166 captured repliesDiscussion pagination complete · Source accounts, not a confirmed diagnosis
THIS DISCUSSION / SOURCE-DERIVED OVERVIEW
Discussion summary
YOUR RESEARCH996 What best year?
Reported or suspected cause
so bad
Reported cause
No successful repair reported for this finding.
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Identified cause
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Reported fixes
Read evidence and context
Explicit resolution reports before identified causes, performed actions and suggestions. Within each level, matching component labels precede direct query mentions and inherited thread context; successful versus unsuccessful discussion counts, owner confirmations and independent discussion support determine order. This is not a probability of success.
Discussions that report identifying a cause
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0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.
0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.
Reported cause
The issue is so bad with the "improved" motor that even the ceramic bearing upgrade is not considered adequate and a solid bearing is suggested to reduce the IMSB risk.
Leading evidence: 'so bad' (1 discussions report identifying this cause; no attributable repair resolution). Across 1 matching discussions, the most frequently mentioned possible cause is 'so bad' (1 discussions; 1 report identifying it and 0 suggest it). The most frequently discussed action is 'Inspect bearing retainer' (1 discussions). For that action, 0 discussions report a resolution and 0 report an unsuccessful attempt. No action has an explicit, attributable resolution report under the current rules. These are forum reports and suggestions, not a confirmed diagnosis.
Source reports, not a diagnosis or a success probability. Counts refer to discussions and can overlap.
Explicit resolution reports before identified causes, performed actions and suggestions. Within each level, matching component labels precede direct query mentions and inherited thread context; successful versus unsuccessful discussion counts, owner confirmations and independent discussion support determine order. This is not a probability of success.
Discussions that performed work without a confirmed outcome
1
0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.
0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.
Replace clutch last summer and was both disappointed/pleased
Performed · outcome unconfirmed
No successful repair reported for this finding.
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Reported fixes
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Unsuccessful attempts
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Discussions
Read evidence and context
Explicit resolution reports before identified causes, performed actions and suggestions. Within each level, matching component labels precede direct query mentions and inherited thread context; successful versus unsuccessful discussion counts, owner confirmations and independent discussion support determine order. This is not a probability of success.
Discussions that performed work without a confirmed outcome
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0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.
0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.
Performed · outcome unconfirmed
When I replaced the clutch last summer and was both disappointed/pleased to see this.
Explicit resolution reports before identified causes, performed actions and suggestions. Within each level, matching component labels precede direct query mentions and inherited thread context; successful versus unsuccessful discussion counts, owner confirmations and independent discussion support determine order. This is not a probability of success.
Discussions that performed work without a confirmed outcome
1
0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.
0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.
Performed · outcome unconfirmed
But that's only because I preemptively changed the IMSB and AOS on the 996, although both were working fine.
Explicit resolution reports before identified causes, performed actions and suggestions. Within each level, matching component labels precede direct query mentions and inherited thread context; successful versus unsuccessful discussion counts, owner confirmations and independent discussion support determine order. This is not a probability of success.
Discussions that performed work without a confirmed outcome
1
0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.
0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.
0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.
0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.
Suggestion
I believe that the replacement is adequate as a pm item, but if you are refering to failures of the replaced bearing in the early v late m96 then youre way off.
These are separate views of the same evidence. Frequency alone does not establish a fix, and these counts must not be added together.
so bad
No successful repair reported for this finding.
1
Identified cause
0
Suspected cause
0
Reported fixes
Read evidence and context
Discussions that report identifying a cause
1
0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.
0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.
Reported cause
The issue is so bad with the "improved" motor that even the ceramic bearing upgrade is not considered adequate and a solid bearing is suggested to reduce the IMSB risk.
Counts describe captured discussions, not unique people or a diagnosis. Author identities are not reliably stored. Exact duplicate evidence is counted once across matching discussions; one discussion counts at most once per action/state. Multiple repairs reported together remain a combination. Suggestions and failed attempts do not establish a fix. Matches cover whole discussions and can include related faults, model variants and incomplete threads.
166 eligible posts · 0 unverified posts · 1 discussions match the subject in their title or opening post.
Rennlist: 1 discussions
0 evidence records excluded for query context · 1 excluded by outcome qualification · 0 adjusted by outcome qualification.
2 acknowledgements have no verified action link; they do not establish a repair result.
Outcome without a verified action link
When sump baffling changes did not fix it, they added a couple liters of oil to the sump.
I recently sold my 2000 Boxster S to pursue my dream of owning a 911.
I have decided the 996 is the best entry point for "capturing" the dream. My question to all or any who might be interested is this: Should I consider all MY's or avoid the early ones?
