useridchallenged

Maintained entirely by Porsche, with most services done ahead of schedule rather than late.

I'm extremely concerned that I have a second oil scavenging pump - probably manufactured at the same time as the failed pump - waiting to fail in the same way. I'm going to see if I can get both pumps replaced as a precaution.

I think that not only am I out of warranty, but I'm SOL on this one.

This was a bit like having a heart attack in the ER - best possible place to have the pump fail was in (at?) the hands of the dealer.

useridchallenged

Who is Jake Raby? Fellow Rennlister?

ADias

Why did the dealer open the engine? Ask them to talk to the regional rep and get you a factory rebuilt engine.

porsche52

Uhh totaly different style of pumps dude!! So yeah there feeling lucky!



I have seen this type of failure before, not very common, but have seen it. You never know what PCNA is going to do, I bet they will offer you a 50-50 split on parts and labor or something along those lines. They may cover the whole thing, you never know.

The last time I was in California for factory training, they said if the engine can be re-built for less than a re-man engine, then it will be. No more exchange engines at the rate we were doing them a couple of years ago. So all your IMS failure engines will now be torn down, inspected, and most of the time be rebuilt. The same for Cayenne too, far less engine failures, but they will be inspected and rebuilt if it makes econmical sense. So that being said, this engine will probably be rebuilt.

Just curious, did they take that pump apart to see if there was any metal/debri that could have been sucked into pump causing it to fail? The clearances in those pumps are pretty tight, it would not take much foreign debri to lock that thing up. Maybe the pump is not the root problem, just a byproduct of the real problem yet to be discoverd? Just thinking out loud here....

machina

He built two motors for my racecar, now he is getting into the watercooled stuff. He is the mad scientist of boxer motors. He is the real deal.

Jake Raby

Jake Raby

I have already documented this mode of engine failure.. It occurs when foreign object debris becomes lodged in the scavenge pump...

This is the image of what occurred in the instance I documented, the pictures are very similar to yours.


Unfortunately, the scavenge pump is driven from the exhaust camshaft main drive, which does not have any keys or dowels to hold it in place, just 4 very small 6mm fasteners with very low torque values. When the scavenge pump became lodged in my instance it ended up retarding the exhaust cam timing as it commenced with the breakage of the scavenge pump and it's primary drive. When the cam timing became retarded it allowed piston to valve interference which shattered all 3 pistons on that cylinder bank, bent all the valves, destroyed the heads and bent the camshaft..

This is the piece of FOD that was found in the scavenge pump


And this piece came from here...


So, what actually occurred first was a partial timing chain failure, that led to this... All the service in the world will not keep this from occurring, it is a faulty part.
More pics of similar occurrences here
http://www.flat6innovations.com/engi...es-illustrated

Basically, these pumps are well lubricated and fairly well made. My guess is that something caused the pump to fail, just like what happened in my instance. When we prepare our updated engines I make a modification that will not allow foreign objects to enter the scavenge pump body.

If the dealer isn't willing to repair this- I am.. No problem..
Lots of dealerships and their techs are calling US about these types of issues, because we have been going internal with these engines at a deeper level than they have, for a much longer period of time.

useridchallenged

Jake, that was very englightening!

Can the engine be repaired back to 100%, or do I have to worry about forces that during the timing chain failure will cause problems elsewhere in the engine that might not appear until a few months or years later?

Just trying to determine the best path - repair or replace.

Jake Raby

Its hard to say.. Until the source of the pump failure is determined and until the pistons and valves are inspected for collisions its all guess work unfortunately. Since you were not driving the car when this occurred, its hard to say bexactly what happened prior to and during the moment of failure and thats never good.

ADias

I agree. The dealer holds full responsibility and must restore the engine to full working condition.

stout

Would be very surprised/saddened to see this dealer and/or PCNA and PAG fail to stand up and replace this engine.

That chain failure is scary stuff, but I've seen it before thanks to Jake...

pete

cello

"Enlightening", is one word. 'Scary' is another (ref the link provided).

useridchallenged

Talked to PCNA today and opened a case. PCNA's price words: "good will is not likely".

I've since learned that after the oil scavenging pump seized, the tech continued to drive the car for 5-7 miles at freeway speed. The hole in the valve cover was towards the top, so the amount of oil lost was not enough to trigger an engine warning light. I'm wondering what other damage might have occured to the engine while there was a loose chain and loose pump gear in the valve cover during that time.

Jake Raby

"good will is not likely".
What the hell does that mean?? Good will? How about whats just plain fair?

997, esq

They will always tell you it is "not likely" at first. A lot of people give up, after that. It also sets expectations -- so people will feel more grateful when the manufacturer comes through with a partial payment. I certainly wouldn't give up easily on this one. I would guess it is at least possible that some of the work they did created the debris that got sucked into the pump, although I leave it to much more knowledgeable folks like Mr. Raby to opine ...

Jake Raby

The scavenge pumps only scavenge the heads and since there was obviously some debris opposite of the scavenge pump body position. The hole in the cam cover would suggest that something failed at the intake cam drive, something in the sprag clutch assembly, or something that was picked up by the chains and ejected through the cam cover.. The area where the exit wound is located in the cam cover is opposite of the scavenge pump's location-

This debris that made an exit from the cam cover may also be the same debris that was ingested by the scavenge pump, causing it to seize and then totally fail.. Whatever was ingested should still be in the body of the pump, embedded between the vanes of the pump. Pieces of the puzzle are still missing..