M96.70 piston pin circlip failures???
03-15-2010, 04:01 PM
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M96.70 piston pin circlip failures???
Hi folks, it's been some time since I've been on Rennlist. I've been doing a little research on the topic issue and did some searching on these forums for answer but have come up short handed.
Car is a 2001 Turbo, previously a Ruf 550T model. Tial A28's, methanol injection. ~600whp. ~5K miles onto the car after the work and the motor started emulating a click with a typical tone like a broken piston skirt or ringland. Customer dropped off the car and I finally got to tearing the motor apart.
Issue.....#3 piston pin circlip failed, pin gouged sleeve bore. Circlip lost into the depths of the case. The piston also cracked at the pin boss, but I'm unsure as to if it's the culprit to the circlip failure or a fracture due to the force exerted when the pin came in contact with the sleeve while running. The motor was running, and right up until I pulled it into the garage was not even spitting a wisp of smoke from the pipe. compression was down from all other bores by ~60psi due to the 1/4" x 1/16" deep groove cut the full length of the piston travel.
I'm curious to know how frequent of an issue this is with this motor? I've personally never experienced it with the M96. This is a complete factory internal motor and one that to my knowledge and from visual inspection has never been opened up before. Mileage about 55K last I checked. While being owned by the customer(also good friend) the car has never seen track duty nor any RPM above ~6800, although has been using all of that 600whp in the normal RPM range to good use!
Just looking for some insight and opinions as to whether this was some freak incident or a common occurrence. At this point it's quite apparent the motor will require a full rebuild and I wouldn't dare risk not replacing all the circlips at this point. Any info is better than nothing
I will take pictures and post them if requested.
Best Regards
-Adam
Car is a 2001 Turbo, previously a Ruf 550T model. Tial A28's, methanol injection. ~600whp. ~5K miles onto the car after the work and the motor started emulating a click with a typical tone like a broken piston skirt or ringland. Customer dropped off the car and I finally got to tearing the motor apart.
Issue.....#3 piston pin circlip failed, pin gouged sleeve bore. Circlip lost into the depths of the case. The piston also cracked at the pin boss, but I'm unsure as to if it's the culprit to the circlip failure or a fracture due to the force exerted when the pin came in contact with the sleeve while running. The motor was running, and right up until I pulled it into the garage was not even spitting a wisp of smoke from the pipe. compression was down from all other bores by ~60psi due to the 1/4" x 1/16" deep groove cut the full length of the piston travel.
I'm curious to know how frequent of an issue this is with this motor? I've personally never experienced it with the M96. This is a complete factory internal motor and one that to my knowledge and from visual inspection has never been opened up before. Mileage about 55K last I checked. While being owned by the customer(also good friend) the car has never seen track duty nor any RPM above ~6800, although has been using all of that 600whp in the normal RPM range to good use!
Just looking for some insight and opinions as to whether this was some freak incident or a common occurrence. At this point it's quite apparent the motor will require a full rebuild and I wouldn't dare risk not replacing all the circlips at this point. Any info is better than nothing
I will take pictures and post them if requested.
Best Regards
-Adam
Last edited by P-Car962; 03-15-2010 at 06:29 PM. Reason: removing company name
03-15-2010, 09:05 PM
#2
Race Director
Hi folks, it's been some time since I've been on Rennlist. I've been doing a little research on the topic issue and did some searching on these forums for answer but have come up short handed.
Car is a 2001 Turbo, previously a Ruf 550T model. Tial A28's, methanol injection. ~600whp. ~5K miles onto the car after the work and the motor started emulating a click with a typical tone like a broken piston skirt or ringland. Customer dropped off the car and I finally got to tearing the motor apart.
Issue.....#3 piston pin circlip failed, pin gouged sleeve bore. Circlip lost into the depths of the case. The piston also cracked at the pin boss, but I'm unsure as to if it's the culprit to the circlip failure or a fracture due to the force exerted when the pin came in contact with the sleeve while running. The motor was running, and right up until I pulled it into the garage was not even spitting a wisp of smoke from the pipe. compression was down from all other bores by ~60psi due to the 1/4" x 1/16" deep groove cut the full length of the piston travel.
I'm curious to know how frequent of an issue this is with this motor? I've personally never experienced it with the M96. This is a complete factory internal motor and one that to my knowledge and from visual inspection has never been opened up before. Mileage about 55K last I checked. While being owned by the customer(also good friend) the car has never seen track duty nor any RPM above ~6800, although has been using all of that 600whp in the normal RPM range to good use!
