No 3 Bigend.
01 July 2001, 10:13 PM
#61
Modifying the oil pump pressure relief valve is good for a couple of reasons, first off a little extra pressure in the system is good although overdoing it can blow seals out, more importantly the standard piston in the relief valve is prone to stick, it has a machined annular groove in it which has a sharp edge to it, as its running in an aluminium bore then there is a risk that the piston can pick up and stick especially if prolonged high revs are used, when the revs drop the piston stays where it was. So now you have the engine running at lower rpm and the pressure valve is stuck open, pressure is now much lower than it should be under the conditions of the moment. Again this can lead to oil film breakdown and pick up. Solution is to polish off the sharp edges or replace the piston with one that does not have the groove. These are the oil pump mod that is normally done.
Do I sustain high revs ? I have wired my check engine light as a shift light, its set to 6500 rpm and thats when I change under almost all conditions, since I have max power at 7000 rpm then this sits me nicely in the meat of the torque curve (max torque at about 3800rpm) ... no point pushing higher unless forced to by conditions, although the redline is at 8000 for the later cars I would certainly not advocate running a car for any length of time at that level unless it has been specifically set up to do so and that lets out all road cars IMHO. Again, we have high performance cars but they are not designed to sit on the red line for any length of time, the only real change that allowed the later cars to rev higher was to the valve train, be safe and watch the rev counter.
The choice of oil filter relief pressure is surely one of the reasons that Subaru are so picky about oils, under cold conditions the relief valve could open but only if the oil viscocity is low enough, so a 10-60 oil is more likely to open it than a 5-40. Interesting that Subaru specify the 5-40 for normal use, they aadvise against the 0-40 as they haven't tested it yet that would be least likely to open the relief valve.
Observing oil pressure I noticed that my car has 6 bar normal pressure and 2 bar idle pressure when hot, as revs increase pressure increases proportionaly, at 3000 rpm it makes about 5 bar, at 3500 its 6 bar, at 2500 its about 4 bar. When cold, idle presure is 6 bar at start up and progressively drops as it warms up but it only settles down to its hot settings after the oil temp is above 80 degrees, hence my waiting for that temp to be reached before boosting the car.
So maybe the choice of oil viscocity also has an impact on this. Some oils also carry a higher level of detergent in them than others, an oil like this could dislodge debris from the engine internals, cold starting could allow this debris into the bearings, a hot spot could occur due to pick up, bearing failure could then occur but ... that would be just as likely to happen to any of the bearings except that the middle crank bearing oil feed is bigger than the others as it has to cope with two big ends, this would explain why No 2 or 3 bearings seem to be prone, given that logic says that flow is greater to the centre main and that would explain some of the circumstances that may be occuring to cause these bearings to fail. I normally use a 5-40 oil as that is approved by Subaru, I have tried other grades but found the engine much noisoer when cold. Thats not to say that I think that a 10-50 is a problem, far from it, Subaru are pretty picky about the oil spec that should be used though and they will have calculated the oil filter relief valve pressure based on their oil recomendations. After market filters may not have the same attention payed to the relief valve setting.
As a thought would those who have suffered engine failure be interested enough to participate in some research ? If the circumstances and history of the vehicle up to the failure were known then it would be possible to analyse the data and look for trends, info needed would be make, MY, mileage, sevice habits, oil used, when last serviced, circumstances of failure, events leading up to failure (if not incriminating of course) and so on. Info would need to be detailed and quite specific.
I'd be happy to do the analysis and provide the info to all interested parties. Seems to me that is something we could be doing to help ourselves.
Do I sustain high revs ? I have wired my check engine light as a shift light, its set to 6500 rpm and thats when I change under almost all conditions, since I have max power at 7000 rpm then this sits me nicely in the meat of the torque curve (max torque at about 3800rpm) ... no point pushing higher unless forced to by conditions, although the redline is at 8000 for the later cars I would certainly not advocate running a car for any length of time at that level unless it has been specifically set up to do so and that lets out all road cars IMHO. Again, we have high performance cars but they are not designed to sit on the red line for any length of time, the only real change that allowed the later cars to rev higher was to the valve train, be safe and watch the rev counter.
The choice of oil filter relief pressure is surely one of the reasons that Subaru are so picky about oils, under cold conditions the relief valve could open but only if the oil viscocity is low enough, so a 10-60 oil is more likely to open it than a 5-40. Interesting that Subaru specify the 5-40 for normal use, they aadvise against the 0-40 as they haven't tested it yet that would be least likely to open the relief valve.
