What a GREAT thread, and PRODUCTIVE !!!!.

What with no.3 going on the motorway, and as Pat mentioned, even on a bench dyno, I think "oil surge" should be discounted. This assumes that the correct oil level is used.

I'm PARANOID about the oil I use, and how often it's changed. However, I only change it after about 3.5k.

I'm convinced that some oils suffer from poor "film strength", and this is certainly contributing to n.3 failing. The results on Stefs oil will be VERY interesting.

Fuelling is an interesting issue. Whilst no.3 might also have the last injector in the system, it's also the closest to the fuel regulator, and therefore, I would expect it to have the most stable pressure. The standard injectors are more than able to cope, until there is a fair increase in power. Even Nicky Grists 22b still runs the standard 440cc inj', even though it does have an uprated pump.

I don't think no.3 is running lean, but I do think some tuners are just chucking extra fuel in, in an attempt to solve the problem. The only way of telling for sure, would be to have a lambda sensor on each branch of the exhaust manifold.

I have an EGT sensor on both the left, and right side of the exhaust, and whilst no.1/3 run hotter on cruise, no.2/4 run hotter under load.......surprised me too !!!!!.

I guess it's possible that a fuel regulator sticks, but if the problems are "fuel" related, I would expect to see far more evidence of this on the pistons.

It's very frustrating that failed engines aren't investigated a bit more closely, and at least then we might start to understand the problems.

There seems no discrimination between UK, or imports, and to some extent MY, tuned, or standard. I'm sorry to say that as Prodrive/IM seem totally uninterested in solving the problem........it's probably down to us.

We could certainly start by getting the oil of a cross section of cars analysed (think it costs about £15/20) this will give a lot of information, and at least eliminate some of the possabilities. Maybe SIDC could sponsor this.

Then, maybe when other cars lets go, the parts could be taken to an "experienced" engine builder for inspection (Stef, maybe we could start with yours ).

One way or another, we need to get to the bottom of this, and save a lot of owners the money, and grief Prodrive/IM appear not to give a **** about, once they have your money.

Mike,

Oil surge, is oil surge, if it's an issue it's just as likely to happen in "one" lap, as it is in several, and if it's the accumulative effects of "oil surge",

1) your cars are just as likely to suffer, even more so with your "proffessional drivers) pulling far more "G" than any "normal" Scooby driver, ever could.

2) As for "thoroughly prepared", to the "highest standards", unless you are stripping the engines down, to make sure there are no signs of damage, or "pick up" on the barings, etc', your statement is totally contradictary.

3) You use the examples, of "flat out around a track", and standing quarters, are the VERY THINGS that your press and demo cars suffer every time there is a magazine article.

HOW YOU HAVE THE BL*ODY CHEEK TO CLAIM WE ABUSE OUR "PRIDE, AND JOYS", AND VOID OUR WARRANTYS, YET YOUR CARS, DRIVEN BY THE TOTALLY UNMERCILESS PRESS, ETC', ARE UNEFFECTED, IS BEYOND ME

You positively PROMOTE track days, NOWHERE do you exclude them from your warranty, but renege on honouring a claim by stating "ABUSE". I for one would love to hear the oppinions of a qualified legal person.

Mark.

 

Can't help but notice, but considering the length of this thread, there are not many first-hand reports of MY98 engine failures. This BBS will tend to attract Impreza owners who like to rev the nuts off cars because we are enthusiasts. Because of this, you would expect more failures in Scoobynet members. So why so few reports?

D.
(Owner of MY98 without engine failure so far).

 

I think I have to agree with most of what Mike says.

To expect a road car to be covered under warrenty in race conditions is expecting to much.

I do drive my car very hard on twisty roads most of the time, but traffic ensures the engine and brakes get some rest. I also think that it is not possible to create the sustained high G loading on the road that you can on a track. Even on the best roundabout or clear sweeping corner you do not have the same margin for error.

I could also argue that Santa Pod is no harder on a car than the driving it get on the road. But you have to draw the line somewhere.

However I have to disagree with you Mike on the Subject of demostration cars being sold to customers who do not realise they have been used on track. I think this is very wrong. Very wrong, sorry I ment very wrong

 

Scooby breakers local to me with a choice of engines including WRX. Dont know what they are like.E-mail is intrested and I will get tel no.

Nige K
New Mills,Derbyshire

 

I agree John.