Having owned the Boxster, I am aware of the IMS and RMS challenges that "appear" to haunt the 996. I also understand the importance of proper maintenance and proper driving.
I appreciate any and all comments. Presently, I am leaning toward a 2002 with 3.6. Definitely 6-speed. Preferably a Cabriolet.
Thanks in advance and very happy to be a new member of the forum.
Well done Sir. Well done.
When I asked the same question ages ago (4 months) people said the later the year in the car cycle, the better. So 2004- 2005. But I would never fault you for buying a 2002. They are all amazing works of art.
Good luck in your search! Take your time and you will realize that dream.
What's your budget? 997's are already going for $35K on Autotrader.
p.s.
I don't want to quibble with your own choice but I find it strange when someone dreams of owning a Carrera and opts for a Cabriolet.
Hacking the roof off such a beautiful form really takes away all of the classic appeal, particluarly when you look at it from the rear, and you're making some compromises on handling that you'll notice straight away coming from a midengine roadster.
Still a great looking car though.
"Hacking the roof off". It's mid 70's today and late January in Northern California, and thankfully My 996 came pre hacked by Porsche. Looks good to me.
The 911' s daddy, 356 #1 was a open top... but it also had the engine in the middle
I doubt I'll have the $3 million budget for an original 550 Spyder so a modern version will have to do for now.
The plastic windows on the 99-01 are a pain on the cabriolet. My vote would be well cared for 2002, I had a 99 in the past and the VarioCam Plus is nice on 2002+ (but trickier to repair if have an issue) also glass rear window.
Considering who u r, I am very VERY interested in hearing ur aspects for consideration. For certain, the 1999 is going to be the "cheapest." Have a '99 with 49K miles located in town. Two problems being silver and coupe BUT one local owner and asking price is very attractive.
PM if u wish or direct to appropriate link(s).
Many thanks for the quick and helpful responses.
As member of Boxster Register so happy to know rennlist will offer same online support I have found in the past.
Once Carrera found and in the garage, photos will be posted. Must add will not settle for less desired color choices regardless of MY. So must find patience to be a virtue.
earliest 99 you can find. Porsche put everything in and it went down from there
Remember 'gone in 60-seconds' when they drove the 996 through the Dealership window? That was a 99 C2! I fell in love and went out and bought my Speed Yellow 6-speed......
Actually it wasn't.. That car recently sold and was advertised as an earlier aircooled 911 with body mods to make it appear as a 996.
More details
http://www.6speedonline.com/forums/9...lly-996-a.html
Not that I can afford a Lamborghini Miura P400SV, but this logic requires that those who could afford one better drop it from the plans and get a newer model.
I don't think so.
2002+ C4S, updated headlights, full leather, widebody, 3.6l, turbo brakes and suspension.
get IMS retrofit, pick correct oil and change frequently and drive the car.
Personally, the headlights on the Mk1 996 are the best looking. They remind me of a GT40.
When I see a 996 Mk2, I think one thing. Whiner Porsche owner who complains to Porsche that his 911 headlights looked too much like a Boxster. To me the Mk2 lights look weird and simply a change to justify a buyers cost premium.
Well the OP said "best >996<"
Within a generation I think the idea that "newest you can afford" is usually sound. So if someone said "best Gallardo for me to get" then Im going to go out on a limb and guess they dont want a Miura at any price.
With Porsche, we all know that the "Porsche community" guidance is "buy anything except a 996, including some other car" so probably in the Porsche community the rule would be "buy the *oldest* car you can afford as long as its not a 996"
Just checked... 6/98 !!
So care to share the aspects? I'll start - key aspects why I chose my '99... Lightest weight 996 (or 993), LSD, traction control, M030, wire throttle, lowest cost/least depreciation. Wasn't aware of Dual Row bearing & 5 chain was a feature at purchase. But Dual Row was perfect when I replaced it at 100k.
I drive a '99 that was manufactured in March of 1998. This car really is the best most reliable car I've ever owned. So I'm +++ on the 99's.
I've replaced, wheels, tires, complete audio system, every exterior light fixture and 99% of most people ask me of its new. Blows my mind every time I hear that. My car has been on the road for 15 years this coming May.
The post I was responding to was a categorical recommendation that postulated the newest "car" is always best. There was no mention of "newest 996" as you misconstrued the meaning of my response. But I could see how you might read it that way.
Personally, I buy the best I can afford. Sometimes that's also the newest.
So far the Mk1 996's have in their favor: 5 chain motors, Dual row IMS bearings , lighter, less electrical complications and whatever it is that Jake knows that we don't. The Mk2's have cupholders, gloveboxes, a glass rear window and different headlights.
