Twin Turbo LSX Datsun 280Z
04-04-2015, 02:38 PM
#641
I would find it hard to believe your dump pipes are the cause of actual hot oil. If they are in close proximity to the sensor, perhaps the radiant heat is causing some false readings. Where is the oil temp sensor fitted ? At low load, cruise etc etc oil temp should pretty much mirror coolant temp. Only when you start loading things up should oil temp rise above coolant temp. That can be used as a guide to see if either sensor is giving sensible readings. And where is the oil pressure sensor fitted ? again it's always best to remote mount these as it isolates them from engine vibration. Plus if it moves it away from a hot location, that's always a good thing too.
Last edited by oscs; 04-04-2015 at 02:44 PM.
04-04-2015, 02:54 PM
#642
9 Second Club
Exactly my point, you could be getting a false reading due to heat soak into the sensor from the exhaust, as opposed to actual oil temp.
and oil temp under load can and will rise above coolant temp.
At cruise, low loads oil temp should almost track coolant temp to within a very small margin. There is zero reason for oil temp to be higher under these circumstances.
At low loads oil temp absolutely will not be 25deg higher than coolant temp unless there is a major problem.
and oil temp under load can and will rise above coolant temp.
At cruise, low loads oil temp should almost track coolant temp to within a very small margin. There is zero reason for oil temp to be higher under these circumstances.
At low loads oil temp absolutely will not be 25deg higher than coolant temp unless there is a major problem.
04-04-2015, 02:57 PM
#643
Exactly my point, you could be getting a false reading due to heat soak into the sensor from the exhaust, as opposed to actual oil temp. and oil temp under load can and will rise above coolant temp. At cruise, low loads oil temp should almost track coolant temp to within a very small margin. There is zero reason for oil temp to be higher under these circumstances. At low loads oil temp absolutely will not be 25deg higher than coolant temp unless there is a major problem.
On a side note, I could just use a heat gun to check the oil pan temp close to the sensor. I'd imagine that would give me a 5*+\- reading.
04-04-2015, 03:15 PM
#644
9 Second Club
Where the high temps you seen when driving, when stationary, other ?
I'd think when driving airflow around the area should mean your air gap is quite acceptable, so I'm going to guess the high temps you seen where with engine running and car moving very slowly or stopped ? Maybe queuing, or just after a pass or something ?
Are you logging temp as well ? again always handy if you can, sensors are cheap and it's only 2 wires.
I'd think when driving airflow around the area should mean your air gap is quite acceptable, so I'm going to guess the high temps you seen where with engine running and car moving very slowly or stopped ? Maybe queuing, or just after a pass or something ?
Are you logging temp as well ? again always handy if you can, sensors are cheap and it's only 2 wires.
04-04-2015, 03:26 PM
#645
The most recent 215/220 was after some highway pulls/traffic lights and crushing. It settled around 215 or so with coolant temp around 195. Right now though I am sitting here idling with 43psi oil pressure/200 degree coolant temps and about 206 oil temp. This was after crushing around the neighborhood streets with a few small pulls.
04-04-2015, 03:48 PM
#647
9 Second Club
Other variable would be if you're using a different means of temp measurement...ie different sensor/wiring/gauge variations could simply be down to that too.
Knowing which one would be deemed accurate or not
Hence why it would be good to log both on the ecu, and use same type/brand of sensor for both.
When you say sudden, over what time scale ? seconds or hours/days ?
If seconds that would shout wiring/sensor issue, most fluid temp sensors dont have particularly fast response times so a sudden change say 20-30deg over a couple of seconds is just not realistic.
Over days though....good question. To a degree, weather shouldnt really play too much of a part as the engine itself via coolant regulation also regulates oil temp, hence why under light loads they will track each other. Unless it is very large weather/temperature changes, then it may play a part. Just cant see it being huge though as the engine itself is a huge heater even if the oil wanted to run cooler.
Higher pressures, higher engine loads, hot turbos etc would then all try and push the oil temp higher with the engine/coolant then extracting some heat back from the oil ( as well as oil in pan receiving some cooling via the airflow around the pan although that wouldnt be great )
I'm sure oil degradation over time will also have a role in oil temps seen, just not sure how much and it would probably take a very long time. Even oil brand and viscosity can affect oil temperatures. But that wouldnt be sudden.
