How can you detect big end has gone ?
27 February 2002, 12:59 AM
#31
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When my big end went I had no loss of power at all. There was a slight knocking noise which got louder every 5 mins. There is no way of knowing what has failed in the engine till it is taken apart. As a rule of thumb if it suddenly comes on at high RPM in a scooby it is usually a big end. BTW after the rebuild my engine burnt alot of oil due to metal in the oil damaging the tubo seals and wreacking the turbo.
27 February 2002, 08:31 AM
#32
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Mark
Excellent description (far better than I'd have managed
)!
Johny
Take Marks' advice - be very careful with the O rings if you do this - high pressure fuel only needs a very small nick in one of these to escape and on top of a hot engine with high voltages around ....
Also, you don't really need to know the actual flow rates of the injectors unless doing some very clever mapping, just that they are all the same. This will tell you if there is some damage to the pintle. Note it is usual on a production car to find adifference of upto 5% between the highest and lowest.
Duncan
Excellent description (far better than I'd have managed
)!Johny
Take Marks' advice - be very careful with the O rings if you do this - high pressure fuel only needs a very small nick in one of these to escape and on top of a hot engine with high voltages around ....
Also, you don't really need to know the actual flow rates of the injectors unless doing some very clever mapping, just that they are all the same. This will tell you if there is some damage to the pintle. Note it is usual on a production car to find adifference of upto 5% between the highest and lowest.
Duncan
12 March 2002, 02:59 PM
#34
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OK engine is open completely now. No fysical damage on big-ends, crank, crankbearing or big-end bearing. So problem is piston 2 and cylinder 2. However repairing this (4x honing cylinders, 4 pistons, and while we are at it new crank / big-end bearing (not needed but its open anyway) is AS expensive as a new shortblock. So we ordered a new shortblock (and can keep my old one of course for some +200bhp project :-)
We also examined the oil which was in for only 2000km:
- lot of silica, due to open K&N 57i filter
- lot of alu, due to blown piston
- lot of fuel in the oil (2%). Indication of running rich
(which contradicts theory of Subaru NL that 57i and catless downpipe makes it run to lean and therefore the piston has blown)
Subaru NL doesn't do anything for warranty because:
1) One year warranty period is gone (the car is from sept. 99 and currently a three year warranty is given on new subaru's)
2) The car is PPP'd and I signed a letter giving away warranty claims (standard procedure in Holland although Subaru UK provides full warranty on PPP'd cars and soon in Holland a WRX LE (limited edition) is coming out, yep with already fitted PPP and 3 years warranty)
3) the car has a open K&N 57i induction kit and catless downpipe which makes it run lean and burn holes in piston (at least that is what they say).
Costs are EUR 5200 with 4 new plugs, new shortblock, new timing belt, new clutch and new mass-air-flow sensor. Because Subaru NL doesn't do anything my dealer gives me EUR 700 discount. I don't believe my MAF sensor is gone so we are going to test the old one against a new one on the rolling road and select monitor. So probably my costs are EUR 5200 - EUR 700 - EUR 425 (MAF sensor) is ~EUR 4100.
Naturally before we put things all together the injectors are tested too.
I will try building a case against Subaru NL, or K&N if Subaru NL proves that the piston was blown to a too lean mixture, the lean mixture was due to a failing MAF sensor and the failing MAF sensor is due to a K&N 57i induction kit. Personally I think this theory sucks and Subura NL is using it as a bogus reason to get out of warranty claims.
So, what can I do with my old shortblok and cylinder 2 / piston 2 gone. Just put it in my garage (looks nice) or ...
Mark.
We also examined the oil which was in for only 2000km:
- lot of silica, due to open K&N 57i filter
- lot of alu, due to blown piston
- lot of fuel in the oil (2%). Indication of running rich
(which contradicts theory of Subaru NL that 57i and catless downpipe makes it run to lean and therefore the piston has blown)
Subaru NL doesn't do anything for warranty because:
1) One year warranty period is gone (the car is from sept. 99 and currently a three year warranty is given on new subaru's)
2) The car is PPP'd and I signed a letter giving away warranty claims (standard procedure in Holland although Subaru UK provides full warranty on PPP'd cars and soon in Holland a WRX LE (limited edition) is coming out, yep with already fitted PPP and 3 years warranty)
3) the car has a open K&N 57i induction kit and catless downpipe which makes it run lean and burn holes in piston (at least that is what they say).
Costs are EUR 5200 with 4 new plugs, new shortblock, new timing belt, new clutch and new mass-air-flow sensor. Because Subaru NL doesn't do anything my dealer gives me EUR 700 discount. I don't believe my MAF sensor is gone so we are going to test the old one against a new one on the rolling road and select monitor. So probably my costs are EUR 5200 - EUR 700 - EUR 425 (MAF sensor) is ~EUR 4100.
Naturally before we put things all together the injectors are tested too.
