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YOUR RESEARCHBorescoped my 996's cylinders. How do they look?
Leading reported evidence
Fill sump
Performed · outcome unconfirmed
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Performed · outcome unconfirmed · Original poster
5) At 39,200 miles, I had the IMS solution installed and the shop filled the sump with Total Quartz 9000 5W40.
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Performed · outcome unconfirmed · Original poster
I am running the Bilt Racing kit that adds about an inch to the sump along with upgraded baffles and oil return pieces.
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Regarding oil, I ran Miller Nano 40 for over a decade on the street and track but recently went to Driven DI40 on the recomendation from Lake Speed.
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So it recomended reducing the amount of oil used so it didn't overload the FAOS.
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Suggestion · Original poster
Sorry, for some reason I'm not getting email notifications about replies to this thread and I forgot to check back until now.
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Suggestion
which allows us to run 1-2 qts above full which helps dramatically in improving oil pressure and mitigating oil starvation, which the FAOS and MAOS cannot do.
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I picked up an endoscope and borescoped my 911's cylinders. It's got almost 50K miles on it, and figured I'd see what the bores looked like before possibly doing something dumb like buying a supercharger for it. Please have a look and let me know what you think. To my untrained eye, they all seem to look fine.
Car runs well, makes good power, doesn't smoke, doesn't have any external symptoms of bore scoring that I am aware of.
Here is cylinder 1.
The look perfect... exactly what most owners would HOPE to see.
Some big questions to satisfy the curiosity of others...
1. What year and model of 996?
2. How many owners?
3. Where did this car spend most of it's life?
4. Maintenance history: Was the engine ever replaced or rebuilt? What was done to the engine to keep it healthy? Mind sharing the serial number to date it?
5. What oil do you use? haha (coughs) I couldn't help that one!
Thanks!
I thought bore scoring on the M96 generally starts from the bottom of the cylinder and not the top? If so then the OP really should take a look through the sump.
1) '02 911 Cabrio 6MT
2) Not sure how many owners. I probably ought to run a Carfax on it.
3) I bought the car in February 2020 with 38K miles on it from a guy in his 50s on the east coast (Pennsylvania, IIRC). I'm not sure how long he owned it or how he drove it. The 911 is now a few hundred miles away from 50K.
4) The engine hasn't been opened up since I bought the car. I am running the Bilt Racing kit that adds about an inch to the sump along with upgraded baffles and oil return pieces. I installed that kit because I noticed oil pressure fluctuation issues on extended right corners during track duty--sometimes down to as low as 2.5 bar. (The car probably has about 200 minutes of track time on it. Three track days of four 20-minute sessions each, but I didn't run all 12 sessions.) The Bilt Racing kit reduced the fluctuation almost completely--the needle might move a little bit, but I don't think it's ever gone below 4 bar.
5) At 39,200 miles, I had the IMS solution installed and the shop filled the sump with Total Quartz 9000 5W40.
--At 42,200, I changed it for Mobil1 Turbo Diesel Truck 5W40. It seemed to be more prone to aeration as I would sometimes get a cloud of smoke on the first restart after a track session. (I'm assuming oil in the AOS, which I assume is original.) I installed the Bilt Racing kit during this oil change interval, probably around 43K miles. I drained the oil into a clean container and reused it after installing the kit.
--At 46,000, I changed to Joe Gibbs Driven DT40. This seemed a bit more prone to consumption as I had to add.. I forget, a half quart, maybe a quart, during the oil change interval. I did the 911's last track session during this time, and no more cloud of smoke on restart after track time.
--At 49,000, I switched to Mobil1 5W50 European Car formula, since it meets the Porsche A40 spec and I figured it would be less prone to consumption, and I've heard that the M96 runs its oil kind of hot so I figured the extra viscosity of the 50-weight would provide better protection. However, it seems like the oil pressure gauge takes slightly longer (a split second? a second at most?) to go up to 5 bar on cold startup. Presumably because the 5W is more like a 10W if you look at the viscosity at 32F. I don't really feel like the added viscosity when hot is worth the slight delay in oil pressure on cold startup. When I say cold, I mean ambient temp that is anywhere from 50F-90F.
