Crank scrapers, pan spacers, Accusumps ?
06-24-2010, 02:23 PM
#61
Rennlist Member
so, it certainly sounds like you might have fixed and got lucky with the street engine and it is still running today, 40 hours later?
Im very curious about the new race engine that failed. it was a higher rev'er by design and it failed after 10 hours. So, this is where we all need more information. WE NEED VIDEO! everyone should be running a $100 go pro camera every time they hit the track. (or have the expensive motec data aqu. systems) . Why, because when you blew, someone like me with 1000s of laps at thunderhill, can look at it and see, what you might be doing different. certainly, you are not running faster than I am in the new racer (yet.
) But, this proves that its not the G loading. But, where you have the rpm at certain turns, what gear you are in, and most importantly, if the engine build is the same as the street car, or if those baffles, and screens are fine for 6200rpm but not 6800rpm. thats a HUGE difference than just 600rpm, in SO MANY areas of what we are looking at. For example, what if the flow rate was lower proportionally through the screens at 6800rpm. (extremely possible). what was the oil pressure around turn 2 at thunderhill? less than 5 bar. did it flicker or show lower than 5 bar ANYWHERE else?? if so, there is a HUGE issue that could have causes the failure.
I feel bad for you, but Im pretty certain, if you build a 928 engine and just do a stroker or leave it stock, you can run as long as you want without failure following a few simple guidlines.
In the future, I would hope everyone serious in the emperical side of the testing world, would start to click on a camera and film each session, showing driver inputs and hopefullly a somewhat clear view ofthe tach or oil pressure gauge.
Im very curious about the new race engine that failed. it was a higher rev'er by design and it failed after 10 hours. So, this is where we all need more information. WE NEED VIDEO! everyone should be running a $100 go pro camera every time they hit the track. (or have the expensive motec data aqu. systems) . Why, because when you blew, someone like me with 1000s of laps at thunderhill, can look at it and see, what you might be doing different. certainly, you are not running faster than I am in the new racer (yet.
) But, this proves that its not the G loading. But, where you have the rpm at certain turns, what gear you are in, and most importantly, if the engine build is the same as the street car, or if those baffles, and screens are fine for 6200rpm but not 6800rpm. thats a HUGE difference than just 600rpm, in SO MANY areas of what we are looking at. For example, what if the flow rate was lower proportionally through the screens at 6800rpm. (extremely possible). what was the oil pressure around turn 2 at thunderhill? less than 5 bar. did it flicker or show lower than 5 bar ANYWHERE else?? if so, there is a HUGE issue that could have causes the failure.I feel bad for you, but Im pretty certain, if you build a 928 engine and just do a stroker or leave it stock, you can run as long as you want without failure following a few simple guidlines.
In the future, I would hope everyone serious in the emperical side of the testing world, would start to click on a camera and film each session, showing driver inputs and hopefullly a somewhat clear view ofthe tach or oil pressure gauge.
Great thread and very timely. This is my experience . I nearly blew the motor in my street 928 but caught in at the onset of failure by checking my oil filter for signs of wear after every track session as advised by some pretty smart people on this board. 2/6 were begining to fail so I rebearinged added the IJ crank scraper and switched from Mobil 1 to Amsoil. Since that time I put about 40 track hours on the other wise stock engine at T-hill, Infineon , and here at Race City in Calgary with no ill effects.Thats right 40 track hours on a stock motor that nearly failed before switching to Amsoil and adding the I-J scraper kit so One or both of those changes made a huge difference to the durability of my stock motor. I often see a peak of 1.4gs on the trackmate in almost every corner and sustained 1.2-1.3g for over 5 seconds.
Experience 2 not so good
I just blew a race engine after 10 hours that was assembled with the utmost care and attention by some very knowledgable 928 guys. The engine suffered a total catastropic failure due to poor oiling. I was runing the same Amsoil same crank scraper and a pan spacer and cross drilled crank which the street car does not have
Why the failure ? 1.5gs vs 1.4 6,800 rpm shifts vs 6,200 thats the only things I can think of and I am inclined to believe the higher shift point had far more sevre cosequnce than the marginally higher G loading. Same driver same track same conditions same oil.
