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deMort
Dijon


Joined: 21 Mar 2015
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PostPosted: Sun Mar 01, 2020 7:38 pm    Post subject: Bore Score Self Check Reply with quote

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 .
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Alex
Le Mans
Le Mans


Joined: 06 Mar 2014
Posts: 17707
Location: The Ribble Valley, Lancashire

2000 Porsche 996 Carrera 4

PostPosted: Sun Mar 01, 2020 7:43 pm    Post subject: Re: Bore Score Self Check Reply with quote

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



Is that per week or per year?
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deMort
Dijon


Joined: 21 Mar 2015
Posts: 7950
Location: Brighton


PostPosted: Sun Mar 01, 2020 7:54 pm    Post subject: Reply with quote

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 .
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villaman
Silverstone


Joined: 05 Mar 2019
Posts: 139
Location: North Staffordshire 997 C2


PostPosted: Mon Mar 02, 2020 8:15 pm    Post subject: Reply with quote

Thanks deMort..more great information.

The Oracle gift that just keeps giving !
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Mini-Me
Silverstone


Joined: 12 Aug 2013
Posts: 144



PostPosted: Mon Mar 02, 2020 9:20 pm    Post subject: Re: Bore Score Self Check Reply with quote

Alex wrote:
deMort wrote:
Porsche state less than 5% of 997,s have this issue ..



Is that per week or per year?

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!
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TurboSandGT4
Trainee


Joined: 06 Jan 2020
Posts: 67



PostPosted: Tue Mar 03, 2020 8:16 am    Post subject: Reply with quote

are the 997 Gen2 also affected?
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bazhart
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Joined: 20 May 2009
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PostPosted: Tue Mar 03, 2020 10:51 am    Post subject: Reply with quote

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 admin@hartech.org.

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

Baz
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brownspeed
Spa-Francorchamps


Joined: 09 Jun 2016
Posts: 332
Location: Gods favourite city-Manchester


PostPosted: Tue Mar 03, 2020 1:37 pm    Post subject: Reply with quote

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


Joined: 20 Aug 2012
Posts: 6893
Location: Liverpool


PostPosted: Tue Mar 03, 2020 1:42 pm    Post subject: Re: Bore Score Self Check Reply with quote

Alex wrote:
deMort wrote:
Porsche state less than 5% of 997,s have this issue ..



Is that per week or per year?


Hand we all know its 50:50 ie you either have it or you don't Thumb
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jonttt
Long Beach


Joined: 20 Aug 2012
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Location: Liverpool


PostPosted: Tue Mar 03, 2020 1:45 pm    Post subject: Reply with quote

deMort wrote:
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 .


....and we all know how realiable manufacturer official figures are Floor
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Robertb
Dijon


Joined: 01 Sep 2003
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Location: South Oxfordshire

2002 Porsche 996 Carrera 4S

PostPosted: Wed Mar 04, 2020 9:22 am    Post subject: Reply with quote

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.
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bazhart
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Joined: 20 May 2009
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PostPosted: Wed Mar 04, 2020 9:29 am    Post subject: Reply with quote

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 admin@hartech.org

Baz
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drmark
Monza


Joined: 07 Feb 2009
Posts: 170



PostPosted: Thu Mar 05, 2020 2:43 pm    Post subject: Reply with quote

Robertb wrote:
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.


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......
 
  
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villaman
Silverstone


Joined: 05 Mar 2019
Posts: 139
Location: North Staffordshire 997 C2


PostPosted: Thu Mar 05, 2020 9:57 pm    Post subject: Reply with quote

drmark wrote:
Robertb wrote:
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.


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......


Did you get a new engine in the end ?
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drmark
Monza


Joined: 07 Feb 2009
Posts: 170



PostPosted: Fri Mar 06, 2020 6:53 am    Post subject: Reply with quote

villaman wrote:
drmark wrote:
Robertb wrote:
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.