I'll take 5 chains, a Dual row IMSB, simpler electrical, and the PO's depreciation! When I get a new top, it will have a glass rear window.
Actually we all agree a 99 with one MK I light and other as MK II an 8 chain 3 row bearing with rear window in glass with plastic covering. Cup holders added.
My 6/98 996 is not quite the most reliable car I have owned, but close. My 2005 Toyota 4runner gets that award. The 996 is second.
But that's only because I preemptively changed the IMSB and AOS on the 996, although both were working fine. Oh yeah, I just replaced a window regulator too.
And yes, most of my friends think my '99 is still a new car, it looks new and still drives tight. Best bang for the buck I've ever had.
To this, I suggested the OP buy the "newest" 996 he can afford.
BUT I do not know much about cars so disregard what I suggested and listen to Cefalu instead.
I would drive a Mk I & a Mk II and see which you like the feel of better.
Then buy the Mk (whichever you choose) car in the best condition with the options you like best - regardless of the year.
Good post.
Y'all help a Texas RL-er out here. I have had a 951 for years and it is in top show winning shape cosmetically and mechanically. While I truly like the car, I have been looking to change to something I would drive more for a while. But I have been looking at Caymans.
Recently I looked at a 2003 Carrera and while it had the color I wanted and it felt "nice" I did not spring for it as it had only a sketchy history and had a couple of large engine works under warranty. But very few records over all, so I passed on it. But I was surprised at how great it felt from the wheel. Heavier, but planted. Great for real road driving.
I have recently seen a couple of very nice 1999's. My other Porsche buddies think I am going from one step child (the 951) to another ( the 996). I have been here before.
But this thread, and especially with Jakes endorsement emboldens me on the 1999's I saw. Enough to go for a real look and with a checkbook.
Of course I would look for records and some PPI, but besides the IMS, what are the deal killers for a 1999. Or a 2003 for that matter, as those would about bracket it for me. RMS is a problem but not the end of the world I would guess. And it goes with the clutch I would suspect.
My indie shop here says all 996's need a clutch. All the time. If you drove it since you put a clutch in, you are at 50%
, or while you are in there is always a clutch. Ok maybe on that.
He also feels that every switch and electrical component will fail. Yikes - my 1986 951 has had no such problems and only now is the instrument cluster out for bulbs at 92,000 miles and 27 years.
He says look for the 2003's. For interior, for electricals and for better mechanicals.
But I like Brians approach too.
I am out looking - so pile in here if you want. I might soon be in the 996 Forum . Thanks.
My 2002 has treated me very well, but the original owner not so much. He had the engine replaced in 2005 (an M97( and I've been reaping the benefits.
I actually prefer the MkI lights too, but not enough to base a decision on them, and my car weighs in at 3000 # dead - so light enough.
LSD sounds good though.
There are several mag/tech articles about the 3.4's problems vs. 3.6. The general consensus is 3.6 solved many of the 3.4 problems even though it had its own issues as well.
great thread.
my $0.02. I would stay clear of 1998 - 2001. I have a 2003 and love it, though I've had to do the RMS and IMS because they were failing, so whatever that's worth. I think you get one that has had the IMS retrofit done already, why worry. IF you can get a warantee get one, its' worth it, I paid $3500 for Platnium level Fidelity and have made over $9000 of claims on it, slam dunk worth it.
Keep in mind a Cab adds 400lbs to the car so it's like having 2 extra adults in the car, or one if you are from the south, which adds ALOT of weight.
BUT like most have said, and I completely back and agree to, get what makes YOU happy, you are going to love it.
Yeah, like, 98% of all the statistics on the Interwebs are just made up.
FWIW, the Porsche manual states that the empty weight for the coupe starts at 3020 lbs, the cabriolet starts at 3197 lbs -- not insignificant....but not 400lbs.
So it is not surprising that the 0-60 for the coupe is rated at 5.0 seconds; the cab at 5.2 seconds; top speed is rated at 177 for both.
Choose the kind of driving experience you want, rather than worry about a possible .2 seconds (that will be concealed by driver skill & local conditions).
Let's see, driving through the wine country, or on Highway 1, in a coupe or a convertible? I am sure most people can agree that either is great.
But top down is a whole different experience, and is precisely why I own my 996 cab. Well worth the 0.2 second penalty to me.
The Targa's are very cool, hard to argue with that solution.
My hardtop is tucked up in the rafters. Put it on once, to move it from the sellers rafters to my rafters.
Thank you! Those Ruf wheels set me back quite a bit back but well worth the compliments I get.