So what to do now? It is my intention to install a used stock motor and drive as I always have but try to shift between 6000 and 6200 and see how long the thing lasts. I will drive it for the rest of the season or until it breaks. I have over 100 track hours on the stock street car motor so I think the chances are pretty good of lasting the season. I will post how it lasts
I also intend to rebuild the race engine but will lower the rev limiter and will do alot of tuning and R&D
during the winter while down in sunny CA.
Experience 2 not so good
I just blew a race engine after 10 hours that was assembled with the utmost care and attention by some very knowledgable 928 guys. The engine suffered a total catastropic failure due to poor oiling. I was runing the same Amsoil same crank scraper and a pan spacer and cross drilled crank which the street car does not have
Why the failure ? 1.5gs vs 1.4 6,800 rpm shifts vs 6,200 thats the only things I can think of and I am inclined to believe the higher shift point had far more sevre cosequnce than the marginally higher G loading. Same driver same track same conditions same oil.
So what to do now? It is my intention to install a used stock motor and drive as I always have but try to shift between 6000 and 6200 and see how long the thing lasts. I will drive it for the rest of the season or until it breaks. I have over 100 track hours on the stock street car motor so I think the chances are pretty good of lasting the season. I will post how it lasts
I also intend to rebuild the race engine but will lower the rev limiter and will do alot of tuning and R&D
during the winter while down in sunny CA.
06-24-2010, 02:29 PM
#62
Former Sponsor
Great thread and very timely. This is my experience . I nearly blew the motor in my street 928 but caught in at the onset of failure by checking my oil filter for signs of wear after every track session as advised by some pretty smart people on this board. 2/6 were begining to fail so I rebearinged added the IJ crank scraper and switched from Mobil 1 to Amsoil. Since that time I put about 40 track hours on the other wise stock engine at T-hill, Infineon , and here at Race City in Calgary with no ill effects.Thats right 40 track hours on a stock motor that nearly failed before switching to Amsoil and adding the I-J scraper kit so One or both of those changes made a huge difference to the durability of my stock motor. I often see a peak of 1.4gs on the trackmate in almost every corner and sustained 1.2-1.3g for over 5 seconds.
Experience 2 not so good
I just blew a race engine after 10 hours that was assembled with the utmost care and attention by some very knowledgable 928 guys. The engine suffered a total catastropic failure due to poor oiling. I was runing the same Amsoil same crank scraper and a pan spacer and cross drilled crank which the street car does not have
Why the failure ? 1.5gs vs 1.4 6,800 rpm shifts vs 6,200 thats the only things I can think of and I am inclined to believe the higher shift point had far more sevre cosequnce than the marginally higher G loading. Same driver same track same conditions same oil.
So what to do now? It is my intention to install a used stock motor and drive as I always have but try to shift between 6000 and 6200 and see how long the thing lasts. I will drive it for the rest of the season or until it breaks. I have over 100 track hours on the stock street car motor so I think the chances are pretty good of lasting the season. I will post how it lasts
I also intend to rebuild the race engine but will lower the rev limiter and will do alot of tuning and R&D
during the winter while down in sunny CA.
Experience 2 not so good
I just blew a race engine after 10 hours that was assembled with the utmost care and attention by some very knowledgable 928 guys. The engine suffered a total catastropic failure due to poor oiling. I was runing the same Amsoil same crank scraper and a pan spacer and cross drilled crank which the street car does not have
Why the failure ? 1.5gs vs 1.4 6,800 rpm shifts vs 6,200 thats the only things I can think of and I am inclined to believe the higher shift point had far more sevre cosequnce than the marginally higher G loading. Same driver same track same conditions same oil.
So what to do now? It is my intention to install a used stock motor and drive as I always have but try to shift between 6000 and 6200 and see how long the thing lasts. I will drive it for the rest of the season or until it breaks. I have over 100 track hours on the stock street car motor so I think the chances are pretty good of lasting the season. I will post how it lasts
I also intend to rebuild the race engine but will lower the rev limiter and will do alot of tuning and R&D
during the winter while down in sunny CA.
06-24-2010, 03:02 PM
#63
Three Wheelin'
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Greg:
Your right nut is safe. OEM only for now on. The Glyco vs. OEM choice was a very tough and $$$ lesson to learn. Hopefully Porsche will keep their bearings the same and not change sourcing anytime soon.
