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Narrow escape - possible bore scoring.
- Thread starter Hertsdriver
- Start date
FZP
Zandvoort
- Joined
- 18 Jan 2015
- Messages
- 5,878
I'm no expert, but after 5 years of borescore threads and Hartech's input, I've managed to put some tidbits in my memory bank. When OP put up those pics, I was dubious as to whether that was scoring or just marks, but as I'm no expert, I kept my quiet. In the mean time, a few others saw the pics came to a similar conclusion as I did and noted/questioned it. Then to have the person who is, as far as I can tell, the #1 Porsche engine builder in the country, say the same. It's now an open and shut case of misdiagnosis by a "Porsche Specialist"
The mods have absolutely done the right thing by changing the headline as you were unwilling to. There are countless threads where bad news is discussed on here and are allowed to run, so long as it's justified. The mods do a great job on maintaining this ecosystem with just and fair rule, so to say it's pathetic is a reflection on you rather than the mods.
The disappointing thing is it wasnt the OP who made the mistake, but his specialist and he's cut up with this forum. I'd be annoyed at the specialist for missing out on what seems like a good car. Wattso seems to agree as he's parted with his hard earned and us enjoying it.
Good luck with your search, and hope if you're lucky enough to stumble upon another Hartech rebuild, that you get someone with the correct knowledge to interpret the information
The mods have absolutely done the right thing by changing the headline as you were unwilling to. There are countless threads where bad news is discussed on here and are allowed to run, so long as it's justified. The mods do a great job on maintaining this ecosystem with just and fair rule, so to say it's pathetic is a reflection on you rather than the mods.
The disappointing thing is it wasnt the OP who made the mistake, but his specialist and he's cut up with this forum. I'd be annoyed at the specialist for missing out on what seems like a good car. Wattso seems to agree as he's parted with his hard earned and us enjoying it.
Good luck with your search, and hope if you're lucky enough to stumble upon another Hartech rebuild, that you get someone with the correct knowledge to interpret the information
nigel99
Mexico City
- Joined
- 16 Jul 2015
- Messages
- 1,890
I feel for the OP as his intentions for the post were to advise purchaser's not to assume that a rebuilt engine doesn't require a PPI and borescope. This was based on professional advice paid for by the OP.
Who was the specialist that performed the PPI? It would be beneficial to the balance of this thread to have their interpretation of the images.
Who was the specialist that performed the PPI? It would be beneficial to the balance of this thread to have their interpretation of the images.
I see both sides of the argument here. I don't believe that OP started this thread with the intention damage the reputation of Hartech. I think the primary mistake here is the apparent misdiagnosis by the PPI specialist.
However when a world expert like Baz turns up and, based with the evidence in front of him, states they don't think it's bore scoring you have to value that opinion above all else, I certainly did as i bought the car!
Had Baz not have commented I would absolutely not have purchased this car.
I'll shortly be booking it in with Hartech for a "Gold Major" service so look forward to meeting Baz in person :bye:
I'll also stop teasing this new ownership thread and create it today!
However when a world expert like Baz turns up and, based with the evidence in front of him, states they don't think it's bore scoring you have to value that opinion above all else, I certainly did as i bought the car!
Had Baz not have commented I would absolutely not have purchased this car.
I'll shortly be booking it in with Hartech for a "Gold Major" service so look forward to meeting Baz in person :bye:
I'll also stop teasing this new ownership thread and create it today!
bazhart
Barcelona
- Joined
- 20 May 2009
- Messages
- 1,343
It's all down to microscopic measurements of surfaces.
Under huge magnification a cylinder bore in the vertical axis plane looks like a saw tooth and so does the surface of the ring that touches the bore.
Even though our honed bores are around 10 times more round than a new Porsche bore (which we have in stock on a number of new blocks), the surface still under magnification is uneven circumferentially
When the engine is first run the minute high spots on the ring touch the minute high spots of the bore where the point of contact is like the tip of a saw blade tooth and all the forces on the ring (from combustion) push the load onto a very small area and because load over area is high it polishes the surface in vertical lines.
After a minute or two running the sharp points on both the ring and bore are microscopically flattened and the load is now spread over a much wider area and the load/unit area is not sufficient to polish the bore any more.
The result is a much better fitting rings to bore contact surface than you will get from any other combination providing good compression and long life but leaving those small polished marks in the cylinder that have no measurable depth but are visible.
this process is what all engines and all parts in engines undergo during the "running in period" and it is what it is all about.
Bore scoring results in deep grooves that are clearly different.
I must admit that when the Lokasil original surface starts to release silicon particles that the piston rubs up and down the bore to initially lightly score it - the result can look similar to polishing - but those of us familiar with the differences can detect it using our own camera (but not others) and it is obvious when it gets worse.
