Technical Oil Pump fitment question

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Technical Oil Pump fitment question

masterdog

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Hello everybody,

I have a question about the clearance between the oil pump pressure relief valve and the camshaft.
I have recently acquired '72 500f in disassembled state.
It came with 2 engines (original and 600cc from 126) and some spare parts.
I have never worked on these cars before and was wondering if someone could help me with an issue.

While fitting the gear cover I have noticed that although oil pump dogs fit to the camshaft perfectly, the pressure relief valve becomes slightly compressed when the cover is bolted in place.
This becomes especially obvious when attempting to fit 126 cover/pump (the valve on it protrudes further another 2mm towards the camshaft).

Is that normal?

If it is, does that mean that the gear cover gasket HAS to be used (instead of just silicone) for the correct clearance/compression?

Thank you in advance!
 
Yes, the spring pressure of the relief valve WILL initially hold the timing-chain cover away from the crankcase, by about 2-3cm. The important thing is to NOT mix-'n-match the parts. The 500 pump and t/c cover must be kept as a 'set', and the 126 cover also kept as a 'set'. As you have found out, there is a difference between the pumps/t-c covers. You can fit the 126 pump AND 126t/c cover onto the 500.
Some time ago there seemed to be a spate of people suffering low oil pressure problems when the engines warmed up. I am convinced it was because people were "mixing-'n-matching--126 pumps into 500 t/c covers,and the result was that the relief valves were coming into operation as soon as the engines warmed up.
 
Thank you!

Not mixing/matching does make sense, especially with different sizes of gears and shafts...

My main concern was that with 126 cover/pump installed on 500 crankcase/cam there might be different preload on the relief valve spring and it may trigger at a different pressure...

Another thing that I've noticed is that one of the later covers that I have (for 126) has a bigger lip around crank seal that (unless grinded off) interferes with crank pulley (photos below).
 

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