It is really a question of statistics and risk tolerance

Hello all....you'll recall that when we last visited, I had just blown the engine in my '02 Boxster S at a DE at Road Atlanta. Since then I have acquired a replacement 3.2L engine and have ordered the Improved IMS bearing from LN Engineering. I also got their Oil Pan expansion kit and their AccuSump oiling system. Obviously, I am hoping that these measures decrease any oiling or IMS problems at the track. I have also gotten a new AOS assembly from my local dealer and am ordering today a new expansion tank for the cooling system. I have two stock clutches and pressure plates (the replacement engine had one). I am considering an upgrade there as well.

My question to the group is what other items should I replace while I've got the engine out? Water hoses? Power steering pump? Hoses? Any recommendations on a Clutch/Flywheel setup for DE's? What about engine mounts? Am I overlooking any weak points that I should look at improving? RMS?

I want to make the car a great DE car while still being able to take it on the street. Thanks in advance! And Thanks Pedro for the forum!

A starting list might be the list of items Jake replaces as part of his cpo motor program. It is designed to address weak points that can be fixed without seriously going into the block.

-Update the IMS bearing with the LN/ FSI unit
-Replace the water pump
-Replace lifters with FSI updated units
-Replace chain guides and vario-cam wear pads
-Replace clutch assembly
-Replace AOS
-Replace RMS with 997 unit
-4th and 5th timing chains replaced
-Install new LN Engineering lo temp thermostat
-Install LN Engineering Spin On Oil Filter Adaptor (SPOFA)

I'd also replace the oil pump drive shaft (the OEM unit is pretty lame) with the LN unit, and I give Charles Navarro a call about the power steering cooler he was working on...........

“Anything really new is invented only in one’s youth. Later, one becomes more experienced, more famous – and more stupid.” - Albert Einstein

Since you are doing it and not worried about budget, do the coolant tank. They have a chronic cracking problem and are a cheap part - the cost of doing them is in the labor and access, not the parts. Also, you should replace the plastic oil filler neck on the front of the engine (it connects to a hose which connects to the oil filler tube in the trunk). The plastic neck that mounts to the engine tends to get brittle and crack and is a pretty common cause of Boxster smoke screens. A pain to get to as well, but since you have the engine out . . .

As for power steering, if it works fine I wouldn't mess with it.

I would also check all of the heat shielding around the exhaust area - I have had problems with mine coming loose (granted, at 170K+ miles) and it is really difficult to get to to reattach.

I would change out the engine mounts on your 2002. E-mail Pedro. I thought he posted on Porsche Pete's a ways back that he found a much better engine mount than the OEM (and he loves to track his Boxster). I'm not sure if they would work, but didn't Porsche install a "high-tech" engine mount on the newest GT3? I forget what is so special about them (soft middle?). If that would work on a 2002 Boxster, it might be worth checking since the GT3 is meant for the track.

How about the throttle body? If not replace, you should clean it.

And, agree with the coolant tank. Somebody just posted that it cost $1,100 at an Independent shop to replace a cracked tank. There have been several posted issues with tanks on this and PPBB. Since the engine will be out, might as well.

Yes, it is super high tech. It has an electro-reactive gel in it that allows the stiffness of the mount to be changed on the fly using input from sensors around the chassis and the engine. Pretty cool technology, but I believe it requires the equivalent of the sport-chrono pak, which was never available on the 986.

Don't forget:
- Spark plugs
- Spark plug tubes
- Fuel injector seals
- Vacuum hoses
- Oil filer tubes
- Power steering reservoir gaskets (check for moisture)
- Exhaust header bolts

I would skip most of the LN engineering stuff as most of it is a waste of money. You can get away with spending $1500+ less on the project by skipping that stuff and you will never know the difference.

