New L28 rebuild, the no oil pressure routine

[Thekvr]

Hi everyone, I’ve gone through the forums, google, books, etc. and frustrated. Needing help on how to go about this no oil pressure at the gauge.

It is a 1982 L28 from a 280zx in a 1973 240z. Oil pump is brand new.

What I’ve done:

-filled oil filter with oil 

-oil pan is at the full mark from dipstick

-primed pump both with oil and also assembly lube. Removed spark plugs and coil wire. Cranked engine with starter several time at 20 second bursts-nothing

-replaced oil pressure sending unit-nothing

-removed oil pump spindle to distributor and reinstalled oil pump, used a bit to spin the pump counter clock wise through the distributor with a cordless drill-oil squirts out of cam!

-I’ve used suction to pull from the feed line hole with the oil pump removed-sputtered but eventually oil cane through

-spun engine with the oil filter hand tightened then backed off- nothing

-feed oil up through the oil pressure sending unit

Should I just try and start it, maybe cranking it doesn’t spin it fast enough? I could use a beer and some help. Thanks

Edited August 28, 2018 by Thekvr

[Zed Head]

31 minutes ago, Thekvr said:

 no oil pressure at the gauge.

Cranked engine with starter several time at 20 second bursts-nothing

-replaced oil pressure sending unit-nothing

-spun engine with the oil filter hand tightened then backed off- nothing

 

Not super clear that you mean the dash gauge or something else.  Could use more detail than "nothing".   Not clear what nothing means.  Do you mean no reading at the dash gauge or no oil through the cam holes?  Or something (nothing) else?

But the sender and gauge are notorious for reading low and responding slowly.  You could disable the ignition system (pull the coil positive wire) and spin the engine with valve cover off to be sure that the oil pump drive gear is working.  Spin the engine with the starter and watch the cam holes.  I've done that on my garage engines, with a ZX reduction starter, which is slow.  It works, oil oozes out at starter speed.  You could also get a mechanical gauge and mount it in the sender port, to get a faster reaction.

[240dkw]

Did you  remove the oil galley plugs in the block during the rebuild, and of course remember to install new ones.

[Thekvr]

18 minutes ago, Zed Head said:

Not super clear that you mean the dash gauge or something else.  Could use more detail than "nothing".   Not clear what nothing means.  Do you mean no reading at the dash gauge or no oil through the cam holes?  Or something (nothing) else?

But the sender and gauge are notorious for reading low and responding slowly.  You could disable the ignition system (pull the coil positive wire) and spin the engine with valve cover off to be sure that the oil pump drive gear is working.  Spin the engine with the starter and watch the cam holes.  I've done that on my garage engines, with a ZX reduction starter, which is slow.  It works, oil oozes out at starter speed.  You could also get a mechanical gauge and mount it in the sender port, to get a faster reaction.

Sorry about the “nothing”, I meant it to say that I didn’t see any oil pressure reading on the dash gauge.

it seems that there is a tiny dribble from the cam when I crank the engine with the spark plugs out and coil disconnected.

sounds like I’ll look at getting a mechanical gauge ordered

[Thekvr]

18 minutes ago, 240dkw said:

Did you  remove the oil galley plugs in the block during the rebuild, and of course remember to install new ones.

Yes, removed, then had them threaded and plugged.

[Zed Head]

If there's oil to the cam, even a dribble, you're probably fine.  The pump is working.  And you showed that it would pump a lot at higher RPM with your drill motor test.  Once the engine starts you'll be at drill motor oil-squirting speed.

People have your problem often, there are very similar threads out there.

[Thekvr]

14 minutes ago, Zed Head said:

If there's oil to the cam, even a dribble, you're probably fine.  The pump is working.  And you showed that it would pump a lot at higher RPM with your drill motor test.  Once the engine starts you'll be at drill motor oil-squirting speed.

People have your problem often, there are very similar threads out there.

Right on. I really appreciate it. I will give it a shot.

[madkaw]

A drill will actually spin the oil pump up to 50+ psi cold, but a drill probably is doing 2000rpm minimum . Cranking is less than 10 psi so it will only be a dribble. If it squirts with a drill - then your probably be okay . Start it with the valve cover off and clean up the mess later

[Thekvr]

Happy to report that I went ahead and started it and success! Pressure built and good to go. Time to break it in. Thanks for the tips