Bore Scoring - Cayman S Gen 1

[Phoneix]

Hey folks,

I know this an issue that has been discussed many times on here... But bear with me.

I had a 2011 Cayman S Black Edition until recently and sold it to free up some funds, I now have a 130i and though it's a good car it's quite a way off a Cayman so I'm seriously considering a Gen 1 car.

I saw one that looked very appealing (2006, 60k-ish miles), I got it inspected and the boroscope inspection revealed 'striations' in cylinders 1 and 5. The person who inspected it discussed with an independent Porsche engine specialist who said this is probably similar to most cars of this age and mileage. The problem is no one can say if these striations will progress to scoring or if they've been there for 10,000 miles and will stay there till 120,000. I was told by the person who inspected mine (Peter from No5 Garage, seems a very nice guy) that most people don't get the boroscope done so he can't say himself it's fairly routine to have some striations.

I really like the car, it has a fairly unique spec so I considered taking the risk and offering a significantly lower amount than the asking price. However the owner feels there is nothing wrong with the car because it drives fine and has no tell tale signs of bore scoring (no smoke on start up/using oil/rattle/spark plugs blackening) so he's still wanting the full asking price, or thereabouts. I'm quite sure it'll go for near the asking price to an unsuspecting buyer which is a bit sad but the owner is confident in the car.

My question is how many of you have had your Caymans inspected via boroscope and seen striations/scoring? If you have seen either has it progressed to a problem or just continued to drive as normal? I realise there will be a small sample but I'm just trying to get an idea because there's another Gen 1 Cayman I like the look of (2005, 60k-ish) and I'm considering getting an inspection including boroscope. If on the inspection there is some striations/scoring then I guess it is average but I'm trying to save myself another £400-ish.

I wish I could stretch to a Gen 2 but there's a minimum £10k difference for the spec I want (PASM and SC).

Thanks in advance for any input.

[Phoneix]

anonymous said:

[redacted]

Thanks for the reply. I take your point re: PASM and SC, I had both on my Gen 2 and felt on 19s PASM made a big difference but I don't mind smaller wheels. I felt there was a significant lag in throttle response without SC switched on but I guess there are other ways to improve that like you mentioned. Even without them there's a massive difference in price of a 2006 Cayman (14-17k) and 2009 gen 2 (24-28k).

Didn't realise it only affected 3-6, so may well be 'normal'.

[Phoneix]

hartech said:

It is very difficult to identify bore scoring even when you have looked at hundreds of bores and even more difficult if you are not using your own camera in your own workshops as different cameras and angles etc vary the view and photos sent over the Internet vary as well.

It has always been bank 2 (cylinder 4 to 6) that score so almost never bank 1 (cyls 1 to 3).

If you are inspecting a car that has been fitted with Nikasil cylinders you often will see lines of shading that would indicate bore scoring in Lokasil but are not in Nikasil because the surface finish of Nikasil is more reflective than Lokasil and shows up different polish marks with more definition. We have had several engines sent to us diagnosed with 1 to 3 scored bores that were perfectly OK - so it is a difficult area.

They will run OK for several thousand miles after initial bore scoring before evidence is obvious.

Baz

Appreciate the reply. I actually called your place and spoke to Rob (I think that was his name) and he said that it may well be 'normal'. I'm assuming you have scoped many cars, would you say that the striations (not scoring) are common on cars with 60-70k miles. From what I've read on here the reason bore scoring happens seems to be a design fault so would that mean it will eventually happen to almost all the Gen 1 3.4/3.8 engines? Let's say above 150,000 miles. Or have you done scopes on many high mileage cars and they've been fine.

Thanks

[Phoneix]

hartech said:

We've seen bore scoring at under 15K and not seen it on over 100K (although piston coatings are getting well worn by then).

It seems dependent on several factors one of which is the piston temperature reached affecting the piston coating bonding strength, the load between the piston and cylinder bore, the ambient temperature and the rate of heat soak caused when stopping for a while after a spirited drive. Added to that we think there is a variability of the distribution and bonding strength of the silicon in the cylinder walls.

It is clear that if all the drivers from new never thrashed the car - always warmed it up before thrashing it, never exceeded UK National speed limits, didn't give the car full throttle while accelerating (especially in a tiptronic where slipping into first helps before setting off fast), whatever the quality and distribution of the silicon in their Lokasil - their engine would last longer.

But these cars should be able to be driven fast and so how it was driven and a random quality element may all make predictions very hard.

Some new owners drive very modestly and so their cars have a higher proportion that will last longer but some also can afford to treat a new expensive sports car with contempt and cause a lot of premature deterioration.

You can help by lowering the running temperature with a low temperature thermostat, third radiator (as long as it also has a control valve or thermostat), thicker oil viscosity as the mileage increases etc but there is still unfortunately a random element that can bite any owner at any time - but numbers failing are still very low and there are warranties and maintenance systems that could reduce the cost if it occurred to you.

Good luck,


Baz

Edited by hartech on Wednesday 23 September 10:17

Apologies for the late response. Thanks for this info. I guess I'll have to keep looking and try to find without bore scoring and do what you suggested.