Engine blew - options? advice?
11-25-2016, 07:35 PM
#31
11-25-2016, 08:35 PM
#32
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I bought a very nice boxster S "roller with dead motor" a few years back. With high miles, they go to salvage for about $3000-4000 - maybe a bit more if you have great tires etc - but generally its best to sell them with dead tires etc, and sell goo bits independently. So not a lot of money.
I bought a motor from a reputable dismantler and put it in. The motors was around $6k, I did some upgrades to keep it reliable, and the in/out was about $2500 with parts etc. All in around $10k, with upgraded IMS, chain tensioners, water pump, hoses clamps, and a partidge....nevermind
Here's the rub - a motor may be good or it may be bad. Mine was destined to be a track car. While it ran smoothly and had good compression, the motor deteriorated very rapidly and is basically dead - needing a complete rebuild, 3 track-years later. By contrast my street car, with many miles and quite a large number of track days, is perfect. The point is uncertainty - you can get a well maintained motor or a poorly maintained motor, and its hard ot tell the difference without complete dis-assembly, which kinda defeats the purpose. So you have to ask yourself, "do you feel lucky?". well, do ya?
I did. I was wrong.
I'm now looking at various options again. 1) roll the dice on another used motor (probably a 3.4 or 3.6), rebuild mine (terrific local race shop and LN nickies), or buy a rebuilt motor a race shop has one the shelf (3.4). With in/out, clutch, blah, blah i can;t see any being under $12-14k, and at the top end more like $17k. That said my car will be much faster than stock and have a more durable motor than factory when done. But its not cheap.
You might find a race shop that will buy the roller for more than a dismantler. Good luck - they know the market too.
I do agree that this is a great chassis, and that your car looks beautiful. So maybe its worth $15k - at that point the most troublesome bit will be new or better than...
All the best,
G
I bought a motor from a reputable dismantler and put it in. The motors was around $6k, I did some upgrades to keep it reliable, and the in/out was about $2500 with parts etc. All in around $10k, with upgraded IMS, chain tensioners, water pump, hoses clamps, and a partidge....nevermind
Here's the rub - a motor may be good or it may be bad. Mine was destined to be a track car. While it ran smoothly and had good compression, the motor deteriorated very rapidly and is basically dead - needing a complete rebuild, 3 track-years later. By contrast my street car, with many miles and quite a large number of track days, is perfect. The point is uncertainty - you can get a well maintained motor or a poorly maintained motor, and its hard ot tell the difference without complete dis-assembly, which kinda defeats the purpose. So you have to ask yourself, "do you feel lucky?". well, do ya?
I did. I was wrong.
I'm now looking at various options again. 1) roll the dice on another used motor (probably a 3.4 or 3.6), rebuild mine (terrific local race shop and LN nickies), or buy a rebuilt motor a race shop has one the shelf (3.4). With in/out, clutch, blah, blah i can;t see any being under $12-14k, and at the top end more like $17k. That said my car will be much faster than stock and have a more durable motor than factory when done. But its not cheap.
You might find a race shop that will buy the roller for more than a dismantler. Good luck - they know the market too.
I do agree that this is a great chassis, and that your car looks beautiful. So maybe its worth $15k - at that point the most troublesome bit will be new or better than...
All the best,
G
11-26-2016, 06:39 PM
#34
Theories
I have theories, two eyes and a nose :-) All are potentially of equal value in this discussion. The theories may be wrong.
yes, the car was tracked later in my "career" so it drive it faster and harder - but it also had a deep sump. I'll note that I drove the street car hard - i went right to redline and on certain tracks, where it was debatable whether a 3-4 shift was useful, i'd let it bounce off the rev limiter for 1/4 mile (which for those who care, in a 2.7l 5-sp 986 is about 107 mph). So it was not "babied". The new car I've been short shifting for two years due to progressing oil ingestion that gets worse - and fouls plugs to the point of misfires, above 5500 rpm. So in some ways the track car get easier use (but likely higher Gs more often).
My real theory is that i bought, broke in, and maintained my street car from new. I drive cars easily until fully warm, try not to leave them sitting with adid/diluted oil, and generally maintain them to a T. The used motor was likely ignored at break-in, run hard when cold (awful, but how many cars do uyou see pull out of parking lots and rev to 6k?), used for lots of short trips (accumulates acid and water in oil) and basically not treated well and certainly not as I would. remember this was a 13 year old, low miles junk yard motor bought off ebay after hearing it run on youtube. and it still runs fine for highway driving. I just returned from VIR - 545 miles where it used maybe 100 ml of oil and ran beautifully. Track at WOT 7000 rpm- not so much. It also puffs air out the sump at idle (should be 5 in vacuum). This is consistent with dead rings or oval bores, or both.
