<VV> Cam bearings

[JVHRoberts at aol.com]

They do make split cage needle bearings. Two stroke outboards use them all  
the time. However, I would not recommend them for this application  because:
1. Loss of oil pressure. These types of bearings hemmorhage oil like  there's 
no tomorrow. There's no nice tight clearance to keep the pressure  in.
2. They are VERY intolerant of ANY kind of debris. Get a piece of ANYTHING  
into one, and it's game over. A plane bearing is much more tolerant.
3. Overload a needle bearing, for whatever reason, case distortion, a  
hammering lifter, whatever, and the bearing will also be short lived. 
 
Building up the cam and boring the case is probably the simplest. Boring  the 
case and fitting inserts is also a possibility. These would be the only two  
I would consider. 
 
In a message dated 2/6/2006 11:12:57 A.M. Eastern Standard Time,  chartzel at com
cast.net writes:

Someone  suggested needle bearings on a cam.  This won't work on the 2nd or
3rd  bearing as it would be impossible to install.  The bearing diameters  are
smaller than the cam lobes so you couldn't get them over the  lobes.  You
could use a needle bearing on the small end by installing  on the cam and
then dropping into one block half.  To use a needle  bearing on the gear end
you would have to install on the cam first then  press the gear on.  To me,
the easiest way, if you can't find a better  block, is to bore the block a
few thousands oversize and metal spray or  chrome the cam journals.  Of
course if you ever want to change cams  you would have to metal spray or
chrome the new cam.  I suppose the  wear happens but in 44 years of playing
with Corvairs and racing the  engines on the drag strip and in dune buggies,
I have never seen cam  bearing wear.  I can also say I have never checked  it
either!!!
Clark (ignorance is bliss) Hartzel