The fact that the engine was still running OK should have been a clue.
For the original poster to refuse to edit the topic heading to something more non comital indicates to me that there was another influence on the reasons for the post in the first place and should demonstrate how powerful the Internet can be in damaging legitimate businesses interests when that is intentional.
Regular readers will notice that we do not list competitors names or refer to them in our posts even though on many occasions it would have been easy to do so - but it does leave us vulnerable at times like this.
Really grateful for such support from so many others - thanks a lot guys!
Baz
Under huge magnification a cylinder bore in the vertical axis plane looks like a saw tooth and so does the surface of the ring that touches the bore.
Even though our honed bores are around 10 times more round than a new Porsche bore (which we have in stock on a number of new blocks), the surface still under magnification is uneven circumferentially
When the engine is first run the minute high spots on the ring touch the minute high spots of the bore where the point of contact is like the tip of a saw blade tooth and all the forces on the ring (from combustion) push the load onto a very small area and because load over area is high it polishes the surface in vertical lines.
After a minute or two running the sharp points on both the ring and bore are microscopically flattened and the load is now spread over a much wider area and the load/unit area is not sufficient to polish the bore any more.
The result is a much better fitting rings to bore contact surface than you will get from any other combination providing good compression and long life but leaving those small polished marks in the cylinder that have no measurable depth but are visible.
this process is what all engines and all parts in engines undergo during the "running in period" and it is what it is all about.
Bore scoring results in deep grooves that are clearly different.
I must admit that when the Lokasil original surface starts to release silicon particles that the piston rubs up and down the bore to initially lightly score it - the result can look similar to polishing - but those of us familiar with the differences can detect it using our own camera (but not others) and it is obvious when it gets worse.
The fact that the engine was still running OK should have been a clue.
For the original poster to refuse to edit the topic heading to something more non comital indicates to me that there was another influence on the reasons for the post in the first place and should demonstrate how powerful the Internet can be in damaging legitimate businesses interests when that is intentional.
Regular readers will notice that we do not list competitors names or refer to them in our posts even though on many occasions it would have been easy to do so - but it does leave us vulnerable at times like this.
Really grateful for such support from so many others - thanks a lot guys!
Baz
If I was in the market for a 997 I'd wait until a Hartec car was advertised, either that or try and purchase a cheap a car as possible then take it straight round to them.
They do seem to be a very honest company to deal with and their work must be second to none.
They do seem to be a very honest company to deal with and their work must be second to none.
bazhart
Barcelona
- Joined
- 20 May 2009
- Messages
- 1,343
Interestingly if you strip a new rebuild or new engine after a few hours the main bearing and big end shells have shiny narrow lines on them where the parts are running in - but no one would refer to them as shell scoring!
Later on they wear all over but Nikasil is hard enough once a few high spots are rubbed down to last almost for ever especially being oleophilic.
Baz
Later on they wear all over but Nikasil is hard enough once a few high spots are rubbed down to last almost for ever especially being oleophilic.
Baz
Kryton said:
Can i just humbly point out ..
It's only a small percentage of cars that suffer from this and not every single one !
Score marks of some degree are not unusual as Baz has pointed out and as i've seen .. its how they are interpreted by the garage that seems to be the issue here .
description of a score mark ..
: a mark or cut that is made in a surface with a sharp object .
Ref .. http://www.learnersdictionary.com/definition/score
No.3
Whether that is at a microscopic level or far larger is not relevant .. the marks are score marks ... this topic does seem to be about what we call them After all so this is what i found and what i will call them ..
Marks in a bore are bore score .
In this case the marks are what i would class as pretty normal and nothing to worry about .
Has the op been told the same ? it doesn't sound like it hence this thread .
Actual bore score is far far deeper marks followed by smoking , noise , oil usage and black tail pipes .
The tread name was never going to be correct and indeed could be very damaging for a company so it had to be altered ... but the op has also been vilified when the blame imho rests with the garage that told him what .. well .. game over basically ? very wrong .
I don't think he covered himself in glory by not changing the title but he has acted on the advice of professionals .
The reality was it's pretty normal marking and under magnification ( which is what these cameras do ) makes it look far worse than it actually is .
i do actually have a question for Baz .. as long as he doesnt have issue with my post .. which i'm happy to discuss if needed but not to argue over ..
the image below ..
I had always assumed the marking far right was the rings bedding in , a high spot if you like .. i would appreciate your agreement or what you consider it is .
EDIT ..
Just to add ..
I consider Hartech to be one of the market leaders in providing an alternative to the original and somewhat flawed porsche design .. their work in this field has saved many owners imho ... i for one am grateful even though i don't actually own one .
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