stevie1982

iTrader: (16)

hi

been looking around at version 5 sti's around the 8-9k mark and have noticed that alot have had engine rebuilds due to mainly oil pump failure and other reasons.

1)what is the deal with rebuilds would you spend that kind of money and buy one?

2)or buy one that has had no talk of engine rebuild?

3)it looks like a common issue so would it not be worth buying one already done and save thousands of pounds if it was to happen to you?

what are the general feel about this as i am a bit unsure
some help would be great please, anyone got any experiance in it

thanks

steve

New_scooby_04

iTrader: (4)

Steve,

Engine rebuilds are much more common on JDM classic STi's, especially the latter ones, than UK models as they were set up for 100 RON fuel. Typical scenario: the new owner gets an Sti, puts just SUL in them gives it death for the first couple of weeks (showing the performance off to mates etc) and the big ends fail. Sti 5 and 6s -in common with UK counterparts- also have notoriously weak Mass Airflow Sensors (MAFs) a failing MAF can take an engine out through detonation very suddenly.

I personally would not buy a classic Sti unless it had been remapped for lower RON UK fuel as soon as it hit UK shores, OR had, had a complete rebuild having failed and been remapped for UK petrol immediately after.

1) It's hard to say what a rebuild involves; depends what damage occurs. You'd be looking at around 2k to have one done after the kind of scenarion I mentioned above though. I would contact someone like David at APi and ask him what you should expect of a rebuild if you find a car you like that has had one, that way you can be sure you won't be buying one that's had corners cut.

2) If it'd been remapped early on, yes.

3) Depends if its been done properly. A dodgy build might only get 100 miles before it fails again!! If it's been done well, it'll most likely out-live the rest of the car!

My advice: seek expert help from a reputable Subaru engine builder. David at APi gets my vote.

Ns04

Terminator X

iTrader: (7)

Steve.

My STi V had to have an engine rebuild & it was due to failure of the oil pump ... cost me £3k. My advice is still to buy one as they are awesome machines (specially if you can get one for £8k!) & just make sure you uprate the oil pump & get a remap for UK fuel. Should have no probs then. You'll be able to blow most cars in to the weeds once you get one of course

TX.

Shark Man

How can two eccentric gears "fail" ?

Unless you lot mean the pressure relief valve - which is common

APIDavid

iTrader: (4)

Nearly 1000 engine rebuilds on all Subaru turbo types done here since January 2001 [ When we started counting TBH ]

NEVER seen a failed oil pump, they can't and don't. Seen damaged ones
AFTER the debris of the failure gets dragged in.

The failure is nearly always a fuelling problem, either by poor AFr or the temperature of the AFr causing detonation [ pinking ] which overloads the crank bearings via shock load down the con rod which being as small as they are cannot take the abuse. OR the piston crown melts first and drags alloy all up the cylinder wall. If the oil pump failed then you would expect to get damaged crank main bearings and they are rarely in a poor state even in the most catastrophic blow ups.

Most regularly the failure is on No. 3 cylinder; which is the last to get fed by the one ended fuelling system, nearest the turbo so it gets hotter than the others, farthest in the supply line from the oil pump, farthest from the water pump.

Should the oil pump fail at any time the bearing nearest the oil pump would give up not the farthest.

Stevie 1982 If you want a no obligation chat about options, give me a call

David APi
www.apiengines.com

GC8

I was going to say that an 'informed source' had told me that theyd never seen a failed oil pump; but I thought better of it.....

Its my opinion, that this myth has been, and still is perpetuated by the charlatans and pretenders who collectively call themselves mechanical assessors; as they vainly look for ways to weasel out of waranty claims on their employers behalf. Another crock of ****, in a similar vein, is the 'TMIC doesnt work at high speed' bollocks that they perpetuate; again attributed to a design defect in order to evade justified claims.


Simon

RAF1

iTrader: (5)

Personally i'd go for one that has had a rebuild (By Specialists) and not done too many miles - then just get a re-map and hope for the best

Raf.
p.s. Also looking for a STi5 and have seen some cars on their 2nd/3rd rebuild...!!!

Terminator X

iTrader: (7)

David.

I didn't mean that the oil pump was broken, only that it had failed as in failed to work properly ...

AFAIK the oil pump in the STi V is not that good & all things being equal it should be replaced for a better one ie a bigger one as the original can struggle to get the oil pumped around the engine when the going gets tough. My problem was that the oil did not get to where it needed to go, engine was starved of oil and it caused something to go bang. I'm not mechanically minded so don't quiz further me on it

R19KET

David,

Whilst I've never seen an oil pump fail due to "gear failure", I have seen pumps with jammed oil pressure release valves, and it's NOT due to a bearing failure.

I've also known of pressure release valves to jam, and then release themselves, also without bearing failure.

There will always be a certain amount of "debrie" in the engine, whether it be from wear, or deposits coming free, that's why engines have oil filters !


Mark.

Shark Man

More likely your damage was cased by excessive leakage within the lubrication system which was beyond the pump's capacity.

