500 Cam blocks

M

MotoV

Hero member
I acquired some after market cam blocks, marked with AG. My question is are there different size bores for different years. The reason I ask is that the bores do not fit over the cam journals. What is the spec for the diameter bores with tolerances?
 
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Thanks Rob the spec I need is for the plain block - not using roller bearings. I'll need to confirm but I recall the cam journals were in the(corrected) 18.05 range
 
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MotoV said:
Thanks Rob the spec I need is for the plain block - not using roller bearings. I'll need to confirm but I recall the cam journals were in the 18.5 range
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I've used both bushes and roller bearings in Monty over the years. No change in cam blocks over that time.
 
LaverdaIan said:
I've used both bushes and roller bearings in Monty over the years. No change in cam blocks over that time.r
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These are aftermarket blocks. they are not intended to use bushings or bearings. The A dimension (18), from the graphic above, sounds like a nominal size for the bearing. What I intended to ask for was the bushing inner diameter and tolerance. Sorry for the confusion.
 
MotoV said:
These are aftermarket blocks. they are not intended to use bushings or bearings. The A dimension (18), from the graphic above, sounds like a nominal size for the bearing. What I intended to ask for was the bushing inner diameter and tolerance. Sorry for the confusion.
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Surely the bushing inner diameter is given the tolerance, the diameter of the end of the cam? B in the workshop manual above.
Are you sure your cam ends haven't been turned down due to needle bearings eating in to them, which is what they do?

A is the internal bushing or bearing measurement.

I don't get your problem.

Paul
 
The cams do measure greater than 18...18.055 & 18.050... ahhh ..that's out of spec. The existing BUSHINGS, that fit, both measure 18.08. That allows for the specified 0.03 clearance. The aforementioned aftermarket cam blocks measure 18.011, 18.037, 18.032 & 18.013, based on the shown mimumum clearance the blocks need to be bored to 18.090...or get the :unavailable" new cams. It will be easier to bore/ream the cam blocks.
Thanks
 
MotoV said:
The cams do measure greater than 18...18.055 & 18.050... ahhh ..that's out of spec. The existing BUSHINGS, that fit, both measure 18.08. That allows for the specified 0.03 clearance. The aforementioned aftermarket cam blocks measure 18.011, 18.037, 18.032 & 18.013, based on the shown mimumum clearance the blocks need to be bored to 18.090...or get the :unavailable" new cams. It will be easier to bore/ream the cam blocks.
Thanks
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What is the brand of the after market blocks..? I got some branded A.G. that work well, fitted to the Formula and now Monty as well. No bushes or bearings required (other than middle of course) as they are complete enclosed type same as 1000 units..
 
LaverdaIan said:
What is the brand of the after market blocks..? I got some branded A.G. that work well, fitted to the Formula and now Monty as well. No bushes or bearings required (other than middle of course) as they are complete enclosed type same as 1000 units..
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They are marked AG. They are not the problem - it's the cam journal that is oversize
 
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