One thing that would be of interest would be to analyse the temp of oil round the track.

I know the temp probes are normally mounted in the sump, but surely this doesn't give an accurate indication of the oil temp around the bearings etc.

If it is a case of oil overheating, then surely a simple measure would be an oil cooler, which was mentioned earlier I believe.

And perhaps offering a service, similar to Tyres Northampton, for oil and filter changes on the day, before track sessions commencs and after.

Logistically may be a bit of a nightmare....

Think we will have to get a group of people together to decide whether this can be taken forward through more official channels.

Again i agree with John - if this type of situation was ever represented in court, IM would have a very hard time justifying their actions.

Still think it would be a great idea for Prodrive to offer a track pack......

 

taking the temp of the oil in the sump is the best place to do it, as that is where the oil collects after it has just passed through the bearings etc.

The oil is slightly cooler than this when it reaches the first bearing as it passes through an oil/water cooler that is standard on the impreza turbo engine.

By the time it reaches number 3 bearing it will be hotter as the earlier bearings heat the oil, also the flow rate is reduced by the time it reaches the last bearing, it's simple hydraulics, the longer the travel and the greater the obsticles the lower the flow rate. Also the oil is spilling out of the side of the bearings, it doesnt stay entirely in the galleries and within the bearing caps, so again you are loosing flow rate by the time it reaches number 3.

Presure isnt really what counts in bearing feed, its flow rate, you need the presure however to give the flow requirement in the impreza engine, i hope that makes sense.

The impreza actually runs at a very high oil presure compaired to say, a cosworth engine. My cosworth at full revs is running just 4 bar oil presure and 2bar at iddle. The impreza runs a couple of bar higher than this i believe, i would be interested to do some analasis as to why this is so.

 

There's no doubt in my mind that there is a basic problem with the Subaru engine. Therefore I find it frustating to see Mike Wood blaming the type of use that the cars get. I have driven another car much harder on the road and on track days, it revs to 7,500 rather than 7,000. It now has 125,000 miles on the original engine. Only problem has been oil seals. Subaru motor lasted 12,000 miles. It is a very real problem, I know of people whose cars have never seen the track (and drive slowly) who have had this problem, so track use (or abuse) should not be blamed.

I appreciate Mike taking the time to reply, but why do we get no constructive advice on how to prevent this? The only advice appears to be "slow down". This is not really an option for many of us and not what this car is meant to be about. The car is fundamentally a great machine and no-one here has binned their car and bought something else. Although I was sorely tempted when offered an Evo VI RS at a very good price. I like the idea of SIDC involvement, but this should not really be necessary. Maybe SIDC should limit its involvement to including a section in the FAQ or having a separate page detailing some precautions that could be taken. There are lots of good ideas in this thread. I think that Pat has probably contributed much to steer us in the right direction, and am not convinced that Mike's perfectly correct statements are leading us to the true cause and consequently the ultimate solution .IM or its representatives should pick up the ball with this one. Maybe Mike could get one of his engine guys to draw up a list of good advice that the SIDC could host on its website. Do Subaru Japan have anything to add? I understand that they have been investigating this problem. What conclusions have they reached?

 

Great thread!

How many members of the BBS have suffered engine failure?

It would be beneficial to know what mods had been done to each - could you post the details?

I also don't think we should be too hard on Mike/Prodrive - they don't represent Subaru (do they?), but I guess could lose a large chunk of business if they started getting too much *behind* us

Richard

 

Just being realistic for a moment. I'd be amazed if Mike, working for Prodrive with close connections to IM/SUK, would ever be sanctioned to 'officially' post advice about making cars 'safer' on track. Lets face it, they are sold as road cars and that's what IM can (un)reasonably expect them to be used as. By posting a full description of how to make the car safer for track use Mike would appear to be sanctioning, even encouraging it. And that's not what IM want, it will lead to earlier failures, not just of the engine, but other component parts too. Then there would be more claims on what would become 'consumables' - standard discs, suspension etc etc as more people started doing it, and did it more often and enthusiastically knowing that their engines were 'safe'.
I hate it too, but I don't think this *very* public forum is the place for discussion with Prodrive about it, it seems they can only keep restating the company line, and with good legal/contractual reason.
I think it'd be great to get a few people together in a pub, in unnofficial capacities but any information gleaned should be made public without reference to the source, be it Prodrive, a local Subaru garage or whoever.
Regards,
Chuck

 

Mike/Mark/John

Good comments.

