plpete84

According to the comments on youtube, he was running LiquiMoly 5W40, which is not the best choice. He would mostly short shift at 6500rpms which I suppose is what he intended to not hit the red line. I think this may have to do with oil starvation and a not ideal oil for how hard the car was being pushed. There is a Oil Pressure Stability thread over in the 996 land where it's been proven that many of the deep sump options don't necessarily produce the results that are advertised.

Carreralicious

Are you saying that by not hitting redline, it further worsened the problem?

plpete84

Not at all. Just clarifying. From the video, the guy said that he was short shifting during each session. Whether shifting at around 6500-6800rpm actually counts as short shifting is up for debate when the red line is at 7200, I suppose.

Wayne Smith

Lower revs during situations requiring high torque can cause the crankshaft to back feed more load between the piston and the cylinder wall. But that is usually a consideration for much lower revs that incite bogging.

Dk27

Is it more or were his downshift blips going over redline too? Also the video cut out, but did he just shut the engine off with the oil temp that high. I tend to run my last lap slow, and then in the paddock tool around until oil temps are close to 200. Even on 90+ days my oil temp was never that high though. I have a similar setup only with the added LN deep sump. Even with the sump long right hand sweeps you'll see pressure dip, with the scavenger pumps not able to return the oil in the heads. check out this thread with a lot of good data and convo on the oil pressure to this point:https://rennlist.com/forums/996-foru...stability.html. Also there is a solution being worked on here for the m96/97 engine :https://rennlist.com/forums/996-foru...ds-v2-2-a.html

groovzilla

Watching the video is just another great example of why I would never buy a car that has been tracked.
I remember having arguments in the 996 forum about tracked cars and most guys tracking their car trying to convince me a tracked car gets no more abuse than a non-tracked car.
Just watch some videos of rookie track drivers and easy to understand my logic.

Bruce In Philly

I totally agree... there are a few pieces of twisted logic here: 1) Porsche engines are made for tracking.. so no extra wear, and 2) Anyone who tracks a car knows what they are doing. Phooey... I spent some time on the track with my Boxster S.... it is tough on a car.

Peace
Bruce in Philly (now Atlanta)

DesmoSD

He kept on driving too. That's probably what put it over the edge.

At 8:00

bheit1

From what I've read bore scoring is primarily caused by high revs in cold weather before the engine is warm. The rings expand faster than the surrounding cylinders and tend to bind. In cold weather drive at about 2k rpm or less until the oil warms. Or better yet, store the car when it's cold. The suggestion for a third radiator doesn't make sense. You want the engine to warm up as quickly as possible, without destroying it.

Petza914

Actually, you don't. You want the engine to warm up as gradually as possible and why the Low temp thermostat is desirable. Scoring in a 997.1 is not caused by the piston growing too fast relative to the cylinder bore - it's it's the opposite where the bore is growing too fast because there isn't good coolant flow (which is why it usually starts in #6 which is furthest away from the thermostat when it opens) and then the piston rocks in the bore, the skirt hits the wall, and that's where the scoring begins. Look at photos of bore scored 997.1 Pistons and you'll see this is the contact area. The 997.2 seizea the way you describe where the piston gets too tight in the bore. The LTT which opens earlier allows the aluminum Pistons and aluminum block expand at a more consistent rate preventing the slop in the cylinder and the piston rocking.

mick997

I guess adding a 3rd radiator with extra cooling positioned before the LTT on m97 engine would delay the thermostat opening - so counter intuitively the 3rd radiator in the warm up stage may make this worse . Its because the LTT is at the inlet to the block not after … under hot track conditions a 3rd radiator when the LTT is open anyway - it would be helpful in providing extra cooling … thought for the day

sandwedge

Very easy to understand and I agree 100%. What's not as easy is to confirm if a car has been tracked or not no matter what the seller says. DME history may be the best evidence.

PV997

This is a great point, the 997.1 and 997.2 have very different engines with very different bore scoring mechanisms. That's why the failure signature and failure rates are so different, in the 9A1 Porsche reduced the cause of the M96/97 scoring, but inadvertently introduced a new scoring mechanism (the siezing issue). Fortunately it appears to happen at a much lower rate than that seen on the 997.1, at least so far.

Good advice for both engines is to not lug the engine and to keep the revs low until the oil is at operating temperature. These are at potentially at odds with each other so it effectively means babying the car until the engine has reached a uniform temp. The goal is to keep engine stresses low at first so the pistons/cylinders can expand uniformly and reach equilibrium. After that have at it.

Beyond that mitigations (thermostat, oil type, etc.) are probably specific to the engine I would think.

cbredesen

How warm and by which measure? Sorry for the noob question but my coolant temp comes up pretty quickly but oil temp takes quite awhile.

Fullyield

oil to operating temperature.