Bore Score Self Check

If you can replace your own spark plugs then you can basically get an idea if you have a problem .

Spark plugs are to us mechanics as a thermometer is to a doctor .. it can tell us a lot about what's going on in an engine .

Whilst a bore scope view will give a slightly better idea ( head off is best ) this is the next best thing and basically all you can do as a check without a scope .

The black tar like deposits on the far left plug are oil contamination .. or build up over time.

You will only get this when there is excessive oil in a cylinder and whilst not always from scoring it is pretty much conclusive .


There were no undue noises or smoking reported from the customer prior to this inspection .


The following pictures are what the cylinder actually looked like on a scope check .. all of Number six cyl .

First picture if opened in a new tab ( chrome ) will give a larger image to view .



This is in no way meant to be alarmist , Porsche state less than 5% of 997,s have this issue ..

This is about what you can possibly look for or be aware of when servicing your cars .

deMort said:

Porsche state less than 5% of 997,s have this issue ..

Click to expand...

Is that per week or per year?

Porsche state or have said its total per unit sold world wide as its been told to me .. that's not for me to argue with i'm afraid .. as you know .. i'm just a grunt !

Grunt ..



Meaning of grunt in English


someone who does an unskilled job.


Lol .

Thanks deMort..more great information.

The Oracle gift that just keeps giving !

Alex said:

deMort said:

Porsche state less than 5% of 997,s have this issue ..

Click to expand...

Is that per week or per year?

Click to expand...

5% per week would mean that all 997's would have suffered bore scoring in within 20 weeks of being driven.
Mine was first registered in 2007 and hasn't had bore score once in more than 12 years!

are the 997 Gen2 also affected?

If you want to find out more about bore scoring it is one of several topics in our report on the the main weaknesses with the Gen 1 engine range (that covers Gen 2 bore problems as well) that you can obtain free from [email protected].

However it is a technical report - long and detailed - not a quick read or fix.

Baz

indentured vehicle mechanic is not a "Grunt" by any stretch of the imagination young Iain sir!

Alex said:

deMort said:

Porsche state less than 5% of 997,s have this issue ..

Click to expand...

Is that per week or per year?

Click to expand...

:hand: we all know its 50:50 ie you either have it or you don't :thumb:

deMort said:

Porsche state or have said its total per unit sold world wide as its been told to me .. that's not for me to argue with i'm afraid .. as you know .. i'm just a grunt !

Grunt ..



Meaning of grunt in English


someone who does an unskilled job.


Lol .

Click to expand...

....and we all know how realiable manufacturer official figures are :floor:

I remember Jaguar and BMW replaced any engines, even those out of warranty that had had nikasil lining failure.

Porsche did themselves no favours at all with their poor treatment of customers as they went from a byword of engineering excellence to 'chocolate engine' manufacturers; you only have to read the comments on youtube or any online forum to see the damage done to their reputation.

I'm not even sure I'd trust a gen 2 as there is enough online to show that bore scoring is an issue, albeit a small one, but that's how it started with the M96/7.

Readers of our report will now know there are several different direct causes of the scoring which can all be in different states at any time and individual or linked together.

The principle cause is that small pieces of grit (silicon nodules) gradually break away from the cylinder bore and then sit between the piston and the cylinder wall until they either escape with the oil, or stick to the piston, or gouge up and down the bore (which releases even more particles like in a road pot hole) to make things worse.

The harder the piston is pushing against the cylinder wall at that time the more damage can be caused and "harder" means more torque which is largely at lower revs.

Lower revs is also a problem because the oil film between the piston and the cylinder wall forms a barrier or space within which the smaller grit particles can float until they might escape.

The lower the revs the more time there is for the pressure squeezing the oil out to reduce the film thickness and therefore the more likely it is that the grit will impinge on something before it escapes.

In that report you will see pictures where the piston coating has peeled off (exposing aluminium), worn off (but still bonded) or picked off in patches. Each of these will cause the grit to tend to stick to the piston where it is just aluminium.

So any engine could have a patch or two of piston coating missing, a bit peeled off or be worn down. Any bore could have surface degradation (but not yet scoring) that means particle release will now accelerate (even though you cannot see any scoring yet).

The distribution of those silicon particles within the aluminium block material matrix is not even enough to predict how soon an area will rapidly deteriorate.

Pictures in the report also show where in some areas oil splash has washed away bore material.

Good evenly distributed and well bonded cylinder bores will last much longer. Good well bonded plastic coatings on pistons will also last much longer. What you might have in these permutations in your engine is anyone's guess and how you (or past owners) have driven the car adds another influence. Thicker oils obviously provide a better space between the piston and the cylinder wall under all conditions for particles to float within causing no damage.

Bank 2 almost always fails in about half the time it takes for bank 1 to fail for two reasons.

