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Re: [Roadsters] Low Oil Pressure

To: "'Bill Cole'" <datrock@centurytel.net>, <datsun-roadsters@autox.team.net>
Subject: Re: [Roadsters] Low Oil Pressure
From: "Paul" <9laser3@bright.net>
Date: Sun, 31 May 2009 18:48:04 -0400
Bill, 

  Eddie could very well be correct in his diagnosis, but let me throw out
another thought.  These old Datsun cast blocks can have lots of flashing on
them.  Flashing that for some reason the factory never removed.  If during
the rebuild a piece of it came loose, it may be stuck in an oil passage
somewhere.
  If you pull the motor back out and all the rotating stuff rotates, you may
want to check out all the oil passages.
  At Sloan Racing I think we've found more flashing in the coolant passages
than oil.  It usually works its way to the radiator.  Anybody rebuilding a
G15, R16, or U20, should take the time to clean up the block before
reassembling.  

Paul
Ohio

-----Original Message-----
From: datsun-roadsters-bounces@autox.team.net
[mailto:datsun-roadsters-bounces@autox.team.net] On Behalf Of Bill Cole
Sent: Sunday, May 31, 2009 1:50 PM
To: datsun-roadsters@autox.team.net
Subject: [Roadsters] Low Oil Pressure

Hi every body, I have a 3 main R-16 that has very low oil pressure. 
Maximum pressure is in the mid 30's. The engine was recently assembled 
and it came in pieces so I have no idea if it had pressure issues before 
it was torn down for the rebuild. Until recently I just assumed the 
gauge was off, then I hooked up a mechanical one and it read lower than 
I would have liked to have seen. I started out with 30wt and now have 
20-50 in it.
       The engine has less than 1000 miles since the rebuild, last week 
I rechecked the rods bearings, front and middle mains from under the car 
with plasticgage and they showed .0015-.002 range. I changed oil pump 
from another 3 main parts engine, I even honed the backing plate to get 
better tolerance and to take away what little wear marks it had on it. I 
tested the pumps and the one that is now in the car pumped better than 
the one I removed. I changed the rocker assembly in case it was causing 
the problem. All that and it still has low pressure on the original and 
on a mechanical gauge too, 10lbs under 2000 RPM and over 2000 RPM. it 
goes up into the 30's. So today I removed the coil wire, spark plugs, 
and the rocker arm assembly and turned the engine over with the starter, 
it went very fast to where I expected oil to surface from the galley 
going up threw the head to lube the rockers, nothing appeared, are my 
expectations wrong, I would have expected oil to flow.
    I'm leaning toward pulling the engine and rechecking everything 
inside. More than likely will also re-bearing it. Any suggestions would 
be appreciated, or if you had similar issues with a rebuild I would like 
to find out what the problem was, it may help me keep the original 
engine in the car. Thanks... Bill
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