Your right nut is safe. OEM only for now on. The Glyco vs. OEM choice was a very tough and $$$ lesson to learn. Hopefully Porsche will keep their bearings the same and not change sourcing anytime soon.
06-24-2010, 03:06 PM
#64
Rennlist Member
So I have heard. Is this a recent change to the glyco bearings? I used them on my engines rebuilds back in '01, and with scots 5 liter euro in '06, but I heard recently, they might have changed? is it sizing or material or consistancy that could be the issue?
I wonder what the bearing clearances were if checked with the new bearings. I always do the check with the platiceen (sp?). I think my bearings were always at the larger 1/3 of the limits.
I have to ask you, and feel free to decline to answer, but could the maze of screens be restricting flow to the sump? after all, its only gravity from the heads and crank that gets the oil back to the sump.
mk
I wonder what the bearing clearances were if checked with the new bearings. I always do the check with the platiceen (sp?). I think my bearings were always at the larger 1/3 of the limits.
I have to ask you, and feel free to decline to answer, but could the maze of screens be restricting flow to the sump? after all, its only gravity from the heads and crank that gets the oil back to the sump.
mk
06-24-2010, 03:16 PM
#65
Former Sponsor
why does porsche do all the calculations, designs, research, comparisosns, and then actually go out and test.....THEN, goes out and races to see if what they have designed, works? because there are so many factors, NO ONE can keep track of them, as well as predict the interactions of their effects.
You have in me, more racing miles than anyone here with the stock system, and not with one engine, more than 5. So, if you dont believe in the tooth fairy, why dont you start studying what Im doing to run faster and pull more gs, yet have engines that do not fail under racing conditions.
The "experts" have tried to apply a lot of concepts, designs and methods that have worked and been deveolped for OTHER cars, but not the 928, and I think that is a huge flaw. hey, they have tested those designs and how many of them have failed? so many, I have lost count and they are not posting their failures here, trust me.
Im not against innovation, but I am skeptical of change from something that appears to work, providing limitations are respected. In fact, do to the experts advice, I have one of the ONLY mods that has really proven to help in the oiling fight, and that is the drilled crank. accusump is effective, but has its drawbacks too. look at all the breather systems that have failed and cost folks 1000s of dollars of valuable track time as well as just time! I have no breather system, no oil cooler, no scraper, no baffle, no spacers, no accusump, nothing modified from the stock set up, yet Im running a 928 in a racing environment and have done so for over 10 years, AND supported another 928 that has ran a proportion of my racing seasons with no problems.
no on here has answered my suspicions regarding the screens restricting flow. some of those designes have been done to help breather systems , gain HP and keep more oil in the sump, but Im very curious if anyone knows if the flow rate based on those screen designs can be preserved.
Now, go ahead and mock what I have done, but you see the videos, my redline shift points, my 110% of the best GT3 cup car time in the world, and you be the judge. Luck or following limitations of the original 928 design. If you were me, would you change anything? The gauge doesnt lie. 5 bar pressure, all the time. when using mobil 1, the oil warning light comes on. Why would I ever want to use Mobil 1 or the other oils that dont seem to keep their viscosity up. Also, what about the foaming characteristics. maybe Amsoil has the ability to not foam as much and keep a major problem from happening.
I dont know, but, i said this a long time ago. I usually find someone in a field that im interested in that is successful, and do what they do, rather than reinvent the wheel. (i.e. Mark anderson and Joe Fan).
you wont see me installing baffles or screens unless you can show me an 928 engine that has survived its install and is being raced for a couple of years.
You have in me, more racing miles than anyone here with the stock system, and not with one engine, more than 5. So, if you dont believe in the tooth fairy, why dont you start studying what Im doing to run faster and pull more gs, yet have engines that do not fail under racing conditions.
The "experts" have tried to apply a lot of concepts, designs and methods that have worked and been deveolped for OTHER cars, but not the 928, and I think that is a huge flaw. hey, they have tested those designs and how many of them have failed? so many, I have lost count and they are not posting their failures here, trust me.
