When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
Charles (you are the only one that can empirically answer this I assume) : What would the flaking of the piston cylinder coatings show up as, if at all, on a UOA? Is it Silicon, or is that (Silicon) from the cylinder walls in addition to aluminum?
Unlikely. The particle size is likely larger than what used oil analysis will see. Blackstone's ICP process can see up to 5 microns and Speediagnostix's RDE process can see up to 10 microns. You are more likely to see pieces stuck to the magnetic drain plug (if one is fitted), in the filter, or in the sump. That said, the UOA will show increased aluminum, silicon, and iron content.
Thanks Charles.
So the piston coating is considered a "metal" and is ferrous ,if so, what, Iron? To clarify my overall question - I am asking if there is no scoring on the piston walls yet, however, flaking of the piston coatings has begun as a precursor to scoring - how can this be evidenced in a UOA assuming all the wear metals you mention above are within normal trends / ranges on the UOA? Or, are you saying that due to micron size of the piston coating material that is 'flaking' off (whatever material that is) the UOA will not pick up on this, however, you may see it in the filter or sump showing up looking like what (shiny silver, dull silver, brown / tannish the color of the piston coating , ferrous or non ferrous ferrous )?
Sorry for the detailed question but most of us here are of the super analytical mindset , which of course has its pros and cons....
Thanks Charles.
So the piston coating is considered a "metal" and is ferrous ,if so, what, Iron? To clarify my overall question - I am asking if there is no scoring on the piston walls yet, however, flaking of the piston coatings has begun as a precursor to scoring - how can this be evidenced in a UOA assuming all the wear metals you mention above are within normal trends / ranges on the UOA? Or, are you saying that due to micron size of the piston coating material that is 'flaking' off (whatever material that is) the UOA will not pick up on this, however, you may see it in the filter or sump showing up looking like what (shiny silver, dull silver, brown / tannish the color of the piston coating , ferrous or non ferrous ferrous )?
Sorry for the detailed question but most of us here are of the super analytical mindset , which of course has its pros and cons....
Yes, the coating is iron and will show up in used oil analysis but only if the particle size is small enough to be seen. That's why I recommend looking at the silicon and aluminum in conjunction with the iron levels as that typically points to cylinder bore scoring. If the coating is already compromised on the piston, it's just a matter of time. Of course using DT40 or even FR50 or DT50 (not for colder climates) will add extra cushion and extend the life of the engine.
The only time you will see the iron coating is if you find a chunk of it, like in this photo:
This is all based off recent memory but is pretty accurate. I have exact numbers/dates around, but I'm not an organized person.
2005 m97 997.1 C2 6MT Purchased November 2022 w/ ~75k mi Currently ~79k mi Light bore scoring in all cylinders
No IMS issues
Bore Scoring: Minor bore scoring found in all cylinders via spark plug scope around March Normal oil analysis results via Blackstone Labs @~77kmi No tick, save for one time after a very spirited drive No issues at this point
More info: Initial condition: Car operated well, but I noticed a coolant leak after a couple weeks of ownership. Coolant was the wrong color. I took it in, it needed a water pump and a cooling system flush.
Driving habits: (rounded to nearest percentage from back-of-napkin math)
10% of driving is done in San Francisco amongst our steepest hills for school drop off
~20% is highway driving between San Francisco and Marin County
~70% is above 4k RPM along the California coast and in the mountains (FYI I'm a very cautious driver—I'm a cyclist on the same roads).
I will be tracking the car shortly (this weekend at Thunderhill 5 mi if my shifter install is finished, November at Sonoma) and will adjust the numbers as I go.
Just submitted my FSI/LN Gauntlet Form and hoping to get in!
My Porsche dealer sold me a 2009 911 C4S in December 2020. It had 80,000 km on it. Was told it was perfect
I was told it wasn’t driven in the winter here in Québec Canada during previous ownership. I use the car in the Canadian winter and love it.
From the very beginning of my ownership, the car took a liter of oil par 1000 km. The Porsche dealer looked at it, use the camera and ruled out bore scoring. They have been adjusting free of charge the oil level ever since, every time the low oil lever light turn on.
I still use the car as a daily driver and doing long trips north regularly from Montréal. Situation is still the same. I am now at 157,000 km after about 3 years.
Still going strong, still burning oil, still going regularly to my Porsche dealer for oil level adjustment.
At least, the car is being wash at every visit!
Last edited by Onoto; 11-18-2023 at 09:38 PM.
Reason: Adding one piece of information
So at 80,000 km it burned 1 liter/1,000 km and now at 157,000 km the rate has remained completely constant still at 1 liter/1,000 km? If your bores were scored I would be shocked if the oil consumption remained constant over that period. I am wondering if the engine wasn't broken in properly and the rings are inhibited. To be thorough, do you know how the camera was used? Did they inspect the cylinders through the sump? This is critical on this engine and the bore scope must be done correctly.
If you have a manometer I would measure the crankcase vacuum. I would also get an oil analysis to levelset.
Silver_TT Sir,
Thanks for a quick answer to my post. I highlighted the suggestion you are making and will do my best to get answers to. I will have a conversation with the chief mechanic at Porsche and see. Will post answer answer I get. Will also look for a lab to get the oil analysis. Thanks for suggestions.
If your bores were scored I would be shocked if the oil consumption remained constant over that period.
I am wondering if the engine wasn't broken in properly and the rings are inhibited.
To be thorough, do you know how the camera was used?
Did they inspect the cylinders through the sump? This is critical on this engine and the bore scope must be done correctly.
