Camshaft bearing

1950 - 1952, M38, questions, discussions, regarding anything related to the M38.
85jeepcj
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Re: Camshaft bearing

Post by 85jeepcj » Sun Sep 24, 2017 4:17 am

I would reverse the cam 180 and insert cam into cam bearing to rule out cam bearing. Check cam journals in block for damage.
I econd getting parts from Ron Fitzpatrick, great prices and service.


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Re: Camshaft bearing

Post by Wolfman » Sun Sep 24, 2017 5:41 am

Hope you have not removed the bearing at this point.
The babbit surface of the bearing is soft.
Insert the cam to the point it stops. Push on the cam and rotate it while pushing in.
Remove the camshaft and inspect the bearing surface. If there is a tight spot, it will now be shiny.
That is where the problem is located.
If it turns out to be one small spot, you can shave the bearing . Using a sharp tool. Shave the bump off. I use a horse hoof trimming knife. You probably don't know what that is. Horse people have them.
I know. Straight out of Uncle Bubba's tricks for engine overhaul.
In days of old, this was common practice and worked quite well. Shaving bearings and trimming horse hooves. :mrgreen:
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Re: Camshaft bearing

Post by Cannon Cocker » Sun Sep 24, 2017 6:49 am

85jeepcj wrote:
Sun Sep 24, 2017 4:17 am
I would reverse the cam 180 and insert cam into cam bearing to rule out cam bearing. Check cam journals in block for damage.
I econd getting parts from Ron Fitzpatrick, great prices and service.
I've done that for both bearings to rule out the possibility of other obstructions. The outcome is the same...restriction begins about 3/4 of the way inside of the bearing.

Regarding Ron Fitzpatrick parts, I must plead ignorant that the host offered parts. When I joined the forum, I was looking for people like you and others on the forum to guide me through my project. I apparently overlooked the "home page" completely. Had I known, I would've never been so rude to the host by asking for suppliers. Since learning this, I've enjoyed exploring parts he offers and have identified much, much more than just the cam bearing I need. Thank you and others for pointing this out.

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Re: Camshaft bearing

Post by Cannon Cocker » Sun Sep 24, 2017 6:55 am

Wolfman wrote:
Sun Sep 24, 2017 5:41 am
Hope you have not removed the bearing at this point.
The babbit surface of the bearing is soft.
Insert the cam to the point it stops. Push on the cam and rotate it while pushing in.
Remove the camshaft and inspect the bearing surface. If there is a tight spot, it will now be shiny.
That is where the problem is located.
If it turns out to be one small spot, you can shave the bearing . Using a sharp tool. Shave the bump off. I use a horse hoof trimming knife. You probably don't know what that is. Horse people have them.
I know. Straight out of Uncle Bubba's tricks for engine overhaul.
In days of old, this was common practice and worked quite well. Shaving bearings and trimming horse hooves. :mrgreen:
I haven't remove the second bearing. I'm glad you piped up. Your suggestion is right on target. Grew up with horses so I know the tool you speak of. Horses are all gone as are the tools but we do have a local Tractor Supply store. I'm also aware of the cam bearing scraper. Would this be better?

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Re: Camshaft bearing

Post by Wolfman » Mon Sep 25, 2017 4:46 am

A cam bearing scraper would be best. If you can find one. Went out with poured bearings in Model Ts and hit/miss engines.
A rounded blade won't be as likely to gouge the round bearing surface as a flat blade.
The advantage of a hoof knife is the blade narrows as it gets toward the tip. They are also very sharp so they easily shave off the soft babbit material with out much pressure, leaving a nice, smooth surface.
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dpcd67
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Re: Camshaft bearing

Post by dpcd67 » Mon Sep 25, 2017 6:22 am

It will work, but I don't like the scraping and cutting of the bearing method; you will cut through the lead surface into the steel backing and that is not good. There is some reason that two bearings in a row got tapered at the back, or have a raised place at the back. You should be able to see a burnished spot where you tried to install the cam.
If it was mine I would want to find out the root cause and fix that; not alter the bearing by scraping it potentially, down to the steel core. While it might not take that much to make it fit, in any case you are thinning the lead surface.
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Re: Camshaft bearing

Post by Joe Gopan » Mon Sep 25, 2017 7:16 am

Have you "staked" these subject bearings in place?
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Re: Camshaft bearing

Post by Cannon Cocker » Mon Sep 25, 2017 7:25 am

Ben Dover wrote:
Mon Sep 25, 2017 7:16 am
Have you "staked" these subject bearings in place?
[/quote
No.

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Re: Camshaft bearing

Post by Cannon Cocker » Mon Sep 25, 2017 7:52 am

dpcd67 wrote:
Mon Sep 25, 2017 6:22 am
It will work, but I don't like the scraping and cutting of the bearing method; you will cut through the lead surface into the steel backing and that is not good. There is some reason that two bearings in a row got tapered at the back, or have a raised place at the back. You should be able to see a burnished spot where you tried to install the cam.
If it was mine I would want to find out the root cause and fix that; not alter the bearing by scraping it potentially, down to the steel core. While it might not take that much to make it fit, in any case you are thinning the lead surface.
Talked with the machine shop and they're going to polish the cam. The cam is original and at 66 years of age, who doesn't need a little polishing. :) Anyway, it'll only cost $10. I have my doubts that this will solve the problem but won't hurt to give it a try. I should've had this done initially. I'll let you know the outcome.

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Re: Camshaft bearing

Post by Cannon Cocker » Mon Sep 25, 2017 7:52 am

dpcd67 wrote:
Mon Sep 25, 2017 6:22 am
It will work, but I don't like the scraping and cutting of the bearing method; you will cut through the lead surface into the steel backing and that is not good. There is some reason that two bearings in a row got tapered at the back, or have a raised place at the back. You should be able to see a burnished spot where you tried to install the cam.
If it was mine I would want to find out the root cause and fix that; not alter the bearing by scraping it potentially, down to the steel core. While it might not take that much to make it fit, in any case you are thinning the lead surface.
Talked with the machine shop and they're going to polish the cam. The cam is original and at 66 years of age, who doesn't need a little polishing. :) Anyway, it'll only cost $10. I have my doubts that this will solve the problem but won't hurt to give it a try. I honestly think it's the bore but should've had this done beforehand. I'll let you know the outcome.

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Re: Camshaft bearing

Post by Joe Gopan » Mon Sep 25, 2017 3:14 pm

Check the condition of the fuel pump lobe, if it is rough, its time to get another cam.
2011 MVPA PIONEER AWARD - MVPA #1064
HONOR GRAD-WHEELED VEHICLE MECHANIC SCHOOL 1960 - US ARMY ORDNANCE SCHOOL(MACHINIST) ABERDEEN PG 1962 - O-1 BIRD DOG CREWCHIEF - 300,000+TROUBLE FREE M-38A1 MILES
LIFE MEMBER AM LEGION-40/8-DAV
7 MIL SPEC MAINTAINED MV'S
COL. BRUNO BROOKS (ARMY MOTORS) IS MY HERO

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Re: Camshaft bearing

Post by Cannon Cocker » Mon Sep 25, 2017 4:21 pm

Ben Dover wrote:
Mon Sep 25, 2017 3:14 pm
Check the condition of the fuel pump lobe, if it is rough, its time to get another cam.
Will do.


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