SlopedDriveway

I was looking for a project and I came across @bobcooper 997.1 C2S Cab that that he was selling on RL.

From what I was told the car had an engine issue - likely a broken timing chain, and water damage to the rear module as a result of the shop it was at leaving the driver window open.

This thread is for documenting the work to bring the car back on the road.

When I got the car I was surprised how wet it was inside. I decided to fully remove the interior so the carpets and padding under the carpet could dry. I left them outside in the sun for a few days. Once they were dry I shampooed and steam cleaned them too.






Then I replace the rear module with one from a cayman and recoded it for 997 cab. This fixed all the electronic issues with the car and allowed me to communicate with the DME.

I figured there would be stored timing error codes or misfires but to my surprise there weren’t. I borescoped cylinders 6 and 1 and with the scope in I turned the engine over by hand and witnessed both banks have valve moving - so it’s not likely that a timing chain broke. Side note that the bores looked really good for 107k miles. Also no clear indication that valves hit pistons so I don’t think the timing chain jumped. There is a pretty good oil leak that I haven’t tracked down the origin of but it looks like it’s coming from the rear of the engine or the oil filter housing.



I was assuming I would be pulling this engine for a rebuild given the suspected timing chain failure, but now I’ve paused that to decide next steps. Curious if anyone here has any input but this is what I’m considering as the next steps.

1. Run the car so I can read deviations, check for misfires, etc from DME.
2. Compression and leak down test.

Here is the current state for those interested:

digs

Wow , quite a project . Have you tried to start it yet ?

bobcooper

Orginal owner here. Very interested to see how this goes. Hoping it’s a less involved fix. The water issue is a mystery as it happened at the first shop and they didn’t bring it up. I haven’t sat down with them to have a frank conversation but I’m going to.

SlopedDriveway

I haven’t yet. I’ve only had it a few weeks and I wanted to make sure turning it over wouldn’t cause more damage. Now that I’ve scoped it and know valves haven’t hit pistons I’ll likely try to start it this week when I get a chance.

da Vinci Dan

If two reputable shops separately told me it was the timing chain, I would think I am missing something.

Did you pull codes? Any relating to timing chain?
If you tried starting it and it was the timing, you would lose the engine, right?
Maybe contact one of the shops? stop by in person?
I'm an solid 3 star home mechanic and would take my time to limit risk of doing more damage.

bobcooper

Actually I think I mis-represented what the shops said. When I sold the car I was trying to set the expectations low — ie be prepared to rebuild the engine.

The second shop was a great shop and the owner/head mechanic told me it had serious timing issues and I think he said it seemed to be an issue with one of the two sides. It ran so I’m sure he didn’t tell me the chain was broken.

He also diagnosed the water issue before he ever discovered any moisture. It was quite impressive to me to experience. When I first met him, we put a battery to the connection in the fuse box since the cars battery was dead and we couldn’t open the trunk. As soon as we did this, he noticed two things. One, the car’s reverse lights lit up. Two, the door switches that open the hood and the trunk didn’t work. He looked at me and said Bob, Cars got water damage. I argued with him because I knew the car had not had any water damage when I was driving it and delivered it to the first shop and I found it hard to believe that the first shop allowed the car to get water damage without telling me . He then took the seats out and showed me the water. We talked about what could be going wrong and he told me there was a serious timing issue and I think he said it was on one side. This time I decided it was probably time to sell as I wasn’t ready to invest the money required to have somebody else fix it and I didn’t have time to do it myself.

the new owner and I talked several times about the car and I wanted him to be very comfortable with what he was getting. As I told him the car was running great up until the catastrophic issue occurred and the last thing I wanted was for him, a fellow engineer, to regret what he purchased from me. so I’ll be following this thread with great interest. I’m really hoping for a good outcome and that he’s as happy with the car as I was. It was my first Porsche and I still miss her very badly. I have a 718 Cayman S on order and I hope I’m as happy with it as I was with my 911 S

SlopedDriveway

Thanks Bob, I appreciate the background and additional information. Glad you’re following along!

