Hi Guys,
I've got a black top S13 SR20DET in my S14. I've been chasing some oil pressure issues, and wanted to get some opinions here.
Oil: 10w30 synthetic
Pressure @ 1000RPM and warm: 7PSI
Pressure @ 3000RPM and warm: 48PSI
Cold PSI during start up: 65-75PSI
I'm mainly concerned about the pressure at idle. I've confirmed the pressures with a Stack electronic gauge, as well as a mechanical gauge. I've done some searching and it seems that my 3k RPM pressure is not so bad, but my idle pressure is very bad. Any ideas what would cause this? Finding a lot of conflicting information on what the pressures should be.
Low oil pressure
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gnubberlang
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2004 Frontier 4x4 Crew Cab 5-Speed - Location: Denver, CO
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Harrythook
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- Car: 98 S70 T-5 (blown up)
95 S14
69 Road Runner (hidden away)
Too many Volvo's
Re: Low oil pressure
This is one of those problems where you have to get very accurate information and advice. Follow the goofball info you find on the web and you might have a very bad day with that motor!
Your idle pressure if correct seems way to low, from my read minimum is 11+ psi. There is a thread on another board directly related to this, with a lot of people posting what pressures they have.
There are a lot of reasons for low oil pressure, so to help in diagnosing this post up a bit more information. Fresh motor? Gradual decrease in pressure, or sudden drop? Any internal repairs recently? Racing it or moderate street driving?
Old domestic motors would drop pressure from weak oil pumps or worn main bearings. More modern cars experience pressure relief valve problems or a failure in the oil delivery system (chain oilers, piston cooling valves, ect.). I would get a handle on this soon as those little spinny things in the turbo really like to have oil….
Your idle pressure if correct seems way to low, from my read minimum is 11+ psi. There is a thread on another board directly related to this, with a lot of people posting what pressures they have.
There are a lot of reasons for low oil pressure, so to help in diagnosing this post up a bit more information. Fresh motor? Gradual decrease in pressure, or sudden drop? Any internal repairs recently? Racing it or moderate street driving?
Old domestic motors would drop pressure from weak oil pumps or worn main bearings. More modern cars experience pressure relief valve problems or a failure in the oil delivery system (chain oilers, piston cooling valves, ect.). I would get a handle on this soon as those little spinny things in the turbo really like to have oil….
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PapaSmurf2k3
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Re: Low oil pressure
You don't have an underdrive pulley do you? Or any pulley that is undamped? Those can destroy an oil pump pretty quickly.
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gnubberlang
- Posts: 37
- Joined: Sun Feb 16, 2014 3:57 pm
- Car: 1995 240SX SR20DET
2004 Frontier 4x4 Crew Cab 5-Speed - Location: Denver, CO
- Contact:
Re: Low oil pressure
Thanks for the replies guys! To answer some of the questions:
Underdrive/undamped pulley? No its a stock pulley, but that is good to know!
Fresh motor? It's straight from a JDM junkyard.
Gradual decrease in pressure, or sudden drop? It's around 65-70 PSI on initial startup, then gradually decreases down to 7 PSI when the engine warms up. To the best of my knowledge it's behaved this way since I finished the swap.
Any internal repairs recently? Nothing internal. I did pull the oil pan to check on the strainer after finding that the oil pressure was low. Found that there was already an S14 strainer in place.
Racing it or moderate street driving? Very mild street use. Everything is stock aside from a FMIC. I've driven it maybe a combined total of 8 hours since the swap that I finished last year.
(Warning: possibly useless background info
)
I finished the swap last year around September. I had temp and vacuum gauges fitted but no oil pressure gauge at the time. The engine seemed to be doing fine, starts every time, very quiet. No knocks, no taps. I took it on the first semi-long distance trip. About one hour into the trip, I noticed the oil dummy light was flickering at idle. I had the car towed back to the house at that point and did the following:
-Changed oil (10w30 again)
-Fitted oil PSI gauge
-Confirmed low oil pressure. Fitted a mechanical gauge to confirm that the electric gauge was reading right.