By the way, my build date was July 98. Newport Porsche loves this car and always tells me never to let this one go. The tech that only works on my car tells me that the early 98 builds were the best of the best. In order to keep pricing from going up year after year, Porsche - like all Manufacturers' finds ways to cut. The (5)-chain motors & Dual row IMS bearings were just one of those cuts - way over-engineered according to Porsche
KrazyK, have you read the Hartech articles? If you had you would know the 3.6's are more likely to have ovality and IMSB failures than the 3.4 5 chain dual row motors.
Didn't your parents tell you to think before you spoke? No hard feelings though, as I love my 98-build 99 C2. As my mechanic says - bullit proof car. If I ever sell it, he, along with the rest of the mechanics want first dibs. That speaks volumes for me!
When I purchased my 40th anniv. 6 years ago (used) I looked into 996's and came across reports of MKI cylinder head cracks....
Per "Total 911" review:
"First, it’s important to point out that it is the early 3.4-
litre engines, made from 1998 to 2000, that are most
susceptible to major failure. The later 3.6-litre engine is
pretty much problem-free. Also, Porsche made many
changes to the 3.4-litre unit over its production life, so the
last of these smaller-capacity engines – made in 2001 –
tend to be more reliable......."
LINK:
http://www.autofarm.co.uk/pdf/Total911_July06.pdf
I think the picture has changed a bit since 2006. I daresay even Adrian's book would probably benefit from an update. Only now does the entire 996 fleet have enough years and miles under its belt to know anything meaningful.
What a fantastic array of information.
Boil it all down and the end result is... no matter what year it's a Porsche and as with all other cars, one lives with the good and the bad. We take our chances every time we pull out of the garage.
Choice is still 996 (various reasons) Cab for certain... unless coupe with sun room is just too good to pass up. Exterior red, white, or black... unless any other color is too grand a deal to pass up. Interior cashmere or black... unless grey too fantastic to ignore. For sure 6-speed. That is non negotiable. Now that that is settled:
LET THE HUNT BEGIN!
Funny how people try to put a spin on "facts" to serve their position.
The 2008 911 article started off postulating the early M96 motor was bad because of the IMSB design. We all now know this was an erroneous conclusion. In fact the "improved" design single row IMSB bearings and 3 chain motors were not an improvement. But I am sure they cost less to build. The early 5 chain dual row motors are a more robust design. The issue is so bad with the "improved" motor that even the ceramic bearing upgrade is not considered adequate and a solid bearing is suggested to reduce the IMSB risk. There are those people of course who maintain there is nothing wrong at all with the bearing and ignore the issue completely. Not a risk I would take.
Next, the article launched into cracked cylinder heads and D chunking. I have seen intermix problems and D chunking failures posted here. But it seems to me these issues are not isolated to early M96 motors, nor are they so widespread at this point you could draw any kind of certain conclusions. Hartech makes no distinction. I would say that when the article was written 5 years ago, the newer M96 engines were newer so failures were less frequent on the later M96 motors.
The 911 article addressed weakness in cyl's 2 and 5. This is generally where the ovality occurs, and according to Hartech the 3.4 and 3.6 motors are not showing any material difference as time passes. In fact there is concern over the increased power of the 3.6 which uses the same liner thickness as the 3.4. The 2.5/2.7/3.2 Boxster motors have thicker liners which do not share the 3.4/3.6 propensity to oval. The 3.4 motor was characterized as defective, but the 3.6 follows along with it in this respect.
Hartech goes on to conclude the that 3.6 adds one new problem to the M96 game, cylinder wall scuffing, and Hartech then concludes regarding the increased displacement M96 3.6;
PRIMARY CONCLUSIONS
In conclusion it would seem that the increased piston thrust loads between the piston and the
cylinder bore that has a relatively small amount of hot oil to lubricate it - combined with less
accurate distribution of temperature control inside the engine and higher cylinder temperatures -
has resulted in the more vulnerable side (Bank 2) running closer to critical operating temperatures
and eventually fail in some case where age and other contributory factors separate one example
from another.
ISSUES THAT RENDER THE Cayman S, 3.6 and 3.8 engines different to the 3.4’s and Boxsters.
The head gasket now fits both sides but has larger coolant holes to the cylinder heads, reducing theproportion of coolant to the cylinders and changing their balance that then run hotter.
The connecting rods are shorter increasing cylinder wall loads and friction.
The torque developed is higher increasing piston to cylinder wall loads especially at low revs –increasing friction.
The oil spray jets are the same size as before and therefore the ratio of oil in the cylinders to surface area is reduced.
The space for the coolant to circulate in the cylinders has been reduced.
The crankshaft is wider (reducing any spray oil to the cylinders buy entrapment).
FINAL CONCLUSION.