Im not against innovation, but I am skeptical of change from something that appears to work, providing limitations are respected. In fact, do to the experts advice, I have one of the ONLY mods that has really proven to help in the oiling fight, and that is the drilled crank. accusump is effective, but has its drawbacks too. look at all the breather systems that have failed and cost folks 1000s of dollars of valuable track time as well as just time! I have no breather system, no oil cooler, no scraper, no baffle, no spacers, no accusump, nothing modified from the stock set up, yet Im running a 928 in a racing environment and have done so for over 10 years, AND supported another 928 that has ran a proportion of my racing seasons with no problems.
no on here has answered my suspicions regarding the screens restricting flow. some of those designes have been done to help breather systems , gain HP and keep more oil in the sump, but Im very curious if anyone knows if the flow rate based on those screen designs can be preserved.
Now, go ahead and mock what I have done, but you see the videos, my redline shift points, my 110% of the best GT3 cup car time in the world, and you be the judge. Luck or following limitations of the original 928 design. If you were me, would you change anything? The gauge doesnt lie. 5 bar pressure, all the time. when using mobil 1, the oil warning light comes on. Why would I ever want to use Mobil 1 or the other oils that dont seem to keep their viscosity up. Also, what about the foaming characteristics. maybe Amsoil has the ability to not foam as much and keep a major problem from happening.
I dont know, but, i said this a long time ago. I usually find someone in a field that im interested in that is successful, and do what they do, rather than reinvent the wheel. (i.e. Mark anderson and Joe Fan).
you wont see me installing baffles or screens unless you can show me an 928 engine that has survived its install and is being raced for a couple of years.
I think Kibort's style of driving has been his saving grace....and his choice of oil is a good one. There are other oils that are up to the task...but I'd have to agree that none of them can be found at Autozone.
It is very unlikely that you will be able to duplicate Mark Kibort's experiences, so I'd look a bit farther and see what others have done to keep the bearings from failing.
This has been discussed at length on this forum, but here's a list of things that can be done to help with this design problem:
1. Bearing selection.
2. Bearing sizing.
3. Crankshaft/bearing modifications to improve oiling. (for higher rpm use.)
4. Cradle modification to "feed" oil to #2/#6 quicker.
5. Lower pan/lower pick-up.
6. Windage trays.
7. Restrict oil to heads...on selective basis.
8. High quality oil.
9. Control sloshing.
10. Eliminate "knocking".
11. Accusump
12. Dry sump. Do not be fooled into thinking this is the complete cure. If you have any problems with #1, #2, #3, #7 or #9...you will still have rod bearing failures.
Pick the things that make sense/you can afford and do those things. Some are cheap. Some are not.
06-24-2010, 03:33 PM
#66
Isn't all of that cheap relative to a professionally built stock engine?
06-24-2010, 03:37 PM
#67
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... So, this is where we all need more information. WE NEED VIDEO! everyone should be running a $100 go pro camera every time they hit the track. (or have the expensive motec data aqu. systems) . Why, because when you blew, someone like me with 1000s of laps at thunderhill, can look at it and see, what you might be doing different. certainly, you are not running faster than I am in the new racer (yet. ) But, this proves that its not the G loading.
) But, this proves that its not the G loading.In a car so near to perfect front to rear balance it would be easy to influence by suspension or driving style whether you have an understeer or oversteer attitude. This will affect where the bulk of the oil shifts to in the engine and where it will be struck by the rotating assembly. This is why it would be useful to have a camera trained on the clear plastic tank I described along with data logging that will allow those images to be correlated with track position, etc. This might allow a distillation of things that you do while driving that you are unaware of.
06-24-2010, 04:46 PM
#68
Three Wheelin'
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FWIW... Here is what I have observed and measured with 928 rod bearings.
1.) There are at least three varients of the Glyco boxed, non-OEM bearings. The most notable difference is those made "in Germany" vs. those made "in Poland". The shell thickness of the Polish Glyco's measured thinner than the the German Glyco's by 0.0002" - 0.0003". These measurements were taken using a Mitutoyo 0.00005" resultion SPC qualified half ball / flat anvil micrometer. If you add up the stack, the Polish Glyco's allowed more rod bearing clearance by the whole span of the clearance range as stated in the WSM. I found this disturbing and chose to size rods only after I recieved the bearings that were to be run.