Given that, my comment above that there are good motors and bad ones. Its hard to find out which are which. people don't do this to ruin a motor, they do it out of ignorance. Just driving to to church and for a quick jaunt to do some errands on nice Sunday;s is being good to the car, no? (truth: hell NO!)
Given that i hold hope that if i build a new motor and break it in myself, and maintain it myself, and drive it like its made of china until fully warmed up - it will last like my street car has ( and every other car I've ever had from new).
I'd need to go back and count my track days in each. I have not.
G
yes, the car was tracked later in my "career" so it drive it faster and harder - but it also had a deep sump. I'll note that I drove the street car hard - i went right to redline and on certain tracks, where it was debatable whether a 3-4 shift was useful, i'd let it bounce off the rev limiter for 1/4 mile (which for those who care, in a 2.7l 5-sp 986 is about 107 mph). So it was not "babied". The new car I've been short shifting for two years due to progressing oil ingestion that gets worse - and fouls plugs to the point of misfires, above 5500 rpm. So in some ways the track car get easier use (but likely higher Gs more often).
My real theory is that i bought, broke in, and maintained my street car from new. I drive cars easily until fully warm, try not to leave them sitting with adid/diluted oil, and generally maintain them to a T. The used motor was likely ignored at break-in, run hard when cold (awful, but how many cars do uyou see pull out of parking lots and rev to 6k?), used for lots of short trips (accumulates acid and water in oil) and basically not treated well and certainly not as I would. remember this was a 13 year old, low miles junk yard motor bought off ebay after hearing it run on youtube. and it still runs fine for highway driving. I just returned from VIR - 545 miles where it used maybe 100 ml of oil and ran beautifully. Track at WOT 7000 rpm- not so much. It also puffs air out the sump at idle (should be 5 in vacuum). This is consistent with dead rings or oval bores, or both.
Given that, my comment above that there are good motors and bad ones. Its hard to find out which are which. people don't do this to ruin a motor, they do it out of ignorance. Just driving to to church and for a quick jaunt to do some errands on nice Sunday;s is being good to the car, no? (truth: hell NO!)
Given that i hold hope that if i build a new motor and break it in myself, and maintain it myself, and drive it like its made of china until fully warmed up - it will last like my street car has ( and every other car I've ever had from new).
I'd need to go back and count my track days in each. I have not.
G
11-26-2016, 06:47 PM
#35
Drifting
'"This is consistent with dead rings or oval bores, or both."
You may be interested to read what Baz at Hartech has written about this ? Search term "thrust face" . It is a partially un-resolvable inadequate cooling issue. Better lubrication helps.
Paraphrasing him, oval Bank 2 bores are likely, particularly 5 & 6. Try a leakdown test comparison between 2,3 & 5, 6 ? New rings for 5,6 would just make matters worse according to the experts. Time for Nickies?
You may be interested to read what Baz at Hartech has written about this ? Search term "thrust face" . It is a partially un-resolvable inadequate cooling issue. Better lubrication helps.
Paraphrasing him, oval Bank 2 bores are likely, particularly 5 & 6. Try a leakdown test comparison between 2,3 & 5, 6 ? New rings for 5,6 would just make matters worse according to the experts. Time for Nickies?
11-27-2016, 02:37 PM
#37
Race Director
This:
It also puffs air out the sump at idle (should be 5 in vacuum). This is consistent with dead rings or oval bores, or both.
coupled with:
progressing oil ingestion that gets worse - and fouls plugs to the point of misfires, above 5500 rpm
suggests an AOS problem more than "oval bores" or "dead rings".
It also puffs air out the sump at idle (should be 5 in vacuum). This is consistent with dead rings or oval bores, or both.
coupled with:
progressing oil ingestion that gets worse - and fouls plugs to the point of misfires, above 5500 rpm
suggests an AOS problem more than "oval bores" or "dead rings".
11-27-2016, 02:59 PM
#38
AoS - No and clarification as to why
Hi Macster -
Actually not. A dead AoS is indicated by a INCREASE in vacuum in the sump at idle. This vacuum results from a failed diaphragm, resulting in more of the intake vacuum being applied to the sump. Note this is measured at idle, when manifold vacuum is highest.
Clinically, i have re,moved and inspected two AoSs when similar points were made. they were perfect. I wish it were so simple, but it is not.
There's vastly more data behind this story, but it would take pages to relate and even PCA tech committee mechanics tend to get lost when i relate it verbally - although that may be attributed to beer :-)
G
Actually not. A dead AoS is indicated by a INCREASE in vacuum in the sump at idle. This vacuum results from a failed diaphragm, resulting in more of the intake vacuum being applied to the sump. Note this is measured at idle, when manifold vacuum is highest.
