Oil pressure uneven

[jeanp]

Hi, i did change my engine lest fall. I had problems with my head

one valve was not adjustable anymore so i bought that engine rebuilt

from Datsunparts LLC think that was a mistake. The thing is burning oil

and i got uneven oil pressure. It runs great pulls hard but burns oil

and scarry uneven oil pressure. my other engine use to be dead center on the

oil pressure gauge this one goes up and down. and i cannot figure the 

patern. It is not linked with reving it can be high at low rev and low at high rev and vice versa.

complete aleatoire patern. Any body have an idea where to start.

 

 

 

Thank`s

 

Jean-P

[siteunseen]

The oil pressure sending unit by the passenger's side motor mount, to the right of the oil filter, could be bad.  Clogged up or maybe just a loose wire connection.  They are cheap too.

 

Unplug the wire and clean the brass on the unit, then squeeze the wire connector so it will fit nice and tight.  That's what I would do first.

 

Edited June 19, 2015 by siteunseen

[djwarner]

my other engine use to be dead center on the

oil pressure gauge this one goes up and down.

 

If your oil pressure was dead steady with your old engine, it had the problem. Oil pressure should vary with the temperature of the oil and RPMs. When the engine is not warmed up, the oil pump must generate more pressure to circulate the thick oil. As engine RPMs increase more oil is pumped and will increase the output pressure. As the engine warms, it gets thinner and easier to push through the engine and thus less pressure is generated.

 

The next question is whether you are burning oil or leaking it. Does the exhaust blow blue smoke? All the time or only after sitting at a stop light? How many miles have you put on the engine since the re-build? Some piston rings take a while to seat and seal properly. 

 

And finally, how much oil is being lost? How many miles do you drive before you are down a liter of oil?

[Patcon]

Another question, did you reuse your old oil sender or did the new engine come with one?

[jeanp]

Thank`s for fast answers

 

I burned a liter in 250miles, there is 750miles since rebuild and i did change oil at 400miles and there was no grind in it.  I have blue smoke when i leave a red light if i push-it. If i go smootly as soon as i will push it.  have blue smoke almost every time i push it after idling or just smooth riding. I do not push it near red line yet but this engine and the one before realy like to

be pushed. My diagnostic would be valve seals but i cannot beleive that they were not changed. every pieces in there looks new.

[jeanp]

Ho just remember in the breakin starting procedure sent with the motor

there was adjust valve and the number given there were warm numbers

And i did not check my Datsun manual i took these for cash i did adjust all valve to these numbers was suprised that they were all to tight.

I ran the engine for 200 miles like this and i recheked my valves i took the number in my Datsun manual.

they were all wrong to loose. But did not pass much time so i found  the document shipped with the engine gave

hot numbers for valves but say adjust before start. duuhh. anyway now they are OK adjusted but i did ran the engine

with loose valves for about 200 miles

[jeanp]

I did reuse my old sending unit. I will order a new one i think.

[jeanp]

I dont think it`s leaking oil because my garage floor is not covered with oil and the engine is completely clean 1 liter of oil

would have leave traces if it was leaking i think.

[Zed Head]

This won't make you feel better or help your problem directly, but it might help you if you find problems.  Better check your wipe patterns n the rocker arms.

 

And Datsun Parts LLC is now California Datsun.  Give him a call.

 

http://www.classiczcars.com/topic/50485-rocker-geometry-woes/page-1

 

http://www.classiczcars.com/topic/51455-datsun-parts-llc-gone-to-the-dark-side/

[siteunseen]

If there's no oil stains on the floor, that motor is burning it.  Could be the rings or the valve seals.  Get a loaner compression gauge from your local auto parts and do a compression test.  I've read if you don't use the "condom" on the valve stems when installing the seals it causes damage, maybe a slight tear.  I've never installed them myself so I'm just repeating what I've read.

[jeanp]

Hay Zed head i am in these 2 pages of good reviews i think i will call him,

I did send him an E-mail but he is slow on answers

[jeanp]

With the first post so as everybody nows I did had to elicoil one of my valve cover

hole that was stripped to.