Knowing which one would be deemed accurate or not
Hence why it would be good to log both on the ecu, and use same type/brand of sensor for both.
When you say sudden, over what time scale ? seconds or hours/days ?
If seconds that would shout wiring/sensor issue, most fluid temp sensors dont have particularly fast response times so a sudden change say 20-30deg over a couple of seconds is just not realistic.
Over days though....good question. To a degree, weather shouldnt really play too much of a part as the engine itself via coolant regulation also regulates oil temp, hence why under light loads they will track each other. Unless it is very large weather/temperature changes, then it may play a part. Just cant see it being huge though as the engine itself is a huge heater even if the oil wanted to run cooler.
Higher pressures, higher engine loads, hot turbos etc would then all try and push the oil temp higher with the engine/coolant then extracting some heat back from the oil ( as well as oil in pan receiving some cooling via the airflow around the pan although that wouldnt be great )
I'm sure oil degradation over time will also have a role in oil temps seen, just not sure how much and it would probably take a very long time. Even oil brand and viscosity can affect oil temperatures. But that wouldnt be sudden.
04-05-2015, 12:58 PM
#649
9 Second Club
That only really controls fore/aft movement on the crank. So no that on it's own wouldnt affect oil pressure
Is there a lot of crank endfloat ?
I guess if they were really bad, it could cause a very slight drop in pressure, but the thrust is basically fed via oil dumped from the centre main bearing. It isnt fed from a pressurised source as such
Is there a lot of crank endfloat ?
I guess if they were really bad, it could cause a very slight drop in pressure, but the thrust is basically fed via oil dumped from the centre main bearing. It isnt fed from a pressurised source as such
04-05-2015, 01:02 PM
#650
That only really controls fore/aft movement on the crank. So no that on it's own wouldnt affect oil pressure Is there a lot of crank endfloat ? I guess if they were really bad, it could cause a very slight drop in pressure, but the thrust is basically fed via oil dumped from the centre main bearing. It isnt fed from a pressurised source as such
04-05-2015, 01:18 PM
#651
9 Second Club
Obviously crank, cam, lifters, rockers, rings etc etc are all magnetic though
Have to say though....I pulled mine apart recently as oil pressure had been bad all year and couldnt be bothered looking at it, just ran it anyway. I'd changed oil a couple of times because of it towards the end to inspect filter etc but mine didnt really show much material.
When I got it apart though...some of the main bearings were completely fucked lol Worst I'd ever seen
Was really surprised at how little debris there had been in the oil during a change, but the Autokraft pan actually seemed to trap a lot of it in the pan as there was a good bit in it when I stripped it for cleaning.
04-05-2015, 01:31 PM
#652
Yeah I'm not sure what to think. I just cut open another filter after 30miles of mixed driving and there is still some flake but not nearly as much as before. It is more finely ground at this point.
I'm probably just going to rip the motor out and see what I find. I have to pull the trans anyways so why not.
I'm probably just going to rip the motor out and see what I find. I have to pull the trans anyways so why not.
Last edited by oscs; 04-05-2015 at 02:26 PM.
04-05-2015, 06:11 PM
#653
Meh. Looks like a little bearing material. When you push the stock crank hard it will work the middle 3 mains over time
How full of flakes where the pleets of the filter?
I always had some bearing material.
How full of flakes where the pleets of the filter?
I always had some bearing material.
04-05-2015, 07:09 PM
#654
Hot idle pressure is about 40. Crushing pressure is 65.. Since wrapping the dump my oil temps are back down to 215-220 after some hard pulls @7lbs. Everything seems fine but I'm still going to pop the caps off And check for wear while the trans is out. The more I think about it the more I don't know what my hot idle pressure was before. I went back through some old threads and I was seeing 30-40 at some point. Not to mention that was when it was colder outside..
I think for now I will keep driving the car and closely monitor the oil pressure and temps. When it comes time to swap transmissions I will cut the filter open and drop the pan for further inspection.
Also I have since setup the low oil pressure safety on my ECU to prevent further issues.
I think for now I will keep driving the car and closely monitor the oil pressure and temps. When it comes time to swap transmissions I will cut the filter open and drop the pan for further inspection.