I will try building a case against Subaru NL, or K&N if Subaru NL proves that the piston was blown to a too lean mixture, the lean mixture was due to a failing MAF sensor and the failing MAF sensor is due to a K&N 57i induction kit. Personally I think this theory sucks and Subura NL is using it as a bogus reason to get out of warranty claims.
So, what can I do with my old shortblok and cylinder 2 / piston 2 gone. Just put it in my garage (looks nice) or ...
Mark.
12 March 2002, 04:04 PM
#35
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Mark
Ouch! Sorry to hear that your problem is going to cost so much - good luck in getting a contribution from elsewhere.
I'm interested in your analysis of the oil, in particular the amount of fuel in it. Have you considered that the amount of fuel could have been due to the holed piston - the injector would have carried on injecting when you ran the car with the hole in the piston, and the unburnt fuel would be forced into the crankcase.
Duncan
PS I'd be suprised if the K&N filter caused it to run weak enough to blow a piston by itself. Normally if you lean out the mixture too much on an injected car you will get detonation on all of the piston crowns, and the evidence will still be visible on the surviving pistons and plugs.
Ouch! Sorry to hear that your problem is going to cost so much - good luck in getting a contribution from elsewhere.
I'm interested in your analysis of the oil, in particular the amount of fuel in it. Have you considered that the amount of fuel could have been due to the holed piston - the injector would have carried on injecting when you ran the car with the hole in the piston, and the unburnt fuel would be forced into the crankcase.
Duncan
PS I'd be suprised if the K&N filter caused it to run weak enough to blow a piston by itself. Normally if you lean out the mixture too much on an injected car you will get detonation on all of the piston crowns, and the evidence will still be visible on the surviving pistons and plugs.
12 March 2002, 10:28 PM
#36
I think Duncan has it right.
Its almost certain that the excess fuel has come from the piston damage, I think that you mentioned that you had driven the car for a while after the "event" so its not suprising to find excess fuel. Have you seen the piston? Does it look "melted" or "fractured"?
Its almost certain that the excess fuel has come from the piston damage, I think that you mentioned that you had driven the car for a while after the "event" so its not suprising to find excess fuel. Have you seen the piston? Does it look "melted" or "fractured"?
14 March 2002, 10:05 AM
#37
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Duncan, Bob,
Yes I did consider the fact of 2% fuel in the oil to come from the broken piston. However please consider that:
- on saterday it detonated (I think) at 6500-7000 rpm in 4th gear. Sunday till thursday the engine run fine apart from a rattle at cold. Now I think the piston and/or cyl. 2 got wrecked a bit and piston slap occurred (it weren't any bearings, we checked remember!). On Thursday the piston melted at 180km/h and apart from rolling to the side of the road the engine was cut immediately.
When you look at the piston of cyl. 2 you see a small hole (1 mm) in it. Furthermore on another place I see some top/side damage (didn't see the piston out off the cylinder though). The wall of the cylinder is damaged too at the top. Today I get a digital camera and will make photos of it all, including the big-end / crank bearings.
The other pistons / cylinders show no damage at all (on top, I didn't take the pistons out of the cylinder)
Mark.
Yes I did consider the fact of 2% fuel in the oil to come from the broken piston. However please consider that:
- on saterday it detonated (I think) at 6500-7000 rpm in 4th gear. Sunday till thursday the engine run fine apart from a rattle at cold. Now I think the piston and/or cyl. 2 got wrecked a bit and piston slap occurred (it weren't any bearings, we checked remember!). On Thursday the piston melted at 180km/h and apart from rolling to the side of the road the engine was cut immediately.
When you look at the piston of cyl. 2 you see a small hole (1 mm) in it. Furthermore on another place I see some top/side damage (didn't see the piston out off the cylinder though). The wall of the cylinder is damaged too at the top. Today I get a digital camera and will make photos of it all, including the big-end / crank bearings.
The other pistons / cylinders show no damage at all (on top, I didn't take the pistons out of the cylinder)
Mark.
14 March 2002, 12:04 PM
#38
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Mark
I'm happy to respond to you on this subject, but do not want to do so in public in case it prejudices your case with Subaru Netherlands (who may also read this board). If you would like to "talk" further, drop me a line with your Email address or post here confirming that you are happy to discuss this in "public".
Cheers
Duncan
I'm happy to respond to you on this subject, but do not want to do so in public in case it prejudices your case with Subaru Netherlands (who may also read this board). If you would like to "talk" further, drop me a line with your Email address or post here confirming that you are happy to discuss this in "public".
Cheers
Duncan
14 March 2002, 04:36 PM
#39
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Duncan,
My e-mail adres is Mark.Kuijper@achmea.nl
I like open, honest discussion / communication. If its really my fault that I modded the car and it has blown up, so be it. I'll pay the euros, wine for 2 minutes about it and through my BoxsterS / Impreza in a powerdrift and forget about it.