Although earlier designs didn’t usually suffer this problem – the increases in power output combined with the reduction in cylinder block coolant flow and balance, the direction of the oil spray jets and the quantity of oil present - have pushed the later engines even closer to that limit and as a result some fail when mileages get higher, bore clearances increase, piston coatings wear thin, oil deteriorates, radiators leak, etc, etc – i.e. some engines with some driving conditions – just slightly go over that safe limit for a few seconds and this then results in the scoring we are concerned about.
My take away from the 911 article was it was premature to draw any conclusions between the 3.4 and 3.6 in 2008. They sure got it wrong in the IMSB issue.
Maybe this is why Jake likes the early 996's
[My take away from the 911 article was it was premature to draw any conclusions between the 3.4 and 3.6 in 2008. They sure got it wrong in the IMSB issue.
Maybe this is why Jake likes the early 996's[/QUOTE]
Amen!
Funny how you just did the exact same thing....
I believe that the replacement is adequate as a pm item, but if you are refering to failures of the replaced bearing in the early v late m96 then youre way off. It has been documented here on this forum that those 5 or 6 failures were due to incorrect installations and the like. Not the bearing itself.
What I know is what I read from the bearing suppliers. The single row bearing is not as robust as the dual row. There have been many technical discussions here about bearing speed, loads etc. From what I read, the single row bearings have a larger diameter which leads to higher bearing velocities, and force/unit area stresses, than the dual row. I personally think this issue has been raised to a level of hysteria.
And yes, I have heard Jake say that in virtually every failure, the replacement install was done incorrectly and that has led to failures. I don't have a breakout of the replacement failures for single vs double.
Honestly, here I am writing like an expert and all I know is what I read here. But I did actually change my own dual row IMSB myself, successfully I might add, so at least I know where it goes, how it works and what it looks and feels like. Which makes me an expert compared to the majority of people here.
What gets me are the people who spout off how superior the later M96's are based on an old article, when the newer M96's have there own host of issues too.
With my 2000 Boxster S there was some uncertainty as to whether the IMSB was a single row or double row. From the information I could gather, one could only be certain after removing the bearing or at least inspecting the bearing retainer. Chassis numbers cannot verify which was used.
Is there accurate information regarding when the 5 chain and dual row bearing was replaced with 3 and single for the 3.4 996? Build date? Chassis number?
Also the idea that Porsche would use less quality parts and materials as the "years" progress in a particular model ie 996 seems odd to me. Generally price increases occur MY to MY so to say parts and materials are cheapened to save them money just seems a bit odd to me. I assume improvements as the model years appear. Are these "improvements" only superficial such as headlamp change to appease customer complaints? Please set me straight.
The information regarding which bearing that is employed in a 2000 and 2005 car could not be less accurate. These REQUIRE visual inspection.
As for 3 chain Vs. 5 chain:
All 5 chain 996 engines were 3.4
All 3 chain engines are at minimum of 3.6L
My guess is that the variance of reliability from car to car (now affected by its manufacture, how it's been used and how it's been maintained) is far stronger than attempts at generalizations about model years.
The Porsche engineers responsible for making engine design changes are not offering their insight as to why they made the changes they did. So it's pure speculation as to why they made them. Changes are usually made to improve something, bottom line? defective design? list the ways. But as they say, it is what it is.
The BMW M60/62 engine used in 540/740/840i's started off as a 4.0 V8 and featured a
dual row timing chain with all steel cog
turning points. The M62 was later released in LARGER displacement as a 4.4 liter with a
single row timing chain and a plastic
idler guide. Do the math. And yes it's a big issue now with single row timing chains sawing through plastic idler guides. next came the variable valve timing (VANOS) version, and boy is that fiasco.
I am very glad I have the first version dual row V8 4.0 version in my 840Ci.
That 'something' isn't necessarily the product itself. Sometimes, it's a manufacturing process. These engines were hand assembled on a bench. The 996 was designed and built during a financially difficult time for Porsche, and they were getting production engineering advice from Toyota at the time. An 'improvement' could just as easily have been made to shave an hour off the build time as to make the product work better. We just don't know, and never will.
For those who want particular detail about the IMSB design, the following was cut from a discussion over on Renntech I was following. This bearing analysis was not done by Jake, but by a company that primarily makes replacement airplane components and sells an M96 IMSB replacement:
When you start a project that involves a ball bearing, the first steps are to figure out the loads and speed the bearing will operate under. The loads will be used to determine the rolling contact stress. Intuitively, you might think the peak contact stress to be directly at the point of ball contact, but actually it is just forward of the ball and below the surface. It is easy to visualize if you think of a heavily loaded wheel-barrow tire rolling over soft earth. The wheel pushes forward soil, so it is like the wheel is always trying to "climb out" of a depression. As long as the contact stress is below the material yield point, the bearing survives. From a practical standpoint, the higher the contact stress, the more distortion. The more distortion, the more heat generated. Heat makes the steel softer. So, when designing for big loads, you need bearings with either lots of *****…. or big ***** to keep heat down. Speed factors determine which approach is used.
