datsun-roadsters
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Re: oil pump

To: datsun-roadsters@autox.team.net, paul@winresearch.com
Subject: Re: oil pump
From: walter@omni.sps.mot.com (Thomas Walter)
Date: Tue, 19 Oct 99 21:04:10 CDT
Paul,

On the oil pump, buying a new one is cheap insurance.

Still they are very robust, and I have not heard of
a roadster oil pump "just dying".  

Typically the can wear some, resulting in lower oil 
flow and lower pressure. Also the pressure relief 
is a simple piston & spring. It is possible for the 
piston to get jammed in a wrong position, leading 
to low or HIGH pressure.

I do like to take the bottom cover of the pump off
and inspect it for wear. If the oil has been changed
on a normal basis, and nothing drastic ever happened
to the engine (i.e. loosing a time chain on a U20,
which ground the aluminum cam cover into pieces sucked
up by the oil pump!) then the oil pump really is a 
long life item. If you see scoring, or groves, in the
bottom cover plate you already have an idea of the
damage to the pressure reliefe piston & bore. Not worth
the risk.

Sometimes I do just a 'fresh up' rebuild that had standard
rings, bearings, and the timing chains. Usually around 60,000
miles there is not much wear,  but if tearing down an engine
to inspect it... might as well put in new rings and rod
bearings while you are in there. If the pump looks fine,
and clean, it is a good sign the motor was well cared for.
In that case I'll reuse.

The oil pump gasket is onion skin thin. I bought about a
dozen internal gaskets some years back. I would not use
RTV, nor a thick universal gasket, as the gasket thickness
is also part of the pump clearance. Not sure if those gaskets
are still available, but do use the correct item.

Cheers,

Tom Walter
Austin, TX

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