3.2 Engine exploded!!
 

Yes, you read that correctly.
Its a sad day, but this is a story about what happened, with the hope that you might help me figure out where to go from here...

5 years ago I found a 1985 3.2 Carrera that was just right for me and purchased it.
I love these cars and never intended to buy or build a garage queen, but rather to drive it quite regularly.

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I began the joy of slowly improving the car as time and money made it possible.
I then saved for 3 years to do a major overhaul on the car.

• New paint
• Rebuild my transmission
• Rebuild the motor and upgrade to 11.2:1 compression twin spark 3.2
• Redo the interior
• New wheels & tires
• Refresh window seals, glass and suspension

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I stripped the car and pieced it out as I worked with vendors to restore my car.
I sent the engine long block to a reputable engine shop to source the final parts and assemble. Once it was assembled I picked it up, finished assembly and installed it with the new trans.

Life was good for 18 months. The engine HP increased to 255 at the crank and the car felt great. The car isn't perfect, but I did almost all the work myself and Im very proud of what I was able to accomplish with some careful planning and a lot of help from this forum. I learned a tremendous amount about my car through this process.

Then, I lost spark in the lower spark plugs.
It took a few trips to the shop to help figure it out, but we eventually identified the culprit, an ignition fault in the signal splitter.
While I was waiting for the ignition problem resolution to arrive, I was driving the car as a single plug and while exiting a nearby freeway, the clutch broke.

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So I sent the car back to the shop to instal the ignition solution and investigate the broken clutch. Turned out to be a failed Kennedy Engineering Product Stage 1 clutch.
I sent it to them and they replaced the diaphragm and sent it back. The shop re-installed the new clutch and the ignition solution. Everything seemed good after the first short alignment test drive. I went in to pick up the car the next day.
Prior to arriving the shop took the car out for a quick test drive to verify all was good.
30 yards from the stop sign at the exit from their parking lot of the shop - the #6 conrod burst through the main case.

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After draining the oil an ARP conrod bolt fell out of the drain plug.
It is obvious though from other shards that fell out, that the oil pump is damaged too.

After some diagnosis, it seems clear that the ARP rod bolt gave way, but whether that is from product failure or some other condition, I don't know.
I went to see the scene of the incident and the short 30 yards from the stop to the point of detonation, isn't enough distance to allow anyone to abuse the motor. Aside from which, the motor has a sensible rev limiter and stronger than factory valve springs that should prevent anyone from detonating the motor under acceleration.
Also, the shop has a strong reputation and I had the shop owner working on my car.
Im quite confident it was not their fault.

So..... Im now (probably) staring at a $15-20 000 problem.
I dont have the cash just lying around, which is why Im turnning to you guys.

Now what??

Man, I feel for you.

Was the bolt actually broken? Possible that maybe the builder didn’t torque that rod bolt/nut?

Best of luck in getting it sorted out.

That is sickening. Maybe time to drop a 3.6 in! Best of luck and keep us posted.

Gee, that really sucks - should we run a gofundme campaign? I think a LOT of pelicanites would chip in.

what do the piston, rings and wrist pin area of the rod look like?

Allan,

I'm very sorry to see this as I know full well how expensive this is to repair.

Unfortunately, these issues don't just "happen" like it was an act of God; its always human factors so I'd strongly recommend having detailed forensics done to find out why this happened and how to prevent a recurrence.

To date, I've never seen a failed ARP rod bolt (and we've installed thousands), its always a bearing/lubrication failure of some kind. It can result from a poorly made bearing, a clearance issue, dirt (especially when its #1 or #6), insufficient oil pressure or volume, and a host of other things. Detonation can trigger this as well so that should not be overlooked!!

Good luck,

I guarantee you that if ARP is the culprit, they’d want their hands on that bolt!

There isn’t much worse than ‘Uncle Rodney’ showing up, other than a totally munched chassis. Feel for you.

Ouch !!!

Will running a high CR setup without the twin spark do this ?

If the intact bolt fell out it would suggest it was not tightened to the correct torque and just fell out. If a broken bolt fell out that is another matter that APP might want to look at it.

Sounds like that high of compression on single plug would cause detonation. How many miles were run with only the single plugs working? Can this wreak havoc on the pressure plate too? Wonder if it is all connected to the dual plugs being out for a while? That has to hurt, truly. Gorgeous car, beautiful engine! Sooo much work to make it what you want. My buddy has a 2.7 that was in a 914 that has the same carnage. At that point, it’s a short list of what you can keep. Such a shame for a street car. I’m looking at my broken head studs thinking I’m lucky right now.

You would think there would have been a pretty nasty knocking before the letgo. Nobody heard anything?
Never seen a broken ARP bolt either. Improper torque would be my guess if it came out intact.

What kind of pistons?
How did the divots on the end of the rod get there?
Did the flailing of the lower rod cap when the bolt let go cause those divots before full seperation?
Is the failed clutch indicative of detonation also in some way?
So much metal cracking and catastrophically failing in different parts of the engine so close together in time frame is really odd

The shop is suspect. Maybe they money shifted and then lied.

Who built it?

Hmmm.... soooo... regardless of the cause... the fact remains that the damage happened while it was under the shop's responsibility.

I'm not sure what you are going to do... but if this happened to me, I would make sure I recorded and/or written down everything that was spoken to me and record a timeline of everything that happened up to that point.

I would also be contacting some lawyers to discuss my legal options... because as I mentioned, the car was under the responsibility of the shop while it was in its possession.

The only option you have on your own is to take the engine apart, assess all damage and start searching online for replacement parts. But I'd still contact lawyer before going this far, if anything just to protect yourself. After all... what if you found that the damage was caused from someone revving your engine WAY TOO HIGH?!

Sorry to hear about your troubles.
Hopefully you will be back on the road soon

Have a chat with the shop that did your seats as well.
Those wrinkled leather seats should be redone, IMO.

Could you show us a picture of the conrod bolt?

Oh dear :-(
Sorry for you.

Hi Allan..very nice 911 sorry about the troubles...but as Trakrat said ..totally the shop responsibility do not take no for an answer.......i also think the torque was not on that rod correctly done...unless you and ARP peeps will find some material flows..
Ivan

WOW, so sorry for your loss. Completely agree that the engine rebuilder is most likely responsible here

by the way, just a detail, nothing to do with the rod-fail... I read the shop did the rebuild and upgrade... why don't they seal this area according to the tech bulletin and as everybode here knows as well :confused:

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

Exactly what I think.


Sent from my iPhone using Tapatalk

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.


Sent from my iPhone using Tapatalk

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....")

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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?