The Ford Barn

BTERRY29 · 09-10-2022, 06:37 AM

Hypothetically speaking. If you have a cracked Babbitt in a bearing cap, why would you not be able to use one from another engine as long as both engines crank journals measure the same. Or could you?

Rookie question. Thanks in advance

jack backer · 09-10-2022, 07:04 AM

You can, just fit the cap correctly. .0015 clearance for hydrodynamic principal needs

Bob Bidonde · 09-10-2022, 07:05 AM

Using a bearing cap from another engine has been done. On one occasion, a rod bearing cap found behind an out-of-business gas station was fitted to a Model "A" engine. I have successfully swapped a rear main bearing, but it took a lot of trial & error fitting by scrapping the bearing with a knife.

BTERRY29 · 09-10-2022, 07:44 AM

Quote:

Originally Posted by Bob Bidonde

Using a bearing cap from another engine has been done. On one occasion, a rod bearing cap found behind an out-of-business gas station was fitted to a Model "A" engine. I have successfully swapped a rear main bearing, but it took a lot of trial & error fitting by scrapping the bearing with a knife.

out of curiosity, why did you have to scrape it? If both engines cranks had the same journal size, i would assume the caps would have the same internal dims.

chrs1961815 · 09-10-2022, 10:17 AM

Quote:

Originally Posted by BTERRY29

out of curiosity, why did you have to scrape it? If both engines cranks had the same journal size, i would assume the caps would have the same internal dims.

Not necessarily. There were several different versions of caps from Ford, aftermarket replacement ones, and all the different design caps that engine rebuilders have made over the years.

Flathead · 09-10-2022, 10:53 AM

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Also how well the line bore jig was centered.

nkaminar · 09-10-2022, 10:14 PM

Yellow Timesaver can be used to fit a cap or a complete bearing, see link below. The powder is mixed with water and smeared on the bearing. The bearing is then tightened until tight but not so much that you cannot turn the crankshaft over. The crankshaft is then turned until the bearing loosens up. The bearing is then cleaned and the pattern examined. A uniform grey surface is the goal. The process is then repeated until the bearing is fitted. Everything should be cleaned up then, assembly lube smeared on the bearing, and enough shims added to provide the correct clearance. Alternately you can take one shim out at a time to make the bearing tight and when the uniform pattern is obtained just stay with the resultant shim pack.

The yellow Timesaver only laps the soft babbett and not the steel journal. This is best done with the engine out of the car and upside down on a stand. The crank should be able to be lifted out to clean up everything. If the rods are done, the crank does not have to come out but the rod separated from the crank to clean the bearing.

In my opinion, Timesaver does a better job than scraping the bearing. With scraping there are always some low spots and some high spots and the bearing has to be broken in to provide the proper uniform surface. If you scrape the bearing, install it tight and then break it in by running the engine slowly for a while and for short times.

The crank can be turned by hand but using a right angle variable speed drill motor saves your arm and does a faster job. You have to use an adapter to use a socket wrench for the crankshaft pulley nut.

https://www.snydersantiqueauto.com/p...d=980308&cat=0

ursus · 09-10-2022, 10:38 PM

QUOTE: "The powder is mixed with water and smeared on the bearing."

My understanding is that the powder is mixed at about 10% w/v in motor oil and smeared on the bearing. If mixed in water it will cut much more aggressively and may take the mirror bright finish off the crank journal

CT Jack · 09-11-2022, 08:23 AM

Many good suggestions being posted as solutions for the short term. My personal experience tells me, if you are seeing cracked babbitt it will not be too long before all the bearings will be in need of replacement.

Richard Knight · 09-11-2022, 09:57 AM

Time-saver is mixed with OIL.

Jim Brierley · 09-12-2022, 11:44 AM

When the [U]block[U] is bored when new at the factory, it is not bored with precision, when the babbitt is poured into the block is when precision comes into play, and it then locates the crank precisely where it belongs. the result is the O.D. of the babbitt may be on a different center line on different blocks, so caps may or may not be interchangeable from one block to another.

jack backer · 09-12-2022, 04:09 PM

So basically you might have to fit the cap, let the plastigage be your guide.

nkaminar · 09-12-2022, 07:39 PM

Sorry, my mistake. Oil not water. It has been a while and I was depending on my memory.