With regard to loadings on the road, most convoluted motorway intersections are now coated in Duragrip. I can assure you that on some of these I am able to pull far more G, and for longer, than I can through Redgates/Hollywood. M11/M25 is one which MarkA may wish to comment on, M1/M25 is another that has made me smile.

But I still don't think oil surge is the problem. I have several customers in the Far East and Australia that race their Imprezas every weekend in various series. These guys run standard sumps and do not lose their engines. They are on modified suspension and R rated tyres.

Mike, you and I should, if the surge theory held water, have lost about 10 engines in the last two years. I have not lost any... and I don't think you have either. With regard to fuel surge, I have had this happen on the road and get frequent calls from customers that experience it. I agree that you have to be trying/very low on fuel.

With regard to the Autobahn example, several cars have gone bang on the Autobahn. I can think of two prominent owners that have suffered on the way to/from the Ring.

Sorry about putting Motec units in the Prodrive Group N cars. I should have qualified that by saying it applied to the Group N teams that I know. These all run MoTec now.

Here's a question (or 2)... did you increase the fuel to no. 3 in the PPP? Did you measure the AFR (Lambda) on no. 3 when mapping?

The point about the fuel regulator keeping this injector accurate is valid, providing there is sufficient pressure to be regulated.

With regard to abusing the cars and what is and is not acceptable use, I do have to agree with you about Santa Pod. This does, in my opinion, clearly breach the warranty. It is a timed event which positively encourages owners to drive the car as unsympathetically as possible. There has never and will never be an SIDC Santa Pod day.

With regard to circuit use, I strongly disagree. The majority of insurance companies do too. There is a massive difference between exploring the limits of your car within the safety of a circuit environment and "using its performance" on the road.

Sorry Mike, but there have been far too many fatalities in Imprezas. Some have been dealer salesmen, many have been new owners, ALL HAVE BEEN ON THE ROAD.

This is something that I feel VERY strongly about and one of the reasons why, as SIDC Chairman, I will encourage every member to take their car on a track day.

When people tell me that they are not good enough drivers to take their car on the track, I remind them of the statistics.

The SIDC has worked very hard to promote and maintain a responsible image of its members. If SUK, want us off the tracks, what will happen to that image? Of all of the serious crashes over the past few years (I know of 9 fatalities and numerous "cut outs"), none of the drivers had attended an SIDC track day. I must add that I do not know if the Anderson Perth salesman who killed his passengers had been on one of JohnS's Knockhill days.

When an Impreza makes a hole in the scenery, it's a big hole. If insurance premiums get any higher, cylinder number 3 will be the least of Subaru UK's problems.

 

Go away for a few days and see what develops. A very interesting and informative thread

I have only heard of a very small number of engine failures (not restricted to MY98 or UK cars), which doesn't mean to say that they don't happen.

The one thing that all the failures that I have heard of had in common, has been an "extended" period of hard use at some point shortly before failure. Whether this be a track day with long sessions, or several hours of non-stop very high speed Autobahn type driving. However, I have also heard about an engine letting go under very controlled circumstances on a bench dyno, when all pressures, temps etc were very carefully regulated, but the end result was the same.

I do have a photo of an Impreza sump, which has been modified slightly (supposedly similar to the mods made for Group N), and I've posted a copy to JF for his views.

On the whole, I don't think that the Impreza engines are inherently unreliable, or this BBS and other forums would be full of people reporting problems. However, I do think that if you do wish to use your car hard on the track, then you would be wise to take a few precautions such as fitting a baffled sump, and keeping track sessions short and plentiful. Perhaps it's not the uprated braking that is causing the problems, but the fact that cars with better brakes can stay out on track for much longer (and at higher lap speeds), than those with the standard brakes ?

 

John,

I'd disagree with that - there are loads of imprezas with uprated brakes etc, that have hard lifes on tracks - which don't seem to suffer.

The only thing that seems clear to me at the moment is that an Impreza is not sufficiently engineered to be used reliable on track.

That is essentially what IM/Prodrive are saying.

What R19KET says is spot on - it is absolute BS that Prodrive/IM will inspect their demo/track cars sufficiently to say they are in tip top condition.

NO WAY will they strip the engines down. We're just being fobbed off as usual.

