Want to confirm Oil Gauge proper readings..

[Grandavi]

New engine build, (almost everything new including a 5mm shimmed oil pump) and I am paying attention to my gauges for once... lol.

Now.. on a 7MGTE in my 1988 Supra, I beleive the proper Toyota readings are as follows:
4.3psi (0.3kg) @ idle
36-71psi (2.5-5.0kg) @ 3000 rpm

So, watching my gauges because Im scared shitless about having an issue.. lol (no more money to toss at the car for now) I noticed that at idle, my oil gauge will gradually drop to about 0.5-0.6 bar (no lower). Cold start is 4.5 bar (pretty sure kg/cm2 is bar) and normal cruising is 2.0 - 3.0 bar.

I think this is all good, but want confirmation as I am looking for any sign of internal issues.

Thinking of getting an external oil gauge because not sure how much I can trust the dash one. Also, I am a bit disappointed that it wont show you when your running out of oil (bad turbo can suck oil out really really fast.. ). Dont like idiot lights but there is nothing to grab your attention should the oil actually fall below safe levels.


and I really want to find the fellow who designed my dipstick...

 

[Dan_Gyoba]

Your oil gauge is in kg/cm^2. 1 kg/cm^2 is not 1 bar. (Though it's pretty close.)

Therefore, the idle reading at 0.5 is at or above the TSRM spec of 0.3, and the cruising reading is also within spec.

My '89 was at about this until rod knock started, now it reads somewhat lower. (Rod knock was not due to oil starvation, but side effect from having had a BHG and then sat unrepaired for a very long period of time.)

My '90 reads about the same when warm.

 

[Grandavi]

Good.. I was worried because I never noticed it going to 0.5 before...
Amazing the things you notice when your scared.

 

[IndigoMKII]

It's been said the dash gauge is VERY inaccurate, I will be updating all of my dash gauges with newer more accurate gauges and sensors. I'll be cutting out the holes in the gauge cluster for my new gauges, going for that stock look.

 

[jetjock]

Crack me up...

 

[radiod]

It's been said the dash gauge is VERY inaccurate, I will be updating all of my dash gauges with newer more accurate gauges and sensors. I'll be cutting out the holes in the gauge cluster for my new gauges, going for that stock look.

The stock gauge isn't typically inaccurate, just slow to respond.

 

[drew_flux]

The stock gauge isn't typically inaccurate, just slow to respond.

this is very true. the basic design of the gage includes a signal dampener to stop gage neddle fluctuations.

 

[IndigoMKII]

so wait, you can tell me the exact psi inbetween those massive gaps.

 

[supraguy@aol]

... Also, I am a bit disappointed that it wont show you when your running out of oil (bad turbo can suck oil out really really fast.. ). Dont like idiot lights but there is nothing to grab your attention should the oil actually fall below safe levels....

Alot of cars run oil switches that throw up an idiot light if you fall below 5psi. I added one of these to my block(screws right in) and will run an idiot light and buzzer.
This is because while i constantly scan my coolant temp and oil pressure whilst driving, I occasionally look up to steer the car.
I'll also be running a coolant overtemp switch in the same manner.

 

[radiod]

so wait, you can tell me the exact psi inbetween those massive gaps.

That's different than being plain wrong. You can get a pretty good idea as to what's happening still with the markings that are on it. There's a difference to the needle deflection giving false information and the markings making it hard to get exact readings. If you are worried about it and need to figure out if there's an issue, always best to hook up a mechanical gauge to test with.

 

[IndigoMKII]

That's different than being plain wrong. You can get a pretty good idea as to what's happening still with the markings that are on it. There's a difference to the needle deflection giving false information and the markings making it hard to get exact readings. If you are worried about it and need to figure out if there's an issue, always best to hook up a mechanical gauge to test with.

Do you also think the speedo and tach are accurate as well?

 

[radiod]

Mechanically driven speedometers can be thrown off by as much as over or underflating your tires. Assuming you are running with stock diameter tires is it a good enough representation of what you need to know? Yes. I'm not saying gauges can't be out of calibration, but when everything is working properly, the stock oil pressure gauge is accurate. People have run a stock and aftermarket guage at the same time and looked at the results between the two in the past....

http://www.supraforums.com/forum/sh...essure-gauge&p=8154712&viewfull=1#post8154712

If you want to check to see if the stock gauge is in good working condition the TSRM has instructions on how to do so:
http://www.cygnusx1.net/Supra/Library/TSRM/MK3/manual.aspx?S=BE&P=42

And as I said before, if you're noticing issues that make you question the stock gauge, undo the electronic pressure sender and hook up a mechanical one and check it.

