linderpat

Thank you Charles - this is all very helpful.

silver_tt

Wait to get the UOA back from SpeeDiagnostix ...... and it should corroborate what you are seeing visually with the borescope

8KaboveMSL

I had a ticking sound as well and while it first alarmed me (I know I have scoring in one of my bores) I eventually realized that the rate of ticking and the frequency content of the noise were quite distinct from that of bore scoring. It turned out to be a few broken weld joints on some supports (guessing I broke those bottoming out on a speed bump I didn't see coming). Anyway, someone here suggested taking a rubber mallet to the exhaust system (when cold obviously) to see if anything rattled. That's how I found my issue. Took the car to an exhaust shop and $20 later the joints were re-welded and the noise was gone.

Worth a look . . .

I'm adding the pic of my scored bore, you'll see the difference when you compare it to your pics. Mine is still early stage but it has progressed beyond streaking. 06 C4S w/ 59k miles,

Ericson38

Charles,

According to FSI, the 2.7 liter Cayman/Boxter base engine is not susceptible to scoring, while the 3.4 liter S is susceptible.

Cylinder Bore (Scoring) – Flat Six Innovations – Porsche Engine Experts (flat6innovations.com)

Is that due to cylinder wall thickness in combination with less side loads between piston to bore, or is there something in the material sense.

Thanks

BamaPCar

This is what I'm thinking too. For some reason I was getting a progressively pretty rough idle this morning as the engine was warming up. I'd occasionally hear a faint & sporadic sound as it was warming up too....sounded something like between a "tap" and a "puff". However, it still runs smooth as silk as always when above 2K rpm.

I did run up to 6500-ish rpm a few times after driving 25 mins and the rough idle went from moderate to minor afterwards. Still puzzling though.

One other thing.....@Petza914 I know you've dropped the sump on these cars plenty of times. Is it normal for you need to top off periodically after refilling with oil after dropping the sump? My oil level has gone from right at the full mark after refilling to at the minimum mark....so I had to top off about .75-1 qt.

ZuffenZeus

It's the material composition of the piston. Porsche chose to use cast pistons in the 2.7L engine in the 987 Boxster/Cayman.

Petza914

I haven't noticed that actually, but I also know my car with the MantisSport.deep sump takes exactly 10 quarts to be at the top mark the next morning, so the couple times I've refilled it after reinstalling the sump l, I've just put in the 10 quarts.

If you had the oil filter off and refilled the car before starting the engine and then drove it and checked it the next morning, you'd be a 1/2 quart or so low from the filter filling up.

BamaPCar

That likely was the culprit! When I filled with 8.5 quarts of Driven DT40 the oil level gauge fluctuated between full and overfill. Was trying to figure out a way to take some oil out without draining completely.

I generally fill the filter housing halfway too during oil changes, so I drained the filter housing. I guess the low oil this morning was from the filter housing getting refilled.

Petza914

According to Jake, you should not prefill the filter at all. The reason is that the oil in the filter becomes an impediment to the air before and after it moving through as quickly as possible to get oil into the motor. You get a little splash from what you put into the filter but it then takes a lot longer for the remaining air to evacuate and the steady oil supply to happen.

BamaPCar

Very good to know, thanks Pete! I had a 0.5-1 second mild grind/scrape sound this time when I first started the engine after refilling with oil. I sure hope the already-saturated filter didn't prevent oil from cycling for a split second and cause any damage! I guess I'll know with time.....

Petza914

You'll be fine. That noise was probably timing chain scraping from a tensioner that's getting lazy or possibly the starter Bendix not retracting fast enough if the starter is old.

Charles Navarro

That's not streaking. I'd say that's very early stages of bore scoring, especially if this was found on bank 2.

I'd change to DT40 (or if your ambient air temps are high enough maybe even DT50 or FR50) and just monitor it. You'll want to make sure you check fuel trims, check for vacuum leaks, and anything else that might be contributing to this issue.

I've seen engines with scoring at this level go quite a long time assuming any other issues have been corrected and the oils mentioned above are used until it gets bad enough that you have to take it off the road. You'll know when it's bad when wear levels jump and oil consumption starts to rapidly increase, coupled with piston noise and sooty tail pipe.

Charles Navarro

The cast pistons are also iron plated where the forged pistons have a iron coating applied on the skirts (e.g. Ferro-print). The iron plating on the cast pistons is much more durable and the cast pistons expand less too.

silver_tt

I would be curious if you can please post your SpeeDiagnostix results when they come later.

BamaPCar

@Charles Navarro many thanks for sharing your assessment, Charles. Although I'd rather know the truth, it is a punch to the gut, of course! I drive the car about 6,000 miles/year. Any very wild guess at how much time it has left before a rebuild? Sounds like I sadly need to decide how long I can realistically keep the car before value plummets too far.

Unfortunately I can't justify a rebuild with Nickies if it still has some usable life & value left. Probably best for me to cash out now, and save up hoping I can (realistically) afford an air-cooled car several years down the road. I know the Nickies rebuild will be worth it to someone else though.

Will definitely share with the group.