Clinically, i have re,moved and inspected two AoSs when similar points were made. they were perfect. I wish it were so simple, but it is not.
There's vastly more data behind this story, but it would take pages to relate and even PCA tech committee mechanics tend to get lost when i relate it verbally - although that may be attributed to beer :-)
G
11-27-2016, 06:18 PM
#39
Race Director
Hi Macster -
Actually not. A dead AoS is indicated by a INCREASE in vacuum in the sump at idle. This vacuum results from a failed diaphragm, resulting in more of the intake vacuum being applied to the sump. Note this is measured at idle, when manifold vacuum is highest.
Clinically, i have re,moved and inspected two AoSs when similar points were made. they were perfect. I wish it were so simple, but it is not.
There's vastly more data behind this story, but it would take pages to relate and even PCA tech committee mechanics tend to get lost when i relate it verbally - although that may be attributed to beer :-)
G
Actually not. A dead AoS is indicated by a INCREASE in vacuum in the sump at idle. This vacuum results from a failed diaphragm, resulting in more of the intake vacuum being applied to the sump. Note this is measured at idle, when manifold vacuum is highest.
Clinically, i have re,moved and inspected two AoSs when similar points were made. they were perfect. I wish it were so simple, but it is not.
There's vastly more data behind this story, but it would take pages to relate and even PCA tech committee mechanics tend to get lost when i relate it verbally - although that may be attributed to beer :-)
G
Also, at idle it is hard to believe the engine would have enough blowby to overcome the considerable low pressure that is available from the intake at idle. And with that much unmetered air I would think the engine would run poorly. And light the CEL.
11-27-2016, 07:27 PM
#40
AoS
99% of AoS failures are diaphragm failures due to hot oil damaging the semi-permeable rubber. Agreed?
The only other failure mode would be for them to clog. That would in fact reduce manifold vacuum - to near zero or below.
A clogged AoS will not pass oil to the intake. But i am passing huge volumes - which collect in the breather from the intake to the AoS. Again, tons of detailed data that I don't have the time to go through unless we want a specific thread on this (happy to start one and invite you) - but the bottom line is that much ( as in very much) oil is moving through AoS - so its not clogged. Use is very, very condition specific however - RPM, load, and get this -- duration and direction of g-load. and its consistent.
I have worked out what i think is happening Somewhat convoluted, but answers every conflicting piece of data. And it all begins with blow by.
If you do want to discuss more, let me know.
G
The only other failure mode would be for them to clog. That would in fact reduce manifold vacuum - to near zero or below.
A clogged AoS will not pass oil to the intake. But i am passing huge volumes - which collect in the breather from the intake to the AoS. Again, tons of detailed data that I don't have the time to go through unless we want a specific thread on this (happy to start one and invite you) - but the bottom line is that much ( as in very much) oil is moving through AoS - so its not clogged. Use is very, very condition specific however - RPM, load, and get this -- duration and direction of g-load. and its consistent.
I have worked out what i think is happening Somewhat convoluted, but answers every conflicting piece of data. And it all begins with blow by.
If you do want to discuss more, let me know.
G
11-27-2016, 09:25 PM
#41
@GFL When you bought your roller, did you made extensive check on all the content of the oil and coolant that could left in the pipes and front coolers ?
I.e.: if the car was a roller", than, great chance that the engine blow up. If engine blow up, what went in the oil before the fatal stop, going up to front for being cooled down ?
When I was thinking about getting a roller, it was one of my worries : How can we clean all the circuit, and be sure at more than 100% that these pipes and coolers are REALLY-REALLY clean ?
Also, I think we should all keep on mind that our brave M96 do not like so much the lateral G.
If you dismount your (OEM) sump cover, and see the OEM plastic oil baffle, with the rubber oil doors, they are flappy (like a salad that is outdated) at bench garage temperature, so, I just cannot imagine how these "doors" can close, when they are at oil temp during active sessions on a warm track day !!!
I'm also a firm fan of low temp water thermostat, this enable the engine to run 6 or 7 °C lower than the OM temp. (Since the era of the catalytic converters, OEM love to run engine a bit warmer, become cats do a better job when temp is higher. But, frankly, our engine is much more happier when coolant stays around 80°C, (instead of 86 or 87°C !!)
Well, my two cents, ..to try to keep up the best possible engine, ..in such a BEAUTIFUL chassis that these Boxster are ! (after 30 years of 911's as daily, ..I love the Boxster so much.)
(My last track day ..was two day ago in Laguna Seca !!!)
