3T GTE Tech

[TheToyman75]

Toyo AL,

Why do you have a cut down sump ?
The Toyota oil filter to use for the 3T is part number 90915-YZZD2 and its a short filter.

3J,

Your take on the 3T oil pressure seems sound, the real question tho is how high an oil pressure is to high ?

[toyo-al]

Rod, the sump I got with the engine was cut-down. I think it was destined for a Gemini or something similar, so was cut to accommodate the engine cross-member. I have a 2T sump to use, but I'm thinking maybe some sort of extra inner-walls to reduce chances of oil starvation before it goes on my engine.

Cheers for the part number, I'll grab a couple of them in hindsight!

Al

[3jcelica]

Toyman,

How high is two high? Good question based on sound engineering principles hydraulic systems usually have a design pressure of 2 times working pressure, test pressure of 1.5 times working pressure. So what is the standard working pressure, I don’t know but educated guess based on what most oil pressure gauges read to would be 100psi, therefore anything over 100psi working pressure and we a eroding a design safety factor.

Toyota being good engineers (always looking to improve reliability and quality of product) has probably taken this into account when designing their oil filters, ryco are trying to make as much money as they can so therefore start working in the margins of safety factors.

Also the highest reading gauge I can find is 150psi by autometer phantom series. So you could potentially run up to 150psi but you are pushing the design limits of the system which could lead to other failures, including but not limited to turbo failure if orifice is not sized correctly, and god know what flow you are actually getting through your engine, but expect the oil to get hotter.

When I tried to put my American made 3t standard oil pump in last night to reduce flow and therefore pressure I found that it must have been designed for a mid engine sump, so was no good, so instead of replacement oil pump option I have moved onto porting the pressure relief valve option. But how much to port is the next question? theortically as little as possible to achieve the appropriate flow (don’t know how much the pump flows, and what flow the engine requires), practically you could go as large as possible while still keeping the piston housed appropriately (so it doesn’t relive at 0psi). So did some rough calcs and figures 8.5 mm to 10.5mm should give me what I need (calculations based on what ports sizes I had previously in the con rods and turbo feed to what I have now. Yet to test my theory, might do this at lunch time.

Did some quick searching on the internet this morning about oil pressure relief port sizing, and these crazy DSM guys seem to have a need to do it also. It should be noted that they seem to be taking there ports from ~10mm diameter out to over 16mm dia, so I am being quite conservative here.

Have a read here. http://www.dsmtuners.com/forums/arti...e-porting.html

On thing I did notice was around the oil relief port was some material discoloration and what looked like hairline surface fracturing, wish I had taken photos now, but a phone camera was not going to give it justice. This would indicate to me localised heating due to trying to shove a non compressible fluid through a small hole.

Going down the porting path has its advantages because by decreasing the pressure to what it should be (as set by the pressure relief spring) should increase flow velocity through the engine and therefore potentially keep the oil cooler. In other words if you want higher pressure to protect your engine set it via the spring, not the pressure relief port.

I will be testing this after noon and post result tonight, hopefully it is ported enough other wise sump back off and port some more which is so much fun working under the car with oil dripping on my head.

I have thought about this way too much and my head hurts, but need to solve this reasonable fast.

Roger

[steeko]

Interesting info 3J. As most of us want to / already run a larger turbo and intercooler.

Isn't just fitting an oil cooler the easiest option to increase volume and decrease pressure?

[3jcelica]

Steeko,

yes running a cooler could help, depending on how it was plumbed, if plumbed to return back through a turbo line that has been reduced from 6mm to ~.8 to 1.5mm (as required for a GT series garret turbo) may not fix your problem, if plumbed directely to the sump, may be too much relief, may need a about a 6mm pipe to retrun to the sump too achieve desired results.

Starting to think that the oil cooler is less of the problem, but the turbo line and the con rods and clearences, as I belive the thermostatic shut valve does shut the flow on the sandwich block at a certain temp ~80deg, and either way the oil cooler returns through the turbo line.

Roger

[3jcelica]

Ok tested my modified pressure port, and cold idle was about 100-110 psi, previously off the gauge, let the engine warm up a little and the pressure starts droping as you would expect to about 70-80psi idle however still going off the guage when reving and blew a cheap ryco filter seal out when reved to 2000rpm when cold.

So further porting out tonight taking the port out to 13mm if possible.

Roger

[Joshstix]

Are you sure there are no other issues with this rebuild? No chance that bearing shells have been put in wrong to block off oil galleries etc?

I just find it hard to get my head around the oil pump being that effiient to push tripple figure pressures even if the clearances have been tightened up a bit.

I'm no expert and the last engine I rebuilt has a hot idle minimum oil pressure of ~2.5psi but something just seems a bit off to me.

