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Old 05-15-2019, 06:34 AM   #1
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My conclusion: tell me if I知 wrong

Just finishe the post mortem on my 3.2 engine that blew all to hell at the track. It seems pretty clear what happened and I think I know why. New video:
https://youtu.be/IrJl2uHrzaY
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Old 05-15-2019, 07:25 AM   #2
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Just finishe the post mortem on my 3.2 engine that blew all to hell at the track. It seems pretty clear what happened and I think I know why. New video:
https://youtu.be/IrJl2uHrzaY
That's a very interesting analysis and breakdown of various layers of the engine. So, it sounds like the core problem was caused by lack of oil lubrication.
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Old 05-15-2019, 08:11 AM   #3
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Yep, oil starvation is the most common reason for an m96 track driven motor to scatter parts. High G left sweeper followed by a deep braking zone, and/or downshift over-rev cavitating the oil pickup.. Bye bye!
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Old 05-15-2019, 10:07 AM   #4
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Yep, oil starvation is the most common reason for an m96 track driven motor to scatter parts. High G left sweeper followed by a deep braking zone, and/or downshift over-rev cavitating the oil pickup.. Bye bye!
Also, another related failure could be caused when the con rod bolts stretch, which leads to a spinning bearing, loss of oil pressure...

It is assumed that the connecting rod bolts stretch by continuous high rpm's (metal fatigue perhaps..?)
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Old 05-15-2019, 10:47 AM   #5
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Interesting that your Mantis Sport deep sump kit 2 wasn't enough to prevent starvation, maybe it was rod bolt stretch?
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Old 05-15-2019, 11:46 AM   #6
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I think that the problem was not caused by insufficient oil from the sump but rather blocked oil passages. I mention this in my previous video about the engine swap. See around minute 11:30. Threads of orange silicone sealant may have made their way into those little channels and holes that lubricate the crank. The extreme heat weakened the bolts and bang!
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Old 05-15-2019, 12:12 PM   #7
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I think that the problem was not caused by insufficient oil from the sump but rather blocked oil passages. I mention this in my previous video about the engine swap. See around minute 11:30. Threads of orange silicone sealant may have made their way into those little channels and holes that lubricate the crank. The extreme heat weakened the bolts and bang!
I was wondering about that; blockage rather than an issue with a high G turn. Brad Roberts posted some data a while back that led me to believe that the high G starvation issue is not as relevant to the Boxsters as it is to the rear engine models. I may have misunderstood though.

Great videos, thanks for posting them.
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Old 05-15-2019, 04:49 PM   #8
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Thanks for posting. You make it not so intimidating. I learned a bunch.
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Old 05-15-2019, 04:52 PM   #9
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Also, another related failure could be caused when the con rod bolts stretch, which leads to a spinning bearing, loss of oil pressure...

It is assumed that the connecting rod bolts stretch by continuous high rpm's (metal fatigue perhaps..?)
Can you elaborate on this please? Trying to understand. Thanks
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Old 05-15-2019, 05:17 PM   #10
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Also, another related failure could be caused when the con rod bolts stretch, which leads to a spinning bearing, loss of oil pressure...

It is assumed that the connecting rod bolts stretch by continuous high rpm's (metal fatigue perhaps..?)
The fastest way to stretch rod bolts? Downshift over rev. Zing it past redline during heel/toe with no load on the motor a few times while entering a corner and rod bolts become stressed/stretched.

Clogged oil passages is another possibility especially if someone was *liberal* with sealant when replacing the pan or adding a deep sump. If that was the cause you could probably fish the oil passages and find it. Another telltale sign is the oil pickup screen completely jammed with excess sealant.
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Old 05-15-2019, 06:24 PM   #11
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Quote:
Originally Posted by Topless View Post
The fastest way to stretch rod bolts? Downshift over rev. Zing it past redline heel/toe with no load on the motor a few times while entering a corner and rod bolts become stressed/stretched.

Clogged oil passages is another possibility especially if someone was *liberal* with sealant when replacing the pan or adding a deep sump. If that was the cause you could probably fish the oil passages and find it. Another telltale sign is the oil pickup screen completely jammed with excess sealant.
Possibly guilty of the first situation but definitely guilty of the latter. Many orange snakes found in the pickup screen and one can assume that there were smaller pieces that squeaked by! Did I mention how stingy I was with a better sealant on the new install?
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Old 05-15-2019, 07:29 PM   #12
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[QUOTE=Topless;595182][B]The fastest way to stretch rod bolts? Downshift over rev. Zing it past redline heel/toe with no load on the motor a few times while entering a corner and rod bolts become stressed/stretched.



This is the only reason I put aftermarket R&R rods in my rebuilt engine.
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