2.) More recently, I have observed that the OEM bearing shells have stiffer steel backs and have a slightly longer arc length (~0.0007" - 0.0010") to the "Glyco" boxed counterparts. The OEM bearings have the Glyco logo stamped in the backer, but also have the Porsche OEM markings as well. The OEM bearings measure about 0.00015-0.00025 thicker than the German Glyco's and are very tight in tolerance to one another, 0.00015 across three full sets, now measured. IMHO, the slightly longer arc length helps with bearing crush into the rod / rod cap... a good thing given what's been observed with the rod failures.
3.) The "made in Germany" boxed Glyco's are pretty sold out and would appear to have ended production in the first half of 2006.
All in all, GB puts it very sucinctly... USE OEM BEARINGS... no doubt for me !
1.) There are at least three varients of the Glyco boxed, non-OEM bearings. The most notable difference is those made "in Germany" vs. those made "in Poland". The shell thickness of the Polish Glyco's measured thinner than the the German Glyco's by 0.0002" - 0.0003". These measurements were taken using a Mitutoyo 0.00005" resultion SPC qualified half ball / flat anvil micrometer. If you add up the stack, the Polish Glyco's allowed more rod bearing clearance by the whole span of the clearance range as stated in the WSM. I found this disturbing and chose to size rods only after I recieved the bearings that were to be run.
2.) More recently, I have observed that the OEM bearing shells have stiffer steel backs and have a slightly longer arc length (~0.0007" - 0.0010") to the "Glyco" boxed counterparts. The OEM bearings have the Glyco logo stamped in the backer, but also have the Porsche OEM markings as well. The OEM bearings measure about 0.00015-0.00025 thicker than the German Glyco's and are very tight in tolerance to one another, 0.00015 across three full sets, now measured. IMHO, the slightly longer arc length helps with bearing crush into the rod / rod cap... a good thing given what's been observed with the rod failures.
3.) The "made in Germany" boxed Glyco's are pretty sold out and would appear to have ended production in the first half of 2006.
All in all, GB puts it very sucinctly... USE OEM BEARINGS... no doubt for me !
06-24-2010, 05:40 PM
#69
Rennlist Member
I think you would have to prove this to me, because, at 1.5 gs, i have perfect oil pressuer that doesnt wiggle or wonder for turns more than 6-7 seconds long. (on 335 and 305 DOT slicks) If the pickup uncovered, would there be a hickup of pressure? there is not, so I suspect that you might be off with the unproven theory that the pickup is uncovered and that the oil is whipping aroundthe rotating assembly. as you can see, there are many of the oil paths that end up lower than the rotating crank assembly , but sure there is oil flying all over the place for sure, I just dont think it is a problem.
I think it would be very cool to have a clear plastic oil tank to see REALLY what is going on on an engine stand.
mk
I think it would be very cool to have a clear plastic oil tank to see REALLY what is going on on an engine stand.
mk
I am not sure why you say that. Sustained 1.3G is an approximate surface angle of the oil of 52 degrees; 1.5G is an approximate angle of 56 degrees. Both these angles are well past the point where the pickup is uncovered. The pickup is being fed by aerated oil brought around by the rotating assembly.
In a car so near to perfect front to rear balance it would be easy to influence by suspension or driving style whether you have an understeer or oversteer attitude. This will affect where the bulk of the oil shifts to in the engine and where it will be struck by the rotating assembly. This is why it would be useful to have a camera trained on the clear plastic tank I described along with data logging that will allow those images to be correlated with track position, etc. This might allow a distillation of things that you do while driving that you are unaware of.
In a car so near to perfect front to rear balance it would be easy to influence by suspension or driving style whether you have an understeer or oversteer attitude. This will affect where the bulk of the oil shifts to in the engine and where it will be struck by the rotating assembly. This is why it would be useful to have a camera trained on the clear plastic tank I described along with data logging that will allow those images to be correlated with track position, etc. This might allow a distillation of things that you do while driving that you are unaware of.
