Philster

For the record, I am aware of the OP's engine being a 997.1 variant. I made a point about how the IMS/B was dropped and how the cylinder walls were coated in a different material in 997.2 variants.

Both are considered to be improvements over previous designs. Am I going to come out and declare that they are? No... I don't have enough information.

They might very well be improvements and you at Flat6 will very likely still see 997.2's coming in with scoring and other issues (chain issues leading to damage). At the end of the day, all that can be done is mitigating the issues, but I certainly don't expect them to be 100% resolved --- EVER!

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Philster

I hear ya.

I've never driven my car in temps under 60 degrees. I know that in 80-degree weather I have to be about 10 minutes into my ride to see oil temps at 175. A few minutes later, it's up to 200+. When it was in the 60's., it was easily 15-20 minutes to get it warmed up. I can't imagine what a 10-degree Fahrenheit morning with howling winds would be like.

I've never driven my car for less than 30 minutes. My oil gets to 220 every time. But it's not DD.

Just knowing how long these engines run cold and that the oil is colder much longer, and the ungodly am't of time it must take in the dead, cold, dark of winter, and with old oil, which probably has some level of water in it... it can't be pretty inside that engine as Joe Porsche is 15 minutes into his ride. The car is toasty and warm inside. His butt is warmed by the seats. All seems right in the world. Cabin is nice. Meanwhile the engine isn't ready... even after 15-20 minutes... or even 25 minutes...

cvtbenhogan

Very interesting thread. Actually fascinating.

Wonder if scoring is inherent in the flat six design.

Philster

Anyone interested in this thread, you're obliged to read the following, with incredible, upfront and quick insights from Flat6. Here ya go:

https://rennlist.com/forums/996-foru...cylinders.html

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beden1

So, if the potential for engine damage exists while driving a Porsche in colder climates, then what are the proper RPM shift points before the car warms to optimium operating temps? 3,000 RPMs, under 4,000 RPMs, or under 5,000 RPMs?

LexVan

Under 4,000.

Tip. Throw a 100 watt shop light under your car in the garage to warm your oil for cold morning starts. Or get a heated garage.

beden1

I used to warm the engine room in my boat during the winter with a shop light. It helped the engines turn over quicker and smoother.

Bruce In Philly

Cold engine starts: Last winter I had to park my 2009 C2S outside and drive it on those terrible mornings we had. No choice. I followed the manual advice... drive it. I kept the RPM below around 3500.... let it idle until the engine changed pitch, then off I went. Drove it easy.... but.... had to go.

I will let you know when it blows up!

Peace
Bruce in Philly

Sniff

This is the first commentary I've read that omitting the IMS wasn't smart. According to many posters on this forum, the lack of an IMS bearing in the 997.2 DFI engine was a major improvement. So, is this no longer the case? Jake, can you please expand on your remarks? Much appreciated.

Sean

Schpee007

With cold weather driving being a theme in this thread I am trying to gather some data to analyze over here:

https://rennlist.com/forums/997-foru...your-data.html

Thanks.

Sniff

I vaguely remember reading something in my 997.1 owner's manual which said not to let the car sit and idle in order to warm it up after initial start. I figured this was for emissions / fuel economy purposes. Anyone know if this is the real reason?

Sean

Philster

The thinking behind not letting the engine idle cold (just start and drive) is that idling actually takes longer to warm up an engine, which lets it run rich (cold start comp settings. Rich means wet with fuel, but there is a reason to do this), which isn't nice to cat converters when done too long. Also isn't very friendly to engine combustion.

The thinking is that a faster warm up by controlled, conservative driving gets combustion optimized faster, which is better for everything inside the engine, from internals that might get carbon, to cats and plugs. So, yeah, it is also enviro friendly.

This has been fairly common advice across many brands for decades anyway.

Bruce In Philly

I wondered about this too..... Coupla suppositions:

1 - Omission of the IMS was a marketing-driving-engineering decision to stop the market chatter and worry about the next gen engines. Remember the "leaked" vids of the then new engine on a test horse being spun around under full throttle?
2 - Eliminating the IMS among other "moving parts" reduced the cost of parts/assembly... it was a pure accounting move
3 - This was a natural evolution of manufacturing and design that resulted in a better, more reliable engine that can be a platform for lower emissions and higher power attainable from DFI and other technologies?

I dunno...... bottom line was Porsche had a real problem with those engines designed when Porsche was failing, it was never race tested, and designed to be cheap to assemble and be a single engine platform for all sports cars.

It was time to dump it and fix it.

Peace
Bruce in Philly

LexVan

Yes.
Yes.
And does nothing to warm up the gear box.

Fahrer

The use of an IMS reduces the stress on the cam chains ( separate chain for each bank). The issue is the use of a sealed ( with grease) ball bearing for the IMSB. The use of a cylindrical/sliding IMSB would have increased reliability but necessitate pressure lubrication.