Observing oil pressure I noticed that my car has 6 bar normal pressure and 2 bar idle pressure when hot, as revs increase pressure increases proportionaly, at 3000 rpm it makes about 5 bar, at 3500 its 6 bar, at 2500 its about 4 bar. When cold, idle presure is 6 bar at start up and progressively drops as it warms up but it only settles down to its hot settings after the oil temp is above 80 degrees, hence my waiting for that temp to be reached before boosting the car.
So maybe the choice of oil viscocity also has an impact on this. Some oils also carry a higher level of detergent in them than others, an oil like this could dislodge debris from the engine internals, cold starting could allow this debris into the bearings, a hot spot could occur due to pick up, bearing failure could then occur but ... that would be just as likely to happen to any of the bearings except that the middle crank bearing oil feed is bigger than the others as it has to cope with two big ends, this would explain why No 2 or 3 bearings seem to be prone, given that logic says that flow is greater to the centre main and that would explain some of the circumstances that may be occuring to cause these bearings to fail. I normally use a 5-40 oil as that is approved by Subaru, I have tried other grades but found the engine much noisoer when cold. Thats not to say that I think that a 10-50 is a problem, far from it, Subaru are pretty picky about the oil spec that should be used though and they will have calculated the oil filter relief valve pressure based on their oil recomendations. After market filters may not have the same attention payed to the relief valve setting.
As a thought would those who have suffered engine failure be interested enough to participate in some research ? If the circumstances and history of the vehicle up to the failure were known then it would be possible to analyse the data and look for trends, info needed would be make, MY, mileage, sevice habits, oil used, when last serviced, circumstances of failure, events leading up to failure (if not incriminating of course) and so on. Info would need to be detailed and quite specific.
I'd be happy to do the analysis and provide the info to all interested parties. Seems to me that is something we could be doing to help ourselves.
01 July 2001, 10:40 PM
#62
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MRT (www.mrtrally.com.au) offer a fuel rail kit and wrote me the following in an email:
"The fuel rail kit is AU$450 exchange or AU$650 outright and includes
everything you need to replace the fuel rail on the effected side of the
engine. It is designed as a direct bolt on replacement.
You don't mention what other modifications you have made to your car. This
modification is really only needed on cars running high boost, or cars used
in racing/rallying. "
greetings
ric
"The fuel rail kit is AU$450 exchange or AU$650 outright and includes
everything you need to replace the fuel rail on the effected side of the
engine. It is designed as a direct bolt on replacement.
You don't mention what other modifications you have made to your car. This
modification is really only needed on cars running high boost, or cars used
in racing/rallying. "
greetings
ric
02 July 2001, 01:35 AM
#63
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Bob Rawle/
Very good idea Bob, I only hope those who have had troubles will give you the info you require. This could be of great benifit to us all.
Please assist Bob Rawle all you can.
Very good idea Bob, I only hope those who have had troubles will give you the info you require. This could be of great benifit to us all.
Please assist Bob Rawle all you can.
02 July 2001, 01:49 AM
#64
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<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:<HR>As a thought would those who have suffered engine failure be interested enough to participate in some research ?<HR></BLOCKQUOTE>
An excellent idea Bob, I'll get "my Drivers"
onto it when they return from Germany.
Would it be best to email you the detailed data for your examination, rather than using the BBS
Richard
An excellent idea Bob, I'll get "my Drivers"
onto it when they return from Germany. Would it be best to email you the detailed data for your examination, rather than using the BBS
Richard
02 July 2001, 09:21 AM
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Yep, I'll send a mail too if that's ok.
This may be simplistic (as I'm a simplistic person
), but if a high proportion suffer from these failures after a service, how many of the cars have had the engine flush favoured by most Subaru dealers?
Could this not be dislodging contaminents also?
This may be simplistic (as I'm a simplistic person
), but if a high proportion suffer from these failures after a service, how many of the cars have had the engine flush favoured by most Subaru dealers?Could this not be dislodging contaminents also?
02 July 2001, 09:48 AM
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Bob, there is one thing that doesn't quiter make sense to me.
Unless there is a specific failing in the subaru engine, the fault you are pointing your finger at seems to be generic to all cars.