-Pulled pan to check on strainer. Looks good and is S14 style.
Underdrive/undamped pulley? No its a stock pulley, but that is good to know!
Fresh motor? It's straight from a JDM junkyard.
Gradual decrease in pressure, or sudden drop? It's around 65-70 PSI on initial startup, then gradually decreases down to 7 PSI when the engine warms up. To the best of my knowledge it's behaved this way since I finished the swap.
Any internal repairs recently? Nothing internal. I did pull the oil pan to check on the strainer after finding that the oil pressure was low. Found that there was already an S14 strainer in place.
Racing it or moderate street driving? Very mild street use. Everything is stock aside from a FMIC. I've driven it maybe a combined total of 8 hours since the swap that I finished last year.
(Warning: possibly useless background info
)I finished the swap last year around September. I had temp and vacuum gauges fitted but no oil pressure gauge at the time. The engine seemed to be doing fine, starts every time, very quiet. No knocks, no taps. I took it on the first semi-long distance trip. About one hour into the trip, I noticed the oil dummy light was flickering at idle. I had the car towed back to the house at that point and did the following:
-Changed oil (10w30 again)
-Fitted oil PSI gauge
-Confirmed low oil pressure. Fitted a mechanical gauge to confirm that the electric gauge was reading right.
-Pulled pan to check on strainer. Looks good and is S14 style.
-
Harrythook
- Posts: 52
- Joined: Mon Mar 23, 2015 12:46 pm
- Car: 98 S70 T-5 (blown up)
95 S14
69 Road Runner (hidden away)
Too many Volvo's
Re: Low oil pressure
Couple of things:
Low oil pressure at high engine heat is usually an indication of internal wear. Find a diagram of where the oil is pushed to from the oil pump and in most motors its to the critical areas first. Worn main bearing can cause the drop as heat expansion will cause greater clearance and greater leakage. Old school high volume pumps helped because there was still oil moving to do its job. Not gonna help you here.
The pressure relief valve used in this engine should be a spring loaded shuttle, as oil pressure increases with rpm it will over ride the spring pressure and allow the shuttle to bypass. Usually this will become evident as a problem once off idle, as the pump spins up more pressure.
I am unsure as to the pickup and the sealing of that. I have seen many times in engines that use seals (o-rings) on the pickup side have leaks that will cause this problem. If it is severe enough you can actually see bubbling or cavitation evidence if you pull the dipstick while the engine is running.
I would get some heavy weight oi, like castrol gtx 20-50. Dump current oil (save, since new) and replace with heavy oil. Allow car to fully warm, take it out for normal to moderate ride and monitor pressure via the mechanical gauge. Lets see if that increases pressure at idle.
Low oil pressure at high engine heat is usually an indication of internal wear. Find a diagram of where the oil is pushed to from the oil pump and in most motors its to the critical areas first. Worn main bearing can cause the drop as heat expansion will cause greater clearance and greater leakage. Old school high volume pumps helped because there was still oil moving to do its job. Not gonna help you here.
The pressure relief valve used in this engine should be a spring loaded shuttle, as oil pressure increases with rpm it will over ride the spring pressure and allow the shuttle to bypass. Usually this will become evident as a problem once off idle, as the pump spins up more pressure.
I am unsure as to the pickup and the sealing of that. I have seen many times in engines that use seals (o-rings) on the pickup side have leaks that will cause this problem. If it is severe enough you can actually see bubbling or cavitation evidence if you pull the dipstick while the engine is running.
I would get some heavy weight oi, like castrol gtx 20-50. Dump current oil (save, since new) and replace with heavy oil. Allow car to fully warm, take it out for normal to moderate ride and monitor pressure via the mechanical gauge. Lets see if that increases pressure at idle.