Datsun Roadster Forum-311s.org

I've developed 30w 70 RACiNG oil
better order now

OK, I have finally been able to get things checked out, now to decide if I have a problem or not.

I have 4 pressure gauges that cover 0-100 psi, 3 from air compressures & the one oil pressure test gauge that I compared using an air pressure regulator & found they were all within 5 psi@ 80 with the one I used on the engine in the middle.

I changed out the break-in oil for Castrol Classic 20W-50, which is what I intend on using from now on out.

With the engine warmed up I got the following pressures:

800 rpm - 25 psi
1200 rpm - 60 psi
2000 rpm - 65 psi
3000 rpm - 70 psi
4000 rpm - 70 psi

Based on this I'd say that the pressure relief is opening at 70 psi, which I think should be fine.

My dash gauge is way off in comparison, but they have never been all that accurate, plus I am using a new aftermarket sender, so no idea how close it is to OEM.

I have all new engine bearings & used Plasti-gauge to verify the clearances & the clearances were all within limits so I am assuming the higher than expected pressure is caused by the higher flow rate of the 2L pump in a 1.6L engine.

Thanks for all the suggestions & insight onthis!

Peace, Pat

It's the 20w50
Go to 5 w30

As recommended by others, I swapped out the 20W-50 classic Castrol for Valvoline VR1 10W-30. The pressures dropped a bit, but not really all that much 30PSI @ idle & about 60PSI @ 3500RPM.

Since the highest oil pressure is below the relief valve setting I don't see that I will be blowing the oil filter, so I am comfortable with the current oil. I haven't been able to find any 5W-30 oil with ZDDP but I will continue looking. I would rather purchase oil that has the flat tappet package in it rather than add it, I really don't trust mixing products, they may work fine to start with but if one manufacturer makes a change who knows.

One more variable that I'm still looking at is that I purchased an aftermarket pressure sender from Paul @ Datsun Roadster Parts that I haven't been able to verify its specs in comparison to OEM but as long as the pressure isn't too high or nonexistent, I'll probably just go with it as is.

Have a great evening, & keep cool, it's supposed to run right at 100 all week.

Peace, Pat