Engine Failure - Survey
13 September 2002, 03:11 PM
#61
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Just my 2c but after an engine failure it is no surprise that the oil presure relief valve is jammed open. The debris in the sump is not filtered out until the oil filter which is placed after the oil pump.
All that protects the oil pump is a course wire mesh, the metal shavings or whatever will get right through this and are likely to jam in the oil pressure relief valve sleeve - sticking it in the open position.
Andy
All that protects the oil pump is a course wire mesh, the metal shavings or whatever will get right through this and are likely to jam in the oil pressure relief valve sleeve - sticking it in the open position.
Andy
13 September 2002, 05:32 PM
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At the risk of appearing ignorant what exactly are "Filter primed" & "Engine Primed" Just want to check yo see if there is something I should be doing that I'm not Ive got an MY01
13 September 2002, 06:16 PM
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Jock,
if your doing your own servicing id be very surprised especially on a car this new (watch the resale value go
) but priming the oilfilter is basically filling it with the 1/2 ltr it needs and you also prime the engine by removing (ht leads?) and manually crank it? or something like that to get the oil moving round.
Tony
if your doing your own servicing id be very surprised especially on a car this new (watch the resale value go
) but priming the oilfilter is basically filling it with the 1/2 ltr it needs and you also prime the engine by removing (ht leads?) and manually crank it? or something like that to get the oil moving round.Tony
13 September 2002, 08:24 PM
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Well here's the info on mine, bit of a weird one compared to some of the others.
1 Subaru sti5 saloon
2 1998 (my99)
3 43k
4 split left hand exhaust camshaft, piston crunched valve + head
5 March 2002
6 max 2000 miles
7 no comment
8 castrol when it went
9 oem
10 cant remember was so long ago lol
11 eh? sorry didnt understand the question
12 optimax + NF (had been using NF for two weeks, previous attempts with millers had returned bugger all difference)
13 dry but cool march day
14 aps fmic, aps induction, link ecu, power enterprise 1820 turbo, 550 injectors,scoobysport dp, blitz mid + back, / Never got chance to find out lol
15 1.5 bar
16 general use, going to work. no track days though quite hard road use at times.
17 80 mph sitting in a line of traffic passing slower hgv's (made dor a fun experience heading for the side of the road!)
18 quite high though not max
19 see above
20 couple of minutes (though this was about 18 months prior with only link, zorst and blitz filter
[Edited by ptholt - 9/13/2002 8:37:22 PM]
1 Subaru sti5 saloon
2 1998 (my99)
3 43k
4 split left hand exhaust camshaft, piston crunched valve + head
5 March 2002
6 max 2000 miles
7 no comment
8 castrol when it went
9 oem
10 cant remember was so long ago lol
11 eh? sorry didnt understand the question
12 optimax + NF (had been using NF for two weeks, previous attempts with millers had returned bugger all difference)
13 dry but cool march day
14 aps fmic, aps induction, link ecu, power enterprise 1820 turbo, 550 injectors,scoobysport dp, blitz mid + back, / Never got chance to find out lol
15 1.5 bar
16 general use, going to work. no track days though quite hard road use at times.
17 80 mph sitting in a line of traffic passing slower hgv's (made dor a fun experience heading for the side of the road!)
18 quite high though not max
19 see above
20 couple of minutes (though this was about 18 months prior with only link, zorst and blitz filter
[Edited by ptholt - 9/13/2002 8:37:22 PM]
14 September 2002, 11:01 AM
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my engine is still under investigation so I'll post the findings asap.
Now - here is one for you guys to think about. I have been told twice that the cranks on Jap imports - especially STI's is very poorly finished, and it may be this that causes the bearing failures. Apparently the UK model cranks are far superior.
Has anyone got any hard facts/evidence of this yet ??
Now - here is one for you guys to think about. I have been told twice that the cranks on Jap imports - especially STI's is very poorly finished, and it may be this that causes the bearing failures. Apparently the UK model cranks are far superior.
Has anyone got any hard facts/evidence of this yet ??