Just looking for some insight and opinions as to whether this was some freak incident or a common occurrence. At this point it's quite apparent the motor will require a full rebuild and I wouldn't dare risk not replacing all the circlips at this point. Any info is better than nothing
I will take pictures and post them if requested.
Best Regards
-Adam
Car is a 2001 Turbo, previously a Ruf 550T model. Tial A28's, methanol injection. ~600whp. ~5K miles onto the car after the work and the motor started emulating a click with a typical tone like a broken piston skirt or ringland. Customer dropped off the car and I finally got to tearing the motor apart.
Issue.....#3 piston pin circlip failed, pin gouged sleeve bore. Circlip lost into the depths of the case. The piston also cracked at the pin boss, but I'm unsure as to if it's the culprit to the circlip failure or a fracture due to the force exerted when the pin came in contact with the sleeve while running. The motor was running, and right up until I pulled it into the garage was not even spitting a wisp of smoke from the pipe. compression was down from all other bores by ~60psi due to the 1/4" x 1/16" deep groove cut the full length of the piston travel.
I'm curious to know how frequent of an issue this is with this motor? I've personally never experienced it with the M96. This is a complete factory internal motor and one that to my knowledge and from visual inspection has never been opened up before. Mileage about 55K last I checked. While being owned by the customer(also good friend) the car has never seen track duty nor any RPM above ~6800, although has been using all of that 600whp in the normal RPM range to good use!
Just looking for some insight and opinions as to whether this was some freak incident or a common occurrence. At this point it's quite apparent the motor will require a full rebuild and I wouldn't dare risk not replacing all the circlips at this point. Any info is better than nothing
I will take pictures and post them if requested.
Best Regards
-Adam
The GT1 race engine used titanium rods -- lighter and stronger -- which had to reduce the strain on the piston pin and clips. I'm not sure but I suspect the circlips are stronger too and maybe piston pins, even pistons.
Sincerely,
Macster.
03-15-2010, 09:41 PM
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Both freak occurrence and common when you mod engine and engine that delivers stock around 357whp to deliver ~600whp.
The GT1 race engine used titanium rods -- lighter and stronger -- which had to reduce the strain on the piston pin and clips. I'm not sure but I suspect the circlips are stronger too and maybe piston pins, even pistons.
Sincerely,
Macster.
The GT1 race engine used titanium rods -- lighter and stronger -- which had to reduce the strain on the piston pin and clips. I'm not sure but I suspect the circlips are stronger too and maybe piston pins, even pistons.
Sincerely,
Macster.
Indeed true. I torn the motor down to the cases today and found all six rods all bent. #3 was bent so much that it came into contact with the crank throws. That likely caused a sudden side load on the pin(which was likely pinched due to the bent rod) and popped the circlip out of it's seat.
Pic of the bent rod
Customer stopped by today and we'll be going ahead with a complete rebuild and some R&R rods or similar.
Thanks guys, guess I jumped the gun on this one.
03-15-2010, 11:43 PM
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Was the owner running on 91 octane fuel? How much boost was run on the engine? Please check #2 rod bearing???
Here is my take... I have seen 4 engines running methanol lately that have ended similar and worse. What is happening is that we are turning the flat 6 plenum into a wet chamber. We are leaning out certain cylinders.. The ECU cannot trim the fuel to the lean hole if at WOT.. Especially if you are running 91 octane and adding the alcohol for fueling and octane/detonation protection.
Besides the rod bearings how did the ring lands "look"
Here is my take... I have seen 4 engines running methanol lately that have ended similar and worse. What is happening is that we are turning the flat 6 plenum into a wet chamber. We are leaning out certain cylinders.. The ECU cannot trim the fuel to the lean hole if at WOT.. Especially if you are running 91 octane and adding the alcohol for fueling and octane/detonation protection.
Besides the rod bearings how did the ring lands "look"
03-16-2010, 12:20 AM
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93 octane, 3:1 methanol/water mix(75% VP M-1) Boost ~1.5bar on Billet Tial Alpha A 28's(ramped up GT28RS's essentially)
I'm looking into that methanol distribution as well. I may possibly rework the system to a multi port setup for better distribution. Currently it's a twin nozzle delivery setup in the Y pipe. It's an Aquamist system that works fairly well, But I too think that flow in the plenum is not proper for fluid distribution.
Ringlands all "look" alright but I'm going to be x-raying the slugs before considering reusing them. Check the cases and mag the crank as well. Too early to speculate at this point though.
I haven't split the case yet. 9pm rolled around and I just got the even bank of cylinders/slugs off the motor and decided to call it a night from the shop. I likely won't get back to this one again until next week as I've got some other cars to attend to beforehand.
