Oil pump (crankshaft front) oil seal failures, my answer.

[Chris Wilson]

So VVTi and UK Spec which, all run MAF are included in the above ?

 

I haven't come across an unmodded VVTi with second turbo failure that's done a seal, nor a UK one. Has anyone else?

[Chris Wilson]

Ok, loads of scary sh1t then.....

 

Is a 'well monitored' AFR gauge is a reasonable way of recognising the symtoms?

 

*MAYBE*, but bear in mind that if an engine is really rich a wideband cam read weak, due to misfires. IMO don't use an engine that has sequential problems until it's fixed, and if you want a single turbo use a proper standalone ECU mapped properly from the word go (no driving around "off boost" until someone maps it, tweaks the map, blah blah).

[gsportcars]

I have read this thread and the others on the same topic and I could do with an answer to a small question...

 

As mentioned before I had been out mapping my car running single turbo and Autronic SM4 standalone ECU when I got crank seal failure. I have since replaced the seal but have not yet completed the mapping. My engine was sitting for a long time without running too as I bought it from a breakers yard for my IS200.

The car drives fine and I have revved the engine to about 5k with no problems so far. The seal originally went at high rpm as have others.

 

The question I am asking is should I be expecting my seal to fail again once high rpm is reached or not. ie; is it a certainty that the seal will fail again because the original problem is still present??

 

I have also changed my oil twice to flush the engine since.

[Chris Wilson]

If it goes again I'd fit a new pump and check everything bearing and bore / piston wise for wear, too.

[Terminator]

I don't know if this has been covered, apologies if it has.

I am making an assumption, here oil seal failures are mainly occurring in modded TT, ie BPU and more or single cars.

 

Toyota designed the engine to be capable of 500bhp ish on the stock internals then detuned it to give 320 ish. What we probably never know, is when the sump was designed. I believe this could be significant factor in failures. The design of the oil pump pickup and windage plate(top baffel), may have been design to be adequate for the level of G, in a stock car, to which the oil may be subjected during hard driving.

 

Add a lot more house power, suspension that enables the car stick to the track and to pull higher G's. Suddenly, what was a good sump and pick up design, may expose a weakness.

 

I think 1G is simulated, in sump and oil pickup design, by rapidly tipping the sump at 45 degrees. At higher G's, say 1.5 the simulation requires a 60 degree tilt. Given that engine oil in a perfect engine will have some petrol dilution, its viscosity is close to that of pump fuel, so moves about the sump like water. I have, for some time thought the stock pick-up has an unnecessarily large diameter. Given all the above, I believe it is quite possible for the pick up to suck air in extrema conditions. The resultant momentary loss of adequate lubrication/pressure, would accelerate component deterioration considerably. Given all the other factors mentioned by Chris and others, if starvations is added to the list, it is not surprising a number have had pump/seal problems. An engine would be at full chat so the absolute worst possible time for the pump and seal.

 

I have a few spare sumps kicking about, I might half fill one with water and see what happens. Would anyone like to hazard a guess at to how much oil is in the block, pump and filter under full pressure so I can estimate how much oil to simulate.

[Thorin]

Good info and thanks for all the work investigating this Chris, it does sound like that's the probable cause after seeing the dismantled pumps.

 

Phil's post regarding the sump is interesting too.

[Terminator]

Does anyone have any idea of the volume of oil in the oil ways, head and filter when the engine is running. I have several sumps open at the moment so would like to test out my assumptions.

[Digsy]

the oil filter will hold about half a litre but that should sta pretty full once the system is primed. the head and lube system may well hold up a full litre during running.

 

all the smup surge testing I've been involved in was up to 1g. yes, at the design stage we ensure that the pickup is covered at min fill with 45deg tilt. this is then tested for real in a car. tbh i'd be surprised if many people were exceeding 1g lateral routinely.

 

if you let the oil level get VERY low then it may become an issue.

[gsportcars]

If it goes again I'd fit a new pump and check everything bearing and bore / piston wise for wear, too.

 

Will do. I have a spare stripped engine here too that I can steal parts from anyway to test etc.

Thanks.

[SUPRASUZUKI]

I ran the engine tilt test rig at Land Rover for about 18 months. The Gemini Diesel engine (2.5Tdi Disco etc) ran perfectly well at 35deg tilted either left or right and 45deg nose up or down.

 

The acid test was running at max power at these angles for hours on end.

 

The V8 faired less well as aeration caused the tappets to rattle (hydraulic, as oposed to the Diesel's pushrods).