14 September 2002, 06:38 PM
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Bob, may it be a bad batch of cranks that is affecting the STI's of a particular age.. ? As other people have stated I think there is more than one reason/type of failure!
14 September 2002, 07:23 PM
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Thanks Tony, you are right Its still getting dealer serviced. I'm not to worried about about the resale value. Its a great drive even just OEM so I'll have it for quite a few years. Once my 3 years warranty are up i'll get into the mods. Cheers
15 September 2002, 02:21 AM
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From what i have heard its a lot of STI 5 models which tend to let go. I now they had a dodgy MAF sensor which doesnt help, but come on, i know someone who has sti 4 with nearly 80K miles with not one problem. OK he brought it over with 30K miles so i dont know if that had anything to do with it.
As i said its mosty STI 5's that i have heard go bang! Has anyone heard of an STI 6 letting go or even a V-Limited model letting go? Maybe Subaru were aware of a certain problem and rectified it in time.
Cheers
Gerry
As i said its mosty STI 5's that i have heard go bang! Has anyone heard of an STI 6 letting go or even a V-Limited model letting go? Maybe Subaru were aware of a certain problem and rectified it in time.
Cheers
Gerry
15 September 2002, 04:32 PM
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people are sprouting a lot of spurious comments here, which is making things cloudy.
So far, there has been such a diverse model and specific component failure rate, that it would be stupid to assume its just stis and not anything else. PLenty of uk cars have gone. There is no visible distinction between uk crank and sti crank. There has been a batch of motorport cranks which were just out of tolerance, but these did not come from the cars first, they were intended for accurate rebuild which would require machining anyway.
and also there is no mechanical difference in a v limited whatsoever, its purely cosmetic. The only potential difference is the use of normal gearing and transmission instead of the full type r/ra gearbox and centre diff. But again this is not engine related, so why on earth would this be something to consider?
all we know, is that all types of imprezas have so far been affected, new and old, wagon and saloon, jap and uk, 208, 215, 276, 2.0 and 2.2, all have had spurious big end bearing failures, and not just no.3 but 1,2, and 4 too!
potentially sticky oil pressure relief valves may be a cause, which would be consistent with the engines failing on lift off, as a result of the engine not turning fast enough for the relief valve to be displaced to the correct position, and hence sub 3000rpm lack of oil pressure.
I have heard from rally teams that they have never had any problem with sticking oil pressure relief valves and that these are used on all competition engines, but then they are rebuilt far more regularly.
Regardless of this reassurance, I am going to buy a roger clark motorsport oil pump and have a look inside and probably use it for my replacement engine.
So far, there has been such a diverse model and specific component failure rate, that it would be stupid to assume its just stis and not anything else. PLenty of uk cars have gone. There is no visible distinction between uk crank and sti crank. There has been a batch of motorport cranks which were just out of tolerance, but these did not come from the cars first, they were intended for accurate rebuild which would require machining anyway.
and also there is no mechanical difference in a v limited whatsoever, its purely cosmetic. The only potential difference is the use of normal gearing and transmission instead of the full type r/ra gearbox and centre diff. But again this is not engine related, so why on earth would this be something to consider?
all we know, is that all types of imprezas have so far been affected, new and old, wagon and saloon, jap and uk, 208, 215, 276, 2.0 and 2.2, all have had spurious big end bearing failures, and not just no.3 but 1,2, and 4 too!
potentially sticky oil pressure relief valves may be a cause, which would be consistent with the engines failing on lift off, as a result of the engine not turning fast enough for the relief valve to be displaced to the correct position, and hence sub 3000rpm lack of oil pressure.
I have heard from rally teams that they have never had any problem with sticking oil pressure relief valves and that these are used on all competition engines, but then they are rebuilt far more regularly.
Regardless of this reassurance, I am going to buy a roger clark motorsport oil pump and have a look inside and probably use it for my replacement engine.
16 September 2002, 12:16 AM
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Let us know what you think of the Roger Clark Motorsport oil pump Adam M. Regarding the V-Limited variation, when i was in Cyprus last year my cousins car (Sti 6 Type r v-ltd) which was getting a rebuild had a closed deck block as standard so i assumed that all the V-Ltd models have this. I think all RA's have the same block as well.
