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THIS DISCUSSION / SOURCE-DERIVED OVERVIEW
Discussion summary
YOUR RESEARCHIs Any Bore Score Too Much Bore Score
Reported or suspected cause
because everything broke
Reported cause
No successful repair reported for this finding.
1
Identified cause
0
Suspected cause
0
Reported fixes
Read evidence and context
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Discussions that report identifying a cause
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Reported cause
tough to say really on what the initial cause was because EVERYTHING broke.
Leading evidence: 'because everything broke' (1 discussions report identifying this cause; no attributable repair resolution). Across 1 matching discussions, the most frequently mentioned possible cause is 'because everything broke' (1 discussions; 1 report identifying it and 0 suggest it). The most frequently discussed action is 'Recommend 20 years ago - it's clear' (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.
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Performed · outcome unconfirmed
That's up to the seller and buyer to figure out, but a full rebuild is start at $20k replacing everything that needs to be changed on the car/engine.
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Performed · outcome unconfirmed
After all, it's a "performance car" and along with the positives come some negatives - partially due to how these cars are used (they sit around in the garage sometimes for weeks or months at a time, and then we jump in and "drive them like we stole them"...).
After all, it's a "performance car" and along with the positives come some negatives - partially due to how these cars are used (they sit around in the garage sometimes for weeks or months at a time, and then we jump in and "drive them like we stole them"...).
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Performed · outcome unconfirmed
It's a calculated risk, as is purchase of any used vehicle.
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Suggestion
The manufacturer recommended oil changes at much higher intervals, This specific problem that has been found and there are no remedies that have been proven to work.
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Suggestion
The key is to drive it, and maintain it - 5k mile oil changes are a must, using a high quality oil (not even going to open this can of worms - read, read, read), address certain issues at set mileage or time based intervals (water pump, cam chain pads, IMSB, fuel filter, etc.).
The key is to drive it, and maintain it - 5k mile oil changes are a must, using a high quality oil (not even going to open this can of worms - read, read, read), address certain issues at set mileage or time based intervals (water pump, cam chain pads, IMSB, fuel filter, etc.).
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After all, it's a "performance car" and along with the positives come some negatives - partially due to how these cars are used (they sit around in the garage sometimes for weeks or months at a time, and then we jump in and "drive them like we stole them"...).
After all, it's a "performance car" and along with the positives come some negatives - partially due to how these cars are used (they sit around in the garage sometimes for weeks or months at a time, and then we jump in and "drive them like we stole them"...).
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Suggestion
The key is to drive it, and maintain it - 5k mile oil changes are a must, using a high quality oil (not even going to open this can of worms - read, read, read), address certain issues at set mileage or time based intervals (water pump, cam chain pads, IMSB, fuel filter, etc.).
The key is to drive it, and maintain it - 5k mile oil changes are a must, using a high quality oil (not even going to open this can of worms - read, read, read), address certain issues at set mileage or time based intervals (water pump, cam chain pads, IMSB, fuel filter, etc.).
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Suspected cause
If there isn't anything wrong with the bores with the piston at TDC, it was likely a dirt particle or some other fod that scratched the bore and likely isn't bore scoring.
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So I got the car I've been looking at/negotiating the price on PPI'd today (2001 C2). Superficial engine things checked out, spark plugs all looked good, Bank 2 was fine, but when we got to Bank 1 (driver's side), we noticed slight bore scoring in cylinder 1. It was not as sever as the photos on Jake's site (
http://flat6innovations.com/cylinder-bore-scoring/
) more like an area about 45 degrees of the cylinder wall and not very deep or pronounced. This is on a dealer maintened engine with 79K on it plus IMS Solution installed at about 60K.
So, how bad is this? Cananyone say anything about the expected affect on performance or the expected longevity? Or, is it simply a diagnosis of "it will continue to get worse and there is no telling how fast it will degrade?
Any experienced or educated answers are welcome and appreciated.
Thanks
Smith Volvo? I thought bore scoring was uncommon on the drivers side especially a consistent mild climate like California where is the car from originally? Sounds strange.
It isn�t going to get any better with time. I find it hard to believe that with the cost associated from rebuilding these engines, you would consider purchasing one with this sort of an issue?