06-24-2010, 05:47 PM
#70
Race Director
Guys.....No matter how many engines we blow or whatever "fix" we come up with, MK will NEVER change his mind..... I consider MK a friend and he is one of my drivers on the lemons team (along with Sean and Mark A), but this is one aspect of 928 racing we will NEVER agree on...honestly from his experience I can respect his thinking....the stock stuff works for him...so he has no reason to change....my experience and Seans has been less than good using the stock stuff
I DO agree that more data-testing is needed.....Doc brings up interesting points about MK's driving, maybe subconsciously, could be a huge factor...& this makes sense since MK is a very smooth driver....but so is Anderson.... We did two races together in the Lemons racer and I have reviewed all the video, lap times etc & even the G force data from Seans Traqmate...YES the G forces were lower due to the street tires, but still have better than 1.2G....pretty good for 225/50-16 street tires....the engine survived 18 hours on track in two days on 1 oil change with EXCELLENT oil analysis that showed no oil overheating (it did hit 300F at times) and no bearing wear....
Now that I installed the R comps I have not yet changed or tested the oil...but I will after the trackday tomorrow! From what the gauges tell me on track it will be fine.....but the analysis will tell...
As for track time on a 928 engine....32 hours and counting on my current motor.....runs great!!!! with only a 3/8th spacer and OB pan.....not even an oil cooler :>)
I DO agree that more data-testing is needed.....Doc brings up interesting points about MK's driving, maybe subconsciously, could be a huge factor...& this makes sense since MK is a very smooth driver....but so is Anderson.... We did two races together in the Lemons racer and I have reviewed all the video, lap times etc & even the G force data from Seans Traqmate...YES the G forces were lower due to the street tires, but still have better than 1.2G....pretty good for 225/50-16 street tires....the engine survived 18 hours on track in two days on 1 oil change with EXCELLENT oil analysis that showed no oil overheating (it did hit 300F at times) and no bearing wear....
Now that I installed the R comps I have not yet changed or tested the oil...but I will after the trackday tomorrow! From what the gauges tell me on track it will be fine.....but the analysis will tell...
As for track time on a 928 engine....32 hours and counting on my current motor.....runs great!!!! with only a 3/8th spacer and OB pan.....not even an oil cooler :>)
06-24-2010, 06:01 PM
#71
Rennlist Member
conservative driving running 1:37s with a 3000lb car and 370rwhp at laguna?
In the stroker, with holbert pieces:
http://www.youtube.com/my_videos_edi...t=%2Fmy_videos
in the holbert car. (stock 5 liter)
http://www.youtube.com/v/Sih48Dby9d0
Look, there may be a difference in terms. Conservative, vs thoughtful. Yes, I try and run the engine, from warm up to racing that makes sense for it to go as fast as mechanically possible, and not put any undue stress that doesnt make the car go any faster. if that is conservative, then yes. However, Anderson has driven my car, it came back in one piece. (although he wasnt pushing it too hard IMO). by the way, we also drove the same 928 in the 24hours of lemons, and it survived and didnt see any gross differences in driving style or abuse to the car.
If you even watch my last video, I was cringing, having to hit the rev limiter toward the end of my race, after I was left with only 2 gears and doubt I would even be able to have 2 gears by race end . (shift linkage coupler became lose from original install at Andersons place) Do you see any place where I am leaving time on the table. I blip, hard, try and match gears and take the engine to near redline on every shift that makes sense too. of course, now I know, by looking at my HP curves, that 6300 might be the best shift point in most all cases, though it sure doesnt sound as good down the mains straight!
my theory, is that there could be a lot of operation of the 928 engine, through high g loading, sweepers, where the rpm is in too high of a range. also, there could be poor warm up process with owners to anxious to "hit it" on the track before all the parts are heat soaked. miss shifts, low oil level, bad oil, scrapers and screens that are too restrictive, bad fitting bearings, etc.
-M
In the stroker, with holbert pieces:
http://www.youtube.com/my_videos_edi...t=%2Fmy_videos
in the holbert car. (stock 5 liter)
http://www.youtube.com/v/Sih48Dby9d0
Look, there may be a difference in terms. Conservative, vs thoughtful. Yes, I try and run the engine, from warm up to racing that makes sense for it to go as fast as mechanically possible, and not put any undue stress that doesnt make the car go any faster. if that is conservative, then yes. However, Anderson has driven my car, it came back in one piece. (although he wasnt pushing it too hard IMO). by the way, we also drove the same 928 in the 24hours of lemons, and it survived and didnt see any gross differences in driving style or abuse to the car.
