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View Poll Results: Poll: Have you had bore scoring on your 997.1 or 997.2 engine?
Yes, 997.1 (05-08 MY)
Yes, 997.2 (09-12 MY)
No, 997.1 (05-08 MY)
No, 997.2 (09-12 MY)
Voters: 317. You may not vote on this poll

Poll: Scored cylinder failure for your 997, Y or N? tell us (yr, 997.1 or 997.2)


Old 09-05-2017, 12:55 PM
Join Date: Dec 2014
Location: MidWest
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Originally Posted by Sporty View Post
Note that all the people saying "no bore scoring" most likely really mean that they have not exhibited external symptoms yet (if they ever will that is). My point is that without a proper borescope you just don't know, and even then you may not be able to diagnose 100% (according to the master Jake R).
Has anyone with reasonable mileage scoped their car and found absolutely no signs of wear? I feel like some wear is inevitable with a boxer engine.
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Old 09-05-2017, 04:23 PM
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Originally Posted by snethss View Post
Has anyone with reasonable mileage scoped their car and found absolutely no signs of wear? I feel like some wear is inevitable with a boxer engine.
My car was scoped at about 130k miles and tech said nothing unusual was found. But it did have a very high rev life and presumably the kind of frequent oil changes you'd expect in a track car.

It burns about a liter in 4k/miles. Motul 8100 5-40.
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Old 09-08-2017, 11:28 AM
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Anyone using this data for a future lawsuit?
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Old 09-12-2017, 10:18 AM
Join Date: Nov 2009
Location: bolton uk
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Just looked at the statistics you have provided and I think using the whole number of both types of car to assess the percentages is misleading.

From your own figures for the 997.1 the failure percentage is 15% (one in every 6 and a half cars) and for the 997.2 it is 2% (one in every 50).

This makes the 997/1 15 times more likely to score than the 997.2.

It is also interesting to note that many 997.1 cars are driving OK, no oil consumption problems nor signs of a problem but have actually already started scoring (about one in 3 we find) - but this I usually only damaging one side of the piston (the thrust side) and usually only on bank 2 and will probably only deteriorate very slowly over more than 10K, whereas the usual scoring mode of a 997.2 is perfectly Ok for a long time then a full seizure on both sides of the piston and is usually terminal when it occurs and they are much younger and on average have covered less miles - still far less likely to occur but time will alter the figures.

The 997.1 failures are more related to piston coating loss and the deterioration of the silicon particle bonding in the cylinders releasing particles to interfere with the piston coating whereas the evidence we have so far uncovered suggests that the 997.2 failures are more associated with a very slow process of the bores in some cylinders shrinking in diameter in the thrust direction and eventually pinching the pistons (especially when driving with too much power while the whole engine is not fully warmed up).

This means that 997.1 cars are probably really failing at a higher percentage than the present 15% and 997.2 will probably increase in failure numbers more rapidly as mileages and hot cold heat cycles increase promoting shrinkage.

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Old 09-12-2017, 02:07 PM
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^^^Garbage in, garbage out.
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Old 09-21-2017, 11:17 PM
Join Date: Jun 2012
Posts: 48

quick update, my 997.1 started ticking in the 80km in Southern Ontario. this mid year i passed emsissions, and now today crossed over 120km. it is much louder but it does not seem to want to die.

only change is running liquid moly 10W60 year round and burns about 1 litre per 1,000km or less.
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Old 11-27-2017, 02:44 PM
Join Date: Oct 2017
Location: Canada
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Well unfortunately suspicions were confirmed..

997.1 (M96.5)
scored bores on Bank#2 Cyl 4 and 5. Cyl 6 looks ok still.
Original complaint was higher than normal oil consumption at ~ 1L/900km (although still within Porsche specs). Smoking at cold start (occasionally depending on what angle I parked at)

Car still runs fine, bank 2 (LH side) tail pipe does look blacker than the other. Plugs looked ok, but cyl4 and 5 were oily (not sure how old they are). Oil filter was inspected at the last change and was perfect.
Looks like I'll be planning a bottom end build. Maybe 3.8? Stay tuned..
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Old Today, 05:28 AM
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997.1 2007 4S X51 66k miles, bores inspected at 65k and nothing unusual reported. No measurable oil consumption over the last 1000miles.
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Old Today, 05:08 PM
Join Date: Nov 2017
Location: Chicago
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Has bore scoring been found to be mileage dependent? Is there a mileage at which problems most commonly crop up, if they do occur?
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Old Today, 05:37 PM
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Join Date: Dec 2011
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2006 C4S with 77000km (48000mi)
Just had the engine scope and found scoring in all the cylinder bore. One had a bit of oil seepage.
In the 3000km we've had it show no oil consumption at all and no startup smoke. No trace of burnt oil on the tailpipe.
Had 16 ignitions at Range 6(!) but that was at 600hrs. 1900 on it now. I don't believe that is an issue at this time.
What was recommended and done were to go to a lower temp thermostat and a higher zinc content oil Motul 5w-40 X-cess (not shilling just stating the facts)
I'll keep everyone updated for any changes. Fingers crossed
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