It would be interesting to get some decent mag this information to try and prompt IM etc in to doing something - again - I think there would be a fair case for Trades Description etc to investigate potentially misleading demos.

How many franchised delaers have track demo cars as well? Listers is maybe the most prominent, but how many others.

Surprised IM/Prodrive don't come up with a Track Pack -they'd sell bucketloads.......

Another thing - maybe coincidence - but how the hell did IM find out about Stefs car in Revs?

 

CraigH, this is a public access BBS. Most of the franchised dealers read this BBS. When i had a problem with my own car when it was suffering piston slap. I was very unhappy about the fix they proposed and put that on this BBS.

When my car went to be inspected, i was shown a printout of my comments by the service manager, who happened to agree with them. I got a new short engine when IM wanted to install just a new piston originally.

IM and the franchised dealers are reading this BBS regularly, they know what we do with our cars.

My gut feeling still is that the main cause of problems is the oil you are using isn't good enough for track days, i agree with pete that if it was down to surge in the main, we would have seen many more engine failures by now. I still believe a baffled sump kit would be a sensible precaution. Prodrive made one for a reason.

I'll try and find a lab today for your oil stef, one of our rally car sponsors from last year was an oil company and offered us full testing facilities on our oils, i'll track down the contact in the next day or two and get you in touch with them.

 

Whilst I feel this thread is 100% valid in it's content, this will be my last post on the subject because it has all now been covered to the extent that I am prepared to comment upon.


John
As you appreciate, both IM and Prodrive sell parts and cars through their dealers for ROAD use.
Prodrive separately sell competition parts for the homologated cars which are based on Japanese spec cars, for competition use only.
Our agreement with IM is that we do not supply parts for Japanese spec road cars or competition parts for UK spec road cars.

The reason we modify the cars for Tarmac Rallying on slicks is to ensure an adequate safety margin so that the engine will last the rally.
The oil pump pressure regulator is reshimmed not the gears.
We used to use Mobil 1 5W40, but changed to BP Visco 5000 as we were told that the Mobil 1 was going to become unavailable. We recommend that the oil is changed after every leg of a rally so it will only do about 300km max.
Group N regs do not allow extra oil coolers, but as oil temp is normally around 110 degrees this is not an issue. 150 is considered to be OK bearing in mind the oil is changed very frequently.

What could be a problem is the cumulative effect of oil degradation over time which may then lead to a failure in another circumstance such as on the motorway etc and surprise surprise, this will normally be found in cylinder no3. Even the WRC engines run hotter in this cylinder so I suggest it's a feature of this engine layout rather than an inherent fault. It would be very unusual for any engine to have exactly the same conditions in every cylinder. As I said previously every mechanical part ever invented will have one element that fails first.


IM and Prodrive do not promote track days for customers to drive their own vehicles, although the relative safety of these venues is used to demonstrate the cars. Both IM and Prodrive are acutely aware of the responsiblilties we have to minimise the risks involved to our customers and own representatives.
The cars used for any demonstration are wholly at the risk of IM and Prodrive and as far as Prodrive is concerned, our demonstrators are sold to customers who have complete knowledge and understanding of what the car has been used for previously. I assume the same is valid for the cars IM use. We also take every step possible to ensure that the vehicles are mechanically perfect when they are handed over.

On the subject of Santa Pod, how many people do several full bore starts a day in an attempt to get the quickest time over 1/4mile? It can't be a coincidence that Stef has had his gearbox rebuilt 3 times under warranty. Also wheel bearing failures are a feature of cars used on tracks, particularly if the kerbs are used extensively.

Occasionally parts fail in normal use. That's why manufacturers supply products with warranties so that the customer has the reassurance that if anything goes wrong in normal use it will be repaired. It's a commercial fact that warranty is paid for out of the unit profit. If there is more money spent on warranty than is provided for then the price will go up. It's only really insurance at the end of the day. More claims = higher premiums. We must remember this applies to everything we buy and is not in any way a statement of fact about IM's reluctance to cover warranty on cars used on Race tracks.

Yours finally

Mike

 

Thanks again for the info mike.

What you are saying is reinforcing what I have said for a very long time now and a practice I have followed in all my competition and track cars.

The oil MUST be replaced after every track day you attend.

