Main and Rod Shim Sequence ???

[40 Deluxe]

I don't know about millions since there were only around 5 million made but I'm sure a lot of them were shade tree repaired. A lot probably ended up in scrap iron drives during the war too. If a crank broke, you just went to the junk yard and bought another engine or you went to the used car lot and bought another car. It depended on how much money you were making at the time. During the war, folks had to make due with what they had since auto manufacturing dried up but there were still used cars available from service men going overseas. My Pop sold his 35 Tudor in Florida before he and his crew left for the ETO. He bought a 41 Tudor after he got back in late 1945.

Adjusting the bearings was an accepted service procedure back then. In fact, the Model A Instruction Book says "If a bearing has become loose it should be adjusted by an authorized Ford mechanic." Many A's, probably most, needed at least a valve and ring job during their lifespan which included adjusting the bearings unless it was a backyard job. My question is, How many broken cranks resulted from the resulting "bowing" effect? In spite of all the adjusting that went on, A's did not have a reputation for breaking cranks (such as Chevy's reputation for broken axles at that time).

 

[ursus]

Thanks for the informative discussion. So I think that I get it … about the normally greater wear on the center main. It seems that the best procedure for an "in the car" adjustment would be as follows.
First set up the front and rear bearings to .0015 - .002 and note the amount of shims that were removed.
THEN, take that same number of shims out of the center main and just live with the slightly greater clearance at that bearing. Thus avoiding the bowing that would have resulted from going to .0015 - .002 at that center bearing.
Makes sense to me .
Joe B

I agree, and recall my Dad telling me to adjust the front and rear mains first and the center main last. He also said that I might not be able to get the center as tight as the others and that was OK.

 

[Kohnke Rebabbitting]

Model A's had a lower breakage, because of the bigger shaft that was used, then the Model T's that had, or have about a 65%, or a little higher, crack rate. This is all caused by out of alignment, shaft and bearings.

There are two types of bearing adjustment.

No. 1 normal adjustment, .006, or less, which is doable, and safe.

No. 2 Try to save bearing mode. After you have .006 of shims used, you now would have an egg shaped hole, that if it were a oil pressure engine, most of the oil would be pushed out the sides of the bearing, to be thrown into the pistons, by the crankshaft, to create, an oil burner.

This is why K.R Wilson, recommended pouring every engine in this condition.

Also, your center line of the crank, and pilot shaft, and bearing would off, as in alignment

Herm.

 

[Kohnke Rebabbitting]

Adjusting the bearings was an accepted service procedure back then. In fact, the Model A Instruction Book says "If a bearing has become loose it should be adjusted by an authorized Ford mechanic." Many A's, probably most, needed at least a valve and ring job during their lifespan which included adjusting the bearings unless it was a backyard job. My question is, How many broken cranks resulted from the resulting "bowing" effect? In spite of all the adjusting that went on, A's did not have a reputation for breaking cranks (such as Chevy's reputation for broken axles at that time).

To answer your question, on what we have found, was about 33 cranks, in about 55 years, not broke, but cracked, and not usable. We have never used any crank shaft, with out magnafluxing it first, on any kind of car.

Thanks,

Herm.

 

[40 Deluxe]

To answer your question, on what we have found, was about 33 cranks, in about 55 years, not broke, but cracked, and not usable. We have never used any crank shaft, with out magnafluxing it first, on any kind of car.

Thanks,

Herm.

Thanks for the info, Herm. That's a low figure, for sure. And I imagine a lot of the engines that hit your shop have been ridden hard and put away wet! How many engines would you estimate have gone through your shop in those 55 years?

 

[Kohnke Rebabbitting]

Thanks for the info, Herm. That's a low figure, for sure. And I imagine a lot of the engines that hit your shop have been ridden hard and put away wet! How many engines would you estimate have gone through your shop in those 55 years?

Give, or take 500 engines. Way more then that in just babbitt jobs. There was a Guy in Minneapolis, that would bring, 18 to 22 blocks at a time. He would do the machine work, and then brought them for babbitt. He used to work for Gopher, engine, nice guy.

Model T's, about 400, not counting Babbitt Jobs.

33,000 Spun poured A, Rods, That many , or more in Model T rods.

For many years we had 5 to 6 full time Employees.

That is not counting all the other makes of cars, and tractors, and all kind of industrial machines.

One thing I can brag on is, in 55 years to date, we have never lost a bearing to bad workmanship. The reason for that is if there is even a small imperfection, that won't bother, it goes back, for repouring. At the time of finish machining, whether the bearings are in finished Semi, or completely done.

Thanks

Herm.

 

[Kohnke Rebabbitting]

More pictures, same Motor.

 

[Kohnke Rebabbitting]

Just a few pictures left.

 

[40Pickup]

Another question for Herm, if apologies in this thread!

If I understand it correctly, one of the reasons the peening babbits is to allow the babbitt to have full contact with the engine block.
Is also the reason to compress the babbit to achieve a higher density.
If so, how deep does peening effect go, it looks like you're peening very hard.

After many mil and bearing clearance has become excessive,
how much depends on,

Wear of crankshaft?

Wear of babbitts?

Compression of the babit?

I understand that it may be due to various causes, but is there a rule of thumb?

Hard for me to explain, hope it's understandable.

Thanks
Jorgen

 

[PalAl]

PalAl - Excellent article. Thanks!!

Glad it was good informative reading. Honeymooned in the Pocano's Fifty years ago Sept. What an amazing area!Hard to believe my bride has put up with me for all those years.................

 

[Kohnke Rebabbitting]

Another question for Herm, if apologies in this thread!

If I understand it correctly, one of the reasons the peening babbits is to allow the babbitt to have full contact with the engine block.
Is also the reason to compress the babbit to achieve a higher density.
If so, how deep does peening effect go, it looks like you're peening very hard. " END QUOTE "

Yes, the Babbitt has to be 100% contact with the saddle. When you peen, it has to be done very hot. When Peening, you should be able to see the Babbitt move under the end of the Peening tool, ever so slightly. Babbitt compression, is just a good side effect, of peening. You have to keep the tool moving, and over lap. The ends of the thrust also has to be Peened, it takes practice. Do NOT peen into the Bearing radius.

After many mil and bearing clearance has become excessive,
how much depends on,

Wear of crankshaft?

Wear of babbitts?

Compression of the babit?

I understand that it may be due to various causes, but is there a rule of thumb?

Hard for me to explain, hope it's understandable. " END QUOTE "

It all has to be considered.


Thanks
Jorgen

Thanks,

Herm.

 

[50Trucking]

MY PROBLEM IS THAT WHEN I TOOK OFF THE ROD CAPS THERE WERE NO SHIMS IN THE CAPS. Is there a setup where no shims are used or is this crank just worn out?

 

[Jim Brierley]

The center brg. wears the most because the #2 & 3 pistons are both putting force in an alternating manner, thus forcing the center main down in alternating directions. Not because of the flywheel weight. Firing order of 1-2-4-3. #2&4 should be in bold print, I'm not very computer literate.