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Old 10-20-2013, 08:20 AM   #56
Kirk
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Join Date: Jul 2007
Location: Texarkana, Texas
Posts: 959
Quote:
Originally Posted by Jamesp View Post
Kirk,

Thanks for pointing out the bearing life factor. Do you have independent calcs on IMS bearing life utilizing the 1.2 factor? I'm deciding what to do with my IMSB right now and have not had time to do more than look up the 1.2 factor for rotational arrangement. I'll run the calcs later, but would like to see a second set to verify my work. This may have a big impact bearing selection.
James, I'm not trying to design a new bearing for this application, so I have not run any calculations. I have no interest in providing any competition for LN, IMS Solution, Flat 6, or TuneRS. I am just searching, exploring, discussing, and even arguing about what is the best fix. It's difficult though because there is money involved here and some people are pushing their products with pretty hard sales methods. You have to read what is out there pretty carefully.

For example, IMS Solution has this statement on their website:

"By replacing the factory sealed ball bearing with a pressure fed oil-lubricated plain bearing, the IMS Solution eliminates potential damaged caused by foreign object debris, eliminating 11 wear components from the assembly."


I think this is misleading at best, but more likely deceptive. 11 wear components are eliminated, really? I call baloney on that one in a heartbeat. The bearing is eliminated and the weak shaft that presses into the inner race of the bearing is eliminated. So what are the 11 components then? Well this is an extreme stretch, but I honestly think they are counting the eight individual balls in the bearing as being separate "components", the inner race, the outer race, and then the shaft = 11. When Porsche assembled these engines though they only bought two components from suppliers - the bearing and shaft. Calling that 11 components to try to make the change seem more significant is baloney.

So tread carefully and try to sift through the baloney.

If you want to post your calculations for sizing a bearing, feel free to. I am sure you can get some good feedback. You are limited though simply by what will FIT inside the IMS. If you look at off-the-shelf ceramic bearings be careful about the cage material. Most use a nylon cage. I don't believe the IMS Retrofit does. I believe that is what makes their bearing "custom" is that it probably uses a steel cage or some other metal. I would check the temperature rating for the nylon cages that are standard on ceramic bearings. I don't believe they will hold up in this environment and I believe that is the main factor that stops most folks from just grabbing any old ceramic bearing and selling it as an IMS fix.

Kirk Bristol
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2000 Boxster S - Gemballa body kit, GT3 front bumper, JRZ coilovers, lower stress bars
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1986 911 Carrera Targa - 3.2L, Euro pistons, 964 cams, steel slant nose widebody
1975 911S Targa - undergoing a full restoration and engine rebuild
Also In The Garage - '66 912, '69 912, '72 914 Chalon wide body, '73 914

Last edited by Kirk; 10-20-2013 at 08:46 AM.
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