1UZ Experts - Oiling issues. Again?!?

[stradlater]

So I've killed another 1uz so it would seem.

And again it seems to be through oiling issues.

Here's the main two problems that I found:

1) the oil very very quickly became black (in 100k's type quick). It appears to me that it's just running rich and that's why but it still seems odd

2) The engine developed a whine, and upon pulling the rocker covers off I can see that the cam lobes are fairly well scratched/marked which I would think tends to suggest oil starvation? Would that be right?

On that basis, I'm worried that my oiling setup isn't right.

So I wanted to get peoples opinions on a few things.

A) My oil pressure starts at 80~100 PSI then drops to around 30 psi at idle when warm. However, sometimes on decel, the oil pressure (as seen by the sensor) goes to 0psi. Is that normal? I would have thought not? What is expected oil pressure, and is it expected to fluctuate much?

B) I have a turbo oil feed going out of the original oil pressure sensor hole. It's a -4 line, that is quite long and can dip below the level of the base of the engine (not below the sump). Could that be a problem? The turbo seems ok, doesn't blow smoke and doesn't seem to have any bearing issues but I thought that maybe running a line that big and that long could be a problem?

C) My oil drain goes into the alloy part of the sump above the baffle. I wouldn't have thought that was a problem either, again the turbo doesn't smoke at all - but can anyone see a reason why this would be a problem?

D) Do you need to shim up the 1uz oil pump? I don't want to kill another motor due to oil issues. I have the standard oil filter and oil filter location, I can't see any issues there. I haven't modified anything else oil flow wise.

E) Could engine temperature (water) be an issue to the oil flow? I know the engine gets hot sometimes, up to 98 degrees ish, but I make sure it comes back down. I haven't got an oil temp gauge, but I thought maybe the heat of the water is causing issues with the oil?


Any thoughts appreciated.

[JustenGT8]

The UZ oil pump is a good bit of gear, so unless it's on the way out that won't be the issue. The oil line might need a restrictor...what turbo. It's still unlikely to result in a top end engine failure though?

Any mods to the oil system? remote setup? anything like that? what filter are you using? any mods to engine?

and what exactly has failed? just scored lobes?

[oldcorollas]

A) no oil pressure on decel could be due to air being picked up somehow?
any chance that oil pickup is loose and moving around/breaking seal with block/pump? (i'm not familiar with the uZ setup.. sorry)
where is the new oil pressure sensor location?

B) if you have oil pressure int eh turbo feed line, then it doesn't matter what direction or height it goes.. pressure is pressure. -4 is only 3/16" ID?

how does the oil pressure change when warm, when increasing revs from idle? it should increase lineraly, then stop at XXpsi... shimming oil pump will not increase the rate of oiling up to that point (can't change volume), but moves the max pressure upwards.. may or may not be useful..

hot oil will escape bearings etc quicker and might lead to lower pressure..

can you put in an oil temp sensor somewhere?
hot oil and oil with lotsa petrol will turn black quicker...
oil is usually a fair bit hotter than the water.. could be 120-130 or so.. or much more... and turbo will heat oil up more too..

but yeah, 0 oil pressure at any time (assuming sensor is seeing real pressure) is never good..

[/random thoughts]

[stradlater]

Justen - I'm guessing it's possible that the line requires a restrict-er, but it seems unlikely?

As for the filter, it's a standard ryco one, there is no remote filter, it's just the standard one the LS400 comes with. The original oil pressure sensor hole is T-ed so I have an aftermarket sensor off the T as well as the turbo oil feed line from there.

There's no mods to the engine, save for the turbo of course. I can't think of anything else that would even come close to being a mod?

The whole reason this motor was broken in the first place is because it was making a whirring/whining noise in line with RPM, deep down in the heart of the engine. I thought maybe it was the water pump, ripped that off and it's fine. Changed the cam belt, but buggered up the process so I snapped a valve. Hence the new engine now.

What I can see is an exceptionally clean head/cam area, with scoring on the cam lobes. Compared to the replacement motor I have which has near mirror finish on the lobes. So I figured there was oiling issues in the head. Pretty much a deduction from there. Almost every lobe has scoring.

[stradlater]

OC -

A) The oil pickup was on solid, I checked it out before. The oil pressure sensor is in the same location, just off a T now. I thought that maybe that was causing the problem? Can't see how though.

B) I thought the length/direction of the line wouldn't be a problem.

As for pressure VS heat. It appears to be high when it's cold, 80~90 then can hit above 120 psi, but then when it warms up, idle seems to sit around 30psi. Then it goes up. I have seen it flash up to 120psi when it's warm and under the pump, but I can't help but think that's the oil pressure gauge playing up.

Putting an oil temp sensor in there could be a bit of a problem. Don't really have a spot for it.

Was thinking that maybe I don't have enough oil in there and with the turbo arrangement, whilst braking, maybe there isn't enough in the sump to get picked up?

[JustenGT8]

Your oil pressure sounds fine, exactly what mine does.

Mine will dip pretty low on hard cornering/braking (slicks though) and i upped the oil weight to help (which it did). But, i have a custom sump/oil pickup so hard to compare.