Cheers
Gerry
Cheers
Gerry
16 September 2002, 12:44 AM
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I agree with Andy. I reckon the vast majority of engines that have let go, will have sticking oil PRV's. Anyone who's seen inside an engine where a bearing has let go, will understand.
I'd put money that the RC pump is merely using a replacement piston, without the grove in it, and it will probably be slightly longer, to increase pressure.
If they are so confident that this is the cause of all the failures, ask them if they're prepared to put in writing, they'll guarantee the engines against bearing failure !!!
If you get CR*P in your oil, you're going to have a problem. If you want to increase your oil pressure, drop another washer in the back of the valve. Subaru already put one in there from the factory !!!!
Mark.
I'd put money that the RC pump is merely using a replacement piston, without the grove in it, and it will probably be slightly longer, to increase pressure.
If they are so confident that this is the cause of all the failures, ask them if they're prepared to put in writing, they'll guarantee the engines against bearing failure !!!
If you get CR*P in your oil, you're going to have a problem. If you want to increase your oil pressure, drop another washer in the back of the valve. Subaru already put one in there from the factory !!!!
Mark.
16 September 2002, 02:07 AM
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GGR claim pretty much the same thing about the oil pump. They say they have never seen an engine fail that has been fitted with their 'uprated' pump.
I have.
I put it down to the flywheel that we used, but I suppose that not checking all the tolerances while building may also have been a factor. It was a good std original crank, rods, and new subaru bearings used in the engine, along with Mobil 1 motorsport. enigne primed on the starter etc..
The first time that the engine had any hard use ( ie revved hard to 8000 under load ), it died.
Whilst I do think any modifications that may help the problem from happening again are worth while, That one mod. alone I dont think will do it. Doesnt anyone do a relief valve like uprated minis, and rover V8' where they use a ballbearing type plunger to seal the hole, which cannot stick in the bore??
Again, Im no expert, but just my thoughts.
I have.
I put it down to the flywheel that we used, but I suppose that not checking all the tolerances while building may also have been a factor. It was a good std original crank, rods, and new subaru bearings used in the engine, along with Mobil 1 motorsport. enigne primed on the starter etc..
The first time that the engine had any hard use ( ie revved hard to 8000 under load ), it died.
Whilst I do think any modifications that may help the problem from happening again are worth while, That one mod. alone I dont think will do it. Doesnt anyone do a relief valve like uprated minis, and rover V8' where they use a ballbearing type plunger to seal the hole, which cannot stick in the bore??
Again, Im no expert, but just my thoughts.
16 September 2002, 10:24 AM
#75
I know the uprated valve can up the pressure, but at the expense of how much flow?
The concept of restricting the oil flow in an engine is somehow questionable to me.
Paul
The concept of restricting the oil flow in an engine is somehow questionable to me.
Paul
16 September 2002, 08:16 PM
#76
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I would have thought that the standard Subaru oil pressure of almost 100 psi would be adequate ? no ?
My last Chevy engine which had a dry sump and adjustable oil pressure valve was recommended to run at 60 psi, any more than that was deemed to be wasting power driving the pump. (and that was a 104mm stroke throwing around a 104mm diameter piston at 8000 rpm)
The oil pressure only pushes the oil around the engine, it is a different hydrodynamic process that creates the oil film/wedge between the bearing and crank..........Pavlo, I'm sure you could expand on this
My last Chevy engine which had a dry sump and adjustable oil pressure valve was recommended to run at 60 psi, any more than that was deemed to be wasting power driving the pump. (and that was a 104mm stroke throwing around a 104mm diameter piston at 8000 rpm)
The oil pressure only pushes the oil around the engine, it is a different hydrodynamic process that creates the oil film/wedge between the bearing and crank..........Pavlo, I'm sure you could expand on this
16 September 2002, 09:06 PM
#77
Sorry, my fluids lectures were quite general and orientated to ground vehicle aerodynamics!
I think it's a lottery.