The piston goes up and down in the bore at least 700 times per minute, and as many times as 7000 times per minute. If the bore is scratched, scored, pitted whatever, it�s living on borrowed time, Once the lining is compromised the wear continues at an elevated rate.
True, this is counter to most information that is being thrown around. However, I have a sample size of one that indicates this is not so strange. My engine only showed traces of bore scoring in cylinder #1. Then again, maybe there's more than one case of this...
i think climate is just one aspect. Another is how long do you let the car sit after starting before driving off. Also, it may just be luck of the draw!
Well, if it's not "sever", it's definitely not a problem...
There is no such thing as "ok" bore scoring - once it's there, it only gets worse. Tell yourself whatever you like, but problems like this don't fix themselves...
If I remember the information correctly any bore in the engine can score. True bank 2 is the bigger offender. However, any bore can score. It will not get better. Don't know how long it will last. Assume at this level it's NOT making any "ticking" noise??
DITTO on 808's question above.
There are so many 996s out there that I don't know if I would bother with one that has signs of bore scoring. When I bought mine its something I wish I would have known about, but like many I was concerned mainly with the IMS and the leaking RMS which were both addressed within 5 months of purchase. Over a year later it seems like bore scoring is a bigger potential threat. At least you can be retroactive about the IMS but with bore scoring you are more limited and eventually you will be building a new engine. So while I have no ticking its still in the back of my mind and one of these days I will scope it but if I had known more and my current car had showed signs I would have passed.
I suppose it's all relative. My daily driver has 208k miles, my truck has 62k miles, and my 996 has 15k miles. For my 996, I'd be surprised if i ever get up to 70k miles on it. I'm still new to these cars. I did some research before i bought, but I've only had mine a couple month so far. I did the IMS as soon as I got the car only to then discover more information about bore scoring. It seems that the more you read about these care, the more confusing it gets. I hear/see plenty of info that says these 996's are tanks and then read stuff that makes it seems like it's only a matter of time before the engine has some catastrophic failure. In the end, I've decided to enjoy the car as much as i possibly can! It's always been a dream of mine to have a 996, so I feel very fortunate to have one!
Keep on reading and weighing the "facts" (there are plenty of real and "alternative" ones floating around). ALL engines will eventually fail in some way - including the M96. It seems like the occurrence of engine failure is elevated here, but that's mostly a function of "the nature of internet forums" - i.e. people come here to commiserate with others who share their passions and problems. These cars (including the engines) are very well made/engineered - this is not to say that they have no problems - they do. After all, it's a "performance car" and along with the positives come some negatives - partially due to how these cars are used (they sit around in the garage sometimes for weeks or months at a time, and then we jump in and "drive them like we stole them"...). The key is to drive it, and maintain it - 5k mile oil changes are a must, using a high quality oil (not even going to open this can of worms - read, read, read), address certain issues at set mileage or time based intervals (water pump, cam chain pads, IMSB, fuel filter, etc.). Get "Tuned in" to the normal noises, feels, smells of the car and don't ignore when something changes or something new shows up - identify and address the cause as well as the symptom before it turns into something substantial.
Good luck
Not much to add to dporto's comments. But I agree with you. Drive it and enjoy it.
Do your homework and stay ahead of the oil changes. Especially if the car sits, undriven, for long.
Yes - there is plenty of confusing and conflicting information on these cars. Learning who to trust, and believe, is half the battle.
Welcome and best of luck with your "new" 996.
Every car will _eventually_ have some catastrophic failure - but not every car gets you in the feels like the 996 does. Don't save your 996 for the next owner...enjoy it while you've got it, don't overthink it.
[QUOTE=dporto;16387663]Keep on reading and weighing the "facts" (there are plenty of real and "alternative" ones floating around). ALL engines will eventually fail in some way - including the M96. It seems like the occurrence of engine failure is elevated here, but that's mostly a function of "the nature of internet forums" - i.e. people come here to commiserate with others who share their passions and problems. These cars (including the engines) are very well made/engineered - this is not to say that they have no problems - they do. After all, it's a "performance car" and along with the positives come some negatives - partially due to how these cars are used (they sit around in the garage sometimes for weeks or months at a time, and then we jump in and "drive them like we stole them"...). The key is to drive it, and maintain it - 5k mile oil changes are a must, using a high quality oil (not even going to open this can of worms - read, read, read), address certain issues at set mileage or time based intervals (water pump, cam chain pads, IMSB, fuel filter, etc.). Get "Tuned in" to the normal noises, feels, smells of the car and don't ignore when something changes or something new shows up - identify and address the cause as well as the symptom before it turns into something substantial.