I wasn’t aware you were not allowed to sell competition parts to UK spec cars, seems a little silly that policy, as its stopping people from improving the safety margin on there cars and thus reducing possible warranty claims. Seems rather illogical to me, then again so does the banning of imports from using franchised dealers for service's etc.

I think the thing to do now is wait and see what the results are from the analysis of stefs oil. Mike is right in saying that the week link to an engine is where the problems will manifest themselves first, that’s simple logic.

If at the end of the day, we don’t have oil surge problems, just oil spec and degradation problems then that is very good news for us, because its an easy fix.

I am far from impressed that Prodrive and IM are using track days to promote the car and then saying it invalidates the warranty. I would love to see that one in a court case, because it's giving the impression that track use is OK for the Impreza.

I would not expect IM to cover track consumables like brakes, I would still expect them to cover the engine, gearbox, diffs, hubs etc.

IM/Prodrive need to stop using track day promotions and state clearly in the warranty book that track day use will invalidate the warranty, or they should honour warranty claims irrespective of whether the car has been used on track.

They are leaving themselves wide open to legal action and are not being totally transparent about the cars capabilities.

 

I will keep out of this thread for my own reasons..

But.. I have been testing oil temps.. and oil surge...

I have never experienced oil surge on my car.... I have run from 3/4 oil to 1-1/4 oil (oops slightly too much) with no problems.

I'm not concerned about IM/FHI/Prodrive in respect of cars and warranties... I dont have a warranty so I dont care... lol

Stick to the thread topic..engine failures..and the reasons why they happen.

Cheers,

J
My oil temps have peaked to 120 degrees.... this is with Mobil 1 Motorport...again no problems. The stock cooler is fine for normal use.

I did once have a turbo failure with Castrol RS... but we wont go into that one.

I always reckonmend changing the oil after a trackday.

In relation to Stefs oil, bear in mind it isnt "stnadard" oil.. I believe it is a Valveline brand oil.

His temps were 210F max ? (sensor in the sump).

My oil pressure (upto 100 degrees) is 6bar off idle.... with higher temps the pressure has dropped to 5 bar.. again no issues (yet).

I have seen a few failures associated to faulty oil pressure relief valves. This can either be attributed to a design fault, or an oil issue.

The new idea is to run an external feed to the oil gallery for number 3, ensuring it is feed plenty of oil. I have yet to try this.

Another good idea, which I would suggest (which I havent done) is to up the oil pressure by a bar... this is achieved by shimming the spring (or fitting a new one).

J.

J.

 

Hi

Earlier in the thread somebody was speculating that the piston slap problem and the no3 big-end problem might be related.

If that is the case then my 98 has the pistonslap on the wrong cylinder.On my car its the rear on the passenger side making the noise (which I think is no4?).I have verified this by disconnecting the injectors one at a time.Im sure other people had it on this cylinder too.

Also has it been established that no 3 big end bearing is the last in line.I read a post by Pat which said no 2 and no3 big ends are fed from no3 main bearing.Can anybody confirm this?

I know the Impreza engine is a strange design but on a five main bearing crank(which I think the Impreza must be) no3 main is normally half way along. If the above info is correct then its strange that no3 big-end is the furthest from the supply,I would have thought it was one of the closest.

To back this up if you look at the engine from above no4 big end is definitely nearer the flywheel than no3 so the oilway design must be unconventional for no3 to be last.

I would love to see a 3d picture of the oilways

PS where I work there are large turbines that run continuously at 8000rpm 365 days a year.They have lubricating systems similar to cars.The lube oil is not changed to a fixed schedule but when lab analysis says it is required.This routine analysis also checks for the metals from which the bearings are made so faults are detected before they cause a failure.

It has to be said that oil analysis seems the way to go.

Andy

 

andy, no3 is the rear passenger side!

 

AndyMc, John Felstead,
I called in at R.N.Golden, Huddersfield this afternoon to have a problem with my door sorted out.

Whilst Andy the foreman mechanic was fixing it, I was aking about the engine configuration.

He says it is a 5 main bearing crank engine, but the earlier NON TURBO versions used to have a 3 main bearing crank.
Cylinders no 1 & 3 are drivers side, 2 & 4 are passenger side, making no 4 the back passenger side cylinder, No 3 the back drivers side cylinder.

As for the MY 98 engine knocking, he said that was on NUMBER 4 cylinder caused by a batch of engines being built up with pistons too small for the bores they were going into.