 

The BMW 6cyl Diesel (was used in the Range Rover) used to fall apart under the same conditions. Clearly not developed for mud plugging.

[dandan]

The BMW 6cyl Diesel (was used in the Range Rover) used to fall apart under the same conditions. Clearly not developed for mud plugging.

 

Interesting

[tDR]

The reason i was aking about VVti failures was because myself and a friend who is a true ECU expert believe that the VVti may not suffer as much oil dilution with a failed turbo as it used AF metering, so is intelligent enough to know that depite the throttle angle and speed the airflow itself isn't greta enough to warrant more fuel. the MAP sensored models, unless they have pretty trick and failsafe 3D mapping, will add more fuel, without the airflow, hence go mad rich once off the Lamda. This also falls into place with seal failure being unknown (???) on the N/a's.

 

I don't get that at all Chris, my understanding of MAP sensored models is that fuel is added according to MAP sensor output voltage, itself determined based on pressure detected from it's inlet manifold pressure reference line. IE 0.5bar pressure = x part of the fuelling map, 1.2bar = y part of the fuelling map.

 

In fact I'd go as far as saying that a MAF equipped car would be more likely to overfuel given that an air leak (quite common - IC joiner hoses etc) at any point in the system beyond the MAF (always just after the air filter at the entry to the system) would be unknown by the ECU as it would be fuelling for the amount of air metered by the MAF and less air would actually be getting ingested by the engine.

 

Tell me if I'm missing something fundamental here?!?

 

Cheers,

 

Brian.

[Chris Wilson]

This may well be another potential reason for oil dilution, I am no ecu / electronics expert, by any means. The owner would still have to drive some considerable mileage with a none functioning sequential system to do damage though. It seems that fail safe has its limitations.

[Ian C]

If a turbo fails, i.e. doesn't compress air any more, I would have thought that both metering systems would behave normally. They would only see up to atmospheric pressure/flow due to the failed turbo and the ECU would fuel accordingly.

 

If there is a boost *leak* then a MAF overfuels badly while a MAP carries on normally. That's because the MAF reads the air, the ECU spits out the fuel for it, and then the air exits stage left before reaching the engine

 

I can't see a MAP sensor based ECU overfuelling under any failure circumstances apart from the MAP sensor reading atmospheric only when driven off-boost/idling.

 

-Ian

[Tricky-Ricky]

If a turbo fails, i.e. doesn't compress air any more, I would have thought that both metering systems would behave normally. They would only see up to atmospheric pressure/flow due to the failed turbo and the ECU would fuel accordingly.

 

If there is a boost *leak* then a MAF overfuels badly while a MAP carries on normally. That's because the MAF reads the air, the ECU spits out the fuel for it, and then the air exits stage left before reaching the engine

 

I can't see a MAP sensor based ECU overfuelling under any failure circumstances apart from the MAP sensor reading atmospheric only when driven off-boost/idling.

 

-Ian

 

That is one of the reasons that most high power, originally MAF based systems switch to MAP, the ECU will only fuel to the pressure map by whats actually entering the engine.

However i do agree that the Supra ECU is prone to chucking too much fuel in on the std map, but i am not sure that this could be enough to cause bore Wash, or contaminate fuel enough to cause oil pump damage, or other components for that matter.

[wkdtime]

*MAYBE*, but bear in mind that if an engine is really rich a wideband cam read weak, due to misfires. IMO don't use an engine that has sequential problems until it's fixed, and if you want a single turbo use a proper standalone ECU mapped properly from the word go (no driving around "off boost" until someone maps it, tweaks the map, blah blah).

 

Chris, what sort of AFR's are we talking about when the car is deemed too rich and thus would result in borewash?

 

AFR's' @ boost?

AFR's @ cruise?

 

Are both just as significant?

 

Regards,

 

-Wkd

[Sharpie]

Some owners are nailing the FMS on

 

OK, flat head screws.

 

http://img394.imageshack.us/my.php?image=fms3wh.png

[Tricky-Ricky]

Some owners are nailing the FMS on

 

OK, flat head screws.

 

http://img394.imageshack.us/my.php?image=fms3wh.png

 

For some reason a lot of owners in the US where having trouble pushing the seals out, god know why! although i suspect its more down to being badly fitted in the first place during rebuilds, but all this fix does is to stop your badly fitted seal from moving, it will NOT prevent the seal from failing due to worn oil pump!