Good luck
[/QUOTE
While those are good points for a new car owner, these cars are 20 years old plus. The manufacturer recommended oil changes at much higher intervals, This specific problem that has been found and there are no remedies that have been proven to work.
Pretty simple really, but the car and hope it doesn�t get worse, when it does address the situation by spending about as much as the car is worth, or move on to a car that doesn�t have these known problems that are associated with it. It�s really a monetary argument as if all of us had the money to spend,I for one wouldn�t be dealing with a 20year old car, but driving a new one.
[QUOTE=cdk4219;16387755]
Wow... talk about circular logic! It doesn't matter what the manufacturer recommended 20 years ago - it's clear that they were wrong. Nothing I recommended was pertaining to a new car purchase. If I wanted to drive a Lexus, I'd buy a new one. In fact, if I wanted to drive a 991 or 992 I'd buy one of those. The fact is, my 996 is perfect for me. I bought it for cash, pay for all mods with cash and have built it exactly as I want it to be. I couldn't go out tomorrow and buy another one like it. Yes, it's a monetary argument - These cars are WAY more expensive than the $15-$20k price of entry (which is about 1/4 or less the initial selling price when new). If you expect to be in for the long haul, it will cost you many times your initial buy-in price to stay in the game. If you're just testing the waters/thinking about this sort of purchase think hard and long before taking the plunge.
My question to you is , does it really matter? The guy is contemplating purchasing a car with evidence of the expensive problem. It may be different if he already owned the car and is trying to figure out when it�s going to go south, but he�s not. Would you buy this car knowing the fix is probably as expensive as the car?
If the car you own has developed the problem, either drive it or fix it. If your contemplating purchasing a car with this problem, at the price point these cars are, it would be better advice to move on and find one that doesn�t show signs of this particular known problem.
The real simple answer to the original question is that any bore problem that is found with a plated cylinder design isn�t going to stay the same or get better with time. The only repair that can fix the issue is costly. I really find it hard to believe that anything but this answer could be found on a Porsche forum, especially a 996 thread.
It does matter. It is usually bank 2 that scores first, not bank one. If there isn't anything wrong with the bores with the piston at TDC, it was likely a dirt particle or some other fod that scratched the bore and likely isn't bore scoring. Bore scoring typically starts at BDC and makes its way up the bore as the problem progresses.
The Lokasil bores are not plated - they are raw aluminum that is etched to expose the silicon matrix that supports the pistons and rings.
So you would suggest that the OP go ahead and purchase the car with the possible issues? Or better yet would you purchase the car with the possible issues?
If it was me, yes. That would be negotiated at time of purchase and I would just plan that I would be budgeting for a build at some time in the future. It's a calculated risk, as is purchase of any used vehicle.
Charles - you have my cylinder blocks. If you look at post #5 of this thread - that is a photo of cylinder #1. I did not detect any significant scoring in the other cylinders. Maybe I didn't look closely enough. What is shown in that photo: is that not bore scoring?
Regarding scoping bank #1 from the sump - is that even possible? I had a hell of a time even accessing #4 and #5 when I took a look.
I can't comment on anything as your original cylinders are aluminum chips already. From the picture, it looks more like scuffing, however that amount of damage would have been a downer regardless. It's possible coolant in your oil from the cracked #5 was the source of your abnormal cylinder wear.
We usually don't scope bank 1 from BDC as I have never seen a block with scored bores in cylinders 1, 2, or 3 without cylinders 4, 5, and/or 6 being scored.
Not having a picture of what the OP saw for the scratch in cylinder #1, I can't definitively say in his instance it's actually bore scoring or just a scratch from fod from poor air filtration.
this was one of my cylinders at 96k miles. The valve seat broke apart but I was idling at a gas station and turned it off within a second. Dunno if the scoring as due to the valve seat but sure doesn't look like it. Regardless, we chose to leave it as is.
Car went another 80k miles (Had 180k at castatrophic failure on track). Car had more than its fair share of 'hot suppers' and track time (at least 5-8 per year, every year since 1100 miles on the odometer when new).
