RMS related to break-in?

[z12358]

This may have been mentioned before here but it was a new angle for me and thought others (especially new car owners may find it interesting). Just read a possible explanation for the RMS. Basically, it states the root may be extensive "short hop" driving during the break in period:

http://townhall-talk.edmunds.com/WebX?14@@.ef37f9b/950!keywords=allin%3Amsgtext%20boxster

"Regarding RMS and break in, I can only tell you that my sales manager (who formerly worked at Porsche headquarters and seems to have a lot of technical/engineering knowledge) gave me that advice. He indicated that a high percentage of the RMS issues they had on 996's (and Boxsters) could be traced to a lot of short hop driving during break in. The typical story is Dr. X. buys a new 911, lives 5 minutes from Johns Hopkins but just can't resist driving the car back and forth from work, day after day, during what should be the break-in period. The engine, oil and seals never get a chance to fully warm up and expand, then cool down and seal/seat. A year or two later, bingo, RMS leak. "

[Perfectlap]

nahh....

it's a poor design or theory or concept bla bla bla which is innately prone to failure.
You just can't have something "floating" and not except some to move out of dead center thereby causing the seal to break.

Very interesting that they would try and lay it on the driver doing mere casual drives. A car should be able to withstand short drives without potentially damaging a very expensive engine. Other makes have figured out how do it on much smaller budgets. Sometimes I think Porsche and their employees are like Pete Rose insisiting he never bet on baseball. C'mon already you screwed up!!

[z12358]

perfectlap, I agree. There is no excuse for RMS. Still, if there truly exists a cause-effect statistical link between short drives during break-in and increased probability of RMS later on, one would be foolish to disregard it. Of course, such a link would be very hard to establish, even harder to prove, but it wouldn't hurt to avoid those short drives during break-in, as much as possible.
Z.

[MNBoxster]

Hi,

C'mon guys, a little common sense here please. Why can't people accept that RMS failure is inherent on the M96 engine? It's nothing you do, or fail to do. Stop trying to let Porsche off the hook for such poor engineering, I mean even Kia got this one right!

Shaft Seals have been around far longer than the Automobile (think Locomotives, Steam Engines and Industrial Machinery). It's very straightforward stuff. I've owned 2 cars whose Main Crank Seal was just a piece of Rope! And, if they were installed correctly, they didn't leak, even the slightest, for well beyond 30k mi.

Theoretically, the crankshaft should not move, therefore a butyl rubber seal seated against the shaft should provide a seal adequate for the 45-55PSI of Oil Pressure. But, this presumes that the Seal and the Shaft are center-aligned.

OK, so it's not a perfect world and the Crank does have some float, but the book says this axial play should measure 0.05 to 0.24 mm, that's an incredibly small degree of movement, well within the deflection capability of a Butyl Rubber Seal.

So, it isn't the Crankshaft's fault. But, if the Seal is installed off-center (as when the Bore opening in the Block is cast that way), it can reach it's limit to flex and still maintain sufficient pressure around the Crankshaft to seal. And this is why there is premature RMS failure on the M96 engine.

Now, there is direct contact between the Rubber Seal and the Crankshaft, so eventually even a small amount of friction, multiplied by hours of use will result in the Seal failing, in that way, it is a sacrificial part. But, most Automotive Crank Seals go 100k mi. and beyond before this occurs and the Seal fails normally.

Porsche should get in front of this and not only admit the issue, but solve it, remember, they are producing the same piece of hardware today, essentially unchanged since it first was produced 11 years ago now. For a Company with the history, prestige and price point that Porsche has, it's just a disgrace. Compounded maybe by the fact that now they're pointing the finger at the driver and crying Operator Error...

Happy Motoring... Jim'99

[z12358]

Jim, the Porsche guy gave the other guy some advice. That's all. It wasn't a press release that blamed the customers for the RMS. I agree, the fact that the RMS problem happens so often and has remained unresolved for so long is inexcusable, and this thread did not intend to provide an excuse for it either.

RMS happens to some, and doesn't happen to others. No one can prove that short drives during break-in contribute (among other factors) to increased chances for RMS, but no one can prove that it doesn't either.

Z.

[MNBoxster]

Originally Posted by z12358

Jim, the Porsche guy gave the other guy some advice. That's all. It wasn't a press release that blamed the customers for the RMS. I agree, the fact that the RMS problem happens so often and has remained unresolved for so long is inexcusable, and this thread did not intend to provide an excuse for it either.

RMS happens to some, and doesn't happen to others. No one can prove that short drives during break-in contribute (among other factors) to increased chances for RMS, but no one can prove that it doesn't either.

Z.

Hi,

But since no one can prove it (because it just isn't so), it shouldn't be presented as a possible cause. Where's the critical thought? This is how Urban Myth happens. Maybe the Salesman was just being a Salesman, ever think of that?

No one can prove that it doesn't? Well, lets see, there have been approx. 160,000 Boxsters produced and RMS failure, as best as can be estimated (since Porsche isn't saying, or tracking 2nd hand cars or independent shops), is running between 20-25% (a little conservative based on this Forum's own poll, but it's a casual poll and not subject to strict controls, and 20-25% is what a PCNA Area Service Rep told me in a conversation with a Dealer who confirmed his number).

So, that would mean that between 32,000 and 40,000 cars have been affected. Even if that many people disregarded the Break-in procedures (to varying degrees), that's still too high a failure rate to blame soley on the operator.

Not proving a negative does not open a possibility, that it could happen. Just because one can't prove there aren't little green men from Mars does not raise the possibility in the least that there are. Or that since water freezes at 32°F (given normal conditions), but because all water hasn't been frozen, or measured, that there's a possibility that it may not all freeze at 32°F, that somewhere there may be a mystical volume of water which will behave differently than the laws of physics demand. At least in the real world, that's how it works, now Kurt Vonnegut's Ice Nine might be an exception were it not just fiction. Don't confuse the metaphysical with the physical..

Happy Motoring!... Jim'99

[z12358]

"But since no one can prove it (because it just isn't so), it shouldn't be presented as a possible cause. Where's the critical thought? This is how Urban Myth happens. Maybe the Salesman was just being a Salesman, ever think of that?"

Short drives were suggested as just ONE POSSIBLE factor contributing to the increased chances for RMS. They were not suggested as the ONLY sure (proven) factor.

What critical thought did you use to conclude that in no way possible would short drives affect the chances of an RMS? In absence of a scientific statistical analysis of the data and a proof, all we're left with is the explanation and the reasoning behind the suggestion ("green men on Mars"). The explanation made sense to me. You know much more than I do about cars and it didn't make sense to you, and I respect that. Still, even if avoiding short drives (during break-in) decreased the chances of an RMS by 5%, to me it would stil be a worthwhile "sacrifice".

I repeat, I do agree that the RMS should not happen at the rates it has been happening, so let's not go there again.