 

[Grandavi]

No issues on my car for that, its just that when I noticed how low the pressure was at idle, it concerned me a bit as I hadn't noticed it before. (never really paid much attention to the gauge at idle really...)
The dipstick is hugely bad though. I find that I get variable readings that I suspect is because when you pull it out, the end draws some oil up the tube. I wont let anyone read it for me, and even when I do it, I am only 50% sure I have the correct amount of oil.
I tend to run higher than full for safety.

I think I will notch it to hold the oil "more visibly".

Our tach is electronic I believe so should be accurate. My speedo is about 5 kph too fast due to my tires being slightly larger circumference. I tested it using the iphone speedometer app (tried 3 of them for accuracy and they all said the same thing).
My car actually should have less mileage than it has due to that...

 

[grimreaper]

^ think that's backwards, larger tire= slower rotation, slower speed reading and lower mileage output. You'll cover more distance in one rotation than with a smaller tire.

my tires are about 10% larger diameter than stock. My speedo and odometer read roughly 10% lower than actuality.

 

[jetjock]

this is very true. the basic design of the gage includes a signal dampener to stop gage neddle fluctuations.

It does not. At least not in the USDM models.

so wait, you can tell me the exact psi in between those massive gaps.

You're confusing accuracy with resolution. They're not the same thing. And fwiw there are many graduations in the earlier instruments.

Not that any of this matters because the stock gage works fine. Anything more is a waste of time because gages can't be continually watched. Ask someone in my profession how we know that...

 

[Grandavi]

hmm...
Frt rims - 18x8 +35, 225/40zr18
Rear rims - 18x9 +35, 255/35r18

Stock MK3's are 16x7 +37... I think the tires are 225/50r16... so... if I do the math right... aren't my rears slightly bigger?

oh.. wait.. your right.. my speedo is 5 kph lower than what I am doing... (I had it backwards in my head)... thinking helps... lol

Not that any of this matters because the stock gage works fine. Anything more is a waste of time because gages can't be watched. Ask someone people in my profession how we know that...

Exactly why I think I may hook up a warning to alert me if my oil pressure falls too low. Normally I just peek at the oil gauge, but with the new experience of having a bad turbo, now Im obsessing... because I was really worried it was going to let go and just spray out the oil.

 

[jetjock]

Level would be better. Not hard to do. Many cars have it. Fwiw an overtemp alarm can also be easily added using the AC fan switch.

I had an older version of this on my car:

http://www.insightavionics.com/g4single.htm

The beauty is not only does it indicate but all the monitored functions have programmable alarms.

Other firms make similar (and much cheaper) instruments for cars.

Simpler is an electronic dipstick: http://www.intellistick.com/

 

[IndigoMKII]

Yep, that would be amazing to install on my car. As paranoid as I am about every little sound the car makes..

 

[CyFi6]

Level would be better. Not hard to do. Many cars have it. Fwiw an overtemp alarm can also be easily added using the AC fan switch.

I had an older version of this on my car:

http://www.insightavionics.com/g4single.htm

The beauty is not only does it indicate but all the monitored functions have programmable alarms.

Other firms make similar (and much cheaper) instruments for cars.

Simpler is an electronic dipstick: http://www.intellistick.com/

Interesting...but knowing me I think the less information I have the better

 

[Dan_Gyoba]

I would like an oil level switch. Probably would be very useful. I guess I'd have to figure out where the oil level should be in the pan while the engine is running. It's got to be lower than with it sitting, I guess it's a matter of how much.

I don't like oil pressure idiot lights, since those basically tell you "now you're screwed."

I used to have a Previa minivan, which held a reserve 2L of oil in a tank under the hood. Not completely sure how it decided when to use it though. It started to go through that in the last couple of years of its life. It had to have had some sort of oil level sensor. I remember hearing some sort of pump right after putting the key in, but before turning over. I surmised that it was checking then and pulling oil from the reserve while the key was on, but the engine was not running. Seems a reasonable plan. I suppose that I could set up a trigger for oil level in the same manner, and have it turn on an idiot light until the next time the ignition is off.