Given that the IMS failed, NOT installing the LN upgrade same as cancelling your home-insurance once the mortgage paid "since I never needed it for the past 30years"............" IMHO.
Am sure Byron will be able to better concentrate on the next apex when he doesn't always have to worry about what's going on in the engine-compartment. That must be worth a few tenths on each lap and that's the goal, isn't it?
I also like your Accusump - i could have used it on my old Volvo's after frying a few turbos!
Since you are racing the car, I'd also look into an under drive pulley - this is the lowest cost one I've seen including the hold-down wrench (no affiliation)

[rss.rpmware.com]

I almost installed it (....sorry Boxterra, wasted...) it our 2.5l wheezer, but left it for another day. Interested to hear if anyone have positive experiences. In the meantime the engine is now purring with the temp gauge well below 180F with the new LN thermostat and the larger oil-cooler as well. Cheap insurance to me!

Nils

There is no evidence that the LN parts have a longer life. In fact, since they are not proven, it is an unknown and therefore more of a risk. It's your prerogative to take that risk but don't make unsubstantiated claims about it being better.

Is how the Porsche parts are designed/built and how successful those designs are.

We know a bit about how the LN parts are designed/built, the materials and differences in design between the Porsche-sourced and LN-sourced parts.

We know only from anecdotal telling of how many problems have been reported with engines using each design. We don't have any good statistics...and probably never will.

We have an approximation of how many samples of Porsche-designs have been running for how many miles and how many and for how long of LN's. We know there is a big difference in both the numbers and miles covered between the two suppliers.

Is there is a big enough sample to know with the same surety the failure rate of a specific LN part ? I'll leave that to the statisticians.

What has been interesting to me is the number of reported LN failures across the 7 online forums I monitor.

We also know that the IMS is the weak link in that engine. We don't know why the shaft is failing. I don't even think Porsche knows and they tear them apart to find out what caused the failure. If it was just the bearing that was the problem, than Porsche could have designed a similar one to LN and not had to totally redesign the engine to do away with the IMS. So, IMS failures can be happening for several reasons. To blame the bearing or the LN part is pure speculation. I know when mine died at 10,000 miles. The bolt broke away and put a hole in the engine. All the oil dumped out of the car. Can't imagine the bearing was at fault, and if so, at such low mileage.

"What has been interesting to me is the number of reported LN failures across the 7 online forums I monitor"

Mike - can we get more details please. Are you insinuating none - or are the LN's having issues also?

There are more failures from failed water pumps than IMS bearings according to someone who sees lots of failures.

There are now over 20 different failure causes that have been observed in M96 engines...and the list is growing.

And we could probably say the same sorts of things if someone was examining some other manufacturer's engines in similar detail and quantity.

I am a statistician by trade, so a few years ago I did a (very) informal study on IMS failures by going across all of the major online boards, counting up the number of posted IMS failures in a 12-month period, assuming these were 25% of the total, and divided into Boxster sales - and the number was well below 1%. But, for argument's sake, let's assume that the IMS failure rate in the M96 series is 1%.

So here is the math

Scenario 1: you have a motor with an original IMS. A new Porsche motor, installed, let's say, is $18K. 1% of 18K is $1,800. The LN part, labor, etc., is about $1,800. So, if you are worried about losing the IMS and the cost of a new motor, the numbers are about the same. On a probability basis, the upgrade didn't save you any money. And 99% of the time, you spent $1,800 you didn't need to.

Scenario 2: you have a motor with an original IMS. A used 3.2L motor is, say, $10,000. 1% of 10K is $1,000 - about $800 less than the cost of the upgrade. So in this case, you are definitely better off not upgrading.

So, the question is, does a proactive upgrade ever make financial sense? I think the only time it would make sense is if you are rebuilding the motor anyway, due to a failure or as race prep, and in that scenario, I would use the upgraded Porsche part (the one they put in the rebuilt engines) since Porsche has the most experience with tearing down failed M96 engines and it is reasonable to assume that this would translate to the best redesign.

The other way an upgrade might make sense is for peace of mind. If the thought if an IMS failure is really, really troubling, or if you know that you can't afford a new motor in the very unlikely chance your IMS goes bad (less than 1%) than the question you have to ask is whether or not you peace of mind is worth $2,000? At least for me, it is not. Part of my calculus is that you can spend $2,000 on the IMS upgrade then take the car out on the track and have it drop a valve, and you motor is shot anyway and you are out 2,000 bucks.

It is really an individual choice, but this is how I have thought about it.