If you have a manometer I would measure the crankcase vacuum. I would also get an oil analysis to levelset.
Yup, increased side wall forces with the offset going the opposite way (maybe why the piston only wears on the thrust side). I also believe that having the piston come out of the bore 7mm at BDC changeover (on the 3.6 and 3.8) doesn't help this issue any.
Its almost like Porsche should have made the M96/M97 pistons with no offset, so at least the right bank would have the same benefit (none) as the left one. Would that have increased chances or scoring on bank 1 and reduced it on bank 2 ?
I take it that pistons can't be rotated on the wrist pin 180 degrees to get the offset the same on both banks, due to the fly cuts in the piston head for valve clearance being matched to the intake/exhaust valve head diameters, and or squiter alignment.
Is it wise to have a PPI and Bore scoring scope done at a Porsche dealership that has history with the vehicle and current owner? Would you worry about a possible bias?
I’m looking at purchasing a 2006 CS2 w/45K miles and Trip trans.
Is it wise to have a PPI and Bore scoring scope done at a Porsche dealership that has history with the vehicle and current owner? Would you worry about a possible bias?
I’m looking at purchasing a 2006 CS2 w/45K miles and Trip trans.
I would tend to go 3rd party. I'm pretty sure my local Porsche dealership may have contributed to the scoring on one of the cars I was looking at. It was a very low mileage 2008 C2 3.6. I was shocked to find out that it had initial scoring because of the low mileage, warm climate and extensive service history. Later I saw the tech's getting cars ready for scheduled test drives. They would walk around the lot with a roll-around battery jumper, start the car and then hold it at like 4,000 rpms (cold!) to charge the battery. Yikes! I don't feel like Porsche dealerships (even the techs) consider scoring a problem. Or at least it's not their problem.
I would tend to go 3rd party. I'm pretty sure my local Porsche dealership may have contributed to the scoring on one of the cars I was looking at. It was a very low mileage 2008 C2 3.6. I was shocked to find out that it had initial scoring because of the low mileage, warm climate and extensive service history. Later I saw the tech's getting cars ready for scheduled test drives. They would walk around the lot with a roll-around battery jumper, start the car and then hold it at like 4,000 rpms (cold!) to charge the battery. Yikes! I don't feel like Porsche dealerships (even the techs) consider scoring a problem. Or at least it's not their problem.
YIKES is right - what is the dealership so we can avoid?
Is it wise to have a PPI and Bore scoring scope done at a Porsche dealership that has history with the vehicle and current owner? Would you worry about a possible bias?
I’m looking at purchasing a 2006 CS2 w/45K miles and Trip trans.
There is a bias for the reason you state but the main problem is that when you go to a dealer you don't know who will be working on it. Dealer mechanics range from terrible to solid like many professions. My main concern would be that most dealer mechanics have never done a borescope procedure and have no experience looking at the images. It is easy to see things that aren't there or miss things that are there if it's your first time doing it and you don't know what you are looking at or how to get to it. You have to be patient and have the right bore scope, and it's easier if the car has sat on the lift overnight to let all the oil drain out. A good indy is better than your average dealer mechanic. One of my cars was at the dealer earlier this year to have $15K+ of work done on it (insurance). The dealer mechanic was so bad he didn't hookup one of the lines to the transmission correctly and almost took it out -- fortunately it was me driving the car and not my wife and I stopped driving it and got it back to them immeidately.
I had two close run-ins with scored engines the past two months. One was an '08 3.6 for sale at a Volkswagen dealership. Thankfully I was doing some google searching and found that someone else had scoped the car and posted the results to Reddit. He told the dealer what he found, backed out of the deal, and of course the dealer said nothing to the next guy (me) that came along interested in the car.
The second was an '06 3.8 that was being sold by a very reputable dealer in Florida. It was a very well-spec'd car and had a stack of maintenance records. Mileage was 55k. I told them I would buy it if they scoped the engine. They found scoring but refused to take it seriously. So I walked away. They sold the car the next day to the next guy on the list. So frustrating.
I had two close run-ins with scored engines the past two months. One was an '08 3.6 for sale at a Volkswagen dealership. Thankfully I was doing some google searching and found that someone else had scoped the car and posted the results to Reddit. He told the dealer what he found, backed out of the deal, and of course the dealer said nothing to the next guy (me) that came along interested in the car.
The second was an '06 3.8 that was being sold by a very reputable dealer in Florida. It was a very well-spec'd car and had a stack of maintenance records. Mileage was 55k. I told them I would buy it if they scoped the engine. They found scoring but refused to take it seriously. So I walked away. They sold the car the next day to the next guy on the list. So frustrating.
Would you mind posting the link to the reddit post? I had a similar situation with a 2008 3.6 with 31k miles on it. I was surprised it was already scoring.
Saw a 2008 C4S Cab with 118,000km (~73,320 miles) for sell in Vancouver, BC. Drives fine and interior looks mint. Found an independent shop do a PPI and drop the sump pan for boroscope, no scoring but found a long crack on bottom cylinder 5 (left bank), and I back out the deal. Too bad cause the car run and drives great. The mechanic saw the crack and can't recommend the purchase which I agree.
According to CarFax the car spent its first 10years in East Coast (Ontario) (spotted some rusty header and exhaust bolts), that why I picked a shop to do the scope from the sump instead of spark plug openings. Did some research here on Rennlist and thanks to all the enthusiasts here.
On to the search for the next one....
the rust does look more of an issue once it is on the lift crack on cylinder 5
09-28-2023, 09:30 PM