When you see a ball race that is pitted or flaking, the allowable contact stress limt was exceeded. It could be dirt. lube, or overload that caused the problem.
Now we need to move back in time. Here is a guess as to how the bearing ended up submerged. The engine was designed wet sump, the first Porsche boxer engine with that approach since the 912/356. When they started testing it in the prototype 996, they found the oil pick-up was sucking air instead of oil (with the new suspension and great tires under high lateral "G’s"). When sump baffling changes did not fix it, they added a couple liters of oil to the sump. Cheap fix, new dipstick. But, the bearing (which was designed dry) was now wet when not running. Well,….. someone had to sign off the engineering change forms, including the impact of the change assessment. Now we have a paper trail to the guilty. When the bearing problems started, the cover up began.
So, the guy who messed up ….either found a way to get it blamed on the least liked guy in the group (and is now the area manager), or…..he has long since left Stuggart, and made a career making weinerschnitzel in the Black Forest. You might laugh, but this happens all the time in big organizations. The case everybody remembers ……..is the space shuttle o-ring disaster.
When we do the math on the grease lubed (but not immersed) dual row bearing, it looks really good . Lots of load margin, and the combination of small OD and small ***** keeps the ball speed and centrifugal loads down. No problem at all grease lubed. The problems start when the grease is gone.
The second generation single row bearing is simply the dual row cut in half. It is really that basic. Same ID and OD, half the ball count. So the contact stresses are doubled. We now have a bearing that is far more likely to overheat and die. Based on the failures seen , this is exactly what is happening. These engines should have the hybrid ceramic upgrade done now, don't wait for the clutch to go.
You can’t admit you made a mistake and go backward , so……..you make a third design! You fix the contact stress by putting this big single row bearing in place. The load capacity math on this bearing looks fine, but the limiting speed is very questionable. The increased diameter makes a big jump in ball speed (speed varies as the square of the radius) because the OD of this bearing spins. The ***** are large and heavy, making high centrifugal force that wipes lube off the race. If you are driving around town, and rarely redline the engine, it is OK. Endurance running this design at sustained high rpm is asking for trouble. We have not completed the analysis on the impact of just changing the ***** to ceramic on this bearing. With the ceramic ball’s weight reduction, it will help the centrifugal issue quite a bit. (We do have a ceramic ball version of this big bearing on the road, but it is far to early to tell if the solution is adequate. All indications are it is an improvement, and we can custom make one of these for you if you really want it.) Question is, will it be enough. Since you have to tear the engine down to service this bearing, we are considering making the shaft go back to the (field service capable) dual row. It will require a very precise, cylindrically ground spacer sleeve to make it happen. We would have to do the upgrade in-house to control the fit. More work is needed on this one. Since every engine has to be torn down to fix this bearing, we don’t expect very many sales for a period of years.
So, all this probably happened because ……….no one wanted to tell the boss a $300 bearing was needed to fix it, or the business people could not make a case for spending the money.
What does mass (in the context of a captive bearing) have to do with speed of rotation? The increase in diameter is what you indicated caused the increased centrifugal force that purportedly causes the lubricant to be "wiped" from the race.
I don't understand this claim that the composition of the bearing alone - with no change in dimension - would affect its rotational speed.
Thanks in advance for clarifying.
...the rotational velocity of a sphere has an inverse relationship with its diameter, not a direct relationship. Increasing the diameter of a ball means that the ball must rotate fewer times to travel the same distance. A soccer ball must make more revolutions than a beach ball to travel the same distance. If the soccer must travel the same distance as the beach ball in the same amount of time, it must spin more quickly.
Since rotational speeds should have decreased when the diameter of the ***** in the bearing was increased, the theory that increased centrifugal force causes lubricant to be thrown from the bearing seems counterintuitive.
I didn't write this. Like I noted it came from a competitor of LN/Jake. But the mass of a ceramic bearing is lower than a steel bearing. Thus the acceleration acting on the ceramic bearing results in a lower force than that of a steel bearing.
You will note he says "because the outside of the bearing spins", i.e. The larger diameter bearing race spins faster faster than the smaller bearing race.
That's weird you say that because I was *just* thinking about boobies. huh.
Also - my 2002 has an M97 big bearing motor installed. When I replaced the clutch last summer and was both disappointed/pleased to see this.