Despite what many here say, I think an oil cooler wouldn't be bad idea, and unless someone comes up with some concrete evidence to the contrary, I will be getting one as and when engine/funds require.
Paul
I think it's a lottery.
Despite what many here say, I think an oil cooler wouldn't be bad idea, and unless someone comes up with some concrete evidence to the contrary, I will be getting one as and when engine/funds require.
Paul
16 September 2002, 09:51 PM
#78
STi5/6 TypeRA/R doesnt have a closed deck block, even in V-Ltd form.
The gearing on the V-Ltd is the same as non V-Ltd RA/R's sometimes, sometimes V-Ltd's have a higher 5th but still the same 1st-4th. It depends what mood the STi techies were in.
The STi5 TypeR/RA V-Ltd has the centre diff control.
The gearing on the V-Ltd is the same as non V-Ltd RA/R's sometimes, sometimes V-Ltd's have a higher 5th but still the same 1st-4th. It depends what mood the STi techies were in.
The STi5 TypeR/RA V-Ltd has the centre diff control.
16 September 2002, 10:03 PM
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One common theme in this little lot of blown engines is the oil used - usually a 'general purpose' manufacturer, in el-crapola form. Well, a not obviously suitable type, anyway - semi-synth, etc. Although this isn't exactly a large database to work from 
, it does seem that a good oil might be a Good Thing. I think this has been discussed before - a good oil can reduce the pressure drop on lift-off (or whenever), stopping the engine from going kamikaze.
Isn't this huge dependance on a quality oil a pointer towards where the problem could lie?
Hmm, just read that & thought I should clarify my drivel a tad:
If you are 'trying' to blow the engine (not knowing how to do it in the first place being the amusing part), a good oil will do its best to stop you. However, keep hammering on for long enough & it won't be able to help forever.
[Edited by nom - 9/16/2002 10:07:43 PM]
, it does seem that a good oil might be a Good Thing. I think this has been discussed before - a good oil can reduce the pressure drop on lift-off (or whenever), stopping the engine from going kamikaze.Isn't this huge dependance on a quality oil a pointer towards where the problem could lie?
Hmm, just read that & thought I should clarify my drivel a tad:
If you are 'trying' to blow the engine (not knowing how to do it in the first place being the amusing part
), a good oil will do its best to stop you. However, keep hammering on for long enough & it won't be able to help forever.[Edited by nom - 9/16/2002 10:07:43 PM]
17 September 2002, 10:07 AM
#80
Plenty have gone on quality 15/50 fully synth oil.
I think the common theme, if anything, is doing it just after an oil change.
Is there anything that if marginal on the pump, could break when priming the engine gain for the first time. I am wondering if these valves when on their way out, only stay together when there is plenty of oil about, drain it out and it falls apart. Is something like this feesable? Does anyone have any evidence to suggest problems with the oil pump after failure?
Paul
I think the common theme, if anything, is doing it just after an oil change.
Is there anything that if marginal on the pump, could break when priming the engine gain for the first time. I am wondering if these valves when on their way out, only stay together when there is plenty of oil about, drain it out and it falls apart. Is something like this feesable? Does anyone have any evidence to suggest problems with the oil pump after failure?
Paul
17 September 2002, 11:17 AM
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Having spoken with RC motorsport, their pump does not up the pressure, and is a modified plunger, but as I stated, they dont say how it is modified.
I will take it apart when I get one and run it past R19KET as I wont have a clue what I am looking for.
As far as oil is concerned, not sure about this one. mine let go with the revered motul 300v oil in it. didnt save me!
Moray, did you look at the state of your original oil pump after your snapped rod incident? you didnt have bearing failure, so I am wondering if there is any scoring on the bore of your oil pump since you wont have the bearing fragments in your oil to jam the plunger in the way andy describes.
I will take it apart when I get one and run it past R19KET as I wont have a clue what I am looking for.
As far as oil is concerned, not sure about this one. mine let go with the revered motul 300v oil in it. didnt save me!
Moray, did you look at the state of your original oil pump after your snapped rod incident? you didnt have bearing failure, so I am wondering if there is any scoring on the bore of your oil pump since you wont have the bearing fragments in your oil to jam the plunger in the way andy describes.
