Death of my SPB Engine
#46
Rennlist Member
No, a rod thru the side means a new case. But Porsche still stands behind it for it's core value and there are many other potential good "core" parts in the complete motor assembly as they come to warrant them doing it. Remember that some come with Alt. AC compressor, then oil pan, etc etc etc .
#48
Rennlist Member
#49
Nordschleife Master
Thread Starter
Pictures of the failure below. What I believe happened is the wristpin pulled out of the piston. The rod then rode "solo" until its bottom end failed and went out the top of the case.
#50
Drifting
Which piston was this?
I believe its the drivers side which has the blind wrist pin lock assembly procedure.
One of the trickier aspects of the M96 engine rebuilds.
If that did not seat properly you could get a failure like you described.
mike
I believe its the drivers side which has the blind wrist pin lock assembly procedure.
One of the trickier aspects of the M96 engine rebuilds.
If that did not seat properly you could get a failure like you described.
mike
#51
Rennlist Member
you can certainly see the "solo" ride up and down the cylinder wall...
So if I get this right?...
1. D Chunk failure
2. Piston jambed/split on the chunk on the downstroke and pin ripped out of the piston
3. Rod/Pin go "solo" and hammer the crap out of the remaining piston parts and cylinder wall
4. Rod fails and goes through the case
thats pretty frigin ugly...my box has a factory reman motor in it, god only knows if its one thats prone to this failure...
So if I get this right?...
1. D Chunk failure
2. Piston jambed/split on the chunk on the downstroke and pin ripped out of the piston
3. Rod/Pin go "solo" and hammer the crap out of the remaining piston parts and cylinder wall
4. Rod fails and goes through the case
thats pretty frigin ugly...my box has a factory reman motor in it, god only knows if its one thats prone to this failure...
#52
Rennlist Member
#53
Nordschleife Master
Thread Starter
Drivers side front (#4 I believe).
That is one scenario, but I'm not sure if the missing bits of cylinder happened before or after the wrist pin pulled out. The missing chunks are the right size that the rod could have just pounded them out.
When I was driving the car, it went "flat"; felt just like breaking a rocker. There was no bad sounds at this point. I got off the throttle, and was idling down the track. Then there was a sound and lots of smoke. I turned off the car, and coasted to a stop.
Another 2.5L (its a Spec Boxster)
you can certainly see the "solo" ride up and down the cylinder wall...
So if I get this right?...
1. D Chunk failure
2. Piston jambed/split on the chunk on the downstroke and pin ripped out of the piston
3. Rod/Pin go "solo" and hammer the crap out of the remaining piston parts and cylinder wall
4. Rod fails and goes through the case
thats pretty frigin ugly...my box has a factory reman motor in it, god only knows if its one thats prone to this failure...
So if I get this right?...
1. D Chunk failure
2. Piston jambed/split on the chunk on the downstroke and pin ripped out of the piston
3. Rod/Pin go "solo" and hammer the crap out of the remaining piston parts and cylinder wall
4. Rod fails and goes through the case
thats pretty frigin ugly...my box has a factory reman motor in it, god only knows if its one thats prone to this failure...
When I was driving the car, it went "flat"; felt just like breaking a rocker. There was no bad sounds at this point. I got off the throttle, and was idling down the track. Then there was a sound and lots of smoke. I turned off the car, and coasted to a stop.
Another 2.5L (its a Spec Boxster)
#54
Rennlist Member
Just trying to figure out how the pin boss of the piston could fail without some serious "help", that's a pretty tough hunk of metal. It didn't drop a valve, they're intact, if you holed a piston it normally would just go limp and smoke... just playing sleuth about the fail points on these motors, either way not much in the way of prevention...
#55
Drifting
The picture is not showing a DChunk failure.
In that case the liner literally starts cracking at the top near the heads
and eventually works it way all the way around the cylinder in a semi-circle.
More of a D oval look -- thus the name.
The crack goes all the way through the cylinder wall. It then can separate and
become flying debris in the combustion chamber.
Symptoms can be oil in your coolant. Coolant filling the cylinder when hot, or only at start-up.
Misfires at start up or later (due to the coolant in the chamber).
I thought I might have a picture of a D-chunk -- but I don't on this computer.
However -- he is a start of one on top -- this was a '04 3.6 and you could catch your finger nail on it.
We had bored out to 3.8 with JE pistons as can seen below.
Mike
In that case the liner literally starts cracking at the top near the heads
and eventually works it way all the way around the cylinder in a semi-circle.
More of a D oval look -- thus the name.
The crack goes all the way through the cylinder wall. It then can separate and
become flying debris in the combustion chamber.
Symptoms can be oil in your coolant. Coolant filling the cylinder when hot, or only at start-up.
Misfires at start up or later (due to the coolant in the chamber).
I thought I might have a picture of a D-chunk -- but I don't on this computer.
However -- he is a start of one on top -- this was a '04 3.6 and you could catch your finger nail on it.
We had bored out to 3.8 with JE pistons as can seen below.
Mike
Last edited by txhokie4life; 04-21-2015 at 03:17 PM.
#58
Drifting
Hope we're not scaring the SPB folks away!
m
m
#59
Nordschleife Master
Thread Starter
It really shouldn't. My engine had 120,000 street miles on it before I started racing it. It had lived a hard life. I replaced the engine with a used one, which cost me 4k installed (granted I did the install myself). With an accusump and decent oil, I expect this one to last a while since its in much better shape than the prior engine.
#60
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Thats a great price for a great engine..
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2016 GT4-R
Rick DeMan
DeMan Motorsport
Upper Nyack, NY
845 727 3070
Porsche Sales & Service
Porsche Race services and parts
www.DeManMotorsport.com
2016 GT4-R
Rick DeMan
DeMan Motorsport
Upper Nyack, NY
845 727 3070
Porsche Sales & Service
Porsche Race services and parts
www.DeManMotorsport.com