1998 986 Turbo-Look Cab
172,000 Miles
Dilithium Crystal Supercharger

54K miles, original IMS bearing, 2nd bad AOS. Unless something else breaks that requires removing the engine, I'm not even thinking about the upgrade. I'd call it "self insured".

If there comes a time when the engine has to be out anyway, I'll think about it for more than two seconds. Does anyone know if the Porsche bearing can be installed without splitting the case? Or, what would the price difference be to split the case to put in a new bearing. Worse case scenario, the engine blows up and I upgrade to a 3.4.

I need a 3.4 to keep up with John's Red Lightnin with the Dilithium Crystal Supercharger on the track! Of course, my excuse for being slow of having a 2.7 Boxster wouldn't work anymore.

Dave - 06 987 S coupe SG/NL; gone (but still my first love): 03 986 AS/GG/BK;

1% of 18K is $1,800.

$180 would be 1%

I think you meant "10% of 18K is $1,800".

Nice catch.

1998 986 Turbo-Look Cab
172,000 Miles
Dilithium Crystal Supercharger

As Gary points out, the chance of the LN bearing failing is not 0%. The basis of my point is that we don't know what the real number is. Peace of mind is generally obtained by increasing the certainty of a good outcome. Exchanging 1% failure with unknown % failure does not accomplish this.

On the subject of predicting the % failure, there may not be even a single LN bearing car that has reached the average failure mileage of a Porsche bearing. And even if there were a handful, statistically, there is a very low likelihood of there having been any failures so far even if the reliability is several times worse than Porsche.

Furthermore, LN not only doesn't warranty their product, they recommend a regular schedule of removing the transmission and inspecting the bearing. These facts are a strong indicator of the certainty of reliability. If your confidence in the bearing is not shot (heh) by these facts, then as a last resort I suggest you instead use the money to buy a warranty that at least claims it will cover failure of that one part.

i kept reading his math and sayin dat aint right

Porsche would have fixed it...quietly, of course.

The reason for the IMS was to get rid of the use of timing belts and chains and the need to replace them every 50,000 miles at substantial cost. Definitely not a perfect fix, but then again, no engine is perfect. Toyota and Honda, widely considered to be the paragons of quality, have engine failure issues too.

At the end of the day, I think there is always a trade-off between performance and reliability. The most reliable engine you can get is probably a pushroad inline four. Rock-solid reliable, but heavy and low power. The highest would be a Formula One engine, which needs to be rebuilt after every race.

1998 986 Turbo-Look Cab
172,000 Miles
Dilithium Crystal Supercharger



Edited 1 time(s). Last edit at 12/02/2010 10:27AM by Red_Lightnin!. (view changes)

Multiple issues. Hope the dude who designed that motor is no longer working there.

After what i saw when i opened up my ims bearing, i don't know how it lasted as long as it did. Virtually no lube inside the seals. I can't say the ln is better, but what i saw can't be good.

In any case, it doesn't have a seal on the inside to hold the lube in.

The general theory is that part of the problem stems from not driving the car enough. If you look at the posts, the failures tend to be older, very low mileage cars (though not always) and one of the theories is that if you are not running the engine regularly (at least once a week, several hours plus, etc.) the oil drains out and causes the bearing to fail. Just a theory, but this would be consistent with Al's observation.

1998 986 Turbo-Look Cab
172,000 Miles
Dilithium Crystal Supercharger

Quote
Red_Lightnin!
The general theory is that part of the problem stems from not driving the car enough. If you look at the posts, the failures tend to be older, very low mileage cars (though not always) and one of the theories is that if you are not running the engine regularly (at least once a week, several hours plus, etc.) the oil drains out and causes the bearing to fail. Just a theory, but this would be consistent with Al's observation.

As I understand it, there is no oil to drain out because the OEM bearing is a sealed bearing, sealed on both sides and holding grease inside (unless the seal or the bearing fails).

Regards, Maurice.