As in, hot spots and debris deposited due to poor practice in oil changing. Surely the symptoms of what you describe would cause any engine to fail?
Can you explain why this diagnosis is specific to subaru please?
Unless there is a specific failing in the subaru engine, the fault you are pointing your finger at seems to be generic to all cars.
As in, hot spots and debris deposited due to poor practice in oil changing. Surely the symptoms of what you describe would cause any engine to fail?
Can you explain why this diagnosis is specific to subaru please?
02 July 2001, 09:52 AM
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And one more thing,
I (actually pat) has just installed my oil temp sender in the same position as bob by the sound of it (v close to number three gallery) and am wondering what temperatures people are seeing in normal driving.
I was shocked to see mine rest at low load and on cruise between 90 and 95. After a swift boot up to about 1.1 bar with my foot planted for about ten seconds, oil temp rose from 90 to 100. This surprised me as |I have my warning light set at 105.
This sounded a bit high to me.
Can anyone post there normally viewed temps and the position of their oil temp sender please.
I (actually pat) has just installed my oil temp sender in the same position as bob by the sound of it (v close to number three gallery) and am wondering what temperatures people are seeing in normal driving.
I was shocked to see mine rest at low load and on cruise between 90 and 95. After a swift boot up to about 1.1 bar with my foot planted for about ten seconds, oil temp rose from 90 to 100. This surprised me as |I have my warning light set at 105.
This sounded a bit high to me.
Can anyone post there normally viewed temps and the position of their oil temp sender please.
02 July 2001, 01:36 PM
#69
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This has to be one of the best and highest quality threads that I have read for ages. It reminds me what Scoobynet is all about when I was getting fed up with all the rubbish being posted. Anyway,
Adam - I have my oil temp sender in the same place as you (ie: under the turbo if I've got the cylinder designations correct)and I get very similar readings. I have had the instruments fitted for a few months now and it is surprising how much quicker the oil heats up at this time of year compared to in the colder months. I find that my engine is running >5 degrees hotter now than it was in winter but I think that the most I have seen is 110 a few weeks ago on the SW Scotland run. Also, my oil pressure echoes the figures given by Bob earlier on.
Raymond (MY98)
Adam - I have my oil temp sender in the same place as you (ie: under the turbo if I've got the cylinder designations correct)and I get very similar readings. I have had the instruments fitted for a few months now and it is surprising how much quicker the oil heats up at this time of year compared to in the colder months. I find that my engine is running >5 degrees hotter now than it was in winter but I think that the most I have seen is 110 a few weeks ago on the SW Scotland run. Also, my oil pressure echoes the figures given by Bob earlier on.
Raymond (MY98)
02 July 2001, 09:41 PM
#70
I think it best if anyone wanting to mail details to me did so off line, not everyone wants this info to be public for a variety of reasons and I would not be using owners names (not needed in the analysis) and so confidentiality would prevail. Use the address in my profile.
Specific to Subaru or generic to most cars .... that depends on several things, all cars don't necessarily have the same oil distribution and filter type that Subaru use, some have the bypass valve in the oil pump only, for example, and yes, of course the routine for oil changing should be followed irrespective of vehicle, its only common sense in that respect although maybe not obvious.
The real point, I guess, is the fact that most people assume the Impreza is an infallible machine which it is definately not, it needs TLC as much as the next car. And I am not putting this forward as the reason for failure, merely attempting to open the debate and discussion up into an area that I think is worth examining.
Adam, it sounds like your oil temp's are pretty much in the norm, my cruise is the same, by experiment if I hold zero boost and let the revs build then oil temp runs at 98 deg C. On boost it just creeps past the 100 and swiftly drops back off boost. All this is normal. Maybe your base info led you to believe that cooler temps should be expected, having confused myself, in the past, into believing that sump temps were in the 60's it soon became clear that certain guage sensors can be artificially cooled by air flow under the car. The current car has had the temp sensor in the sump (via sump plug) and in the oil gallery as yours, the oil gallery position shows faster reaction to boost, for example, but no real difference in temperature levels as such.
Since the oil is "cooled" by the engine coolant then we should expect oil temp to be at least that (80-85 deg C) when moving and we should also expect oil temp to increase as coolant does.
Oil needs to work at temperature, between 80 and 100 is probably the ideal, less than 80 is too cool IMHO, for perspective my Vauxhall turbo used to run at 105/110 deg c oil temp under cruise, on boost it ran at circa 120 deg C, that was with an oil cooler fitted as well. The Impreza does not seem to run with excessive oil temp as normal.