It hasn't slowed me down at all. If the motor blows up I'll replace it. It'll suck - but what are you going to do?
The above subjected book recently became available for about $75 on Amazon.com. I would recommend both current and prospective 996 owners order it. Besides, having a copy handy will make you a real power on rennlist!
Back in my 993 days, I acquired the 993 version of this pub by the same author. It was encyclopedic in detail with good photo illustrations. I expect this new one to be every bit as useful.
relinuca
Hope this is all true, it makes sense to me, except i just don't understand how can not driving the car increase the risk of failure? What do you think the percentage of C2's that are parked for at least 3 months over the winter? My guess would be at least 75% of all sold. We in Canada should have these things blown up on the side of the road non stop as the percentage of cars that are parked over the winter is probably 90%. I am of the opinion that when the car is parked it's parked, when you get it out of storage, drive it often and don't baby it too much. But i didn't do the research, these people did, so i can't talk about it with too much confidence but without a little further explanation as to how this is bad i have hard time accepting it as a fact. Cheers!
Nedster,
The way I understand it if the bearing seal has been compromised then the only lubrication is from engine oil. If the car has been stored and not brought to temp over an extended period, the bearing would be dry and thus damaged with engine start.
I did this to try and assure less likely catastrophe with my Boxster:
1) Always warm the car to operating temp before driving or at least before getting "heavy footed."
2) Never lug down the engine. Keep the revs at 3K or above when possible.
3) Keep engine oil fresh. 3000 to 5000 max before change. (U can decide what weight best in ur mind.That's another can of worms to be opened)
4)Inspect oil filter after each change looking for metal fragments
5)Once warmed up and ready to go, drive it like u stole it!
During cooler weather in SW Missouri, when not driving it on a regular basis, I would start the car and let it run until it reached 180 degrees or so just to keep the oil "moving."
Maybe that will help with reasoning.
My car doesn't move for 4 months over the winter, i was never convinced as to what is better, starting it once in a while, or just cover it and forget it. Forgetting it is what most suggest, including the book that everybody recommends here "the Essential Companion". Still not convinced one way or the other.
Yes, if the weathers wet, I just start it then move it a little in shop. It rarely freezes here so thats not a factor. The rain certainly is. You cant keep the underbody clean in rainy weather / wet road conditions.
I'm no expert... but from everything I know, starting a car and idling it occasionally is potentially more damaging than a bit of water on the under body.
Most of the info is probably fairly accurate except the failure rate is now much higher than what was stated orginally. I think our poll now shows about %10, which is awful.
Granted that may be high but even if the failure is say,, 6%. That would be the same as 6 out of every 100 aircraft flights resulted in a crash. Pretty scary numbers either way.
As far as the info being accurate, IIRC, the source claimed he had gathered the info from several different places..
The interesting opinions were here:
http://www.linkedin.com/groups/Porsc...946.S.95837230
Long story short, the results of the "research" are iffy at best. It was an extremely small sample size of 996 owners who were more likely to have had the issue than what is probably true, due to it being a sample of internet forum users who were looking for answers to their problem.
[QUOTE=perfectlap;10185010]What's your budget? 997's are already going for $35K on Autotrader.
p.s.
I don't want to quibble with your own choice but I find it strange when someone dreams of owning a Carrera and opts for a Cabriolet.
Hacking the roof off such a beautiful form really takes away all of the classic appeal, particluarly when you look at it from the rear, and you're making some compromises on handling that you'll notice straight away coming from a midengine roadster.
As your profile picture so confusingly illustrates.
I assume you guys realize this thread was initiated over 7 years ago and resurrected today. There was definitely some love for the 99s in the old posts. I have a March 98 build and have been very happy with it.
I also think the most reliable year was MY99.
Good old gas cable, no esp, double row IMS.
Best without navigation and phone, manual seats and suroof delete.
That's what I'm searching for...
[Image-only post; no author-written text. Original image references:]
https://cimg0.ibsrv.net/gimg/rennlist.com-vbulletin/285x177/images_b31a18d62d943b89f9fd41d49300c3672a3c6cd1.jpg
You've been around since 2016 and yet all of your posts (so far) are in this thread. You've got some 'splainin' to do...
And you chose to dust this thread off, for some reason. WTF?
Not annoyed, not disturbed. Just found it odd that a post that hadn't seen the light of day for six years suddenly pops up, and the guy that brought it back has posts in no other threads. That doesn't seem strange?
The rest of you guys can thank me for scaring off the tire kickers....
Good to hear. Despite your first experience here, this is a great place. You have to learn how to filter out the noise. Some of us come off abrasive but, in general, we are goodnatured and just having fun.
