L16 oil pressure prob

[Jayden71]

I have a problem that I have never before encountered on a Datsun.

 

I am running straight 30W in my L16 that only has 3000 miles on rebuild. When I fire it up in the morning or whenever, I have good oil pressure at idle. I have let it idle for 30 minutes straight, plenty of time to get oil up to operating temp, 190 degrees, thermostat open. Oil pressure will stay the same.

 

When I drive it oil pressure is again solid, 45 psi or so. When I come to a stop and idle, oil pressure is gone. If I shut it off for about 30 seconds and start it back up, oil pressure comes back even at idle, and it will stay there too, no jumpin around. If I don't shut it off and drive it, the oil light stays on and I have no pressure.

 

There is no odd noise or vibration coming from the engine that would indicate a bad bearing of any kind. Seems like the oil pump is losing its prime. Can this happen?

 

Also oil level is at full mark all the time. Engine does not use any oil.

 

I just rebuilt the oil pump last weekend. Put a new regulator valve in and all.

 

I don't always trust the oil light so I run a gauge as well and when the light comes on that gauge is at almost zero. Its wierd, it could be 90 degrees outside and I have drivin it for an hour, at idle no pressure. Shut it off for just a bit and then I have hot idle oil pressure.

[datzenmike]

Get rid of that oil pump. Don't take chances with your oil pressure. Something isn't right or was put together wrong.

 

Get a high volume oil pump, I guarantee you won't look back. I did on my 300,000 km L20B and the hot idle oil pressure went up from 17 to 29 PSI with no other change. I got a $10 one from the wrecking yard but you could buy a new one too. Anyone with a stock L or Z series motor should have one on theirs. If the motor is modified, they should definitely have one.

 

The vehicles to look for are:

 

'86.5 and up D-21 Hardbody with either Z24i (throttle body injection), KA24E or KA24DE 4 cyl motors.

 

'87 to '95 WD-21 Pathfinder with Z24i motor. Very rare motor option for the WD-21.

 

'88-'90 240sx with KA24E motor. The KA24DE used after '90 had a different, internal oil pump.

 

'80-'83 280zx TURBO automatic L28ET motor.

 

'81-'84 810/Maxima Diesel motor LD28

 

The High output pumps have internal rotors that are 14% longer than the regular pumps.

 

http://i138.photobucket.com/albums/q251/datzenmike/IMG_0186.jpg[/img]"]

 

BTW, you can't tell from the outside when installed. You have to remove and look into the inlet port. The longer rotors sit higher and are more easily seen with the high output pumps.

 

Here is the reg pump. If you look in the inlet (left side) you can barely see only the top of the rotor.

 

http://i138.photobucket.com/albums/q251/datzenmike/motorHi-volumeoilpump1Lg.jpg[/img]"]

 

Compare to the high volume pump below. You can easily see the rotor sits higher.

 

http://i138.photobucket.com/albums/q251/datzenmike/motorHi-volumeoilpump2Lg.jpg[/img]"]

 

If you buy one, know what to look for as these can or could have been put back into the wrong box.

Edited June 27, 2009 by datzenmike

[Jayden71]

Thank you a bunch for the info Datzenmike. I was kinda thinking I should go that route anyways. I just didn't know which cars to look for.

I will hit the junkyards first and see what I can find

[banzai510(hainz)]

try another oil filter.

Persoanlly the pump works or it dont.

I use the standard pumps and have no proplems. The hi vol might relieve soem of the proplems but wonder if soemthing is blocking a passage.

 

U have a special cam or something? With no plug

[Jayden71]

try another oil filter.

Persoanlly the pump works or it dont.

I use the standard pumps and have no proplems. The hi vol might relieve soem of the proplems but wonder if soemthing is blocking a passage.

 

U have a special cam or something? With no plug

 

 

Nothing special in the engine. Had a shop redo the head, normal stuff valve grind etc. Original cam, cleaned up pistons, cut ridge out, honed cylinders, new rings and bearings, you know basic rebuild all original stuff. Stock L16

 

I will try that first thanks

[Jayden71]

The closest junkyard around with decent Datto parts is prolly over the border in Idaho, 100 miles East. I'll start simple and go from there

[Jayden71]

:confused: Put new oil filter on and the problem still persists. I am gonna hunt down a hi volume pump now. Could the pick up screen in oil pan be gettin plugged?? Its wierd.

[hang_510]

:confused: Put new oil filter on

 

remove it and confirm there is a pressure relief ball next to the threads for the filter.

 

missing = need to plug it!

 

present = next!

[420n620]

have you taken the valve cover off and see if oil is oozing out the cam oiling holes while its running, if so then I believe the screen is not pluged.

is it oozing more when you got good oil pressure and does it change when you loose pressure.

 

maybe something is in your relieve valve and is stuck in there since you said you rebuld the oil pump. thats prob why you have good oil pressure at first but them later you don't.

 

maybe something has gotten into the oil passage when the motor got rebuild and now has found it way into the relief valve. all it would take is something very small to keep your relief valve open to loose oil pressure.

[datzenmike]

:confused: Put new oil filter on and the problem still persists. I am gonna hunt down a hi volume pump now. Could the pick up screen in oil pan be gettin plugged?? Its wierd.

 

New are $70-$100 depending on application. Check the pump in the box! Don't go by the number on it, could have been switched by mistake. Don't pay more than you have to.

[Jayden71]

have you taken the valve cover off and see if oil is oozing out the cam oiling holes while its running, if so then I believe the screen is not pluged.

is it oozing more when you got good oil pressure and does it change when you loose pressure.

 

maybe something is in your relieve valve and is stuck in there since you said you rebuld the oil pump. thats prob why you have good oil pressure at first but them later you don't.

 

maybe something has gotten into the oil passage when the motor got rebuild and now has found it way into the relief valve. all it would take is something very small to keep your relief valve open to loose oil pressure.

 

Cam is getting good oil.

 

Removed filter and the pressure relief ball is present. How can I tell if it is getting stuck??

[datzenmike]

The pressure relief ball behind the filter only opens in the EXTREMELY unlikely chance that the oil filter should get plugged. IF, and I mean IF, it were to plug up the pump pressure would come to bear on the ball valve and push it open allowing unfiltered oil up into, and saving the engine. Seeing as how engine oil is filtered over and over when running, even the oil in the pan would be pretty clean.

 

Probably the pump. Borrow one or throw an old one on and see if it gets better.

[banzai510(hainz)]

only thing I can figure is you took the pump apart.

 

try another one

 

a L motor guy should have a stack of them lying around somewhere next to the starters and alternators

[datzenmike]

I find when cutting the lawn.

[hang_510]

How can I tell if it is getting stuck??

if it moves in/out freely when pushed slightly, its good.

 

i had low idle pressure issues when mine went missing :eek:

 

I find when cutting the lawn.

:lol: :lol: :lol:

[Jayden71]

only thing I can figure is you took the pump apart.

 

try another one

 

a L motor guy should have a stack of them lying around somewhere next to the starters and alternators

 

 

The only reason I took it apart is cuz it was doing this with the old one, except I had no idle pressure at all. Put in new parts and now I have idle pressure. I really can't figure this one out. I'll just start fresh with totally diiferent pump and see what goes

[banzai510(hainz)]

well soemthing is plugging up then

NO 2 pumps are going to do this

[Jayden71]

Oil pressure prob fixxed!!!!!! I got 60 psi at cruisin speed now. I am happy. Kept the same rebuilt oil pump too. Installed new oil pressure sensor and replaced old brittle plastic line. They both screwed up at the same time. My little truck is back haulin some L16 ass around town:fu: