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Low Oil Pressure On Newly Rebuilt Engine:(


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Thank god I thought I forgot somthing in my build.

What is the proper oil pressure at idle mate. I have a tomie oil pump and was just wondering because in the morning im installing a manual oil pressure gauge. I dont trust tye stock r32 gauge.

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already been said. you want at least 10psi per 1000rpm.

on cold startup you will see alot more. I get up near 60psi I think

Being a Tomei pump I'm not sure how they flow at idle, but if it were me I'd just follow the 10psi per 1000rpm

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I started up my motor with 10w 30 oil. I took it for one drive no more than 5 minutes. Im now going to install my manual oil pressure gauge and change my oil to 20w 50 full synthetic by mobil one. This is the weight I always used. I dont even know why I really used 10w30. -_-

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This is the weight I always used. I dont even know why I really used 10w30. -_-

The weight of oil you use really comes down to the driving style and clearances used on the build.

For factory clearances on a street engine the standard weight works best, push it a bit and i go up 1 weight.

I only run 50-60 weight oil on super loose builds for drag or track......i cannot fathom why anyone would be running such a thick oil on tight clearances.

Has anyone thought about oil drain back issues when running thicker oils? Better have those oil returns drilled out and good crankcase venting to help oil drainback.

Even modern Nascar engine builders are running tighter bearing clearances these days with some pretty thin oil weights in their race engines.

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I started up my motor with 10w 30 oil. I took it for one drive no more than 5 minutes. Im now going to install my manual oil pressure gauge and change my oil to 20w 50 full synthetic by mobil one. This is the weight I always used. I dont even know why I really used 10w30. -_-

Use mineral oil for run in which should take 30 -60 minutes. Push it hard and lift off alternately watching for overheating and or leaks. Otherwise you will end up with glazed bores which will give poor compressions and use oil.

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I know what your saying. Im running like .003 bearing clearance. I dont think its to tight but ive always done this. After I install my manual oil pressure gauge ill know exactly what my idle psi and 3k psi is.

Its funny that you would menstion oil drian or return. I have a fully stock r33 motor with about every bolt ons you can have. Single gtx3582r. and run mobil 1 15w 50 as thats there replacement for 20w50. And I dont have no issues. I drag race that car. No head drain or nothing. I puch it hard too. But i now have a build rb26 in a gts4 that im working on getting finished up right now. Its running a tomie oil pump and seems like at idle its at a lower pressure reading than my stock r33 rb26 motor. Ill see whats going on in a few minutes. Im sure that the factory cluster gauge is lieing. At idle after warmed up its just under the first white mark.

Edited by MJTru
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Use mineral oil for run in which should take 30 -60 minutes. Push it hard and lift off alternately watching for overheating and or leaks. Otherwise you will end up with glazed bores which will give poor compressions and use oil.

If I can remember correctly isnt mineral oil normal conversational motor oil like what I used. ??? I used castrol GTX 10w30.
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Are you guys serious when you say push a new motor hard. ??

Whats hard to you guys. Go straigjt to 30 psi. Kml. Are you serious. Or just pull the rpms hard?? Off and on throttle I understand. But it sounds like you guys are saying to just straight up try kill the thing. Lol:D:D

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.003" is loose, run 50-60 weight synthetic oil once your bedded in, however run in on mineral oil only, a lower weight is fine for run in, your not doing full power/RPM loads during run in.

Yes lay into the engine, however.....

Lay in is not rev the bejesus out of it, keep RPM well under half of redline at the start and boost levels very low, remember at first with a fresh hone, a lot of heats going to be generated while the rings rip into the fresh hone, increase revs and load as you progress.

But dont pussy foot it either, the rings will slowly remove the peaks of the hone and never bed in properly.

You need highish cylinder pressures to push the rings against the bores to get a firm pressure on them to the walls to bed them in, dont rev the living daylights out of it or you will generate too much heat and glaze the bores in the process.

Progressivly build the revs as bed in continues, less hone peaks means it can take more without generating too much heat, that takes time and needs to be done progressivly.

Getting on the power aids ring bed in, getting off the power and slowing down under its compression cleans the grit off the bores from the power run.

Yes the link provided above my post is good.

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Ok so I just insalled my manual oil pressure gauge. When cold and strated its at 85 psi at 1000 rpms when hot or reach normal operating temperature it drops to 40 psi at around 950 rpms at idle if I rev the car it jumps to 90 psi right away. Its definitely more than 10psi for every 1000 rpms. Please check the photos of it when its at cold start up and when warm. I also took photos of the stock oil gauge which seems to be working right now. I feel air does be trapped in the gauge are this is why the gauge tend to lie. My oil pressure is with castrol gtx 10w30 motor oil. My bearing clearance is .003.

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post-37293-14039050263336_thumb.jpg

post-37293-14039050431704_thumb.jpg

Edited by MJTru
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Hot 90 PSI is safe if your running your final weight of oil.

If your running a thinner oil now and it goes up on the thicker oil after run in, its a tomie pump, its extenally adjustable, you can adjust the relief pressure.....

Also judge you final oil pressue based on oil temp, not engine temp.

Some loose engines can take up to half an hour of driving and more to get oil temps up to water temp.

Edited by GTRPSI
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Interesting mate. I just came back from running the car. I also got into it. I ran like half rpm's at about 10 psi. All looked good. As I had the power fc data logit recording it all. Afr's were a little lean. But because isn't max load it should be ok.

After driving the car for about 20 minutes the oil pressure was still 40 psi. Well to be exact its like 38 psi at idle. My oil temp gauge is on the way. But I know from just feeling the oil filter its around 75c I think. I ant sure as my comparison is from my r33 gtr that has the stock oil temp gauge. And that never passes 80c. I think its in Celsius. Im just going off of my r33 gtr oil filter feeling. This is bad and I know this. But untill my gauge reaches, ill never really know. What I forgot to mention is the bore was ok and I never bored the block. Its still the stock bore.

Edited by MJTru
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Ok so I looked at the link on how to brake in a motor. Thanks for that it was very interesting stuff. I never in my widest dreams think thats the best way. But it makes total sense.

I actually did this to. Kml :D

As I was driving the car a r33 gtr that just landed on the island came up from behind. So that was my opportunity. We went at it and wow I ant even know what happened, but was it ever embarrassing. The car had no power didnt want to go at all. I even stalled out as the r33 left us. Next thing ya know the car didnt want to start as if my battery was dead. Thank god I had 3 friends inside, and they gave me a push start. We then came home. I couldn't even sleep late night I was so bugged.

So it was sunday, the day we race.

Knowing well enough I can't race the car all I did was fine tune the fuel pressure from 37 psi to 40 psi and installed a new waste gate I had. Still lost to why the car was popping and all the previous night. So after heading out to the tracks I had a few drinks and I made up my mind to give it another go.

Like holly shit I ant know what happened maybe the motor needed a heat cycling like the link mentioned. But man it eat up 1.5 bars. I couldn't believe what I was feeling. And the HKS Came setup pulled so hard after 5k its as if the cars wants more rpms. Im so amazed by the difference. After I got home first think I looked at was oil pressure hot it was still at 38 psi and at 3k its around 100psi. This is with 10w30 mineral motor oil. Im thinking of going with a 40 weight oil tho. But I will make up my mind when my new oil temp gauge reach. The one I have right now is mest up.

Thanks for all the help guys. ^_^

Edited by MJTru
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