If you even watch my last video, I was cringing, having to hit the rev limiter toward the end of my race, after I was left with only 2 gears and doubt I would even be able to have 2 gears by race end . (shift linkage coupler became lose from original install at Andersons place) Do you see any place where I am leaving time on the table. I blip, hard, try and match gears and take the engine to near redline on every shift that makes sense too. of course, now I know, by looking at my HP curves, that 6300 might be the best shift point in most all cases, though it sure doesnt sound as good down the mains straight!
my theory, is that there could be a lot of operation of the 928 engine, through high g loading, sweepers, where the rpm is in too high of a range. also, there could be poor warm up process with owners to anxious to "hit it" on the track before all the parts are heat soaked. miss shifts, low oil level, bad oil, scrapers and screens that are too restrictive, bad fitting bearings, etc.
-M
While there can be no doubt that Mark Kibort has had some great "luck" with his Amsoil and conservative driving, there can also be no doubt that his is a unique experience. I guess that if Mark Kibort was to "loan" Mark Anderson his car, there would be hot oily pieces coming out the side of the block very quickly....and I think Mark Kibort would agree with this statement.
I think Kibort's style of driving has been his saving grace....and his choice of oil is a good one. There are other oils that are up to the task...but I'd have to agree that none of them can be found at Autozone.
It is very unlikely that you will be able to duplicate Mark Kibort's experiences, so I'd look a bit farther and see what others have done to keep the bearings from failing.
This has been discussed at length on this forum, but here's a list of things that can be done to help with this design problem:
1. Bearing selection.
2. Bearing sizing.
3. Crankshaft/bearing modifications to improve oiling. (for higher rpm use.)
4. Cradle modification to "feed" oil to #2/#6 quicker.
5. Lower pan/lower pick-up.
6. Windage trays.
7. Restrict oil to heads...on selective basis.
8. High quality oil.
9. Control sloshing.
10. Eliminate "knocking".
11. Accusump
12. Dry sump. Do not be fooled into thinking this is the complete cure. If you have any problems with #1, #2, #3, #7 or #9...you will still have rod bearing failures.
Pick the things that make sense/you can afford and do those things. Some are cheap. Some are not.
I think Kibort's style of driving has been his saving grace....and his choice of oil is a good one. There are other oils that are up to the task...but I'd have to agree that none of them can be found at Autozone.
It is very unlikely that you will be able to duplicate Mark Kibort's experiences, so I'd look a bit farther and see what others have done to keep the bearings from failing.
This has been discussed at length on this forum, but here's a list of things that can be done to help with this design problem:
1. Bearing selection.
2. Bearing sizing.
3. Crankshaft/bearing modifications to improve oiling. (for higher rpm use.)
4. Cradle modification to "feed" oil to #2/#6 quicker.
5. Lower pan/lower pick-up.
6. Windage trays.
7. Restrict oil to heads...on selective basis.
8. High quality oil.
9. Control sloshing.
10. Eliminate "knocking".
11. Accusump
12. Dry sump. Do not be fooled into thinking this is the complete cure. If you have any problems with #1, #2, #3, #7 or #9...you will still have rod bearing failures.
Pick the things that make sense/you can afford and do those things. Some are cheap. Some are not.
06-24-2010, 06:24 PM
#72
Former Sponsor
So I have heard. Is this a recent change to the glyco bearings? I used them on my engines rebuilds back in '01, and with scots 5 liter euro in '06, but I heard recently, they might have changed? is it sizing or material or consistancy that could be the issue?
I wonder what the bearing clearances were if checked with the new bearings. I always do the check with the platiceen (sp?). I think my bearings were always at the larger 1/3 of the limits.
I have to ask you, and feel free to decline to answer, but could the maze of screens be restricting flow to the sump? after all, its only gravity from the heads and crank that gets the oil back to the sump.
mk
I wonder what the bearing clearances were if checked with the new bearings. I always do the check with the platiceen (sp?). I think my bearings were always at the larger 1/3 of the limits.