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......


Did you get a new engine in the end ?


Yes, sorry Smile
 
  
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drmark
Monza


Joined: 07 Feb 2009
Posts: 170



PostPosted: Fri Mar 06, 2020 6:54 am    Post subject: Reply with quote

villaman wrote:
drmark wrote:
Robertb wrote:
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.


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......


Did you get a new engine in the end ?


Yes -sorry, should have been clearer.
 
  
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berni29
Indianapolis


Joined: 24 Oct 2009
Posts: 2335
Location: Kent


PostPosted: Fri Mar 06, 2020 11:01 pm    Post subject: Reply with quote

Hi

You can buy very inexpensive inspection scopes on Ebay/Amazon these days including wireless ones. I bought one just last week.

Im pretty sure you could get a half reasonable look at the bores with one of the smaller headed models.

I bought mine to help try to track down an oil leak and have a better look inside my sill.

All the best

Berni
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bazhart
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Joined: 20 May 2009
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PostPosted: Sat Mar 07, 2020 12:24 pm    Post subject: Reply with quote

A word of warning - inexperienced views of different bore scope cameras can easily mislead the viewer into conclusions that are wrong.

There is no substitute for looking first, then fully stripping and inspecting hundreds of engines - after which you can at least reliably interpret the views from your own camera (as we can).

In realist there will be very few engines that on stripping and inspecting will not have some wear somewhere on a piston and/or bore but a lot of it is not serious and the car will probably run for high mileages afterwards as it is not usually a fault that stops it working.

By now there are plenty of specialists who can read into oil consumption, tail-pipe discolouration etc to decide of a boroscope would be advised and plenty who can then advise how soon remedial action is worth considering.

Overall mileages and the wear we see on crankshaft journals is also another factor that might combine with boroscope analysis to vary the advice resulting.

As a very general rule of thumb (and prone to exceptions) crankshaft bearings are usually worn to under the white metal bearing surface in the highest wear areas (about 24 degrees after TDC) by 75K and cranks too worn to re0use after 150 K (if they are still running by then).

Early 996 3.4's with hard coated pistons usually will not bore score by 150K but cylinders will have distorted oval and be prone to cracking or "D" chunking by then unless they were exceptionally good original castings in the first place.

Later engines with plastic coated pistons are more difficult to advise about since there are 3 different causes of piston coating loss and variations in the distribution of silicon in the cylinder bores and the bonding strength.

We created our oversized engine alternatives to try and provide an incentive to consider rebuilds before so much wear and damage has taken place that the cost escalates just to get back to a reasonable starting point and many are taking up that option now. Meanwhile those engines we have rebuilt some time ago are beginning to be reported to have covered high "second life" mileages and still be running very well.

We are also not sitting on our laurels with plenty of R & D continuing and new improvements under test while machinery and equipment are constantly being upgraded to pursue the best possible quality rebuilds at the most competitive prices.

Baz
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deMort
Dijon


Joined: 21 Mar 2015
Posts: 7950
Location: Brighton


PostPosted: Sat Mar 07, 2020 7:28 pm    Post subject: Reply with quote

Can i just .. Humbly point out ..

This post is about how when changing your spark plugs you can see if you might have an issue .. ie oil deposits on x1 plug and can get it checked if needed .

A simple diy if you like .

The scope pictures i posted leave no doubt as to the problem here but they were a secondary check after the plugs were removed .



This is kind of getting Hijacked into a general purpose discussion or Publicizing a business ..

That's fine but please .. if you want that .. Make your Own Thread ...
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Thank you all so Very much .

She's not going until july 2020 though .



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C11BRA
Imola


Joined: 30 Mar 2015
Posts: 767
Location: North London. Herts.


PostPosted: Sat Mar 21, 2020 8:26 pm    Post subject: Reply with quote

Plug photos here from a mates 2006 4S.





He is experiencing some oil consumption too.
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