Also I have since setup the low oil pressure safety on my ECU to prevent further issues.
My oil temps on cruise are 210ish btw. When I hurt a bearing they went up to 220-230 and pressure dropped 15-20 psi at idle.
04-05-2015, 07:26 PM
#655
One of my buddies had the same issue but it was on a factory motor, procharged. Rise in oil temp, drop on pressure. He drove it and destroyed bottom end in about 600 miles. He never looked to see what really happened though to cause the failure, just chalked it up as a loss.
I really hate to read this and I hope it's not the case. I know the time/money invested is substantial. I really hope the motor isn't hurt. It would be better to know now as down the road though.
I really hate to read this and I hope it's not the case. I know the time/money invested is substantial. I really hope the motor isn't hurt. It would be better to know now as down the road though.
04-05-2015, 10:06 PM
#656
As much as I want to just say **** it and go with it, it's to easy to just fix it. Like I said the trans is coming out next week and the whole front of the car basically un bolts so it isn't **** to rip the motor out and see what happened. What I'll probably do this week is just drop the pan and pull the mains and rod caps and just look. I'll likely find as bearing starting to go. Maybe it's just an easy fix, maybe I have to pull the motor. In the end no big deal it's just bearings.
My biggest issue right now is trying not to **** my wife off by being in the garage all day.. I'll get it sorted out soon though and it's back to the testing grounds.
My biggest issue right now is trying not to **** my wife off by being in the garage all day.. I'll get it sorted out soon though and it's back to the testing grounds.
04-05-2015, 11:58 PM
#657
I've seen worse in filter with a healthy motor. Couple of things to think about:
1. It's only the second change, it's near impossible to get everything 100% clean on a new build.
2. If it is making good oil pressure.........good
3. Check the thrust of the crank. You can do this with a dial indicator on a magnetic base and a pry bar. Ask your engine builder what it was when he put it together and compare numbers. If he doesn't know, and it is below .008".........your good.
4. If the engine is still sounding healthy and running healthy keep running it and just keep an eye on everything
You can use this first experience cutting filters to compare to future builds.
1. It's only the second change, it's near impossible to get everything 100% clean on a new build.
2. If it is making good oil pressure.........good
3. Check the thrust of the crank. You can do this with a dial indicator on a magnetic base and a pry bar. Ask your engine builder what it was when he put it together and compare numbers. If he doesn't know, and it is below .008".........your good.
4. If the engine is still sounding healthy and running healthy keep running it and just keep an eye on everything
You can use this first experience cutting filters to compare to future builds.
04-06-2015, 12:30 AM
#658
I've seen worse in filter with a healthy motor. Couple of things to think about: 1. It's only the second change, it's near impossible to get everything 100% clean on a new build. 2. If it is making good oil pressure.........good 3. Check the thrust of the crank. You can do this with a dial indicator on a magnetic base and a pry bar. Ask your engine builder what it was when he put it together and compare numbers. If he doesn't know, and it is below .008".........your good. 4. If the engine is still sounding healthy and running healthy keep running it and just keep an eye on everything You can use this first experience cutting filters to compare to future builds.
04-06-2015, 05:45 PM
#659
I've seen worse in filter with a healthy motor. Couple of things to think about:
1. It's only the second change, it's near impossible to get everything 100% clean on a new build.
2. If it is making good oil pressure.........good
3. Check the thrust of the crank. You can do this with a dial indicator on a magnetic base and a pry bar. Ask your engine builder what it was when he put it together and compare numbers. If he doesn't know, and it is below .008".........your good.
4. If the engine is still sounding healthy and running healthy keep running it and just keep an eye on everything
You can use this first experience cutting filters to compare to future builds.
1. It's only the second change, it's near impossible to get everything 100% clean on a new build.
2. If it is making good oil pressure.........good
3. Check the thrust of the crank. You can do this with a dial indicator on a magnetic base and a pry bar. Ask your engine builder what it was when he put it together and compare numbers. If he doesn't know, and it is below .008".........your good.
4. If the engine is still sounding healthy and running healthy keep running it and just keep an eye on everything
You can use this first experience cutting filters to compare to future builds.