Hi everyone,

Just had my 997.1 GT3 borescoped around 100-200 miles post engine rebuild. Are these concerning for scoring?

 

Hard to say as those images are super magnified. I wouldn't want any vertical lines on my walls but those may not be any deeper than the machine marks.

These images have been rotated to better display orientation:

 

Would markings related to bore scoring be in more of a vertical pattern?

 

Yes, the vertical lines are scoring/streaking, the cross hatch lines is maching/honing marks. The vertical line in these don't look very deep, but on a fresh rebuild I'd be asking some questions too.

 

I rotated the pictures to for the OP, 997 GT. They are not in the proper orientation. It's the second post of the thread.

 

It is a very unusual move to run a borescope in the cylinder after an engine rebuild, unless you suspect something, or hear something, etc.

What made you suspicious?

 

There ya go. 997, you hearing something out of the ordinary?

 

I bought the car 100-200 miles after a 4.0L build commissioned by the previous owner and as the first order of business, I decided to change the oil and filter. Metal shavings were noted in the filter pleats, but I thought this would be expected as part of break-in. My specialist recommended boroscope since the car is also having some issues at idle and I felt it was running very rough, certainly more so than my .1 GT3 and .2 RS. I gave the go ahead since there's a warranty by the builder and I wanted to make sure nothing is amiss. Alas, this is the result. I've reached out to the shop but haven't heard back yet. I'll keep this thread updated, hopefully with an endorsing review of the builder. Quite disappointing in any case.

 

Did a compression and leakdown test accompany the scope job? If so would you mind sharing the results?

 

I haven't decided to invest into further tests since scoring like this will only get worse as time and miles go on. I do suspect misfires since it is running quite rough. The fact that this is happening so soon after rebuild is an indication for other problems. Hopefully the builder (very reputable in the community) will address this.

 

Yeah, at this point probably no sense going back in to do further tests, the time to do compression/leakdown test would have been during the scope since the plugs would be removed and 90% of the work already done.

 

Quick update

Engine builder doesn't think these are bore scores. They use steel liners with no coating and explained the marks are from end gaps.

I've only had experience with alloy liners with Nikasil coating. In any case, compression tests and leak downs are incoming.