With the exception of low oil levels. Worn bearings are the no.1 cause of lost of oil supply as oil is leaked out from the excessive clearances. What intitates this that is usually as what David says, which creates a vicious circle.

swtmerce

I have a 98 STi version 4 which to my knowledge is the most infamous version of Impreza for having rebuilds. It is having a rebuild as we speak. I bought it at a good price (high mileage and never had a rebuild) knowing that one day I would have to get a rebuild and that day is upon me now. It would have been slightly cheaper for me to get a car which had already had a rebuild but I decided to go with the one I have because I get to decide who rebuilds it, and I will know how it has been treated after its rebuild.

evil_scoobs

Do the later JDM models ever have that problem with cylinder 3 or the engines blowing up?
The 2003 model specifically

New_scooby_04

iTrader: (4)

Hi mate,

If you're talking about the most common fuel pump upgrade i.e. the RCMS one, AFAIK this doesn't flow any more oil at all! It's basically he standard one with a modification to stop something or other "sticking open" which can cause a failure!

Pretty technical explanation eh!!

I'm sure someone on here more knowledgable than I will elaborate.

Ns04

GC8

Cylinder three is the most likely on all cars, because its at the end of the fuel rail. This can be rectified quite easily by converting to a parallel system.

Simon

MMT WRX

Dont beat about the bush Simon, say what you mean.

Trout

iTrader: (1)

From my own experience.

60,000 in an STi V engine. 30,000 were on the standard ECU with induction kit and big exhaust. I also had an AFR dongle (badly) fitted that actually made fueling worse not better.

30,000 with me learning how to map a Link with lots of learning exercises on the way!! Ended up running around 350-360bhp with FMIC, bigger turbo running up to 1.7bar. Lots of track days and about 100 drag runs.

And when we took it out it was still very strong and running perfectly. Not even burning any oil.

The buyer holed a piston two weeks later by fitting the same mods then giving it large down the road on the standard ECU

My observation is that in spite of the horror stories they are a strong engine that can be susceptible to continued fueling issues (quantity and quality) leading to continued unchecked det will eventually kill them in a variety of ways.

Looked after well they will run well for a long time.

Check out how well it has been looked after. Check out oil usage. Check out oil pressure if you can. If they are healthy you could be on to a good thing.

Great cars, find a good one and you will love it.

Rannoch

New_scooby_04

iTrader: (4)

I think that just about sums it up!

What a plonker! What did he expect?

APIDavid

iTrader: (4)

The oil pump in size and shape and fitting is exactly the same on a EJ20 16V single overhead cam non turbo. It might have a different part number but dimensionally they are all the same. There is one with wider [ not bigger ] gears that is the first choice for any performance build.

The oil pump on a WRC car is the same bit of kit. It is re-engineered to make it more user friendly in a competition situation, where it may need attention in a hurry and also for the fact that the cam belt flaps around at high revs and the belt was rubbing a hole in the oil pressure relief valve housing causing failures.

Mark is correct insofar as the pressure relief valve can stick but only if it gets debris, it does not / cannot create debris on its own. So the failing big end or maybe piston crown creates the debris that then sticks the valve.

Allowing for the above, then there is no such thing as bigger or more flow. The pump is driven directly from the crank, so there is no way to make it turn faster. The gears [ subject to the above ] are uniform so no more flow can be gained. They still pump 9 gallons a minute.

What does happen is that the block side of the pump steel cover has a habit of its screws coming a bit loose - allowing oil pressure to leech away instead of going where it should.

However it is not a catastrophic failure just a general weakening of the oil pressure.

But add the lessened oil pressure to the det problem and a bang is coming up real fast.

We have also a high incidence of failures where someone has only owned the car for a short while [ 9 miles is our record ] and the engine goes bang. This is mostly through user ignorance taking it to the red line to show off to their mates and overworking perhaps in some cases , a high mileage unit.

The air flow thing into the scoop has been disproved to my satisfaction as largely untrue, although there must be a reason why they keep getting bigger and uglier.... What appears to happen is that at high road speeds you are almost certainly using a large amount of boost
continuously and that itself causes air intake temps to rise and thus the AFr weakens.

It is more complex than this of course but that is the basics. I don't have the time to write one of those page long replies.

David APi
www.apiengines.com

wrxmania

Do you think there is a benefit then on fitting an RCM oil pump on a car which has a 12 year old STI (still running great)? Is it a good safety precaution, if everything else is right?

R19KET

After 12 years ! No, if it ain't broke, leave it alone.

Mark.

wrxmania

Getting the blts done anyway as a precaution, so may still be worth the investment anyway.

Who can supply them other than RCM - and where is the best price?

Brian.

APIDavid

iTrader: (4)

Oi !! get on with making parcels and sending out stuff - you ain't got time for surfing the net.

David APi

By the way hear hear - leave it alone, or at best take it off and make sure the rear cover is not coming loose. It's a perfectly good bit of kit as-is.

reano

iTrader: (2)

How easily money wise?

APIDavid

iTrader: (4)

Cheaply 40 or 50 quid - nicely, properly, prettily with stainless hose and red / blue unions everywhere £100+ a bit

David APi