Camshaft centre bearing.

[Robert Foreman]

As a matter of interest, how many different sizes of camshaft centre bearings are there? This is for the roller bearing type and not the later split plain bearing.
  I'm especially interested in the outside diameter of the ring.

[dickie65]

Hi Robert,
I can tell you that the Type 65 / Nippy has a larger diameter bearing to allow the high lift camshaft to pass through, the front bearing is a larger diameter as well.
The roller bearings are a larger diameter to compensate.

I will try and get the measurements posted tommorow, I have a dead crankcase in the shed.

[dickie65]

Hi Robert,
The ID of the Nippy centre camshaft bearing is 33.92 mm ( slight surface rust on bearing)
I had to measure with digital caliper then zero before withdrawing the caliper then close caliper to get the measurement as it was impossible to read the caliper in situ.
I hope this will be of use to you.

[Robert Foreman]

Thank you for your time, is there any chance you could try to measure the outside diameter as well please?

[Ian Dunford]

The sports cam rollers are 5/16 by 5/16 inch if any help.

[Colin Wilks]

I've got the outer bearing from my 1934 Type 65 sports engine on the kitchen table. Measuring with a micrometer and telescopic gauge I get the outer diameter to be 1.625" (1.6239 to 1.6256), so 1 5/8", and the i/d to be 1.375" (1.3745 to 1.3753),so 1 3/8".

[Robert Foreman]

Hello Ian, 
  some sports rollers are 3/8" by 3/8".
 Thank you Colin, that's what I expected for a Nippy/65.
  Does anyone have any dimensions for the blown and unblown Ulster's?

[Ian Dunford]

Hello Robert
Sounds as though my ancient brain is further down the slope than I feared.
Memory playing tricks ?

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The Nippy ones are of course 3/8by 3/8ths,
The Ulster ones you require are unknown to me.