3SGTE oil pressure maybe low?

[Toobs]

Are you sure you have enough oil in the sump?
I assume you are not using the standard sump or dipstick, even though the stick shows full you may not have enough oil in there.

[The Witzl]

where was the OEM oil pressure switch / idiot light installed? If this is now the oil feed to your turbo, then do what most do and put a junction in the middle of that oil feed line and put the oil pressure sender there!

Comparing this to my 18RG - i too get a steady 70-80psi when the engine is cold.... then around 30psi at 1200rpm and 65-70psi at 3000rpm when at operating temp.
Thats with GW semi-synth 15W-50.....

I think the location of your sender is giving funny pressure readings

[ae86trueno]

Hmm it was a brand spanking new pump from Toyota

ok it shouldnt be that then

Do you have a oil temp guage on the engine ?? it could just be that the lower spec oil is breaking down at a lower temp, then a good synthetic would. And being a 3sgte they tend to get hot. Ive never had anything other then synthetic inour GT4 so i dont really know.

Ben.

[TurboRA28]

To answer some questions...

Toobs, the sump has definately changed, including the location of the dip stick, but the dip stick marks have been re-calibrated for that. It holds around 6 litres now.

OEM idiot light is in an oil gallery at the back of the head. This is where i've installed my electric oil pressure gauge. So in OEM location still.. Just mentioned that the pressure is read from an oil gallery that has already supplied the bearings and turbo with oil. Not like 4a/18r/3t etc that read the pressure coming out of the pump.

I might chuck some good quality synthetic oil in there and see what readings I get.
Any recommendations on oil a soon to be highly strung 3S will be happy with?

I was thinking the Castrol R 10w-60 oil I think it is.

Cheers
Joel

[oldcorollas]

hot at rpm with K motor was 50psi dead steady (internal pressure relief setting) but when cold, would go to 70-80psi.. this was mobnil1 5W50..

do you have any other area you could lose oil? is there a restrictor in the turbo feed? you could always undo the sump return and see what volume is going thru there...

any other bolts or fittings that could have been left off anywhere?

10W60 will be thicker when hot than a 50W... that is prolly a good thing, esp with turbo, since with turbo heat it could be less than 50W when it goes thru turbo anyway...

[TurboRA28]

No oil temp gauge, but something i'm seriously considering.

Need to find a good place to tap into for that.

Other 3s-gte owners out there with oil pressure gauge in the OEM location on the head, what are some readings you see when the engine is warmed up? eg. idle, 3000rpm, 5000rpm?

I'd just like to compare against mine -

Hot.
1000rpm - 22psi
3000rpm - 40psi
5000rpm - 47psi approx? maybe 50 need to confirm.

Toyota suggests 4.3 psi at idle! and 36 - 37psi at 3000rpm. So in Toyota's book the pressure is ok... But hmm still would like to see it go up more at higher RPM.

[TurboRA28]

No restrictor in the turbo oil feed line, only if there is something internal in the turbo itself. Im wondering if thats where some of the pressure is going?

I've been trying to think of anything I could have missed when building the engine. Bearing clearences were done very anal. Bearings were torqued down and clearances measured with a dial indicator. Then removed and assembled.

All the oil squirters are in there.

The crank doesn't have any grub screws that tap into the oil gallery like the Mitsubishi 4G's have.

[TurboRA28]

This shows the oil diagram - http://ugbox.net/~lance/GT4/Technica...escription.pdf

The only other thing in the oil system that isn't stock is that the 3S used to have an oil heat exchanger thing. That had a thermostat in it and not sure what else. Maybe removing all that has caused some issue.

[Joshstix]

Hi Joel

Do you have a copy of the Gen 3 BGB? I have a digital copy I could probably burn to disk for you if you're going to be at dyno day on the weekend.

Back to the question though, the BGB lists the minimum pressures as
1000rpm 29kpa or 4.2psi
5000rpm 245-490kpa or 36-72psi

With the location of the 3S oil pressure sender it is at the very end of the lubrication chain, all of the losses in the engine occur before the pressure sender so it is going to read lower than most engines.

One thing you can do to pick up a little more oil pressure is to shim the relief valve and in the Gen 3 this is really easy. Simply remove the large bolt from the sum just next to the turbo oil drain, then cut a shim of roughly 2mm thickness to fit into the hollow in the bolt. Put the shim in the bolt then screw it back in. I did this on my rebuild and it picked up a fair amount of pressure, how much I don't know because I run the stock AW11 pressure guage.

[Celica RA45]

he cant do that as he has put it into rwd mode and has a steel sump and he is using st185 gt 4 pump

[Joshstix]

Good point.

In that case it is more of a pain in the butt to shim the pump. You need to pull the sump and then remove the circlip from the bottom of the pump housing that holds the relief valve in and then shim it there. The shim also needs to be thinner than for the Gen 3.

[TurboRA28]

Yeah I should have done that before it all went together

Maybe its all ok and im worrying about nothing. Just really want to see another 3sgte and get a few different pressure readings.

In regards to what Toyota suggest, mine is in spec. I suppose it is when the pressure doesn't go up much as the RPM gets higher is my concern.

Its ashame Toyota dont say what the pressure should be at a few different higher RPMs.

[The Witzl]

minimum pressure is one thing, but "good" pressure is a whole different story
If i was in your shoes i would feel safer with above 65psi at 3000rpm+, but to be honest you dont really know how much is being lost by the time it gets to the pressure sender.

sounds like a PITA dude, i hope you find some answers that quell the fears.

[dynomatt]

As posted in the GT4 dedicated thread:

Joel,

So I had a look at my oil pressure gauge last night. It reads up to 500kpa.

So when I first start a rally, and the revs are up, it's happily at 500kpa...at idle (and remember my idle is very different to yours), it'll sit around 300kpa.

At the end of a stage when the oil is very very hot, it'll get as low as 300kpa with revs, and down around 100kpa or less (at which point my warning light comes on)...so at the end of a stage, I have to keep the revs up to keep the pressure up.

Once it's cooled down again, it's not too bad.

My earlier comments about it breaking down, dont' apply to synthetic oils so much (which is what I run now) but temperature is really a big factor...hot oil is hard to keep pressure.

What do you have now?

I should add...I run an Earls cooler, ST205 style filter adaptor with a remote oil filter and a standard ST185 pump (wish I knew about the 5SFE pump as mentioned...mumble mumble). My gauge reads from the factory point in the back of the head.

My gauge reads in KPA...meaning that my actual pressure as indicated by the gauge is 72PSI when fresh and cold and 43psi when hot.

Hope this helps,
Matt

[TurboRA28]

That sounds quite similar readings to what I am getting.

So when its really hot, and running along at a decent RPM and 43psi, if you give it more revs does it go up? Or is kinda just stops making anything over 43psi? As thats what im finding with mine..

At idle and hot, its just over 20psi, if i give the engine a rev it will up to 40 or so.. But after that it doesn't increase much more with more revs.