| Author |
Message |
    
Bob Pataky
Member
Username: Bob421
CT
Registered: 6-2009
Post Number: 102
| | Posted on Wednesday, July 28, 2010 - 9:31 am: | 
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My question pertains to the cam bearings:
(1) What cam bearings have you been using in the B&P engines?
(2) Do you use the same bearing for the front and rear?
(3) Do you use the narrow or wide bearings?
I realize all the questions ask the same thing but I wanted to cover my bases. I have taken apart a couple B series engines recently and the rear cam bearing (electric PTO end) is centered in the bore. The JD CTM2 manual states the bearing should be set to be flush with the inside of the case. When looking at the cam and the bearing it does not make sense to center the bearing in the bore because only a small part of the cam would make contact with the bearing. The rear cam journal is stepped, one step rides on the cam bearing where the other step is the eccentric for the points. Myself, I would think that you would want as much contact between the cam and bearing as possible.
The two engines I took apart both use the same bearing in the front and rear, the wide bearings with the notch that allows clearance for the cam lobe when installing. When that bearing is used in the rear the notch lines up with the hole for the rod for the points.
If anyone has any insight on this I would greatly appreciate any thoughts.
BTW how does the rear cam bearing get oil? Splash from crank?
Bob421 |
John O'Donnell
Member
Username: Johnod
Wi
Registered: 5-2006
Post Number: 1384
| | Posted on Wednesday, July 28, 2010 - 10:53 am: |
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Bob,
Lubrication on these engines is via an oil pump so it's all pressure lubricated. There is a metal tube internally running from the oil pump side of the engine to the opposite side of the engine. That lubricates the cam bearing you are talking about.
John |
Bob Pataky
Member
Username: Bob421
CT
Registered: 6-2009
Post Number: 103
| | Posted on Wednesday, July 28, 2010 - 11:31 am: |
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John,
The tube that runs front to back only supplies oil to the rear main bearing as far as I can see. There are no oil passages going to the rear cam bearing, no holes in the journal of the block where the cam bearing goes. The front cam journal in the block has an oil passage hole.
No oil can get in from the back of the cam because there is a cam plug sealing the end of the cam so the only way I see oil getting there is via splash.
Bob |