09-10-2022, 06:37 AM	#1
BTERRY29 Member Join Date: Mar 2021 Location: San Diego, CA Posts: 49	Bearing cap question Hypothetically speaking. If you have a cracked Babbitt in a bearing cap, why would you not be able to use one from another engine as long as both engines crank journals measure the same. Or could you? Rookie question. Thanks in advance

09-10-2022, 07:04 AM	#2
jack backer BANNED Join Date: Mar 2022 Location: Chenango Bridge NY Posts: 433	Re: Bearing cap question You can, just fit the cap correctly. .0015 clearance for hydrodynamic principal needs

09-10-2022, 07:05 AM	#3
Bob Bidonde Senior Member Join Date: May 2010 Location: Long Island, NY Posts: 3,472	Re: Bearing cap question Using a bearing cap from another engine has been done. On one occasion, a rod bearing cap found behind an out-of-business gas station was fitted to a Model "A" engine. I have successfully swapped a rear main bearing, but it took a lot of trial & error fitting by scrapping the bearing with a knife. __________________ Bob Bidonde

09-10-2022, 10:53 AM	#6
Flathead Senior Member Join Date: May 2010 Location: Southern Maine Posts: 1,499	Re: Bearing cap question Sponsored Links (Register now to hide all advertisements) Also how well the line bore jig was centered.

09-10-2022, 10:14 PM	#7
nkaminar Senior Member Join Date: Jan 2012 Location: Western North Carolina Posts: 3,897	Re: Bearing cap question Yellow Timesaver can be used to fit a cap or a complete bearing, see link below. The powder is mixed with water and smeared on the bearing. The bearing is then tightened until tight but not so much that you cannot turn the crankshaft over. The crankshaft is then turned until the bearing loosens up. The bearing is then cleaned and the pattern examined. A uniform grey surface is the goal. The process is then repeated until the bearing is fitted. Everything should be cleaned up then, assembly lube smeared on the bearing, and enough shims added to provide the correct clearance. Alternately you can take one shim out at a time to make the bearing tight and when the uniform pattern is obtained just stay with the resultant shim pack. The yellow Timesaver only laps the soft babbett and not the steel journal. This is best done with the engine out of the car and upside down on a stand. The crank should be able to be lifted out to clean up everything. If the rods are done, the crank does not have to come out but the rod separated from the crank to clean the bearing. In my opinion, Timesaver does a better job than scraping the bearing. With scraping there are always some low spots and some high spots and the bearing has to be broken in to provide the proper uniform surface. If you scrape the bearing, install it tight and then break it in by running the engine slowly for a while and for short times. The crank can be turned by hand but using a right angle variable speed drill motor saves your arm and does a faster job. You have to use an adapter to use a socket wrench for the crankshaft pulley nut. https://www.snydersantiqueauto.com/p...d=980308&cat=0 __________________ A is for apple, green as the sky. Step on the gas, for tomorrow I die. Forget the brakes, they really don't work. The clutch always sticks, and starts with a jerk. My car grows red hair, and flies through the air. Driving's a blast, a blast from the past. Last edited by nkaminar; 09-10-2022 at 10:31 PM.

09-10-2022, 10:38 PM	#8
ursus Senior Member Join Date: May 2010 Location: Oregon Posts: 1,375	Re: Bearing cap question QUOTE: "The powder is mixed with water and smeared on the bearing." My understanding is that the powder is mixed at about 10% w/v in motor oil and smeared on the bearing. If mixed in water it will cut much more aggressively and may take the mirror bright finish off the crank journal

09-11-2022, 08:23 AM	#9
CT Jack Senior Member Join Date: May 2010 Location: Hebron, CT Posts: 432	Re: Bearing cap question Many good suggestions being posted as solutions for the short term. My personal experience tells me, if you are seeing cracked babbitt it will not be too long before all the bearings will be in need of replacement.

09-11-2022, 09:57 AM	#10
Richard Knight Senior Member Join Date: Mar 2021 Posts: 130	Re: Bearing cap question Time-saver is mixed with OIL.

09-12-2022, 11:44 AM	#11
Jim Brierley Senior Member Join Date: Jun 2010 Location: Temecula, CA Posts: 4,089	Re: Bearing cap question When the [U]block[U] is bored when new at the factory, it is not bored with precision, when the babbitt is poured into the block is when precision comes into play, and it then locates the crank precisely where it belongs. the result is the O.D. of the babbitt may be on a different center line on different blocks, so caps may or may not be interchangeable from one block to another.

09-12-2022, 04:09 PM	#12
jack backer BANNED Join Date: Mar 2022 Location: Chenango Bridge NY Posts: 433	Re: Bearing cap question So basically you might have to fit the cap, let the plastigage be your guide.

09-12-2022, 07:39 PM	#13
nkaminar Senior Member Join Date: Jan 2012 Location: Western North Carolina Posts: 3,897	Re: Bearing cap question Sorry, my mistake. Oil not water. It has been a while and I was depending on my memory. __________________ A is for apple, green as the sky. Step on the gas, for tomorrow I die. Forget the brakes, they really don't work. The clutch always sticks, and starts with a jerk. My car grows red hair, and flies through the air. Driving's a blast, a blast from the past.