--I'm probably going to do a premature switch away from 5W50 to Mobil1 0W40 Supercar. It doesn't have a Porsche rating, but GM bills it as the one-size-fits-all oil for street and track use in the LT4 (supercharged 6.2L) engine found in the Camaro ZL1, C7 Corvette Z06, and Cadillac CT5 Blackwing. The Z06 runs its oil HOT on the track, usually in the 280F range, and GM says 0W40 Supercar can shrug that off no problem, so the M96 shouldn't have any issue.. That said, I probably won't do any more track days with the 911 as I have at least two other cars better suited to that sort of work.
I rotated the crank so the pistons would be at the bottoms of their travel for each cylinder. I realize that there could be scoring farther down in the bore but, since the rest of the pistons' travel ranges look okay, I probably won't go pulling the oil pan unless I have some other compelling reason to do so.
You are doing the right things. Just keep changing the oil and make sure it's fresh for a track day.
Two things.
1. Make sure you have a fresh water pump.
2. Get the UAOS Track and run an extra quart of oil over full. It will help with oil pressure on the track and it will mitigate puffs of oil from your exhaust.
Water pump? I assume that's because of the impeller pump breaking? I'd forgotten about that being an issue. Stock Porsche water pump, or something different?
As far as the oil level goes, I thought conventional wisdom is that we're supposed to fill it so that the in-dash fuel-level checker was about halfway up. And that filling higher than that could result in aeration. Do you run a 40-weight or 50-weight?
I probably won't do any more track days with the 911, but when the factory AOS fails, I'll get the UAOS track version.
Yes, with the water pump, it's best to replace it every 5 years or so. If the blade breaks off, it can lodge in the head and will create excessive heat and then cracking. Easy to prevent with a fresh water pump.
Regarding oil levels, the Porsche realized it had a problem with the Factory AOSs (FAOS) inability to handle oil levels at full. So it recomended reducing the amount of oil used so it didn't overload the FAOS. The kicker is that running less oil is not good for oil pressure nor good for mitigating oil starvation. So Porsche developed the Motorsports AOS (MAOS) which was more durable than the FAOS on the track. So we all went to it. This allowed us to run the oil levels at "full" versus "partially full".
However, the UAOS Track version was developed over the last few years by
@porschetech
which allows us to run 1-2 qts above full which helps dramatically in improving oil pressure and mitigating oil starvation, which the FAOS and MAOS cannot do. It also eliminates running coolant thru the AOS which both the FAOS amd MAOS must do, which mitigates intermix risk. In addition the UAOS diaphram is 2x thicker than the FAOS and MAOS and its design positions the UAOS diaphram in the engine bay so it can be replaced in less than 5 min saving time and money.
Regarding oil, I ran Miller Nano 40 for over a decade on the street and track but recently went to Driven DI40 on the recomendation from Lake Speed. I have run it for the last year and half on the street and track. My engine likes it and oil tests are good. I am about to go to DI50 since I now have enough tests on DI40 to see how the engine responds on the track. But plan on running DI40 in the cold weather months in Chicagoland
The failure point on the water pump is the actual bearing of the impeller, which in turn causes the impeller to come lose and start to cause damage. If you have a metal impeller, it will grind away some of the block casting but should stay intact. On the other hand, plastic shouldn't cause the same type of damage to the block but you're risking the plastic impeller breaking up into pieces and blocking the water passages as bits of it flow through the engine. Both are bad clearly, which is why it's too easy of a job to not replace the water pump every 60k miles or so. At the very least, pull the drive belt and check if there is any play on the pulley once a year. It takes less than 10 minutes to check and you can do it while draining your oil.
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