The STD size pistons are graded according to their actual diameters, and matched to the blocks with corresponding sized cylinder bores.

In the MY98 scenario, the pistons on NUMBER 4 cylinder were too small, hence the slap, when cold.

Additionally he hadn't encountered No 3 big end problems as an ongoing problem, but they had recently done a rebuild, where No 1 big end had failed.

Cheers MTR

 

sorry MTR but thats nonsense.

Piston slap is not caused by too small a piston, its caused by the piston overheating and distorting. It usually occurs around the 8000 mile mark on the N/A engines. I got this straight from the horses mouth, technical manager at IM after talking to him for some time on the phone.

Number 3 is passenger rear side on a RHD car. If i am wrong on this then the IM technical inspector doesnt know his way round a subaru engine, like i say i havent been inside a scooby engine so i am taking this numbering from someone who should know.

 

Just to clear up a few points,

I, nor anyone else I know of, is claiming that doing track days won't exert the car to increased stress. It will, and I'm sure anyone doing a track day accepts that some components will wear out more quickly, and need to be replaced. I would also suggest that the vast majority of owners who do track days, are more meticulas over the servicing, and care of their car, than the average owner. By this, I don't mean the average owner doesn't care for his/her car, or service it according to IM's schedual.

This problem is not just an issue in the UK. The MY97/98 is well known for problems on every Impreza forum I've read. Wether it be no.3 letting go, or PISTON SLAP.

The MY99 see's the launch of the Phase 2 engine !!!!!!!.

My gripe, is that ALL car manufacturers use TOP SPEEDS, and 0-60's to help sell their cars. QUARTER MILE times are often used too. Prodrive, and IM use track days to promote, and demonstrate their cars, and "performance" products.

How can it be OK to do 0-60mph on the road, but the 1/4 mile at Santa Pod is abuse.

Their "brake kit" is a very recent addition, and I suspect, only exists because of the various Impreza forums highlighting the volume of Brembo/AP kits that are being sold, predominantly for the TRACK.

So, if they are going to Void warranties for track day, and standing 1/4 mile use, this should be made clear to all, both before they buy the car, and whenever they are using "on track" promotional events, to market their products.

Siting "oil surge" is BS, and comparing our cars being used on the track, to the "antics" of Mr.Burns, and colleagues.....LUDICROUS.

J, 210F is only 90C (approx).

Pete, don't know what you mean

I think we should make a start by getting various brands of "used" oils analysed, and also start to record just what oil was being used at the time of a failure.

Maybe we will be able to identify the "good", the "bad", and the damn right "ugly"

Finally, whilst a few people have suffered, the vast majority are still going strong, even thoses voted MOST LIKELY to lose the engine .

If we follow the advice of Pete, John, and such like, I'm sure we'll last for some time yet...... (Dear God, pleeeease....)

Mark.

 

John,
I was primarily asking about the main bearing number situation(5 main bearing as he confirmed), and I then asked which is which cylinder number, and he said 1 & 3 are on the right hand side of the car, which when you look down on top of the engine, appears correct. Its not easy to see with the turbo in the way, and the air inlect to the airbox, but the cylinders on the passenger side'appear' to be farther aft on the engine, when compared to the cylinders on the drivers side,ie farther aft would be numbers 2 and 4.

I have also phoned my friend Tony, whom I assisted with a front pully swap, where we removed the timing belt covers, and belt, and he believes from memory, that the passenger side cylinders are the twoi most aft clinders, compared to the drivers side.

I have just run out to my garage to try and confirm this for myself, and it does appear to be the case, but is not easy to see.

Possibly if you looked closely at the engine on your Sport, you would probably be able to confirm if this really is the case, as the cylinders on your engine, I think will be easier to see, as there are no turbo,intercooler gubbinss to get in the way.

He was fairly straightforward on his response to the piston slap problem, so maybe the dealerships are told one thing and Subaru UK know differently.
Or members of the public, like ourselves are told by IM think we want to hear, or what they want us to believe.

Either story could in actual fact, not be the whole truth nothing but the truth etc I suppose it depends on how cynically we view the explanation/excuses given for component/ engine failure, by manufactures/retailers.

Its is very rare for any manufacturer to openly and publicly admit to blunders, with design/manufacturing of their products,as it can have an unwelcome effect on customer confidence, and ultimately, sales.

The end result either way is a replacement piston and or short motor, gets fitted for free, so that in itself is an admision of liability, by Subaru.

