What a gut punch. Sorry to hear this. Great car...still a great car.

Exactly what I think.


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Yeh get a lawyer!! Sue everybody!! That's the answer!!

It sounds like one shop did the bottom end, you did the top end, the car had ignition problems, a different shop has been making other repairs and anyone of you could have been responsible for not doing something correctly.

Maybe the best thing is to agree on a third party reputable engine rebuilder to do the post mortem and try and determine if there is a clear “guilty” party and then go from there?

Sorry about your troubles. No shop will take responsibility for an engine blowing up during a test drive. Especially if they didn't build the engine. It's not like they reached into the case and loosened the bolt. **** happens with these cars, especially with modified engines. Figure out what went wrong and don't let it happen next time.

After seeing scenarios like this unfold before, l have to say that “rapid acceleration” usually equates to failed clutches, as well as connecting rod bolt failures. From the outside looking in, it would make logical sense to me that at some point something happened that caused that clutch plate to break. The chances of whatever that was leading up to the ultimate failure being related are very good.

Remember the “50 hour rule” folowing an “engine zing”. l am not pointing fingers here, and it doesn’t matter who may have done the “zing”, as it would have clearly happened before it went to the last shop. Maybe there’s a piece of the puzzle that no one has shared?

For a “real” (not Chinese knockoff junk) ARP rod bolt snapping out of the blue are very slim on such a mild engine. l would have to question the torque value that was used when assembling the engine, as it coud have been either left loose, or over- torqued, resulting in this occurrence. Then how well the entire dynamic and reciprocating masses were balanced is another question mark. l have seen imbalance cause weird issues, especially failed clutch plates. A clutch plate is the first component that wil show signs of an over- rev, due to it’s mass, and it’s diameter being so large in comparison to the other components in the engine.

Likely a very good disassembly would find the issues if someone did botch the rod bolt torques. They probably goofed up more than one.. l like to figure things out like this, its pretty much all l do, all day long.

At the end of the day its mechanical. That means there’s only two guarantees:
-It will fail
-It will wear out, if it doesn’t fail first

My question mark right now is the clutch plate, and what caused that to fail. l’ve been using KEP parts like that for over 20 years, and the only time l have seen a failure was when something saw “rapid acceleration”. Misfires are also evil, and they can be equal to hitting the internals with a 10 pound sledge hammer. Driving a car misfiring badly could be another contributing factor. l’ve snapped a crankshaft on a track car shortly after repairing a serious on- track misfiring issue.

Not pointing any fingers, just putting in a question mark where l think it needs to be based on direct experience.

The engine was built 18 months ago?

1 integrated shop equals 100% ownership.


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I wouldn't sue... as it may not be financially feasible. How much is a replacement engine or repairs/replacement parts for the engine?

Obviously engine damage at this level is clearly from excessive RPMs to have the rod break through the casing with that much force... but lawyer fees and court costs may be more expensive than replacing the engine.

Did the shop clearly communicate that they are required to take the car our for a test drive? Does the shop have documentation that the customer has to sign that states that the shop isn't responsible for damage that is not representative of the work done? etc...

Weigh all options before deciding which direction to go. Been in this position before, but I walked away from the shop and chose to never do business with them again.

broken 3.2 - 18 months after rebuild
 

SmileWavy

X2 & agree with Jake's comments above

a LOT can happen in 18 months depending on one's driving techniques

- a busted clutch and admitted driving a potentially detonating engine can be a clue to abusive usage rather than a "mfgr defect"

- if you sue the shop, they'll have credible defense

yes, it's a devastating financial blow - many of us have had similar experiences with modified 911's & other engines of various makes & we just had to suck it up :( $$$

this is from an other-make "race" engine where the shop misfit a press-in piston pin too loose & it came out, destroying the piston, the pieces of which landed on the windage tray & caught twixt the big-end & block walls - with about 100 miles on the rebuild - (shop said "sorry, but....")

http://forums.pelicanparts.com/uploa...1535992386.JPG

http://forums.pelicanparts.com/uploa...1535993087.JPG
.

One good thing about the modern Porsche cars, is the DME stores a lot of this information, and annotates the last hour that different ranges of overspeed occurred. It also manages how many ignition cycles had occurred at each range.
While you can overcome this data log, it is very difficult.

l pull DME overspeed reports from every car while they are being loaded on the transport truck, and l video doing this, sharing it with the owner. l do the same when a car arrives. It keeps everyone honest.... Just like employing a dash cam in every car, every minute that its being operated, or tested. Its what we have to do to protect ourselves, and to forcibly keep things for the record.

Earlier cars aren’t as easy to deal with, and they don’t keep logs.

The damaging thing about a misfire isn’t the misfire, its what cycle the cylinder is on when the misfire occurs. Heavy load, under acceleration with a misfire that occurs when a piston it travelling upward for the compression stroke is about as harmful as it gets to the internals. Like l said, l’ve had this snap a crankshaft before, and it was in 3 pieces when it came out of turn 9 at Roebling Road...

This is a damn shame and my sympathies to the owner. Thanks for sharing your story. This makes for some fascinating reading as we are seeing some serious Porsche intelligence and experience weighing in.

I'll be very interested to see what the diagnosis is.

So nobody thinks running on 6 plugs with 11.2:1 Cr pistons on pump gas had anything to do with it?

Or maybe the fact you may have revved this thing way past the recommended limit?http://forums.pelicanparts.com/uploa...1536012322.jpg


Something screwy is going on here. First a fractured clutch and now this?

Your engine seems to be highly stressed. 11.5? If you rev that thing way up (from colder temps) and snap that throttle closed, that thing is getting seriously into stressed territory. These engines cannot take that. Torque on the bolt is one thing, and the bolt used is another, but if you drive like hell and run it way up before shifting at 11.5 the forces involved are nuts.

Nobody mentioned over-revving the engine. How can it be a fact if you are just speculating?

I agree with Jake. It sounds like It was over revved at some point or the rods were not correctly torqued, especially since the rod bolt came out in one piece.

Can you please PM me the name of the shop you used? I’m also in Dallas and would like to avoid that place like the plague. Thanks and good luck bud.

What's with the TIG goobers on the chain box?