Also, due to the water damage to the rear module under the drivers seat the second shop was unable to communicate with the DME which would’ve been very helpful to confirm their suspicions.

Anyways, I’m thrilled to have the car and I’m enjoying working on it.

Knowing it has been started, and seeing for myself that there isn’t any interference between valves and pistons, I’m inclined to start it this week and check the DME now that rear module is fixed. There are currently no stored codes in the DME which is interesting. I would’ve assumed there would be something there. More to come in the next few weeks.

Petza914

You know, there's a timing chain tensioner right in front.of that huge caked up oil leak mess. I think maybe while things are apart, I'd get a pair of new cam lock plugs and the cam locking tools and replace the 3 timing chain tensioners before I start it. If one of those has failed, that could completely explain the camshaft deviation numbers that led to a timing chain issue diagnosis.

SlopedDriveway

Thanks for the suggestion Petza914 - I completely agree. I just bought the cam/crank locking kit. I'll order the tensioners and plugs too, even if they aren't the issue it can't hurt to replace them at 107k miles.

I'm also planning to dump the oil and drop the pan to see if there are any bits of chain guide or anything else noteworthy.

jchapura

If the engine can be hand cranked a couple of revolutions without incident then you might consider checking the oil level (maybe by changing it?) and then pulling the fuel pump fuse and then having the engine cranked while listening to it and monitoring the oil pressure gage. Have a stethoscope ready.

If you change the oil and filter, cut open the filter to inspect it for visible particles.

SlopedDriveway

Thanks for the suggestion - I will most likely change the oil and inspect the filter before running it. I like the idea of checking oil pressure before running it too. Thank you!

SlopedDriveway

Update:

I drained the oil and cut open the oil filter. Some small dark brown or black plastic bits but no metal. Thinking the plastic might be timing chain guide material.



I swapped the LN spin on oil filter adapter for the stock filter housing which seemed to fix the oil leak. After adding fresh oil I pulled the fuel pump fuse to crank the engine and confirm oil pressure - all good.

Then I started the car. It idles rough with misfires across bank 1. I can upload a video if anyone is interested. Below are the camshaft deviations and error codes it was throwing which confirm the issue is with bank 1.

I don’t think it jumped timing but I do think it needs new timing chain guides, variocam actuator, and timing chain tensioners but if anyone has any other thoughts I’m all ears.

Petza914

That camshaft deviation number is 4x out of the acceptable range. I would replace all 3 chain tensioners or at a minimum the easier IMS tensioner and bank 1 tensioner since those are fairly easy to do and your issue is on Bank 1. Those black and brown plastic pieces are exactly what you suspected - timing chain guide material. Are you hearing any start up chain rattle for a couple seconds on cold starts - that's usually what chips the plastic off the guides as the chain rattles across it before the hydraulic portion of the tensioner pumps up. With what you've found in the filter and the camshaft deviation numbers you're showing, every time you start the car you're doing damage to the guides - once you've chipped away all the the plastic and hit the metal, it's game over. I'd stop driving the car until at least those 2 tensioners are replaced.

SlopedDriveway

Thanks Petza914. I won't be running the engine anymore until I fix the issue, I just wanted to hear it run for diagnostic purposes and to get the cam deviations. My plan has always been to remove the engine to do a bunch of maintenance items but the list is growing. Feel free to suggest more "while you're in there" items.

- Clutch
- RMS
- Remove IMS seal for better lubrication
- AOS
- Water pump and LN low temp thermostat
- Chain tensioners
- Chain guides
- Chains depending on how bad the guides are
- Cam adjuster solenoids
- Oil pressure sending unit
- Spark plugs

Petza914

If engine out, replace the oil level and temp sensor. It's long and difficult to do with the engine in the car. It's a separate sensor from the oil pressure sender.

I'd do the secondary AOS units also - there's one on each bank and all the corrugated plastic hoses and plastic coolant lines that are on the engine.as well.