It may be helpful to you - and to us - to provide details on what you are looking at (model year, etc.). That way we can provide all sorts of opinions (valid and otherwise). Best of luck.
What I am looking for is a manual C2 between 1999 and 2004.
The things I read about IMS failure and bore scoring scare me a little.
That's why I tend to a MY99 - what I could read in the forums there is the double row IMS and the 3.4s are not so prone to bore scoring.
Am I right so far?
Is there a major difference in performance? The MK1 is some kilos lighter...
There's more to be scared of. My 2001 C4 (3.4) just suffered cracked cylinders. I caught it before it became a casualty of d-chunk.
If Jake Raby likes the early 99s the best, there are probably a lot of good reasons.
My take: the dual row IMSB is preferred. But, there are good options in the form of the 'retrofit' and the 'solution' for even the single row bearing.
Bore scoring is mostly a function of oil maintenance and driving style. You can learn a lot more by viewing the videos on the subject.
Performance is good in all iterations. I agree with your take on reducing the amount of 'nannies'.
When it comes to used Porsches, condition is "everything" and detailed written records and receipts rule. Very nice used Porsches are plentiful in major markets, like coastal cities. I happen to prefer cars offered by PCA members, who tend to be **** retentive in a good way.
First step: join PCA and become acquainted with local club members. Plus the monthly Club magazine, Panorama, has an extensive marketplace section.
relinuca
Porsches Forever
True...
Here in Europe 996's are much more expensive than in the us.
Good examples start over here at $30k.
I've always had an eye on the US market and Porsches seem to be cheaper.
pay now or pay later.
how much, roughly will u be into your car after heart transplant?
30k for a 996 and possible* proper 20k plus engine re construction ...well. and you still have a 996.
*This is the wildcard. Only you can decide if you want to deal with this "risk". I know this math has been beat to death. I got a 996. My accountant would have suggested the expense up front I'm sure. He drives a Camary.😎
YMMV
On topic:
best year?
2003
If I wanted to spend that kind of money I would buy a 996 Turbo with the Mezger engine and convert it into a GT2.
But I have children and I'm a normal, hard working guy.
So for a toy this is too much for me.
I also enjoy long holidays in Portugal with my familiy - the Porsche is not #1 on my private priority list.
BTW I like the 996 more. It's a milestone in Porsche history - and the only one without round headlights.
That makes it special.
So I take the wildcard... Otherwise I would buy a Toyota.
I had a Cayman S until 2010 followed by a 1982 SC.
Now I'm up for a 996.
Why an early 99? No PSM, cable throttle, double row IMS, updated headlights,...
I rest my case. These cars should be, imo, toys and paid for with cash, and be able to blown up without and financial stress on your family.
good luck. They are great cars! I'd sell you mine but logistics wouldn't work.
Exactly. Only he can decide what is right for him. Only he knows what is in his bank account. Not me, not you.
If you are referring specifically to my car - when all is said and done, I expect to come in at about $25k spent, for
the car and
, for everything it will take to build a strong and robust engine. Most people would not choose to take the path I have chosen. Many prefer to open their wallet and get the best car they can afford. Not necessarily bad advice. It's just that my wallet isn't that big. I need to make up for it with hard work and spending smart. Everyone is different.
"Wouldn't it be a real drag, if we were all the same".
That's exactly what I think.
Even when you buy a turbo or a 997.2 you're on the save.
Here in Europe there are plenty of these on the market with new engine.
Buying a 997.2 and rebuilding/buying a new engine would be way out of my budget.
True. I saw the price for entry where he is and thought with 'my' wallet. Won't happen again.
25k all in for your car isn't too bad, according to my wallet. Good luck. Enjoying the thread after a lengthy tease of posts 😎
I don't think the cable throttle, and dual row bearing make it valuable, at all. It's the fact that it was built alongside the 993 that really adds value.
Then again, maybe I read that wrong.
I asked this question several years back and appreciated each response.
Suddenly the thread has appeared in my email and apparently someone or some people are upset I have not commented.
When I sold my Boxster I assumed a 996 would be my only choice for a 911 to find its way into my garage. As the date proves it has taken me several years for that 911 to be parked in my garage. I was very specific in what I wanted. Color combo, options, mileage. All that to say it was March of 2019 when I purchased my dream Porsche: 2006 Carrera S Cabriolet. Yes a 997.1
I apologize for any confusion/frustration my lack of participation has caused.
Buy a nice $4K roller, then have the engine rebuilt by the best...That's been my plan from the start and I hope to have plan "A" completed in a year.
My plan "B" motor will be sold to help another 996 get back up on it's feet for someone else.