OEM bearing isnt engine oil lubed....get better tech buddies

unless i'm reading things out of order

Again, not to defend any theory. We dont know. But the theory goes like this:

1. while sealed, all is well
2. the seal begins to fail, and the grease migrates out
3. oil cannot easily enter to replace it
4. seal further deteriorates
5. now tow conditions can exist - hgih pressure, high splash, constant use..... and the reverse
6. in the excellence article, and from track blabber, it seems tracked and other hard driver cars have far fewer incidents

So there are three phases - before breakdown, during, and once nearly trashed. Different needs at different stages. Maybe be BS, btu makes some sense.

Grant

My seals were visually undamaged and intact, but still no grease. My opinion is they were designed to keep grease in, in a different environment, not to keep hot oil out. Over time, hot oil gets in, liquifies the grease, and the mixture leaks out. My belief is that the LN unsealed bearing will let in more oil than the sealed factory bearing and has better balls (npi). While the LN design may not be ideal, on the surface it seems better than the way the factory design performs. Best design - no intermediate shaft, but that is not an option for my car.

unlike the factory unit, it (the LN unit) is designed to catch engine splash oil for constant lubrication. The factory one seals oil out until it is badly failed, then still presents a small catch window.

The LN one also has far higher bearing (balls) surface area, and the bearings are nade out of extremely hard (lower wear, lower heat) ball bearings.

We don't know if it will work, but the idea is quite a change from factory.

Assume you have seen one.. i have one sitting on my desk.

Grant

... that the Intermediate Shaft is mostly sealed and does not get bathed in fresh engine oil.
Some oil seeps into the IMS, but this oil quickly becomes degraded and stagnant because of all the heat cycles.
I don't know how badly the lubricating quality of this degraded oil becomes but this is what lubricates the LNE retrofit bearing which is open (not sealed) to the back.
That's the reason why Porsche's is sealed (lifetime lubrication - according to them).

So, I'll be the guinea pig.
My first bearing lasted 196,800 miles (when I pulled it to be replaced - it was a goner).
At 200,000 my engine broke and I replaced the motor but salvaged the newly installed IMS bearing from LNE.
I promise to run my car with this "new" engine just as hard as before. Of the 200,000 miles on the odometer, 27,500 were track miles.
Let's just wait till I hit 400,000 and then we'll know which one lasts longer and the debate will be over
Yeah, right!
Happy Boxstering,
Pedro

Pedro Bonilla
1998 Boxster 986 - 311,000+ miles: [www.PedrosGarage.com]
PCA National Club Racing Scrutineer - PCA National HPDE Instructor - PCA Technical Committee (Boxster/Cayman)

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Racecar spelled backwards is Racecar

"Racing is life. Anything before or after is just waiting" ... Steve McQueen as Michael Delaney in "LeMans"

"If you wait, all that happens is that you get older"... Mario Andretti

"Being second is to be the first of the ones who lose" ... Ayrton Senna

1998 986 Turbo-Look Cab
172,000 Miles
Dilithium Crystal Supercharger

... for a picture

[i83.photobucket.com]

Happy Boxstering,
Pedro

Pedro Bonilla
1998 Boxster 986 - 311,000+ miles: [www.PedrosGarage.com]
PCA National Club Racing Scrutineer - PCA National HPDE Instructor - PCA Technical Committee (Boxster/Cayman)

---

Racecar spelled backwards is Racecar

"Racing is life. Anything before or after is just waiting" ... Steve McQueen as Michael Delaney in "LeMans"

"If you wait, all that happens is that you get older"... Mario Andretti

"Being second is to be the first of the ones who lose" ... Ayrton Senna

1998 986 Turbo-Look Cab
172,000 Miles
Dilithium Crystal Supercharger

I replied to the IMS problem on PPBB so I'll only make a few points here. The bearing is a Class 1 out of 9, with 9 being the highest standard precision. Motor oils do not have a high enough viscosity to keep the asperities of the surface finishes from contacting in a Class 1 bearing. The grease used probably has a high viscosity oil., but the grease will be used up. With oil, at higher speeds, a "bow wave" will be formed lifting the balls out of contact with the ball groove, i.e. no wear. Oil has a better cooling effect than grease. The ball separator used isn't the best choice for the application.
The LNE bearings should be more resistant to wear than the OEM bearing. I haven't analyzed any LNE bearings, yet.

Ed B