I have to ask you, and feel free to decline to answer, but could the maze of screens be restricting flow to the sump? after all, its only gravity from the heads and crank that gets the oil back to the sump.
mk
I chose to make my screens simple and not impeed the oil path, as much as possible. My stuff is designed to simply allow the oil to fly right through and then not bounce back. Very simple stuff.
Different strokes, for different folks.
06-24-2010, 06:28 PM
#73
Archive Gatekeeper
Rennlist Member
Rennlist Member
So simple even I could bolt it on:
06-24-2010, 06:41 PM
#74
Former Sponsor
conservative driving running 1:37s with a 3000lb car and 370rwhp at laguna?
In the stroker, with holbert pieces:
http://www.youtube.com/my_videos_edi...t=%2Fmy_videos
in the holbert car. (stock 5 liter)
http://www.youtube.com/v/Sih48Dby9d0
Look, there may be a difference in terms. Conservative, vs thoughtful. Yes, I try and run the engine, from warm up to racing that makes sense for it to go as fast as mechanically possible, and not put any undue stress that doesnt make the car go any faster. if that is conservative, then yes. However, Anderson has driven my car, it came back in one piece. (although he wasnt pushing it too hard IMO). by the way, we also drove the same 928 in the 24hours of lemons, and it survived and didnt see any gross differences in driving style or abuse to the car.
If you even watch my last video, I was cringing, having to hit the rev limiter toward the end of my race, after I was left with only 2 gears and doubt I would even be able to have 2 gears by race end . (shift linkage coupler became lose from original install at Andersons place) Do you see any place where I am leaving time on the table. I blip, hard, try and match gears and take the engine to near redline on every shift that makes sense too. of course, now I know, by looking at my HP curves, that 6300 might be the best shift point in most all cases, though it sure doesnt sound as good down the mains straight!
my theory, is that there could be a lot of operation of the 928 engine, through high g loading, sweepers, where the rpm is in too high of a range. also, there could be poor warm up process with owners to anxious to "hit it" on the track before all the parts are heat soaked. miss shifts, low oil level, bad oil, scrapers and screens that are too restrictive, bad fitting bearings, etc.
-M
In the stroker, with holbert pieces:
http://www.youtube.com/my_videos_edi...t=%2Fmy_videos
in the holbert car. (stock 5 liter)
http://www.youtube.com/v/Sih48Dby9d0
Look, there may be a difference in terms. Conservative, vs thoughtful. Yes, I try and run the engine, from warm up to racing that makes sense for it to go as fast as mechanically possible, and not put any undue stress that doesnt make the car go any faster. if that is conservative, then yes. However, Anderson has driven my car, it came back in one piece. (although he wasnt pushing it too hard IMO). by the way, we also drove the same 928 in the 24hours of lemons, and it survived and didnt see any gross differences in driving style or abuse to the car.
If you even watch my last video, I was cringing, having to hit the rev limiter toward the end of my race, after I was left with only 2 gears and doubt I would even be able to have 2 gears by race end . (shift linkage coupler became lose from original install at Andersons place) Do you see any place where I am leaving time on the table. I blip, hard, try and match gears and take the engine to near redline on every shift that makes sense too. of course, now I know, by looking at my HP curves, that 6300 might be the best shift point in most all cases, though it sure doesnt sound as good down the mains straight!
my theory, is that there could be a lot of operation of the 928 engine, through high g loading, sweepers, where the rpm is in too high of a range. also, there could be poor warm up process with owners to anxious to "hit it" on the track before all the parts are heat soaked. miss shifts, low oil level, bad oil, scrapers and screens that are too restrictive, bad fitting bearings, etc.
-M
There are several ways to go through a corner...no one does it the same. I've had three professional drivers in the same car, on the same day, with the same tires...all disagree on what the car does through a particular corner. One will have awful oversteer and the other will have awful understeer. The third will think it perfect. It is all about how you skin the cat.
I would expect that your g-loading in a corner is probably very smooth and there are not huge transitions. Smooth in, smooth out, would be my impression. Alternatively, someone that comes into a corner and tosses the car around, will naturally also be tossing the oil around more. Note that they both might end up getting through the corner in the same amount of time.
06-24-2010, 06:44 PM
#75
Former Sponsor
Yes, they are kind of expensive, especially since you usually have to buy 16 sets to get enough bearings with the proper clearance....but very cheap when they don't fail.