Kevin Johnson and crank scrapers.
06-21-2009, 08:33 AM
#122
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Here is a directory containing all the pics that I have. Some of the pics have text added to them and arrows. The original image is also present.
http://www.crank-scrapers.com/SHORT%20PICS/
Here is a link to the MSI manual. See page 46:
www.boosttown.com/engine/piston_damage.pdf
The "pistonskirt-fracture" image points to the break surface which contains a nodal pattern, apparant starting point and shiny fracture surfaces leading back to the starting point.
http://www.crank-scrapers.com/SHORT%20PICS/
Here is a link to the MSI manual. See page 46:
www.boosttown.com/engine/piston_damage.pdf
The "pistonskirt-fracture" image points to the break surface which contains a nodal pattern, apparant starting point and shiny fracture surfaces leading back to the starting point.
06-21-2009, 08:57 AM
#123
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Porsche spent much time playing with oil levels but the running level is very much a secondary issue with this problem. The oil level issue is fairly easy to deal with and if it were the problem then Porsche would have solved it decades ago. Although my confidence with this wavers because of the M96.
06-21-2009, 09:28 AM
#124
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Porsche never counted on the Dentists' wives pulling much G. 
But the clarion call of those damn double A-arm suspension just begs for faster and faster cornering.
But the clarion call of those damn double A-arm suspension just begs for faster and faster cornering.
06-21-2009, 11:08 AM
#125
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Hopefully one is for GTS and heading this way. Carl promised four week delivery at his web page at time of order but no one who knows history behind scraper purchases is expecting that. As Lizard says, it would just be great to know timetable.
06-21-2009, 11:18 AM
#126
In Your Face, Ace
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Another topic but related:
I received a private message last night from a 928 owner who had held off installing his kit because he had heard about a failure with Abby Short's engine. I did not know this was a topic circulating behind the scenes or possibly there is a thread on it here somewhere -- if I look for it I will likely spend my entire Sunday writing posts instead of working on scrapers.
Abby sent me a number of pictures of a damaged scraper system in situ but first only of some bits that had been fished from the sump. It was difficult to know what exactly had failed and why. When I received that info from Abby I stopped everything to do with 928 scraper production until I could find out what happened. This went on for some weeks.
One of the photos I received later showed a damaged piston missing part of its skirt. I will put it up shortly after I retrieve it from the old harddrive. There is a well developed area of failure analysis with respect to piston failures. Kolbenschmidt is a tier one manufacturer of pistons (they also make or made engine block castings for Porsche). Their educational arm published a guide to diagnosing failures.
With respect to the failure of the piston in Abby's engine the question was whether it was impact damage from some part of my system (?) or a fatigue failure. The two, impact and fatigue, have very unique and characteristic qualities. The picture clearly shows a fatigue failure meaning that part of the skirt fell off and was bounced around the inside of the block. I would not be surprised if there were other impact damaged pistons but causal order is important here.
I will get the pictures and put them up. So far, I have spent one hour on this single post. This is where a lot of time goes.
I'm not sure if you'd find a thread about it but I can tell you I never started one or mentioned the issue on this forum. Your post is the first and only mention of it I am aware of. As you know, I in no way think the scraper had anything to do with my engine failure.
In addition, I will not hesitate to run your scraper again once we do the build up. Just wanted to clarify that for aanyone who may read more into this than truly exists.
06-21-2009, 12:13 PM
#127
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Another topic but related:
I received a private message last night from a 928 owner who had held off installing his kit because he had heard about a failure with Abby Short's engine. I did not know this was a topic circulating behind the scenes or possibly there is a thread on it here somewhere -- if I look for it I will likely spend my entire Sunday writing posts instead of working on scrapers.
Abbey told me it was fine to run it and suggested I do so, went out of his way to tell me that the problem he had did not start with your scrapper, but either a bearing or a broken crank.
I said I did not install they because of the problems he had, not because Abby said anything negative about the scrapper.
There were other reasons I did not install it also, but that has nothing to do with you or your scrapper.
Get your facts right, I asked you simple question "Did you ever figure out why and what happened?"
06-21-2009, 01:01 PM
#128
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Kevin,
If you are really that busy, and having trouble keeping up with things, I would recommend finding another local enthusiast who can do this work and bring them on. Maybe even two.
I understand that we all have strengths and weaknesses. But learning to overcome our weakenesses is a huge part of life and business.
If you are really that busy, and having trouble keeping up with things, I would recommend finding another local enthusiast who can do this work and bring them on. Maybe even two.
I understand that we all have strengths and weaknesses. But learning to overcome our weakenesses is a huge part of life and business.
06-21-2009, 01:51 PM
#129
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Uh, This was behind the scenes until you made this post Kevin.
Abbey told me it was fine to run it and suggested I do so, went out of his way to tell me that the problem he had did not start with your scrapper, but either a bearing or a broken crank.
I said I did not install they because of the problems he had, not because Abby said anything negative about the scrapper.
There were other reasons I did not install it also, but that has nothing to do with you or your scrapper.
Get your facts right, I asked you simple question "Did you ever figure out why and what happened?"
Abbey told me it was fine to run it and suggested I do so, went out of his way to tell me that the problem he had did not start with your scrapper, but either a bearing or a broken crank.
I said I did not install they because of the problems he had, not because Abby said anything negative about the scrapper.
There were other reasons I did not install it also, but that has nothing to do with you or your scrapper.
Get your facts right, I asked you simple question "Did you ever figure out why and what happened?"
I have one of your scrapers/trays for the 928 and I did not install it because of the problem that Abby Short had.
I was never sure what caused the failure of his parts, so I did not install them in mine.
Did you ever figure out why and what happened?
I was never sure what caused the failure of his parts, so I did not install them in mine.
Did you ever figure out why and what happened?
Abby sent me a number of pictures of the bottom end including one that showed a piston facture. Kolbenschmidt is a tier one supplier of pistons (they make engine blocks for Porsche, BTW). Their teaching arm has a manual to diagnose piston failures. There is a clear difference between a fatigue and impact fracture. The piston skirt exhibited a clear fatigue fracture. The piece flying off precipitated the chain of events.
There are many possible reasons for skirt fatigue fractures, none of which are related to crank scrapers.
Abby sent me his system and I am replacing the damaged parts of it at no charge. Not because I have to but because it seems a decent thing to do.
There are many possible reasons for skirt fatigue fractures, none of which are related to crank scrapers.
Abby sent me his system and I am replacing the damaged parts of it at no charge. Not because I have to but because it seems a decent thing to do.
I was not aware that the skirt broke, that changes things.
Thanks Kevin
Thanks Kevin
I apologize for my misunderstanding.
Edit: I should add that the large imbalance in the rotating assembly caused by pieces coming off a piston would easily create a harmonic that focused on the "free-er end" of the crank and wipe the bearing loose with increasing friction. There is a huge amount of energy there and would easily overcome a locating pin.
Last edited by Kevin Johnson; 06-21-2009 at 02:06 PM.
06-21-2009, 01:57 PM
#130
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Kevin,
If you are really that busy, and having trouble keeping up with things, I would recommend finding another local enthusiast who can do this work and bring them on. Maybe even two.
I understand that we all have strengths and weaknesses. But learning to overcome our weakenesses is a huge part of life and business.
If you are really that busy, and having trouble keeping up with things, I would recommend finding another local enthusiast who can do this work and bring them on. Maybe even two.
I understand that we all have strengths and weaknesses. But learning to overcome our weakenesses is a huge part of life and business.
We were then buried in sales from November onwards. More than we had ever received and this continued. We had to drop ebay sales to try to catch up. Just now working out of that.
