The Fastest 928 of all time, blows an Engine!
10-17-2012, 06:29 PM
#76
The Parts Whisperer
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Are there signs of seizing in the small end, big end or piston?
All the engine 'blowup' failures I've ever had seemed to be related to pistons and leaning/detonation and usually in cylinders with feed issues like the corner cylinders in a carbed motor.
Maybe this is just what happens with engines from pro level drivers that have seen many racing hours? I wouldn't know ;-)
All the engine 'blowup' failures I've ever had seemed to be related to pistons and leaning/detonation and usually in cylinders with feed issues like the corner cylinders in a carbed motor.
Maybe this is just what happens with engines from pro level drivers that have seen many racing hours? I wouldn't know ;-)
As for hours this one did not have that many. Way less than my previous motor.
10-17-2012, 06:54 PM
#77
Three Wheelin'
That rod that failed on that VW was a factory rod, these are supposed to be much stronger.... Is this engine exactly like the old engine in terms of specs?
Where the rods new or reused from the old engine?
Where the rods new or reused from the old engine?
10-17-2012, 07:11 PM
#78
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We won't know the real cause until it comes apart and that may be awhile. I was just happy to see that the crank should be fine.
10-17-2012, 07:15 PM
#79
Three Wheelin'
That looks like the small end of the rod and it's split cleanly down the middle and with a healthy pin bore no less, is that so?
What a bizarre failure if that's what it is. That would imply a material problem on the rod but I would expected that to be nearly impossible when there are so many other factors that often cause problems.
Am I seeing that correctly?
What a bizarre failure if that's what it is. That would imply a material problem on the rod but I would expected that to be nearly impossible when there are so many other factors that often cause problems.
Am I seeing that correctly?
10-17-2012, 07:19 PM
#80
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That looks like the small end of the rod and it's split cleanly down the middle and with a healthy pin bore no less, is that so?
What a bizarre failure if that's what it is. That would imply a material problem on the rod but I would expected that to be nearly impossible when there are so many other factors that often cause problems.
Am I seeing that correctly?
What a bizarre failure if that's what it is. That would imply a material problem on the rod but I would expected that to be nearly impossible when there are so many other factors that often cause problems.
Am I seeing that correctly?
10-17-2012, 08:16 PM
#81
Chronic Tool Dropper
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I fondly remember seeing a rod that looked like that after a rollover. OK, it was a ski boat with a scoop on top of the tunnel ram, Took a few seconds for water to displace the incoming air, and a piston to not displace the water. Methinks there may be something extra in a combustion chamber. Maybe a valve, a very large rodent, something that got sucked in. It will be interesting to see what you find at teardown. Anything before that is speculation at best.
Challenges when doing root cause analyses include 'symptoms' are too often confused with 'causes'. A long-ago cartoon showed a long trail of oil and parts across the desert, with a race car at the other end. Two guys standing at the near end, holding a small piece. "Look, it started here with this worn gear!" It's seldom that easy.
Challenges when doing root cause analyses include 'symptoms' are too often confused with 'causes'. A long-ago cartoon showed a long trail of oil and parts across the desert, with a race car at the other end. Two guys standing at the near end, holding a small piece. "Look, it started here with this worn gear!" It's seldom that easy.
10-17-2012, 09:02 PM
#82
Former Sponsor
That's a piece of steel from a connecting rod?
(I obviously have not seen it.)
(I obviously have not seen it.)
10-17-2012, 09:08 PM
#83
The Parts Whisperer
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10-17-2012, 09:31 PM
#84
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Can you flip it over and post a pic of the back side?
Something isn't right. If that's an H-beam rod, the indentation on the rod stem should go all the way up into the small end boss, the one in the pic stops way short. If it was an I-beam rod, the small end would be twisted 90 degrees, but it isn't.
Something isn't right. If that's an H-beam rod, the indentation on the rod stem should go all the way up into the small end boss, the one in the pic stops way short. If it was an I-beam rod, the small end would be twisted 90 degrees, but it isn't.
10-17-2012, 10:09 PM
#87
Three Wheelin'
10-17-2012, 11:41 PM
#88
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10-18-2012, 12:04 AM
#89
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If by some strange thing, a Carrillo H beam rod broke, you'd think the pin end of the rod would still be captive on the pin....like every other broken rod I've ever seen.
To have a "chunk" of broken rod is certainly "incredulous'.
I'm guessing that there is a bit more to this story.
10-18-2012, 01:22 AM
#90
Race Director
bizzare......Carillo H beams are VERY strong.....at the RPM-HP-Torque of Marks engine is far below the threshold of an H beam rod.... Maybe the highly unlikely rod failure.....