Looking into putting R&R rods in this with the 625 hardware. Possibly Pauters as a second choice. Open to other internal options you have preferences to
I'm looking into that methanol distribution as well. I may possibly rework the system to a multi port setup for better distribution. Currently it's a twin nozzle delivery setup in the Y pipe. It's an Aquamist system that works fairly well, But I too think that flow in the plenum is not proper for fluid distribution.
Ringlands all "look" alright but I'm going to be x-raying the slugs before considering reusing them. Check the cases and mag the crank as well. Too early to speculate at this point though.
I haven't split the case yet. 9pm rolled around and I just got the even bank of cylinders/slugs off the motor and decided to call it a night from the shop. I likely won't get back to this one again until next week as I've got some other cars to attend to beforehand.
Looking into putting R&R rods in this with the 625 hardware. Possibly Pauters as a second choice. Open to other internal options you have preferences to
03-16-2010, 12:37 AM
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ECU controlled boost or Electronic "dial" death?? Port injection would be the ticket.. Did this car have any additional fuel pumps?
I recommend Arrow rods, 2nd choice is Carrillo's..
I recommend Arrow rods, 2nd choice is Carrillo's..
03-16-2010, 10:02 AM
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DME tuned by a reputable porsche tuner(won't specify). The real issue is we have no idea how this car was treated/driven by its previous owner. It came from Ruf Autocenter as a Ruf 550T converted car, and currently the only thing left on there from the whole conversion is the clutch.
I've used Arrow in previous builds(Non Porsche). Price will be the determining factor for those. I will have to look into them.
I've used Arrow in previous builds(Non Porsche). Price will be the determining factor for those. I will have to look into them.
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03-17-2010, 04:41 PM
#9
Race Director
In fact, I'd consider replacing the crank just on general principles due the extraordinary radial and axial loads the crank must have experienced. That the crank didn't let go was to me a bit of a surprise. But I don't know if I'd trust it from here on.
Also, if the crank subjected to huge side loads so was block and the main webs, at least the one with the thrust pads. This calls into question the integrity of the block.
Then the cylinders that had the bent rods. Extreme side forces on the cylinder walls could have started hairline cracks in the cylinder walls.
Not my call, and thankfully not my money, but I'd consider that crank and block scrap.
Sincerely,
Macster.
03-17-2010, 06:22 PM
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I will xray and magnaflux all components at my machine shop before I even consider reusing anything Still in the stage of determining the full extent of damage to the motor and I'm sure there are some underlying issues yet to come.
Still in the stage of determining the full extent of damage to the motor and I'm sure there are some underlying issues yet to come.
04-16-2010, 02:41 PM
#11
Former Vendor
93 octane, 3:1 methanol/water mix(75% VP M-1) Boost ~1.5bar on Billet Tial Alpha A 28's(ramped up GT28RS's essentially)
I'm looking into that methanol distribution as well. I may possibly rework the system to a multi port setup for better distribution. Currently it's a twin nozzle delivery setup in the Y pipe. It's an Aquamist system that works fairly well, But I too think that flow in the plenum is not proper for fluid distribution.
Ringlands all "look" alright but I'm going to be x-raying the slugs before considering reusing them. Check the cases and mag the crank as well. Too early to speculate at this point though.
I haven't split the case yet. 9pm rolled around and I just got the even bank of cylinders/slugs off the motor and decided to call it a night from the shop. I likely won't get back to this one again until next week as I've got some other cars to attend to beforehand.
Looking into putting R&R rods in this with the 625 hardware. Possibly Pauters as a second choice. Open to other internal options you have preferences to
I'm looking into that methanol distribution as well. I may possibly rework the system to a multi port setup for better distribution. Currently it's a twin nozzle delivery setup in the Y pipe. It's an Aquamist system that works fairly well, But I too think that flow in the plenum is not proper for fluid distribution.
Ringlands all "look" alright but I'm going to be x-raying the slugs before considering reusing them. Check the cases and mag the crank as well. Too early to speculate at this point though.
I haven't split the case yet. 9pm rolled around and I just got the even bank of cylinders/slugs off the motor and decided to call it a night from the shop. I likely won't get back to this one again until next week as I've got some other cars to attend to beforehand.
Looking into putting R&R rods in this with the 625 hardware. Possibly Pauters as a second choice. Open to other internal options you have preferences to
R&R Makes a fantastic rod.. I would call up Mike and discuss your concerns, what you plan to do with the car, etc.. Hes a great guy and will always shoot you straight.. Pauters are strong but Heavy.. Im not sure what the R&R rods weigh but that would be another good question for Mike..
