jimmiepop

Confirmed. Shopping for a Southern TT. That said, I am told the TT is not exempt.

jimmiepop

Every anecdote I've read has the same pattern. Initially its tapping. Trip to shop. Fouled plugs cure in short term. Oil consumption spikes. Performance deteriorates. Ultimately needs a new engine. Definitely not a "non-issue."

CaptJim

Thanks, plugs fouling is key here for me towards engine failure.

Flat6 Innovations

Until considerable oil consumption occurs a compression test and leak down test will bot show no signs of an issue. Why? Because the issue starts with a tapping sound like a bad lifter and this begins at BDC, well below the lowest point of the cylinder where piston rings travel.

The TT engines have more built in factory clearance than the S engines due to being boosted, this is why they do not have the problem as badly. It still occurs, though.

I called it a few weeks ago when Most of the USA and Canada was seeing near or below zero temps. I knew we'd see huge numbers of "ticking engines that need lifters" in the coming months.. Those engines don't need lifters, they need cylinders and we received three more of these failure calls today.

hahnmgh63

Do you think the Turbo engines oil piston sprayers are a big help too? They do spray the bottom of the pistons and the cylinder walls as the pistons are on the Up Stroke.

Flat6 Innovations

While the extra lubrication can't hurt, the jury is still out on how much volume the squirters can actually move when the engine is stone cold and so is the oil. I add the squirters to all my Cayenne S engine builds anyway, for good measure.

The fact of the matter is the clearances are too tight when fully contracted and piston composition adds to that.

When the cylinder becomes contracted and the clearance goes away, oil doesn't matter as there's no way for it to get into the wear surfaces.

Keep in mind, the piston squirters deliver oil into the under side of the piston crown and not directly into the cylinder. This is done to keep the pistons cooler more than anything, and for that purpose it odes a great job. Of course having oil under the piston can deliver more into the oil control rings to lubricate the cylinder, BUT if the clearance is inadequate nothing in the world is going to solve that primary condition other than serious internal modifications to include different clearances, wear surfaces and piston composition. Thats what I do.

ndx

What about 958 2011+CS engines did Porsche correct this issue ?
Or they just let it slide for so many years ?

2011+CS is not the same exact motor as the previous V8 4.8

Flat6 Innovations

I received a call from a 2012 owner with the same symptoms as described in this thread last week. Looks like it may be inbound from Canada, if so I'll let you guys know what I find.

wrinkledpants

Do you know much about the park heater that the ROW has? I believe the TDi tregs have them (not sure on the diesel cayennes), though the operation is completely automated, and mostly to allow cabin heat since it takes so long for them to heat up. I don't believe they operate when the vehicle is off - at least in the US. I've seen write-ups, though, where owners retrofit the overhead console from the ROW cars, plus the remote, so they operate as a "park heater" in that they'll run and on a timer or with a remote. Wonder if this would be a way to negate the cold start issues that seem to cause the cylinder scoring. Fuel line plumbing, retrofitting the webasto heater itself, new HVAC control unit - I mean it won't be a cheap retrofit.

mcbit

As previously mentioned, conventional wisdom states that the forged pistons should have more clearance as cast pistons are in general more dimensionally stable. The fact that the majority of problems are in normally aspirated engines with cast pistons would seem to negate this theory. Additionally if a piston becomes tight because of clearance issues it is likely to score both sides of the bore which anecdotally is not the case.

Flat6 Innovations

It would take a lot of heat to warm the entire block and a long time for it to warm the deepest parts of the engine. My block heater arrangement couples to an auxiliary electric water pump that cycles on every few minutes to circulate the coolant.. The electric water pump is ran from a 12V DC converter from 110V AC power, just like the block heater.

Its an expensive and complicated product, thats why I have not distributed it yet.

This is depending upon the silicon content of the piston's material, not just that its "forged". Of course, the same holds true for the entire block.

Not really, because the TT engines have more factory clearance built in, and there are some S engines with forged pistons, too. The same conditions and symptoms apply to the S engines regardless of forged or cast.

No, because the engine uses the same piston for both banks of the engine with a single offset. This means that the issue will always tend to follow the offset as load is heavier on that one side of the bore. The offset of the Cayenne pistons is perfect for one bank of the engine and backward for the other. This is why one side must get very bad to start making the ticking sound, while the other will tick even before oil consumption occurs.

In most of the engines I have interfaced with that have this condition the entire bore sees damage, but the area below the piston crown at BDC is always worst, because that area warms up slowest and because its exposed to changeover loads due to the dwell time at BDC. The ticking starts here and thats why it has the rhythm that it has, due to changeover.

Just wondering, how many of these engines have you reconstructed?

wrinkledpants

Of all the various motors I've torn down, I've rarely, if ever, seen a symmetric scoring pattern.


I think it's about 18,000 BTU. Most electric block heaters I've seen around the 5-10K BTU range. I believe if you set it up as the factory did, that the electric pump that runs the "rest" function is the same pump that circulates the heated coolant around the block. At full bore - it'll use probably 20 ounces of fuel an hour.

ndx

My 2011 CS ( Ontario ) is noisy in general during idle...
I wonder if its going too ...

Injector, valve noise ... or something not sure if its normal for them or its a ticking bomb ...

I do have some constant ticking noise but its hot/cold the same 48k Km on car.

westy66

I posted in the other scoring thread... A week before my CTT was going to the dealer for a cracked sunroof, she burned 4 1/2 quarts of oil in 900 miles. Without warning. 56k miles, scored cylinders. Thank god for the CPO, it's getting rebuilt now.

Porsche is going to have to acknowledge this eventually, these are going to start rolling in to the dealers.

jimmiepop

Jake -

I'm getting a 955TT. CA Car; dealer maintained; strong engine. Never seen a cold start. Will be garaging it in VA; where its colder.

What, if anything, can be done to minimize scoring risk?