From:Steve Marks
E-Mail:<steve@microdesign.ltd.uk>
Subject:RE: RE: Cam bearings
Response to:899
Date:Thu Mar 3 06:39:34 2005
Yes the case does move! Thought some of you might be
interested in my story on this and how I got round the
problem. When I got my Hen it was a box of bits with the
camshaft out and bearings missing. I made a new set of
bearings which ran perfectly on the camshaft. But when I
pressed them into the case, the camshaft locked up and
wouldn't revolve. My first thought was a bent camshaft but
running it between centres with a clock on the bearing
surfaces showed less than 1/2 thou runout. Not bad
considering the length! Then I put it in the case without
the centre bearing - revolved beautifully. Concluded that
the holes in the case were not in line. Just out of
interest, I opened up the hole through my new centre bush by
about 5 thou, reassembled and tried again. Still tight. Kept
repeating the process until it would revolve freely. Then
measured the new bore - bigger than the shaft by about 25
thou! Don't have a horizontal boring machine but like to do
as much as I can myself. After a bit of thought, I used a
length of mild steel with the ends turned to fit in the two
end bearings and a cross drilling to take a HSS cutter in
the centre. A hexagon machined on the end of the shaft
enabled me to turn the shaft. Sure enough, it only cut on
one side of the centre hole. To get a fine feed on the
cutter, I removed the topslide from the lathe and clamped
the crankcase to the crosslide. Needless to say the cutter
shaft didn't line up with the lathe centre line but I got
round this by raiding the socket set. A socket extension bar
in the chuck gave me a square drive. Then came a pair
universal joints from the socket set followed by a socket to
fit on the end of my cutter shaft. Running the lathe slowly
with the longitudinal feed engaged cut a perfect finish in
the centre bush housing. I tapped the cutter out a little
for each pass until it cleaned up all round. Then had to
make a new centre bush (again!) to suit the larger O/D.
Reassembled the whole thing and was pleased to see that it
all worked perfectly! 
Then on to the next job.....

----- ORIGINAL MESSAGE FOLLOWS -----
.003 to .005. Front can be setup at .003 as it gets flow
from the cam chest area
center bearing most times will end up at .010 after a few
hundred miles. 
It will find its own spot, the cases move all over during
the heating and cooling.

R



----- ORIGINAL MESSAGE FOLLOWS -----
Hi Guys!
Can anyone help with spec's on camshaft bearing clearance.