2007 Cayman S 987.1 – Full Engine Rebuild – Why?

My friend Greg said “Only a crazy person would rebuild a Porsche engine that is running fine.” Greg, I agree!

As per my thread on this car, I bought it 2 years ago. I think I just beat the Covid used car price inflation. I bought this particular car for it’s color but in general I bought it to be a track car. It was a quick purchase, from 3000 miles away. I got a PPI but those can only go so far. As I did my research, there seems to be a small but non zero chance of them blowing engines when put into track use. This has been a nagging worry with me. 4 days ago I talked to a guy that has blown up 2 engines. 3 days ago, I decided my life is getting too short to worry about my engine when I track the car. So I started to pull it out. That got done today.

Yeah, I didn’t hide my license plate number. Come and get it.

I’m going to attempt to document some things that I think I have determined regarding the reliability of the M97 engine used in the 987.1 Cayman S. Just reading the forums, you might think these engines blow up a lot. But my rule of forums is that the ratio of complaints to compliments is quite high. One of the first things I did was to look at the PCA.org website. If you dig around a little, you’ll find that all those Tech Q&A letters that you find in the Panorama are archived at the website. I searched on some keywords. I would summarize that, outside of IMS bearing issues, things were very quiet in the early days of the Cayman S with respect to engine issues. And as documented by Jake Raby and LN Engineering, even the IMS bearing issue was pretty rare once we get to the M97 engine used in the Cayman. But Jake Raby, LN Engineering, and others aren’t staying extremely busy rebuilding engines for nothing. Again, anecdotaly, certain unfortunate folks take their Cayman to the track and ker-blamo. Bad things happy to the engine. Rare but not unheard off.

So then I thought about the Spec Cayman guys. They push their cars hard. Well, I couldn’t totally get my arms around what they do to avoid trouble but I did find this paper, which had the following short list of recommendations, reprinted here:

Adding Reliability Components and Other Features
The SPC uses mostly stock components with reliability features added for longevity. Chipping of
the ECU is not allowed to limit additional stress on the stock motor and transmission. Reliability
components and features for the SPC are listed below and recommended. Engine
Two keys to longevity of the powertrain are proper lubrication and removal of heat. It should be
added that good quality lubricants are also a must. For the engine, any of the following are
allowed:

1) A deep sump
2) An Accusump
3) An external engine oil cooler 4) An additional center radiator in the front of the car
5) A Porsche Motorsports air/oil separator may be added
Recommended are 1 or 2 above and 4 and 5. Item 3 can be added to help increase engine
reliability. The Accusump is often connected into the system using a spin-on filter adapter and
Aeroquip AN fittings. An external oil filter and the Accusump fittings are screwed into the remote
oil filter block that is added to the system. Various deep sumps are readily available from a
number of vendors.

I also talked to a PCA Club Racer who campaigns a Cayman. He said that in retrospect, the “good quality lubricant” thing had been the answer for him. He once had an Accusump but got rid of it.

OK, so that was the perspective of the club racers. These guys bolt on sticky tires and are braver than I am. I plan to just do DE events with high performance street tires. No suspension mods and no extra sticky tires. My personal philosophy is that no one drives their car any harder than the Porsche test engineers and drivers. I have read a lot of books about the Porsche design philosophy and it certainly leaves no room for the customer to be the guinea pig when it comes to reliability. Sure there have been some notable lapses (IMS bearing, GT3 engine fires) but they try very hard. With my tires and capabilities, I don’t expect to be exceeding their design envelope. Now, strap on some sticky tires and suspension goodies and all I’m going to say is yes, shit may happen. That’s on you.

One common culprit that I read about on the forums is that these engines have an oil supply issue. It only happens in long left hand sweepers. Short answer is, please see above. They certainly didn’t leave the factory this way. Seriously, do you think Porsche never tested these cars in long sweepers? With full instrumentation giving them lots of data about oil pressure. I’m not ready to go there. Unless you strap on those R-comp tires and exceed the factory design envelope. That’s on you.

One interesting perspective I have been made aware of recently is cylinder temperture management issues. Hartech in the UK issued an excellent paper back in 2012 discussing the issue. It’s reproduction here by me is restricted by them but if you contact them they seem to be willing to send it to you if you sign some non-disclosure documents. The very very short version (its 76 pages long) is that Porsche did cut some corners and wound up with cylinder #6 running hotter than the rest. This coupled with the unavoidable physics of flat 6 engines, in their opinion, results in an increased risk of bore scoring in the #6 cylinder. Solutions are pretty simple. Run a thermostat with a lower setpoint. Give your engine plenty of time to warm up before you hammer it. Use a good grade of oil.

So how about the perspective of “what happens as these cars age?”. That is a good question. For that, I can only offer my opinions. I worry about bearings “wearing out”. Specifically rod and main bearings. Under ideal circumstances, they have a very good service life. But then there is the real world. Not waiting for the engine to be fully warmed up before “hammer time”. Stretching out the time between oil changes. Short drives. Overrevs. Varying fuel quality. Cold starts. And seasonal use, with long winter layups. It’s reallly a hot mess if you think of it. Lubrication is the life blood of any engine. It’s a tough gig.

Then there is the hot topic of Bore Scoring. PCA, Hartech, and LN Engineering, among others, have opinions regarding causation. There seem to be some general risk items, running to the extremes of cold climate starts to oil film failure at hot cylinder wall temps.

To be clear, I am not advocating that every Cayman owner panic and loose sleep over engine failures. Porsches are well built cars. Failures are rare. I think they might be a little less rare on older track driven cars but in every DE event I attend, the paddock is full of Caymans. I chat the drivers up and there is little discussion of engine failures. Heck, I put 8000 miles on this car in just a few weeks last summer, with no issues. But to me, taking my car to the track and driving it until failure occurs is not a great financial decision. Fatally broken engines probably aren’t rebuildable. Used engines are becoming expensive (ballpark $10K for an S engine) and you are still left with an unknown engine status. Porsche does list a “short block” for circa $22K, if that floats your boat. So I can afford it and to me, this is a fun project. Call me sick!

So I am left with a 5 owner car with over 100,000 miles. Because I want to stick with the “analog” Cayman 987.1 platform (versus a newer car), I have decided to tear the engine down and baseline it to as new condition. New rod and main bearings. New timing chains and associated components. Cylinders will be massaged by LN Engineering. The heads will be reworked by Hoffman. One improvement will be ARP connecting rod studs. I’m leaning towards a modest deep sump with baffles, although I am not convinced that is a problem for street tire usage. I’ll probaby stick with a stock AOS, due to the rediculouse cost of the motorsport version.

BTW I used a bootleg copy of the Porsche shop manual to guide me in the removal of the engine. All in all, it was a pretty good guide. Although there were some obvious things missing. Really, like it did not suggest that I detach the rubber line from the oil filler port in the back of the trunk. But at some point, you just start looking for things that are not going down with engine (or in my case, are still attached to the car body as I raise it) and deal with them. Frankly the hardest single item was extracting the single bolt at the back of the air conditioning compresser, which is pretty well buried under the intake manifold. But I got it done in about 2 days. The next time, which I hope there will not be one, I could probably do it in a day.

Also BTW, I checked my compression numbers before I got started. 225 to 235 psi. No problems there!

As I joked with my friend Greg, part of me is hoping when I tear the engine down, I’ll find it was one track day away from total destruction. In reality, I expect I won’t see anything amiss. We’ll see. Stay tuned.