Specific to Subaru or generic to most cars .... that depends on several things, all cars don't necessarily have the same oil distribution and filter type that Subaru use, some have the bypass valve in the oil pump only, for example, and yes, of course the routine for oil changing should be followed irrespective of vehicle, its only common sense in that respect although maybe not obvious.
The real point, I guess, is the fact that most people assume the Impreza is an infallible machine which it is definately not, it needs TLC as much as the next car. And I am not putting this forward as the reason for failure, merely attempting to open the debate and discussion up into an area that I think is worth examining.
Adam, it sounds like your oil temp's are pretty much in the norm, my cruise is the same, by experiment if I hold zero boost and let the revs build then oil temp runs at 98 deg C. On boost it just creeps past the 100 and swiftly drops back off boost. All this is normal. Maybe your base info led you to believe that cooler temps should be expected, having confused myself, in the past, into believing that sump temps were in the 60's it soon became clear that certain guage sensors can be artificially cooled by air flow under the car. The current car has had the temp sensor in the sump (via sump plug) and in the oil gallery as yours, the oil gallery position shows faster reaction to boost, for example, but no real difference in temperature levels as such.
Since the oil is "cooled" by the engine coolant then we should expect oil temp to be at least that (80-85 deg C) when moving and we should also expect oil temp to increase as coolant does.
Oil needs to work at temperature, between 80 and 100 is probably the ideal, less than 80 is too cool IMHO, for perspective my Vauxhall turbo used to run at 105/110 deg c oil temp under cruise, on boost it ran at circa 120 deg C, that was with an oil cooler fitted as well. The Impreza does not seem to run with excessive oil temp as normal.
03 July 2001, 01:50 AM
#71
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Since I have been mentioned earlier I would like to clarify:
1, my car had 29,000 hard miles including high speed continental runs just under the rev limmiter. Including 112 miles until it ran out of juice on the way down to Catalunia (of note the last 10 miles were at 56 mph as it became obvious we were running out of fuel
)
2, my car lasted 600 miles after the Powr Engineering rechip.
3, David Poor stated it was not his products fault but a fault of the oil suply to the number 3 bearing.
4, I needed a new turbo as the turbo seals had fried, in the heat.
5, I needed a new manifold as it had gone scarlet with the heat.
6, There was detonation on the pistons.
7, The valve stem seals had fried due to the heat.
In addition the number 3 bearing was smashed with a bent crank both due to localised oil deprivation in number 3, one hypothesis is that detonation on number 3 with associated heat had led to a disruption of the film of oil for the number 3 bearing
Anyway David Poor told me he genuinely believed his re-chip was not at fault. I just thought it was a bit off that they could charge me £700 and then the car fail after 600 miles and then I discover that the "don't worry I will look after you" meant that he couldn't tell me how much it was going to cost when I thought it was all being done for free!
Trying to be open minded I have to say that my cars failure could have been coincidence, as could Mr Cartwrights and Mr Martins 22bs!
Richard Squires car ran faultlessly until induction parameters were changed without the map being adjusted and then banged off the rev limmitter
This is so sad
I just think that it takes ***** of steel to offer car tuning upgrades then cars go bang and then say:"not our fault its an inherent problem with the car"! Thats why you go to experts in the first place isn't it?
BTW I always liked Mervyn
1, my car had 29,000 hard miles including high speed continental runs just under the rev limmiter. Including 112 miles until it ran out of juice on the way down to Catalunia (of note the last 10 miles were at 56 mph as it became obvious we were running out of fuel
)2, my car lasted 600 miles after the Powr Engineering rechip.
3, David Poor stated it was not his products fault but a fault of the oil suply to the number 3 bearing.
4, I needed a new turbo as the turbo seals had fried, in the heat.
5, I needed a new manifold as it had gone scarlet with the heat.
6, There was detonation on the pistons.
7, The valve stem seals had fried due to the heat.
In addition the number 3 bearing was smashed with a bent crank both due to localised oil deprivation in number 3, one hypothesis is that detonation on number 3 with associated heat had led to a disruption of the film of oil for the number 3 bearing
Anyway David Poor told me he genuinely believed his re-chip was not at fault. I just thought it was a bit off that they could charge me £700 and then the car fail after 600 miles and then I discover that the "don't worry I will look after you" meant that he couldn't tell me how much it was going to cost when I thought it was all being done for free!