As far as your issue with the motor in the 1st place id look at the Meth.. I have seen DOZENS and i mean dozens of cars with the exact same issue and the cars all had meth.. Some call it coincidence but when you see 10 blown motors per year and 8 of them have meth you have to face the facts.. The distribution of meth will never be equal which why i call Meth a BAND AID..
MIke
04-16-2010, 02:43 PM
#12
Former Vendor
If rod bent enough to make contact with crank throws I'd think magnafluxing the crank a requirement.
In fact, I'd consider replacing the crank just on general principles due the extraordinary radial and axial loads the crank must have experienced. That the crank didn't let go was to me a bit of a surprise. But I don't know if I'd trust it from here on.
Also, if the crank subjected to huge side loads so was block and the main webs, at least the one with the thrust pads. This calls into question the integrity of the block.
Then the cylinders that had the bent rods. Extreme side forces on the cylinder walls could have started hairline cracks in the cylinder walls.
Not my call, and thankfully not my money, but I'd consider that crank and block scrap.
Sincerely,
Macster.
In fact, I'd consider replacing the crank just on general principles due the extraordinary radial and axial loads the crank must have experienced. That the crank didn't let go was to me a bit of a surprise. But I don't know if I'd trust it from here on.
Also, if the crank subjected to huge side loads so was block and the main webs, at least the one with the thrust pads. This calls into question the integrity of the block.
Then the cylinders that had the bent rods. Extreme side forces on the cylinder walls could have started hairline cracks in the cylinder walls.
Not my call, and thankfully not my money, but I'd consider that crank and block scrap.
Sincerely,
Macster.
Mike
04-18-2010, 02:49 AM
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Crank is being replaced even though this one is not damaged in any way(hard to believe, but tests/checks don't lie). Mag and Xray turned out fine, zero run out, virtually zero journal wear. I have a couple other cranks to choose from here, as well as a couple from UMW that Kevin apparently has on the shelf there. Will be going with the best one between the two of us, likely one he has. I actually need to call and buy it from him ASAP.
Rods going in are Carillos. Picked up a set for a deal far too good to pass on. R&R's were on the list, but this set came in ~$500 cheaper than the R&R's through a good friend.
Pistons....I sent the stock slugs to LN Engineering for developmental purposes. He's going to have forged slugs made up and a few other things as well. More to come of that later.
Agreed the methanol injection is not being distributed evenly in the plenums and the issue is being addressed with full attention. The nozzle position is not ideal and things will be changing. I for one don't believe methanol injection to be a band aid when setup and used properly, but I'm not about to get into a web debate over things of this matter now.
Rods going in are Carillos. Picked up a set for a deal far too good to pass on. R&R's were on the list, but this set came in ~$500 cheaper than the R&R's through a good friend.
Pistons....I sent the stock slugs to LN Engineering for developmental purposes. He's going to have forged slugs made up and a few other things as well. More to come of that later.
Agreed the methanol injection is not being distributed evenly in the plenums and the issue is being addressed with full attention. The nozzle position is not ideal and things will be changing. I for one don't believe methanol injection to be a band aid when setup and used properly, but I'm not about to get into a web debate over things of this matter now.
04-18-2010, 09:59 PM
#15
Former Vendor
Crank is being replaced even though this one is not damaged in any way(hard to believe, but tests/checks don't lie). Mag and Xray turned out fine, zero run out, virtually zero journal wear. I have a couple other cranks to choose from here, as well as a couple from UMW that Kevin apparently has on the shelf there. Will be going with the best one between the two of us, likely one he has. I actually need to call and buy it from him ASAP.
Rods going in are Carillos. Picked up a set for a deal far too good to pass on. R&R's were on the list, but this set came in ~$500 cheaper than the R&R's through a good friend.
Pistons....I sent the stock slugs to LN Engineering for developmental purposes. He's going to have forged slugs made up and a few other things as well. More to come of that later.
Agreed the methanol injection is not being distributed evenly in the plenums and the issue is being addressed with full attention. The nozzle position is not ideal and things will be changing. I for one don't believe methanol injection to be a band aid when setup and used properly, but I'm not about to get into a web debate over things of this matter now.
Rods going in are Carillos. Picked up a set for a deal far too good to pass on. R&R's were on the list, but this set came in ~$500 cheaper than the R&R's through a good friend.
Pistons....I sent the stock slugs to LN Engineering for developmental purposes. He's going to have forged slugs made up and a few other things as well. More to come of that later.
Agreed the methanol injection is not being distributed evenly in the plenums and the issue is being addressed with full attention. The nozzle position is not ideal and things will be changing. I for one don't believe methanol injection to be a band aid when setup and used properly, but I'm not about to get into a web debate over things of this matter now.
Mike