I really get pissed when somebody misuses something in the small letters and throws it at you when it has nothing to do with the problem. Prove to / convince me that the air-filter or decat downpipe wrecked the MAF sensor and therefore the mixture got to lean and the engine was blown and my case / anger to Subura NL instantly stops. Although I'll take up the matter with K&N though then.
Mark.
My e-mail adres is Mark.Kuijper@achmea.nl
I like open, honest discussion / communication. If its really my fault that I modded the car and it has blown up, so be it. I'll pay the euros, wine for 2 minutes about it and through my BoxsterS / Impreza in a powerdrift and forget about it.
I really get pissed when somebody misuses something in the small letters and throws it at you when it has nothing to do with the problem. Prove to / convince me that the air-filter or decat downpipe wrecked the MAF sensor and therefore the mixture got to lean and the engine was blown and my case / anger to Subura NL instantly stops. Although I'll take up the matter with K&N though then.
Mark.
14 March 2002, 07:54 PM
#40
Not sure about the fuel rail flows.
Since the fuel pressure reg is adjacent to no 3 cylinder then the first injector to be fed is no 4? Fuel flows around each injector to get to the next and the injector filter only takes care of itself. So a blocked filter will affect only the injector involved.
The seals are indeed very fragile, I have known one fail a week after injectors were changed. It was lucky that the owner ahd been waiting for a re-map and had not been driving the car, seal had been nicked when the injector was pushed in apparantly. car was stood with bonnet open, seal let go and fuel everywhere. Could have been nasty. Not a job to take lightly.
Since the fuel pressure reg is adjacent to no 3 cylinder then the first injector to be fed is no 4? Fuel flows around each injector to get to the next and the injector filter only takes care of itself. So a blocked filter will affect only the injector involved.
The seals are indeed very fragile, I have known one fail a week after injectors were changed. It was lucky that the owner ahd been waiting for a re-map and had not been driving the car, seal had been nicked when the injector was pushed in apparantly. car was stood with bonnet open, seal let go and fuel everywhere. Could have been nasty. Not a job to take lightly.
15 March 2002, 08:12 AM
#41
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Mark
The type of failure that you have described is the type that occurs when you have the incorrect mixture for a very short period of time at a significant load. For example, if you have a long term lean mixture that causes detonation you will tend to get pitting across the majority of the centre of the piston crown (about 1Euro size).
I do not think that the problem is due to your K&N intake, but I am not a fan of them. The alledged tendancy of these is to lean out the mid range (because of their different flow characteristics across the MAF). Some suggest that damage can be caused to the MAF by excess oil being added to the filter element. If either of these caused your failure it is likely that you'll have damaged all of the pistons to an extent, and not just a "small" hole in the center of one of them.
Similarly, I do not feel that the de-cat downpipe or PPP will have directly caused the problem. Both will mean that you have stressed the engine more highly, and will be running more advance and leaner on full throttle. Again though, these will damage all of the cylinders equally.
The type of failure that you have I have only seen before with injector problems - either blocking/restricting of the fuel flow to the injector because of "crud" in the fuel rail, or problems with the leads to the injector from the loom.
I would suggest that you check the injectors very carefully prior to rebuilding the engine.
On the other hand, take the Boxster out in the mean time and enjoy yourself!
Duncan
The type of failure that you have described is the type that occurs when you have the incorrect mixture for a very short period of time at a significant load. For example, if you have a long term lean mixture that causes detonation you will tend to get pitting across the majority of the centre of the piston crown (about 1Euro size).
I do not think that the problem is due to your K&N intake, but I am not a fan of them. The alledged tendancy of these is to lean out the mid range (because of their different flow characteristics across the MAF). Some suggest that damage can be caused to the MAF by excess oil being added to the filter element. If either of these caused your failure it is likely that you'll have damaged all of the pistons to an extent, and not just a "small" hole in the center of one of them.
Similarly, I do not feel that the de-cat downpipe or PPP will have directly caused the problem. Both will mean that you have stressed the engine more highly, and will be running more advance and leaner on full throttle. Again though, these will damage all of the cylinders equally.
The type of failure that you have I have only seen before with injector problems - either blocking/restricting of the fuel flow to the injector because of "crud" in the fuel rail, or problems with the leads to the injector from the loom.
I would suggest that you check the injectors very carefully prior to rebuilding the engine.
On the other hand, take the Boxster out in the mean time and enjoy yourself!
Duncan
16 March 2002, 01:12 AM
#42
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Mrkimpreza,
I thank you once again for letting us know what is happening. The information could be useful to us and to maybe help us to somehow prevent it from happening.
I'm very sorry to hear that your engine got this damage to it and I hope you get it sorted out.
Regards,
Wrexy.
I thank you once again for letting us know what is happening. The information could be useful to us and to maybe help us to somehow prevent it from happening.
I'm very sorry to hear that your engine got this damage to it and I hope you get it sorted out.
Regards,
Wrexy.
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