You make the call.
How much money would you negotiate for this said car knowing the calculated risk is higher for this particular engine? And how much should he budget for this rebuild?
Thanks for sharing. This is why I asked my question. That's not bore scoring and is likely what they saw. That's from FOD (dirt, carbon off the top of the pistons) being ingested.
That's up to the seller and buyer to figure out, but a full rebuild is start at $20k replacing everything that needs to be changed on the car/engine. I used to say $15k, but these cars are getting old and there are lots of other items that are needing to be replaced that could be reused previously. At the end of the day, you end up with way more car, even though you're in the car more than it is worth. Just make sure you have stated value insurance coverage and plan on keeping the car for the long haul.
My call is scratches in cylinder #
2
(#5) from the valve seat debris being scraped along the bore before you were able to shut it off.
Let me guess what took it out catastrophically at 180k - d-chunk. Your photo shows the start of cylinder cracking in #
1
(6).
Did the spark plug from that cylinder look any different from the others?
It is also possible to pull the headers and look at the exhaust ports. Any cylinder experiencing scoring or any other damage that would cause oil consumption will result in the exhaust port for the cylinder having lots of oily deposits.
No, all six of the plugs looked good. It may be possible to pull the header if I negotiate a lower price with the seller. Previous to the PPI we were at $10K in cash plus $5K in trade for marketing services.
As to oily deposits, would heavy oil/dirt deposits at the bottom of the throttle body T-pipe be an indication of excessive blow by which might indicate scoring or excessive cylinder wear?
No, that is normal. In lieu of a running compression and leakdown test, they can take a manometer reading and that is an overall indicator of engine ring seal. Should be 4.0-6.0" h20 as a very general rule of thumb on a stock engine.
Thank you for the input and ideas, Charles, I really appreciate it.
If the engine ring seal came in within those specs, does that point less toward bore scoring and more toward scuffing?
From what you described, I'm thinking it's not even scuffing. It's a scratch from debris ingested by the engine.
If the seller hasn't changed the oil in a few thousand miles, a used oil sample would show scoring, or at least the start of it, reflecting added wear in the area of Silicon and Aluminum content, which are typically low single digit numbers in these engines. The anti-wear package also would reflect a reduction in available ZDDP based off prior UOA analysis of engines with scored bores.
tough to say really on what the initial cause was because EVERYTHING broke. Pistons, con rods, crankshaft snapped in half. pieces of cylinder missing, etc, etc.
Ironically, the IMS was fine :-)
But it's all really a guess and at a 180k miles, she gave her best (and I got so much out of the car over the years). It went coming out riverside onto the esses at Buttonwillow, chasing a 997 GT3RS, dying the way it was intended until she hits the road and track again next week after a 3 year haitus.
Good birthday present then and now.
Thanks! I'm loving it so far! Spring time cannot come fast enough! What's your opinion on oil change? I'm not going to put a whole lot of mileage on it, so is it something that should be changed every 6 months, 1 year, etc?
Hi Charles, what manometer readings are you getting on an engine with scored bores/bad ring seal?
I have a simple method of measuring the actual blow-by in liters/min,( and eliminating the AOS as a variable) but the examples I have tested while at the dealership were all low mileage examples, and sense I have retired my only test subject is my own 996's and a few others.So I don't have a lot of data points, but I can share this method and chart if interested.
Charles, in that 4.0 to 6.0 inches of H20 range, is a higher number better overall? Attaching manometer to a second oil cap yields ~5.6in at idle on my '99 C2. Thanks for whatever input you can provide.
I can't give a straight answer here. 4 to 6 is a general rule of thumb. For example, if you have Total Seal gapless rings, you can max out the manometer with 15, 20, or more inches of h2o, however readings that high on an m96 or m97 engine with a stock AOS usually indicate a faulty AOS.
For reference, I have a stock 2.7 engine in my 99 Boxster at the moment with a Motorsports AOS and it reads 6.5 to 7 inches of h2o.
Yes. This is the tool we use. It was developed by Tony Callas and comes with adapters for most models as well as his guidelines for testing and evaluation.
https://lnengineering.com/products/t...ment-tool.html
This is a source reference. Confirm exact model applicability in the original material.