Trying to be open minded I have to say that my cars failure could have been coincidence, as could Mr Cartwrights and Mr Martins 22bs!
Richard Squires car ran faultlessly until induction parameters were changed without the map being adjusted and then banged off the rev limmitter
This is so sad
I just think that it takes ***** of steel to offer car tuning upgrades then cars go bang and then say:"not our fault its an inherent problem with the car"! Thats why you go to experts in the first place isn't it?
BTW I always liked Mervyn
03 July 2001, 02:39 AM
#72
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<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:<HR>Richard Squires car ran faultlessly until induction parameters were changed without the map being adjusted and then banged off the rev limmitter <HR></BLOCKQUOTE>
Being, that I was there at the time, please let me state what did or did not happen with my car.
Just for your information NO induction parameters had been changed.
Richard
*edit* Bob we'll email you offline with the full details that you requested. I fervently hope that this important thread does not become derailed.
[This message has been edited by rsquire (edited 03 July 2001).]
Being, that I was there at the time, please let me state what did or did not happen with my car.
Just for your information NO induction parameters had been changed.
Richard
*edit* Bob we'll email you offline with the full details that you requested. I fervently hope that this important thread does not become derailed.
[This message has been edited by rsquire (edited 03 July 2001).]
03 July 2001, 03:07 AM
#73
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This is a great thread now lets not let it go astray. It would be a shame to have a lock put on this one after we are just starting to achieve something.
Any info you have concerning a No 3 big end failure please send to Bob Rawle. You can get his email addy from his profile.
Any info you have concerning a No 3 big end failure please send to Bob Rawle. You can get his email addy from his profile.
03 July 2001, 07:03 AM
#74
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Richard,
I think Anders is referring to the change of exhaust parts.
If one changes an exhaust, in an attempt to gain more power, and after the changes the car does feel quicker, it's likely that the engine is flowing more air. More air, needs more fuel.......
Mark.
I think Anders is referring to the change of exhaust parts.
If one changes an exhaust, in an attempt to gain more power, and after the changes the car does feel quicker, it's likely that the engine is flowing more air. More air, needs more fuel.......
Mark.
03 July 2001, 07:22 AM
#75
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Mark,
I disagree totally.. Induction is pre the engine..
Anyway enough of that nonsense, what we do need is to keep this thread on track and keep the information going to Bob Rawles ..
Somewhere in here are facts that are important to ALL Subaru owners be it... 22B owners, STI owners, UK turbo owners, or even humble Naturally Aspirated North American owners..
Richard
I disagree totally.. Induction is pre the engine..
Anyway enough of that nonsense, what we do need is to keep this thread on track and keep the information going to Bob Rawles ..
Somewhere in here are facts that are important to ALL Subaru owners be it... 22B owners, STI owners, UK turbo owners, or even humble Naturally Aspirated North American owners..
Richard
03 July 2001, 09:57 AM
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I dont want to express the wrong concern but would anyone object if this thread were moved to drivetrain as I think it should be. Obviously i dont have the poor to do this, but in writing this, stef or moray may agree with me so I thought I'd make the point.
This is a very important subject, and the general forum is diluted with other "less" important subjects which will push this one out of contention. In Drivetrain, it may last longer.
This is a very important subject, and the general forum is diluted with other "less" important subjects which will push this one out of contention. In Drivetrain, it may last longer.
03 July 2001, 11:07 AM
#77
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Richard,
I'm not certain what you're disagreeing with, that Anders was obviously referring to the exhaust, or that a higher flowing exhaust will lean the engine out ???
Either way, it's VERY relevent, if your engine let go due to running lean, over heating, detting, and then taking out a bearing. It has to be concidered.
If we want to get to the bottom of the problem, we need the FACTS, and not some excuse to make someone feel better about the situation. How is Bob supposed to analize the data, unless the data is accurate ???.
Mark.
I'm not certain what you're disagreeing with, that Anders was obviously referring to the exhaust, or that a higher flowing exhaust will lean the engine out ???
Either way, it's VERY relevent, if your engine let go due to running lean, over heating, detting, and then taking out a bearing. It has to be concidered.
If we want to get to the bottom of the problem, we need the FACTS, and not some excuse to make someone feel better about the situation. How is Bob supposed to analize the data, unless the data is accurate ???.
Mark.