I.e.: if the car was a roller", than, great chance that the engine blow up. If engine blow up, what went in the oil before the fatal stop, going up to front for being cooled down ?
When I was thinking about getting a roller, it was one of my worries : How can we clean all the circuit, and be sure at more than 100% that these pipes and coolers are REALLY-REALLY clean ?
Also, I think we should all keep on mind that our brave M96 do not like so much the lateral G.
If you dismount your (OEM) sump cover, and see the OEM plastic oil baffle, with the rubber oil doors, they are flappy (like a salad that is outdated) at bench garage temperature, so, I just cannot imagine how these "doors" can close, when they are at oil temp during active sessions on a warm track day !!!
I'm also a firm fan of low temp water thermostat, this enable the engine to run 6 or 7 °C lower than the OM temp. (Since the era of the catalytic converters, OEM love to run engine a bit warmer, become cats do a better job when temp is higher. But, frankly, our engine is much more happier when coolant stays around 80°C, (instead of 86 or 87°C !!)
Well, my two cents, ..to try to keep up the best possible engine, ..in such a BEAUTIFUL chassis that these Boxster are ! (after 30 years of 911's as daily, ..I love the Boxster so much.)
(My last track day ..was two day ago in Laguna Seca !!!)
11-28-2016, 10:02 AM
#42
A bit confused...
Are you talking about the radiators and the cooling system?
I drained and flushed it, yes, but i did nto go beyond that. There was no debris - just a seized motor (timing chain jumped).
If you are talking about anything internal, then no, i did not tear the motor down. I did not rebuild it in fact - as noted I bought a used replacement. I probably should have rebuilt it :-)
As to the doors: "I just cannot imagine how these "doors" can close" - they close when the oil presses against them.They are one way valves. It does nto rely at all on the door material - just like the valves in our circulatory system, they are moved "out" by the flow of oil and pressed back against the frame by the flow of oil (slowing the flow at best I admit). But rather than worry about them -- the better answer is to add a deep sump with a windage tray. And the BEST answer is what I'm working on - a true dry sump.
thanks for sharing,
G
I drained and flushed it, yes, but i did nto go beyond that. There was no debris - just a seized motor (timing chain jumped).
If you are talking about anything internal, then no, i did not tear the motor down. I did not rebuild it in fact - as noted I bought a used replacement. I probably should have rebuilt it :-)
As to the doors: "I just cannot imagine how these "doors" can close" - they close when the oil presses against them.They are one way valves. It does nto rely at all on the door material - just like the valves in our circulatory system, they are moved "out" by the flow of oil and pressed back against the frame by the flow of oil (slowing the flow at best I admit). But rather than worry about them -- the better answer is to add a deep sump with a windage tray. And the BEST answer is what I'm working on - a true dry sump.
thanks for sharing,
G
11-28-2016, 10:09 AM
#43
Former Vendor
I see lots of engines running rich that have less crankcase pressure, which has a spiral effect, since a weak case vacuum reading automatically gives the engine more fuel trim, by default.
This can be a domino effect, and hard to diagnose, and address.
11-28-2016, 11:56 AM
#44
Race Director
99% of AoS failures are diaphragm failures due to hot oil damaging the semi-permeable rubber. Agreed?
The only other failure mode would be for them to clog. That would in fact reduce manifold vacuum - to near zero or below.
A clogged AoS will not pass oil to the intake. But i am passing huge volumes - which collect in the breather from the intake to the AoS. Again, tons of detailed data that I don't have the time to go through unless we want a specific thread on this (happy to start one and invite you) - but the bottom line is that much ( as in very much) oil is moving through AoS - so its not clogged. Use is very, very condition specific however - RPM, load, and get this -- duration and direction of g-load. and its consistent.
I have worked out what i think is happening Somewhat convoluted, but answers every conflicting piece of data. And it all begins with blow by.
If you do want to discuss more, let me know.
G
The only other failure mode would be for them to clog. That would in fact reduce manifold vacuum - to near zero or below.
A clogged AoS will not pass oil to the intake. But i am passing huge volumes - which collect in the breather from the intake to the AoS. Again, tons of detailed data that I don't have the time to go through unless we want a specific thread on this (happy to start one and invite you) - but the bottom line is that much ( as in very much) oil is moving through AoS - so its not clogged. Use is very, very condition specific however - RPM, load, and get this -- duration and direction of g-load. and its consistent.
I have worked out what i think is happening Somewhat convoluted, but answers every conflicting piece of data. And it all begins with blow by.
If you do want to discuss more, let me know.
G
If you are convinced the AOS is blameless and prefer to assign the cause as oval bores dead rings that's your call. And it is probably the right one, too.
