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Okay so I have put my 03 through hell and back. Two turbo kits and a nitrous set up later I decided I wanted a built motor. So I built my motor with forged internals. Before I took the motor apart, the oil pressure was superb. I've got about 750 miles on the engine now and it's definitely not getting better. When I first started it I realized my pressure was a little lower than previous. 5-10 psi at idle (800rpm) which scared me. I presumed it was the oil galley covers leaking since I did remove them and failed to replace the gasket (which doesn't exist). So yesterday I decided to pull the timing cover and make a gasket for them using felpro oil gasket material and a extremely thin layer of sealant on both sides for safe precautions. And today I fired her up. The oil pressure seemed awesome on my test ride down the street! 15psi at 1000, 45psi at 2k. Etc. So I parked it. BTW I have tried different weight oils in the car and it doesn't seem to fluctuate the oil pressure much. I'm currently running 10w30. But on the way to work today, ran smooth, until I parked it. I noticed the oil pressure drop to about 7-10 psi at 800 rpm. I revved it to 2k and it's about at 30. So I'm not sure if my car just wasn't fully warm when I thought the oil pressure was fine or if I blew the home made gasket on the way to work. I'd prefer not take my timing cover off again to see as it is a pain in the behind. I'm about to put my turbo kit and nitrous back on but I'm afraid to with low oil pressure.. For obvious reasons. So let's assume that the oil galley is not leaking oil, what else could be the culprit!?! Are my tolerances off? Is air being sucked in through the pickup tube? (I have a oil pan spacer and a oil pickup tube spacer). Not sure what else to investigate.. Any known ways to increase pressure in these cars?
Unless you radically opened your bearing clearances, VQs typically don't have a problem with oil pressure. Did you replace or modify the oil pump at all? Did you perform all parts of the reassembly yourself?
Dkmura,
I did the build myself. I'm sure I'll regret saying this, but this was my first engine build and was more or less a learning experience. I have owned a handful of Z's ranging from Datsun fastbacks to the new and improved 350s. That being said, I'm fairly competent when it comes to troubleshooting, just not with this. I used the same cam caps and was sure to put them back in their original orientation. All caps and every bolt in the car was torqued correctly. Not sure if the oil is leaking through the rods or what. But is it safe to drive? I'm aware that the oil pressure Influences a wide variety of things including the chain tensioner and valve timing.
Also, I did not remove or even touch the oil pump. I contemplated replacing it but since it was working fine when taken apart, and only has 80k miles, I left it alone.
Also, I did not remove or even touch the oil pump. I contemplated replacing it but since it was working fine when taken apart, and only has 80k miles, I left it alone.
Did stock motor fail thats why you built it or you built it just to throw more power at it?
If it failerd faile you always replace oil pump a a safety so there is no metalic debris blocking tiny passages in the pump...you cant clean pump inside...they are cheap
Dkmura,
I did the build myself. I'm sure I'll regret saying this, but this was my first engine build and was more or less a learning experience. I have owned a handful of Z's ranging from Datsun fastbacks to the new and improved 350s. That being said, I'm fairly competent when it comes to troubleshooting, just not with this. I used the same cam caps and was sure to put them back in their original orientation. All caps and every bolt in the car was torqued correctly. Not sure if the oil is leaking through the rods or what. But is it safe to drive? I'm aware that the oil pressure Influences a wide variety of things including the chain tensioner and valve timing.
Sorry to say, the engine is NOT safe to drive and you risk catastrophic damage if you continue running low oil pressure. Use a separate gauge to confirm your readings and if verified, get ready to shut it down. You will have to pull the engine and go through it piece-by-piece to find the problem.
The biggest obstacle to all this is your expectations: you hand assembled and checked everything and a part of you does not want to believe there's anything wrong. I understand that. But when there a hole on the side of the smoking block and a piston or other metallic debris is stuck in the engine bay, you'll remember you had the chance to fix this...
Did stock motor fail thats why you built it or you built it just to throw more power at it?
If it failerd faile you always replace oil pump a a safety so there is no metalic debris blocking tiny passages in the pump...you cant clean pump inside...they are cheap
The motor ran perfect when taken out. I was attempting to install longtube headers and soon realized it was impossible with the engine in. So I took it out and figured might as well throw a stage 2 clutch on. Then I already had the motor halfway apart..
Sorry to say, the engine is NOT safe to drive and you risk catastrophic damage if you continue running low oil pressure. Use a separate gauge to confirm your readings and if verified, get ready to shut it down. You will have to pull the engine and go through it piece-by-piece to find the problem.
The biggest obstacle to all this is your expectations: you hand assembled and checked everything and a part of you does not want to believe there's anything wrong. I understand that. But when there a hole on the side of the smoking block and a piston or other metallic debris is stuck in the engine bay, you'll remember you had the chance to fix this...
I'm not doubting your statement, I'm just questioning what could be so catastrophic that would throw a piston? It runs extremely smooth throughout the entire rpm range. Idles great. Just low oil pressure. My assumption is that the bearing clearances are loose. Which is not a great issue. In fact some race engines have greater tolerances and run higher weight oil.
