987.2 DFI Carbon on Valves pics

Here are some photos of the valves on my '09 cayman S which is not running as smooth as I believe it should, but never a check engine light. Some valves are fine, some are not. This likely created the cyclic imbalance shown by the oscilloscope which measured vertical engine force via accelerometer mounted on front of engine. This is on an engine that burns no measurable oil, and has 1-2% leakdown, 105k miles. I will try to walnut blast and post results.

I'll be interested in the process and the results.

Photos: 1st: 1/2 way cleaned. You can see the depth of the build up in this pic. Clearly enough to degrade airflow due to the high lip at valve edge. 2nd: Cleaned 3rd: Tools used. 1: Harbor freight sand blaster with 3/8" home depot sink tubing with short piece of brake line inserted into end. 2: Fine walnut shell 3: 3D printed port adaptors to allow sand blaster access hole and shopvac connection to evacuate Walnut shells. I designed 2 different adaptors: center hole and 2 offset holes.

Wow, that's impressive. Likely gained some HP with that procedure.

Excellent work there. Look forward to hear how this has affected your engine's running.

Other information: 1: Took about 15 min to prepare by removing the manifolds and plenum. 2: Took 0.25 to 1 hour per port to clean. I suspect my blaster setup was far from optimal. I tried a number of tip configurations. 3: Be extremely cautious to have valves fully closed when cleaning. Best way is to have the opposite piston valves start opening (pairs= 1-4, 2-5, 3-6). This ensures you are 360 degrees from opening.

Were those pictures taken with a regular camera (e.g. smartphone) or did you have to get some sort of a borescope?

Used my iPhone camera for those pics. As I can't see the valves with engine in the car, many phone pics were used to monitor progress and provide feedback.

Thanks very much for sharing your progress. Am I correct in presuming that you simultaneously shell-blasted and vacuumed the spent shells at each of the intake ports? If so, do you plan to likewise inspect and/or clean the exhaust ports? I'm looking forward to comparing the before- and after- oscilloscope readings [if you plan to re-run that test], along with your subjective assessment, once you've fired it up again. Also, would you mind posting photos of your 3D printed adapters? Sorry for all the questions, but I find your approach intriguing. Sent from my XT1650 using Tapatalk

Yes, blasted and vacuumed simultaneously No plans for exhaust. This almost certainly a property of DFI and therefore limited to intake. I will do oscilloscope as time allows, but there is always a shortage of that.... Photos of the 2 different 3D parts are in the last photo I attached to the right of the blaster tubing. Do you want more detail? Fired up and driving as it only took a few minutes to put back together. I did take a timed reading 2k-7k in 2nd gear, multiple runs, on one particular road before cleaning. When traffic is clear and I have time I will measure the time differential (if any). I am cautious of posting any subjective assessment...

Thanks again, and I hope this solves your problem. To be clear I fully understand: Does the adapter plug into the racetrack shaped port, then the blast media is introduced into the center or offset holes, and the vacuum is applied at the small end of the cone? Sent from my XT1650 using Tapatalk

Below is a cutaway version of the part from the CAD system.

Correct.

Very clever! Sent from my XT1650 using Tapatalk

Very impressive. Walnut shell blasting was quite common in the 1980s-90s, when poor quality gasoline combined with drippy injectors, caused the same sort of buildup on many BMW models. I suspect it will become common again due to the DFI engines.. (that was one of the reasons I wanted the "base" model - it uses old fashioned port injection). Some carmakers are now including an extra injector in the intake manifold to get gasoline to the back of the valves so the cleaning solvents in the gasoline can do their magic. Sort of what goes around comes around (again..) I'm just a bit amazed that the engineers who came up with DFI didn't anticipate this being a problem down the road.

Nice work...

Wait now, was this done with the heads on the car still? Cool setup. I thought most if not all shops were pulling the heads to do this type of work.

Engine still in car. Only prep was removal of plenum and intake manifolds. Just to clarify so these photos do not cause undue concern (not that this ever happens on the internet car forums). This car had no engine codes and ran fine. I had it inspected and test driven by 4 different Porsche shops each with excellent mechanics. All of them said the car was running great and nothing needs to be done. One agreed that something was very, very slightly off after a 30 min test drive. I am confident that it could have continued to be driven for many more miles with no issues. I did this only to make the car exactly like I want, it was not necessary. This should cause no undue concern for those with DFI; the S engine is for those who want the +55 HP and I absolutely not let this be a deterrent.

How did you rotate the crankshaft to close the valves you were working on?

Ratchet/socket on Alternator pulley nut. Belt will likely slip upon hitting compression stroke. To stop slipping, press using fingers of other hand on belt just past alternator to add tension. I used this method for valve cleaning and leakdown test. I added 3 sharpie marks on crank pulley for TDC of each cylinder for my convenience. It seems that they didn't put marks 120deg apart like old Porsches, but maybe I missed them. I have no knowledge of the proper method for this. If anyone knows the "official" way to do this, please post.

Makes sense - thanks for posting

Thanks, any chance you could send me a CAD model of the adaptor so I could 3D print it here? Looking to explore this as well. 120k km in the ODO. Sent from my iPhone using Tapatalk

Man I have been trying to figure out how to rotate the crank on this car.... Didn't think to use an accessory. Nice!

Before At 125k km After, blasted thru.

Nice work @Saabretooth . Did you ever get the 3d model for the adapters? If not, what did you use?

I did. Had to print them and then find time to get it done. It was a lot tougher to use than regular nozzles but hey, we're going for the results right? Sent from my iPad using Tapatalk

Nice. Can you share the 3d printer files?

Anyone who wants the .stl files for personal use, email me and I will send them to you. (only thing not allowed is using my file, then selling them). My only request is that you provide feedback so I can tweek shape. If someone wants the actual prints, I can make some, but would need to charge a little for material and shipping. Saabretooth: Nice work cleaning. Any feedback on the 3D parts?

Thanks, was waiting for your permission to share! Great community spirit! Feedback is that is a bit tricky to use. The shop tends to use these types But the one we made was It got the valves cleaned up as per my previous pictures. Did a couple of other servicing and upgrades at the same time, so I can’t tell if I’ve regained lost hp. Thanks again! Picture of work in progress Sent from my iPhone using Tapatalk

<>

I'm late to the walnut party but as I'd like to try this, I have a few questions. Hopefully there's some experience still around. Is there any particular kind of blasting equipment needed? I've been told that an ordinary sand blaster will do the trick, that true? No need for and extended nozzle of some kind? How much blasting media is required? I have nightmares relating to getting stuff into the cylinders - is the most foolproof way to avoid this to make sure that the opposite valves are open?

Here are the 3d STL files to print your own. port cleaner.STL go.skimresources.com port cleaner 2 hole.STL go.skimresources.com

the two links above are actually directing me to Amazon pages. Would that be possible to email me those files, thank you