Rear main oil leak: What to do next?
 

Now on my 4th attempt to fix large oil leak on the rear main. This is where I stand currently with the engine apart

1) Cut grooves in Babbitt in main cap replicating the original pattern (shown in prior post)
2) Today I measured crankshaft clearance. I could not locate plastigauge around here so used aluminum foil to estimate clearance and this is what I found:

It took 7 layers of aluminum until the crankshaft would not rotate easily. With 6 layers it felt correct. I used my micrometer and measure the stack of aluminum foil thickness several times and got between 0.0027 and 0.0039. There was a small play on the crank that could be felt by hand when trying to move it upwards.

Questions:

1) If this measurement is accurate, is this clearance large enough that can explain massive oil leak on the rear main? I understand 0.0015 is the ideal.

2) I have NO ACCESS TO PROS WHO CAN POUR NEW BABBITT, so I would like to fix using less conventional methods. For instance, can this be fixed by removing a couple of thousands inches from the main cap so the crank will fit correctly? I read many strongly oppose to this. Can you educate me why that is a problem?

Appreciate your input, thank you. Manuel

Re: Model B Rear main oil leak: What to do next?
 

Some guys will sand the cap by rubbing it on sandpaper on a flat surface, but then you no longer have a perfectly round circle for the crankshaft to ride in. If the babbit is excellent, and the caps haven't been sanded before, then I'd be tempted to sand the cap some, even though I don't like to do that. How are the other mains?

Re: Model B Rear main oil leak: What to do next?
 

I have a new inserted mains in mine but with 60lbs oil pressure & drill crank for big ends & it leaks big time , once it back here from CA im going to look for a cure.
Re surfacing the caps , have used grinding paste on a piece of glass, rotating in a figure 8 pattern , gives a nice finish ,

Re: Model B Rear main oil leak: What to do next?
 

Sanding the cap will make it out of round, out of perfectly round. If you take .002" off the face, how much out of round will that be? Not much! Babbitt will conform to the crank in a very few miles.

Re: Model B Rear main oil leak: What to do next?
 

I'm also waiting for this answerhttp://budpics.ga/13/o.png

Re: Model B Rear main oil leak: What to do next?
 

According to your measurements , you would 'only' have to sand caps .001 or so to hit ideal .0015 +/- . How much out of 'perfect' round would this be....not much, eh ? I'm thinking that poured mains will conform to that small adjustment..no ?
I just did this same process on my B project, at the suggestion of a professional engine assembler and got .0015 all mains. I feel good about the results, but proof in pudding will be known when engine fired off...someday :rolleyes: ! Full pressure , poured mains/rods.

What are your intended uses of this engine, i.e.- racing or touring/putting OR just getting huge leak stopped ? I can not stand ANY oil leak, so I'd go for it, especially given that you state that your on your own resource-wise.
Good luck and let us know your final process/results ;).

Re: Model B Rear main oil leak: What to do next?
 

maybe 60# is a bit too much pressure? i thought most like to run 30-40#. Just wondering...

Re: Model B Rear main oil leak: What to do next?
 

You may be correct, that tooo much of a good thing is not good !
I have adjustable full pressure pump (outside block adj) and can probably blow the seals out on my B with a Stipe custom pump. But, I run only 35lb and it seems it like that amount with NO leaks :) !

Re: Model B Rear main oil leak: What to do next?
 

The higher the pressure, the faster the cam gears will wear. I'd think 30 pounds of oil pressure would be plenty.

Re: Model B Rear main oil leak: What to do next?
 

IMHO, the cam gears (crank and cam) are plenty big for high pressure pumps. The weak link I see is the dist drive gear and the oil pump drive tang.

And depending on the application of the motor, 30 psi full pressure system is adequate for touring or daily driving.

J

Re: Model B Rear main oil leak: What to do next?
 

Rick,

a motor correctly machined and assembled has no oil pressure directly on the seals. I have run 90+ in mine with no leaks from the seals or galley. Hoses and filters are another story........

J

Re: Model B Rear main oil leak: What to do next?
 

How do I measure what oil pressure I am running? This is a model B with no modifications and if oil pressure is important as a cause of oil leak in the rear main, then I would like to know what mine is

Re: Model B Rear main oil leak: What to do next?
 

On a stock standard B engine there is very little pressure 5-10 lbs not worth the worry

Re: Model B Rear main oil leak: What to do next?
 

I posted this on the early V8 forum as well but received no input. I believe the model A crowd will be more interested in this information.

I am back to report to you what is going on with my 33 model B engine. For several weeks I worked together with an enthusiastic machine shop owner who accepted the challenge and took the job very seriously. He worked with much care to pour new babbitt and then bore everything to the correct specifications. I spent many evenings with him at the shop after hours to watch his work and provide the necessary technical information I gathered here at the Barn and from several other sources. Yep, we worked late evenings odd hours. The record was one Friday until 3 in the morning when I gave up but he continued till dawn.

