Trouble Shooting Oil Low Oil Pressure (7MGTE)

[kcahrens]

Just got my headgasket done and rebuilt the turbo on my 88 supra. After having it done for about a month now, I've had low oil pressure issues. At first it just seemed all over the place, I would look down while idling at a stop light and see that I'm almost at 0 on the gauge, but then I would start to go and the pressure would build. I think that I've got it down now to where it is normal when it is cold (30 to 40 psi a little lower at idle) then it seem to be dropping when the engine warms (assumingly when the oil is warmer and thinner). The final nail for me was when I drove, pretty much all day, from Bellevue to Auburn, to Seattle then home to granite falls. I rode it kinda hard, I had to keep up with one of my buddies, and i heard some clapping, it was pretty faint, but It's got me convinced that it is some type of oil pump related issue, not a gauge issue or anything.

At first I thought that it could've been debris from my headgasket job, but this doesn't seem likely to me because of the above experience, with the long day of driving. So I'm left believing that it is a issue with my oil pump.

I haven't done too much reading up on the oil pump in the 7mgte, I plan on doing that.... now Any advice or trouble shooting tips would be greatly appreciated.

INFO: 1988 Supra 7M-GTE 190K fresh headgasket job and turbo rebuild in mid february 2011.

Thank For any help guys.

[907mge]

http://store.driftmotion.com/static/...dedoilpump.php

The 7m is known for low oil pressure, hence this upgraded pump on driftmotion. And if you have 190k on the pump then it probably has its share of wear on it. It is also a good idea to measure the pressure with an accurate guage and not the oem dash gauge.

http://www.cygnusx1.net/Supra/Librar...Section=LU&P=4

But if you do need to replace the pump, it won't be fun. In order to drop the oil pan you will either need to pull the motor or drop the subframe.

[kcahrens]

Also, If the oil pump is to blame here, Would an OEM replacement good, or are there aftermarket, more efficient solution.
Intuitionally I would believe that the OEM oil pump would be fine, considering that the 7m is meant to be a high volume, low pressure engine.

[907mge]

Yes it should be alot better since it will have no wear and closer tolerances. I think the upgraded pump is a good idea if you are going for higher hp and want the extra protection. But 190k is alot when you consider that you probably don't know about the maintenance done on the the car over its life.

[kcahrens]

awesome. Is there anything other than on oil pump that it could be? (I guess that chart lists other causes.)

And great... I had a feeling that this wouldn't be fun or cheap. Do I have to worry about replacing anything else besides the pump when upgrading the oil pump? (will having more pressure hurt anything)

another question I have been pondering is what oil is best for my Supra? With the high miles, I want to take care of my engine for the next couple of year while I decide what I want in a rebuild.

[kcahrens]

Yeah, I really don't, from the previous owner, he said that he kept up on it really well from 70k to 190k. (2 timing belts, changed oil religiously, ect)
but I do want to rebuild the engine in the coming years.

[907mge]

There should not be much in the way of the oil system other than the pump that you should have to replaced. But a rebuild is probably not a bad idea. As far as oil I have heard good things about amsoil although they are alittle expensive. http://www.amsoil.com/mygarage/Produ...TOYOTA+SUPRA+0
I have not used there oil yet but the gear oil works very well in my 6spd in my celica.

[kcahrens]

would using a synthetic oil be bad for an engine with high miles like mine?

Do you know what I should look to replace along with the oil pump?