(1) The thrust face (top bank 2 bottom bank 1) runs hotter - so the oil is thinner - so the oil film separating the piston from the cylinder wall is smaller.

(2) The top of the pistons drains off oil when stationary so the start up is drier on bank 2 than bank 1 (the latter of which usually has a small puddle of oil on its thrust face when starting).

When oil consumption is higher, or the N/S tailpipe is darker or scoring is visible from a camera - it is at a later stage - there are many more different primary stages that you cannot see without stripping the engine.

So the variations in component quality, driving styles and oil viscosities influence the eventual outcome too much to offer reliable predictions.

Nikasil has particles 1/10 of the size of those in Likasil (or Alusil) and are better bonded with a much lower release rate and far too small to cause a problem and therefore can run with just aluminium faced pistons with no downside.

Much more in our report available from [email protected]

Baz

Robertb said:

I remember Jaguar and BMW replaced any engines, even those out of warranty that had had nikasil lining failure.

Porsche did themselves no favours at all with their poor treatment of customers as they went from a byword of engineering excellence to 'chocolate engine' manufacturers; you only have to read the comments on youtube or any online forum to see the damage done to their reputation.

I'm not even sure I'd trust a gen 2 as there is enough online to show that bore scoring is an issue, albeit a small one, but that's how it started with the M96/7.

Click to expand...

Good point. When my wife's 997.1 developed this after 12 months and 7500 miles (from new) they mucked us about for months saying 1. it was normal. 2. it was the oil separator and 3. it's "a failed piston ring" and we need the car for 3 weeks to "rebuild" cylinder 6 only.
They refused to a) be honest ( I knew what 1-2 litres of oil/1000 miles, plus black exhaust, and tapping meant so hard to believe they didn't) and b) to do the right thing and give us a new engine. It was a new car FFS.
In the end the dealer (Dick Lovett) fought hard for us but after 20 years of being a Porsche customer I vowed to never buy another one. And haven't (except for a couple of old air cooled ones, but they don't count ... right?).
On a positive note, we have had 60k trouble free miles since - well engine-wise anyway......

drmark said:

Robertb said:

I remember Jaguar and BMW replaced any engines, even those out of warranty that had had nikasil lining failure.

Porsche did themselves no favours at all with their poor treatment of customers as they went from a byword of engineering excellence to 'chocolate engine' manufacturers; you only have to read the comments on youtube or any online forum to see the damage done to their reputation.

I'm not even sure I'd trust a gen 2 as there is enough online to show that bore scoring is an issue, albeit a small one, but that's how it started with the M96/7.

Click to expand...

Good point. When my wife's 997.1 developed this after 12 months and 7500 miles (from new) they mucked us about for months saying 1. it was normal. 2. it was the oil separator and 3. it's "a failed piston ring" and we need the car for 3 weeks to "rebuild" cylinder 6 only.
They refused to a) be honest ( I knew what 1-2 litres of oil/1000 miles, plus black exhaust, and tapping meant so hard to believe they didn't) and b) to do the right thing and give us a new engine. It was a new car FFS.
In the end the dealer (Dick Lovett) fought hard for us but after 20 years of being a Porsche customer I vowed to never buy another one. And haven't (except for a couple of old air cooled ones, but they don't count ... right?).
On a positive note, we have had 60k trouble free miles since - well engine-wise anyway......

Click to expand...

Did you get a new engine in the end ?

villaman said:

drmark said:

Robertb said:

I remember Jaguar and BMW replaced any engines, even those out of warranty that had had nikasil lining failure.

Porsche did themselves no favours at all with their poor treatment of customers as they went from a byword of engineering excellence to 'chocolate engine' manufacturers; you only have to read the comments on youtube or any online forum to see the damage done to their reputation.

I'm not even sure I'd trust a gen 2 as there is enough online to show that bore scoring is an issue, albeit a small one, but that's how it started with the M96/7.

Click to expand...

Good point. When my wife's 997.1 developed this after 12 months and 7500 miles (from new) they mucked us about for months saying 1. it was normal. 2. it was the oil separator and 3. it's "a failed piston ring" and we need the car for 3 weeks to "rebuild" cylinder 6 only.
They refused to a) be honest ( I knew what 1-2 litres of oil/1000 miles, plus black exhaust, and tapping meant so hard to believe they didn't) and b) to do the right thing and give us a new engine. It was a new car FFS.
In the end the dealer (Dick Lovett) fought hard for us but after 20 years of being a Porsche customer I vowed to never buy another one. And haven't (except for a couple of old air cooled ones, but they don't count ... right?).
On a positive note, we have had 60k trouble free miles since - well engine-wise anyway......

Click to expand...

Did you get a new engine in the end ?

Click to expand...

Yes, sorry