What point in the lubrication system does the pressure guage pull it's reading from? I.E is it right at the pump output therefore measuring all of the resistances of the clearances or at the end of the system. Two examples of these with Toyo motors I've played with is 4A which has the sensor close to the pump and the 3S which has the sensor at the back of the head which is the end of the system so you get different pressure readings based on what has already bled off. Is it possible to measure the oil pressure at other points of the system at all to see if there is a major restriction in the system?

[3jcelica]

Joshstix,

Pretty damn confident this engine has been put together properly. Many people experience over pressure with the 3tgte which result in failure of oil filters and spitting out oil filter seals, seems to occur more ofter when the engine has been "built".

Oil pressure is from the standard position which I belive is pre the oil filter on the block.

four oil galleries found on the standard rods have been essentially blocked off due to eagle rods not having the galleries. Additionally the turbo oil ports have been reduced from ~6mm to 1.2mm due to change in turbo. Tolerances only add a small dimension.

When I had this engine with a CT26 (large oil feed pipe) on it the cold ilde after rebuild (forged rods without galleries and CT26) was 90psi droping to 30- 40psi when warmed up.

Throw the gt28 on and the cold idle goes off the scale.

Before rebuild with no changes to oil galleries etc cold idle was 40-50psi and when warm 10-20psi. When the engine was pulled down it was noticed that the pressure relief spring had been cut, so the previous owner was experiencing high pressure also.

Roger

[TheToyman75]

Josh,

The sensor is in the oil gallery in the side of the block,

You can see it in this pic:

If you look at you can see the oil pump is right up front and the oil pressure sender would seem to be the first thing the oil goes past on its way to the filter.

[3jcelica]

Just to wrap up my oil over pressure issues, I layed under the car last night getting covered in oil again.

Pulled the pump out and drilled a 12.5mm hole in the relief port (this port was originally ~8.5). This is the absolute maximum you could drill with the piston still remaining seated and sealing in its home position. Taking no chances I threw the original spring in that had been previously cut by someone else (I don't think cutting of the spring is necessary but really did want to rip the sump off again).

Cold idle 65psi (previously off the guage and spitting out one oil filter seal at just off idle)
give the engine a few revs and it holds steady right on 100psi (pressure relief value dictating pressure). Cold PSI will drop with the engine warmed up, however I belive the max will still hit around the 100psi mark.

I belive I have now moved the restriction from the pressure relief port to the valve where it belongs, and am claiming success on my issues anyway.

I belive my problems were caused by the forged rods that don't have oil galleries and reducing the turbo feed line size, and a system engineered to be spot on for a standard setup (therfore any sticking valves, blocked gallereies or reduction in oil needs such as smaller turbo feeds will results in blown filters). Your millage may vary.

Roger

[steeko]

damn, i read earlier that the eagle rods not having the hole wasn't a big deal..

maybe that is only so on a stock spec engine?

[TheToyman75]

Steeko,

The eagle rods not having the hole will make 7/10's of fuck all difference to the oil pressure and is not a big deal. I think you will find its more the collective effect of the entire upgrade/rebuild process, no 1 step on its own should cause an issue.


3J,

Out of curiosity what oil are you running ?

[3jcelica]

Toyman,Steeko

Yes I belive it is a combination of stuff that results in the need to make these mods. After I blew up the first guage with 20w50 oil I moved to 10w30 to try and improve the situation, still spat out an oil filter seal with 10w30 with a 10.5mm hole in the pressure relief. After I drilled the 12.5mm hole coupled with the cut spring I moved to 15w30 to give me an idea of the response with the oil I wanted to use, and alow some scope for fine tunning.

This is an easy mod to make, just less so when the engine is in the car, I would suggest you drill a hole now if the engine is out say 11-12mm is quite safe and really wont affect anything in a negative way (unless you slip on the drill and score the pistons bore) and give the piston bore a slight hone.

Roger

[3jcelica]

Steeko,

The eagle rods as suggested by eagle should not have a hole as they belive it would weaken the rod. You have to rember these rods are made in the US where they are mainly used on 3t engine normally not having a higher volume pump or atleast not a 3tgte pump. Therfore they probable never experience this issue.

Having said that this is relativey easy to rectify if you find you do have a problem, certainly a lot simpler that modifing the rods (due to the material of the rods)

Roger

[steeko]

advice needed. My 3TGTE is now completely rebuilt, I have been waiting on a new temp sensor from japan before I can take it home (mechanic guarantee's work).

I've been told for the first 1000km's i should be driving at decent revs to bed in the new cylinders - up and down the highway at 100kmh, and also up hill's / mountains to put the engine under load.

Just wanted to make sure this was the best approach as I only have one chance at the first 1000 km's.

Engine is stock standard but rebuilt with BRD 87mm forged pistons, eagle rods, new chains, gaskets, etc, ARP head bolts, stock turbo running 7psi, oil cooled turbo, stock ECU, balanced crank.