I would be interested to hear what you think yourself, looks like being No 3 cylinder if you are able to judge from looking plan view on your engine.

The undersize piston explanation does sound a little bit questionable, as if that was the case, then surely it would be evident immediately, and not after X miles.
Like yourself John, i can only pass on info given by the people from Subaru, a dealership in my case.

Cheers MTR

[This message has been edited by MTR (edited 30 November 2000).]

 

John,

I think you hit the nail on the head.....I think you'll find no.3 is the rear drivers side !!!!!! no.4 is the passenger side, according to the work shop manual.....then again, maybe your "IM tech guy" wrote that too, but on a Friday

Mark.

 

LOL

That is rather worrying isnt it??

Unless i misunderstood what he said (pretty unlikely) i was told the pot number incorectly. hmmmmmm Not good that!

Guess i owe MTR an apology on the pot numbers, the piston slap reasoning i know is right, i have seen the distorted pistons myself.

 

Mark,
This must be a first. One part of one of my post appears to be correct, and Johns wasn't regarding which cylinder goes where.

John,
Just as a general discussion, and not disagreeing with your explanation the specific problem encountered on the Impreza engine, doesn't the relationship of piston to bore clearance along with piston design, ie short or longer skirted pistons have an influence on the likelihood of an engine to display piston slap characteristics.

Back in the 1970's the Kawasaki 500cc triple 2 stroke was renowned for a very noisy engine, with excessive piston slap, which was deemed to be just the way they were. Although if it became very bad, a rebore and new pistons would probably lessen the effect.

Also I remember the Ford 1.9 CVH coversion, (bored/sroked) by Power Engineering, had problems with piston slap (I think that is the term given for a piston that can 'rock' around its gudgeon pin, due to too great a bore clearnce, coupled with too short a piston design).

I believe they attempted to elliminate the problem by experimenting with pistons with differing skirt designs, but do not know if they were ultimately successful.

I thought a shorter piston was prefereable to reduce frictional losses in the bore, but at a trade off with piston stability.
So a racing engine may well have short skirted or reduced skirt pistons , which would be considered not suitable for a high mileage road car.

As usual if I have got the wrong end of the stick, please feel free to point out the error of my ways.

Cheers MTR

 

Just for clarification (hopefully...)

Manufacturers use race circuits for demonstrattion purposes because they are MUCH safer to use compared to the public highway.

There are a relatively small number of cars on the track per mile, they are all going the same way; and if something DOES go wrong, there is a fair amount of space before anything too solid retards your progress. Add into that there are no telegraph poles, lamposts, pedestrians etc., etc., etc., and it is a very attractive safety point indeed.

A lot of companies now ONLY do test drives for prospective customers on the track due to some horrific accidents recently (a Porsche salesman killing his customers in a high-speed off, a Ferrari demo in Loughborough killing both the salesman and customer after crashing and bursting onto flames leaving the customers young son at the dealership waiting for his dad (I saw the photos of the wreckage) as well as the Perth Subaru accident.)

Also most manufacturers will have an experienced instructor sitting beside you to make sure the car comes back in one piece (believe me, it is more than your jobs worth to damage a car you are responsble for on a manufacturer day!!), and it all starts to make perfect sense (as well as a career for me!! )

These days are NOT run as track days, but as a closed public highway for the reasons mentioned above. Other than a few high speed demos by professional drivers (Hi Sport Billy!!! ), the cars are not usually allowed to run at 'full' capabilities to ensure the cars survive.

To compare what Subaru did on the P1 day and any other SIDC day is being WAY wide of the mark in this respect. I should know, I helped organise the P1 for SUK as well as helping to organise the SIDC days. They are TOTALLY different days in all respects and should not be compared. The fact that they were at Doiongton is the only similarity involved.

I have done enough circuit days over the past few years to see the sorrow involved when it all goes wrong, why do you think MY car never goes out on track???

I have recently seen an Impreza that has done 7,000 miles on track, and it looks like a complete bag of s**t that is falling apart compared to my 53,ooo mile example of the SAME age!! (I only use the Impreza as a comparison, I could name a few other cars as well, like an Audi S3, Honda Accord Type R, Peugeot 306 GTI6...)

The moral seems to be........look after the car!!

Rob.

 

DJB.
I asked people to mail me with details, not post them here. They have.