17 September 2002, 11:50 AM
#82
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Adam
I would guess that unless Moray's rod broke just as he switched it off there would still be plenty debris spinning around as the flailing rod carved a channel through anything in its path 
I would guess that unless Moray's rod broke just as he switched it off
there would still be plenty debris spinning around as the flailing rod carved a channel through anything in its path
17 September 2002, 11:55 AM
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this is also true, but then i was hoping that due to the material difference between block internals and bearing material, the fragments would have been too large to get around the oil ways, and specifically through the oil pick up filter mesh before the pump.
17 September 2002, 02:00 PM
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I think a serious area of interest should be on those people who have cars that repeatedly blow - it does seem to happen that way more often than it should (
should? ) and it may be that these few are driving their cars the same way after the 'incident' as before, rather than avoiding the situation. So the fault - which was not fixed - is able to repeat itself. What parts are changed in these cases and - more interestingly - what is left on? One case of four engine blows still had the same MAF which seemed a likely cause, but how about in others? And how about the cars with ECUs that don't use a MAF?
should? ) and it may be that these few are driving their cars the same way after the 'incident' as before, rather than avoiding the situation. So the fault - which was not fixed - is able to repeat itself. What parts are changed in these cases and - more interestingly - what is left on? One case of four engine blows still had the same MAF which seemed a likely cause, but how about in others? And how about the cars with ECUs that don't use a MAF?
17 September 2002, 02:57 PM
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Of limited technical understanding and knowledge here, but while reading something rung a chord with me.
Pavlo points out, at the top of this page, that the one common theme is that they let go soon after an oil service. But then service intervals are 7000 miles...
Bear with me on this
On my old Golf and 318 (both hydraulic tappets) the tappets would be noticably noisier after an oil change. I've always put his down to the new oil. Is there some residue left by the old oil that could contaminate the Pressure Relief Valve causing it to stick???
Feel free to say if this is wildly wrong or easily dismissed.
Mike
Pavlo points out, at the top of this page, that the one common theme is that they let go soon after an oil service. But then service intervals are 7000 miles...
Bear with me on this
On my old Golf and 318 (both hydraulic tappets) the tappets would be noticably noisier after an oil change. I've always put his down to the new oil. Is there some residue left by the old oil that could contaminate the Pressure Relief Valve causing it to stick???
Feel free to say if this is wildly wrong or easily dismissed.
Mike
17 September 2002, 06:00 PM
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I think we all just have to face it. **** Happens, and no-one knows a definate fix for the problem. We will all keep speculating, but as it can take many thousand miles to find out, it may take years to find an answer. At the end of the day, a lot of std engine last well over 100,000 miles, so what makes them different??? Mine lasted til 125,000 miles, tho I did put crap oil in it.. idiot.
18 September 2002, 11:45 AM
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I asked for typical oil temps on the scoob some time ago on a different thread, road v track, with/without cooler etc but either nobody had that info or they did not want to pass it on
Still have not got round to fitting my own gauge yet !
Still have not got round to fitting my own gauge yet !
18 September 2002, 12:47 PM
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Probably of no help here (engine hasn't exploded - yet ) but I have noticed a bit of an oddity with the peak thingy I have on my gauge - the highest it ever reads (visibly) is 95C (when sitting in traffic) but the peak shows as 145C after a couple of typical drives, which seems a tad high... I'm guessing this is a small amount of seriously hot oil that hits the sensor (gallery mounted) from time to time and can be ignored. Or the sensor is nuts (although it does seem to read accurately). Or there's something more sinister going on .
Like I said, probably not very useful...
) but I have noticed a bit of an oddity with the peak thingy I have on my gauge - the highest it ever reads (visibly) is 95C (when sitting in traffic) but the peak shows as 145C after a couple of typical drives, which seems a tad high... I'm guessing this is a small amount of seriously hot oil that hits the sensor (gallery mounted) from time to time and can be ignored. Or the sensor is nuts (although it does seem to read accurately). Or there's something more sinister going on .Like I said, probably not very useful...