The following is a summary of the process with photos that show what was done. Please keep in mind the logistic limitations so you don't make harsh judgements if something is out of the ordinary.



http://i1190.photobucket.com/albums/...1%20Behage.jpg

Babbits look good, certainly better than what it was before. To pour the babbits he melted a tin-based chunk of metal. It is avaiable here only from one supplier. They called it "white metal" and is mostly tin but don't know the exact components. You see that we added shims this time.


http://i1190.photobucket.com/albums/...4%20Behage.jpg


http://i1190.photobucket.com/albums/...3%20Behage.jpg

He is creating oil wells. They were essentially non existing in my prior babbitt job so this will help oiling

http://i1190.photobucket.com/albums/...1%20Behage.jpg

He placed marks before cutting oil grooves. The design of the grooves for model B is different than model A. I used photos from a sample provided by James Rogers, a barner who is a fantastic model A/B rebuilder in North Carolina and whom I had the plesure to visit at his shop last Summer to learn about these motors.


http://i1190.photobucket.com/albums/...5%20Behage.jpg

The grooves go all the way to the front edge and from there down to the oil pan. My previous job did not carry the grooves forward and that was a factor that favor flowing oil to the rear.

http://i1190.photobucket.com/albums/...p%20Behage.jpg

Likewise, the front and middle cap were poured, machined and then the oil grooves were cut.


http://i1190.photobucket.com/albums/...2%20Behage.jpg

The oil tube that was welded before was removed, new metal added, new thread to place not only the oil tube but he also created a thread for the plug. Excess metal was cut to keep clear from the crankshaft. The plug is very thin and made of bronze but has enough thread to keep the plug tight. There was rust and debris inside the oil channel of the main cap which surely contributed to poor oil flow and the rear leak. It was thoroughy cleaned.


http://i1190.photobucket.com/albums/...2%20Behage.jpg

The babbitts were cut/bored/machined to specification. I insisted 0.0015 inches clearance between the bearings and the crankshaft. He said it was too tight but agreed to do it if that is what this motor requires.

http://i1190.photobucket.com/albums/...1%20Behage.jpg

To double check the clearance I sourced Plastigage from O'Reiley in the US


http://i1190.photobucket.com/albums/...2%20Behage.jpg

Put a 2 inches strip of Plastigage on the crank journal and torqued to 100 lbs


http://i1190.photobucket.com/albums/...5%20Behage.jpg

Well, not bad at all! 0.002 seems very close to ideal. The crank rotates by hand and gives the feeling that is fitted. I don't have photos to show the front-end clearance but it was 0.004 inches which I believe is within the correct range

http://i1190.photobucket.com/albums/...e%20Behage.jpg

The crankshaft was checked for any distortion, I believe that is referred as "being true or not". He found 0.002, a slight deformity and was able to apply some heat on certain spots that corrected it. It took him literally one minute to know where to apply heat to accomplish this.


http://i1190.photobucket.com/albums/...1%20Behage.jpg

Shims added to all bearings

http://i1190.photobucket.com/albums/...1%20Behage.jpg

The caps were replaced, bolted, sealer added sparingly to edges, bolts.

http://i1190.photobucket.com/albums/...d%20Behage.jpg

After the crankshaft was fitted and the sealer cured (next day) we added oil through the oil tube and used 10 lbs compression and showed no leaks. He decided to test with up to 30 lbs and still there was no leak. So the engine was picked up and brought home to complete the job. Few days later it was finished, painted and dropped into the car to formally test. Sorry, we have no engine stand to run it so decided to drop in the car and see what happens. Click on these 2 photos to open a video link.

http://i1190.photobucket.com/albums/...Nov%202015.mp4


http://i1190.photobucket.com/albums/...oil%20leak.mp4

So far very good! I see not even one drop of oil. But it only ran about 25 minutes. I could not test further because a different problem presented that required to shut off the engine. I will relate it in a different post.

Thanks to all who have given advice and provided information and in particular to James Rogers from Leicester, NC (Dreamwerks, model A & B Ford engines) for his invaluable insight and generous advice.

Re: Model B Rear main oil leak: What to do next?
 

The plastigauge should be layed lengthwise on the crankshaft.

I would reduce the .004" clearance to about .0015 to .002".

I question the very small radius on the crankshaft. I hope it doesn't break.

Good Luck

BTW, someone did a nice welding job on your block.

Re: Model B Rear main oil leak: What to do next?
 

The thrust looks like there is excess clearance on the rear main.. other than that it looks OK for a beginning pour and bore.... Hopefully the babbit was piened in the block prior to boring to help it stretch out and conform to the block after cooling and shrinking.

What kind of issue that caused you to shut it down after test out?
Larry Shepard

Re: Model B Rear main oil leak: What to do next?
 

manuel,

This may be a strange comment but

Does someone sell INSERTS for babbit bearings?

I seem to remember hearing something about this..

This was a way to replace the Babbitt bearing with replaceable inserts?

Or did you already do that???
If you did not then you might want to consider it.

These are for a model A but, I remember seeing something similar for a model B,
Perhaps the shafts are the same sizes for Model A and Model B? Here it is, sold by Brattons

http://www.brattons.com/prodtype.asp...earchCriteria=

Found Model B replacement bearings at MACS

http://www.macsautoparts.com/ford_me...-oversize.html

Re: Model B Rear main oil leak: What to do next?
 

Frank, you really want to try to follow along more closely with exactly what has already been done, and that the motor is already back in the car.

Re: Model B Rear main oil leak: What to do next?
 

I thought it was still leaking, and would have to be removed to be fixed, unless he wants to add a gallon of oil after each drive.

Re: Model B Rear main oil leak: What to do next?
 

The end of post # 14 states:
" I see not even one drop of oil."