A plain bearing turbo won't need a restrictor for the the turbo (most BBs will as oil pressure is just too high), but if the clearances are big, maybe it is taking too much flow? I run x2 plain bearing turbos and no issue so it does seem unlikely.

There can be issues with filters that have an internal pressure bypass but that wouldn't result in your problem.

The head should have oil splashed all over everything so it does sound like you have a problem and not just an intermitant one? Sludge (something?) blocking the gallery to the head?

A bit weird i have to say as if there's enough oil getting to the cam caps then that should be plenty for the lobes/buckets?

at this stage i'd suggest oiling up the heads/cams. Run some engine desludge cleaner thru it. Add a thicker weight oil and see how it goes?

other than a full tear down i can't think of anything else you could do?

they are tough nuggets so it'll run another zillion kms with the scored lobes

[sc400]

OC -

A) The oil pickup was on solid, I checked it out before. The oil pressure sensor is in the same location, just off a T now. I thought that maybe that was causing the problem? Can't see how though.

B) I thought the length/direction of the line wouldn't be a problem.

As for pressure VS heat. It appears to be high when it's cold, 80~90 then can hit above 120 psi, but then when it warms up, idle seems to sit around 30psi. Then it goes up. I have seen it flash up to 120psi when it's warm and under the pump, but I can't help but think that's the oil pressure gauge playing up.

Putting an oil temp sensor in there could be a bit of a problem. Don't really have a spot for it.

Was thinking that maybe I don't have enough oil in there and with the turbo arrangement, whilst braking, maybe there isn't enough in the sump to get picked up?

i don't know how much different the soarer 1uz is from the ls400 but i run oil temp and pressure from the the oil filter casting i took the sensors and one of the two gallery bungs to a hydraulic place and got adapters to go between them only issue was i had to clock the flats on the fittings

[andrew_mx83]

i know nothing of the 1uz or turbo setups for that manner but all my 7m's die from oilling issues rather than bhg. surely a turbo adds a lot of heat to the oil system...

its harder to know whats going on without oil temps but you can make some educated guesses based off the pressure which will fall across the rev range as the oil warms up. if its given a continuous hard time (several minutes of on throttle/on boost work) you should see your idle pressure much lower than normal and if you know where it sits at what rpm this will be much lower as well.
synthetic oil will help greatly with this, the oil will stay thicker for longer and not become useless at lubricating after 120degrees like mineral oil does.

the drop in pressure under decel sounds like surge (esp if justen has modified his pickup, is this a common problem?), which will get worse as the oil heats up and thins out. i now run a baffle in my 7m sumps to stop this problem on right hand corners, but i used to cringe when i saw the pressure drop away and think of my poor bearings running dry.

how do your main and big end bearing shells look? is there any scoring on the crank journals? also you mention the cam lobes but not the cam journals..... this is important to know and will give a better picture of what is happening. if this were yankie v8 crap scored lobes would point to valvetrain issues rather than oiling issues i think...


shimming the pressure relief valve is usually a win, but if you are seeing 120psi id steer away, i surprised the filter is still coping at that level. more pressure = more heat, i like to keep my engines around 100-110psi MAX. i built a hot one for a bloke with really really tight clearances, its amazing high up in the rev range but cooks its oil like no tomorrow even with a big ass cooler. its just had its pump replaced with a higher flowing unit and standard pressure relief, we are going for flow over pressure now to try and keep temps down. this one was great for oil light under braking after being given a hard time cos it just got too hot and cooked it.

NOTE -after mineral oil goes over about 120degrees (even once), its still toast after it cools back down and MUST be drained immediately. synthetics are a bit more lenient like this.


from the info youve given id say 1 of 3 things has happened-
too much fuel in oil has killed it lubrication properties, metal on metal ouch
oil got cooked and wasnt lubricating anymore
oil surge, pumped air through the system instead of the good stuff.
OR it picked up a bit of shit in the oil which has chewed out stuff, or gotten lodged in the oil feed to the head(s) are the lobes on all 4 cams stuffed or just one bank?


furthermore if this happened to me and i was doing another one i would-
baffle the sump
add large oil cooler
use full synthetic oil of the correct weight
work CLEAN when the motor goes together. like anally clean.
assess tune to not have fuel going past the rings and into the oil
*all this assumes its not an issue caused by your silly hairdrier thing

[stradlater]

Here's some shots of the head.

The marks you can see on the lobes can't be felt, only seen.

[andrew_mx83]

What about under the caps?

[dnegative]

Those lobes look alright, pull the sump off and check the mains?

[thechuckster]

Pull plugs, disable ECU, remove cam cover, crank motor and look for oil coming out around the cam journal caps?

[sc400]

just out of curiosity what brand and grade of oil are you running?

[JustenGT8]

Those heads look disturbingly dry? Cams will be fine so no real harm done...yet. As Chuck says, test for oilage.

Pull that cheapo filter off and check it hasn't collapsed

[sc400]

Those heads look disturbingly dry? Cams will be fine so no real harm done...yet. As Chuck says, test for oilage.

Pull that cheapo filter off and check it hasn't collapsed

ryco filters aren't bad i use them but i also replace them every 2.5 to 3 months lol