Most people know that I have had three new gearboxes in my car, and probably assume they were all a result of me abusing the car at places like Santa Pod.
Just to set the record straight though, it is well known that I used to take my car to Santa Pod a fair amount whilst the car was under warranty. I was genuinely interested in what my car was capable of, even though I knew the gearbox especially would be put under a lot of stress. I wasn't worried though, as I knew if it went bang I'd get a new one (although probably not if they knew about The Pod).
My first gearbox failed after 48,000 miles and dozens of 1/4 mile runs.
The new gearbox immediately started to make a whining noise. Some internal components wer replaced, but the noise remained. I pushed for another replacement gearbox and got it. This one subsequently decided to dump all it's oil out, unknown to me for a week or so, so again started to whine.
Once again I insisted the whole box was changed. I did no track days or 1/4 mile runs with any of the new gearboxes.
So whilst my car has been 'abused' harder than most, only one gearbox failure could possibly be attributed to the way I drive the car. The other two were as a result of a product fault or faulty fitting.
I just don't want people thinking that I've actually gone through two engines and three gearboxes purely becasue of abuse .

Another point that is worth considering is that my turbo actually failed before my engine. I have not yet had a look in the turbo to see what state it is in, but I don't expect it to look too hot!
What happened in the engine to cause the turbo to fail immediately prior to the engine is anyone's guess, but hopefully we'll get a clearer picture soon.
My engine is going to it's winter home next week to have the relevant work done on it.
If anyone knows of anyone that wants to 'rent' a 98 engine out for a couple of months, let me know. I'm getting fed up driving the hearse!

Still, looking on the bright side at least I've finally learned my car wasn't invincible. I may not have been the most mechanically sympathetic driver in the world, and I doubt I ever will be. I just hope the new car can cope.....

Stef.

[This message has been edited by Stef (edited 01 December 2000).]

 

looks that way andy, and no you dont

 

John F,

It's a bloody shame this didn't all take off a couple of weeks ago when my engine was in bits. The mechanic did in fact show me how they had beefed up the bores with the phase 2 engine. They also employed an independant engine specialist who took a number of critical dimensions and he was absolutely staggered that the bores and other components were still at ex-factory specifications despite 20000 miles. For a factory built engine he thought it was about the best he had come across. Actually told me to get my foot down and get the bugger run in! For the record oil has been Shell Helix Plus ( as recommeded by IM ) changed at 7500 miles and driven harder than the above comments suggest aswell, but no track or airfield days.

Of the 5 Imprezas I have had 4 of them had or developed piston slap - 3 Sports and 1 Turbo. I was told it was down to the use of short skirt pistons which #4 cylinder (rear passenger ) didn't particularly get on with, which is where your heat and distortion theory takes over I believe. However, I was told this by an IM tech guy so who knows eh?

Some of you are lucky and can make jolly japes about concerns at a sidelight blowing but from my point of view the Impreza is the most unreliable car I have ever had. The words "engine" and "chocolate" come to mind to be honest. BUT, there is nothing out there like it and I'll probably end up with another when the MY02 comes out .

Finally anyone like me got the Duke Video review of the WRC when McRae won the Championship? David Richards on explaining the reason for the Swedish Rally retirements says something like "...there is an inherent problem in the engine with the oil pressure relief valve......". I will check the actual wording tonight as I seem to remember that he also goes on to say "...that we are unable to cure..." but I will check tonight and confirm for fear of doing Mr Richards a dis-service.

Otis.

 

Ah, but Rob aren't you talking about the Palmer school cars here?

Not really fair to compare them with your road car. Bit like comparing a BSM metro with your Auntie's pride and joy.

Out of interest, Palmer had major problems with engine failures on their 98 RA's. Again bearing failure was the problem. I knew of some unique oil way modifications, on recommendation from companies who you would expect to know better, done to these engines. This resulted in 3 engine failures before the running in periods had been completed.

Before you ask, the mod was to drill out the oil feed hole in the bearing shell, so enlarging it. The thinking, and it must have been a very drunken afternoon, was that this would get more oil into the bearing. Two problems... First - a bearing is a chemically and heat treated unit and drilling holes in it will destroy the surface strength and induce fractures around the hole. Second - one of the problems with Impreza bearings is that they are very narrow. Enlarge the oil hole and there is even less bearing material to take the load. Failure was inevitable.