Busta Rib

OP, sorry to hear about your circumstances. I had a similar dilemma with my 05 Carrera S. It developed scoring at 85K miles. I loved that car: speed yellow, PCCB, cocoa interior, sport seats, etc. If not for the scoring, I would still have it to this day. I was faced with the difficult choice of rebuilding (in all the different flavors and options) or selling at a loss. I chose the latter because 2 years ago, the calculus didn't make sense to rebuild relative to the value of 997.1s at the time. It's a lot different circumstance now where you can get $65K+ for a super clean 997.1 S or 4S. Dropping $20-25K for a DIY rebuild is not that bad as a long-term play. As good as an FSI engine is, I would not go that path because of the wait and cost (Jake has mentioned his prices are increasing to ~$35K+).

If you are invested in your car for the long haul, go the LN path, buy their Nickies, and find a local shop to do the heavy lifting. If you are halfway mechanically inclined and have some friends to help, you can easily drop the engine and remove the top-end yourself and save a lot of money and time. Outsource the machining and assembly of the bottom end, and then reassemble the top end and install the completed engine yourself. If I could do something similar on a 964 engine having never done anything like that before, I am confident most of us here could do the same. You just need the conviction, tools, space, time, and patience. There are so many resources, tutorials, and help on RL to guide you. Regardless of what you do, best of luck.

850tgul

GIF is in no way directed at you OP. I’m sorry for the situation you are in. Just saw this vid pop up on VinWiki and thought it apropos to this thread.

groovzilla

This Thread is the reason I have stressed Bore Scope Inspection on all 997's whether 997.1 or 997.2.
Has to be part of the PPI process for peace of mind. My last 3 997's were all BS inspected with excellent results and those cars were in the 70K-80K miles range.

**My current 997 C4 that just hit 107K miles was Bore Scope inspected this past November at 106,700 miles with nice clean cylinder walls.
2 other 997's I was interested in(06 997S & 07 997S) this past summer showed bad signs of scoring and one had a cracked cylinder wall. This really emphasized the importance of Bore Scope Inspection.

Sporty

Can't believe there has not been a class action suit against Porsche similar to the IMS one a few years back. Or at least for Porsche to step up and offer some type of fix or remedy.

997Fanatic997

I reached out for a 2nd opinion and Bob Hindson Racing in KC said this:

"We can certainly offer a second opinion. However scoping all six cylinders from the bottom isn't really possible. We can pull the oil sump plate (oil pan) and you can see a bit of the crankshaft and piston assembly but the view is essentially obscured. The motor has horizontal pistons which means you can't look at the bottom like you might be able to do so in a vertical (4 cylinder) or V motor. Scoping from the top is the way to go"

seems to conflict with advice i have gotten from others.

Petza914

Scoring starts at the bottom due to piston Rick and the skirts contacting the cylinder walls. In the very early stages, depending on the position of the piston in the cylinder you may not be able to see any scoring or scuffing from the top plug hole even though there's very visible evidence at the bottom of the stroke.

Scoping from the top is easier, but definitely NOT the way to go. Now if scoping from the top shows scoring then there is no reason to go any further because it's always worse at the bottom, so it can be a useful benchmark, but seeing nothing from the top does not mean you don't have to scope from the bottom for the total picture.

frederik

This video explains how to do it:

jchapura

Pete, when borescoping from the bottom, if marks are noted, is there a way to distinguish between scuffing and scoring?

8KaboveMSL

Unfortunately there are a still a lot of indy shops w/ Porsche gold certified mechanics who will answer the same way. I gave up arguing w/ my indy and just had them do a bore scope from the top (missed the opportunity to do that when my plugs were replaced) and found scoring on one cylinder. As Petza says above, that's not definitive if no bore scoring is found but if it is found, the bottoms of the cylinders will likely look worse.

Then I personally put the cars w/ bore scoring into two camps: 1. those with audible piston slap (rhythmic ticking noise) and; 2. those w/o it.

I personally would not drive a car w/ audible piston slap as I would fear causing even more serious (and expensive) damage to the engine. I am trying to continue to drive mine (which doesn't have audible piston slap) and want to see if I can get any insight into:

• what can I do to push out the onset of the piston slap - Oil, Oil Filter, low temp thermostat, 3rd radiator, injectors, driving MO, etc.
• how long can I keep the car going w/o getting the piston slap - (how many miles?, years?)

The second bullet is the money question for me. I know the engine will need to be rebuilt eventually but can I keep it going long enough to get through these supply chain issues? Should I? The incidence of bore scoring is likely to increase as more cars get more miles on them so are parts shortages likely to get worse? Hard to say right now. . . This is what makes addressing bore scoring once it is found such a complex issue for me.

Good luck to the OP, hope it is really just loose parts!

8KaboveMSL

I've read and heard people repeat that if you run a fingernail over it and it catches, it's scoring. Otherwise it's scuffing.

jchapura

Agreed but can one do the "catch" test (or any other scoring v. scuffing test) from the bottom?

8KaboveMSL

I am not sure if somebody can get a finger into the cylinder from below. I suspect it is hard to do so. However, visual inspection of the images from a scope should give you an idea of whether a fingernail would get caught on any imperfect cylinder walls or not. My bore scope pictures (from the top) clearly don't show any deep scoring, but they are from the top. The challenge w/ the NikaSil Lokasil coating on the 997.1 cylinder bores (I believe I read this in a post from the Hartech UK guys about this) is that once it starts coming off and gets suspended in the oil, it starts to act as an abrasive agent on the undamaged cylinder walls. So at some point scuffing will lead to scoring. The real question is how long ti takes for that process to happen. I don't think anybody knows because it's probably a hard question to answer simply and cover every situation. If it takes 100k miles for scuffing to lead to scoring, that's not so bad. But if it takes 20k or 30k miles then that's a lot worse. Given that there are many examples of mid-mileage cars (30k to 60k miles) w/ confirmed bore scoring it is not that easy to just dismiss scuffing.

jchapura

I wonder how large these particles are?
Why might it not get filtered in the oil filter?
If not filtered then an increase in oil change frequency is probably very helpful.
Switching to a "non-bypass" filter is probably very helpful.

8KaboveMSL

not sure how much gets caught in the filter but yes to all.

Hartech apparently has a white paper on the topic available on their website. I haven’t read but you have the synthesized TL;DR version already.

Mike Murphy

Same here. My shop picked 2 cylinders to check from the top only and didn’t find bore scoring, so that means…nothing to me. I have hardly any oil consumption, and my tailpipes look great. Means nothing to me. I mean I’m not worried, I’ll just drive the car as long as I can, but I’m not losing sleep. If bore scoring pops up, I’ll just have to deal with it.