And this is the question I was fearing somebody would ask. I ordered all the engine internals and parts and installed them in about a week. I rushed through it. I did order new rod bearings(the correct size) .. And when torqued down, the motor would not turn. I tried each piston separately and the bearings were just obviously too large. So I conveniently had separated all of my old bearings and had labeled them according to the corresponding cylinder. I put the old bearings back in.. I looked at a chart and read how to tell if they are in bad shape, and according to what I saw, they had normal wear. (only 85k on them) did I do the unthinkable or is this commonly done? New rods with old bearings?
And this is the question I was fearing somebody would ask. I ordered all the engine internals and parts and installed them in about a week. I rushed through it. I did order new rod bearings(the correct size) .. And when torqued down, the motor would not turn. I tried each piston separately and the bearings were just obviously too large. So I conveniently had separated all of my old bearings and had labeled them according to the corresponding cylinder. I put the old bearings back in.. I looked at a chart and read how to tell if they are in bad shape, and according to what I saw, they had normal wear. (only 85k on them) did I do the unthinkable or is this commonly done? New rods with old bearings?
Not really common when i had my evo x built my tuner built every engine on lose side 20w50 oil was his recomendation...maybe try thicker oil
You just should of get correct size bearings from get go... Wait andother couple days for another set to ship
I hope someone more knowlegable will chime in
Not really common when i had my evo x built my tuner built every engine on lose side 20w50 oil was his recomendation...maybe try thicker oil
You just should of get correct size bearings from get go... Wait andother couple days for another set to ship
I hope someone more knowlegable will chime in
Okay that makes me feel more confident in my recent decision.. Slapped the turbonetics on and I'll probably have it started today. I should mention that I have a oil pan spacer so my car holds ~6.5 quarts with the oil lines and all. It's hot where I live so I plan on running Rotella 10-30 or 15-40 unless somebody thinks that would be detrimental to a built Vq?
With 6.5 quarts it in the middle of dipstick?
Do you have oil cooler?
Btw do you have oil burning issue also or low pressure only?
Try thicker one and check the pressure reading.....
Up until today, it has not leaked, smoked or anything other than have low oil pressure.
I started it up today with the new turbo set up and had an issue. It idled fine with good oil pressure. Then I held revs near 3k to heat everything up and smoke just began to roll out of my downpipe. Oil pouring out. I obviously had the crank ventilation set up incorrectly because when I pulled the dip stick there was an enormous pressure release. So I took the caps off the valve covers and put breathers on. It's still smoking when I Rev it but I assume that's just burning off all the oil that I hope just slipped pass the rings/seals. But after I shut it off I noticed a small amount of light brown/ milky substance sitting where the oil was dripping out of the downpipe.. I figured that with all of that crank pressure I somehow blew a brand new headgasket. Then I realized how much compression pressure the headgaskets take and have hopefully ruled that out of the potential issues. It may have just been a small amount of water on the ground that mixed with the oil. Not entirely sure. I'm going to hook up my wideband, oil temp, and boost guage again tomorrow and further diagnose.
Up until today, it has not leaked, smoked or anything other than have low oil pressure.
I started it up today with the new turbo set up and had an issue. It idled fine with good oil pressure. Then I held revs near 3k to heat everything up and smoke just began to roll out of my downpipe. Oil pouring out. I obviously had the crank ventilation set up incorrectly because when I pulled the dip stick there was an enormous pressure release. So I took the caps off the valve covers and put breathers on. It's still smoking when I Rev it but I assume that's just burning off all the oil that I hope just slipped pass the rings/seals. But after I shut it off I noticed a small amount of light brown/ milky substance sitting where the oil was dripping out of the downpipe.. I figured that with all of that crank pressure I somehow blew a brand new headgasket. Then I realized how much compression pressure the headgaskets take and have hopefully ruled that out of the potential issues. It may have just been a small amount of water on the ground that mixed with the oil. Not entirely sure. I'm going to hook up my wideband, oil temp, and boost guage again tomorrow and further diagnose.
If you have oil leaking from dowpipe its probably turbo seals letting it go...also oil doesnt mix with water...that milky substance is worrying
Well the turbonetics has about 2 minutes on it so it's under warranty. But I had all kinds of lube and liquids in the down pipe when installing. So it could have just been that draining out. I'm fairly certain it couldn't be a head gasket. I mean the compression at 7k rpms has to be higher than the pressure that was built from my closed pcv system. I had to do a brake job on my 300zx so I didn't have too much time to work on it today, just tightened down some down pipes
Head gasket easily chceked looking at coolant or oil color...also can perfrom test if exhaust gases are going into the cooland/ radiator even tho liquids look fine...
Test drove it today with the new setup. The thing ran great, no leaks and built an ungodly amount of boost. Just took about 5k for the thing to spool up. The turbo barely affected the oil pressure. It lowered the pressure about 1-2 psi. I'm still running 10-30. I plan on switching to Rotella 15-40 in a couple days to hopefully raise the pressure. Head gasket is fine, coolant and oil both look clean.
08-03-2015, 12:07 PM
Another low oil pressure thread, built motor.
