Quote:
Originally Posted by regular guy
I've never used this technique, so I'm not familiar with it. If I understand it correctly, I should place the bearing on the calibrated surface, and run the gauge until I see a minimum on the dial. I don't mind giving it a try, but I won't be back to the engine shop for at least 6 weeks before I can get to it. And after thinking about it, I don't see how this can be very accurate even though it sounds like a really cool idea. Maybe it's my inexperience with that type of gauge. But here’s my thoughts:
We're talking about measuring bearing thickness with a gauge calibrated to 0.001 mm resolution. The inside diameter of the bearing is approximately 52.00 mm. The accuracy of this measurement at that resolution depends on the needle landing exactly in the zero-degree mark of the bearing. If you miss the zero-degree mark by 1/20th of one degree, then your measurement will be off by 0.0035 mm on a 52mm ID bearing; that's 3.5 times the resolution we're trying to measure. To make this work at 0.001 mm resolution, your angle error can't be more than 3/200ths of a single degree (+/- 0.015 of a single degree). Call me a skeptic, but that doesn't seem possible with the technique shown in those pictures. Maybe I'm just unfamiliar with this technique and it's actually easier than it looks.
But I'm definitely willing to ask the engine shop if they want to set me up and show me how to use that type of gauge. I've seen that type of gauge in the engine shop, so I know they have them. But it's going to take many weeks before I'll get a chance.
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Yes, place a reference or inspection grade 2mm slip gauge on a good surface table. Then zero out a high quality lever type dial gauge on the slip. You can see a witness mark on the shell where they were checked at the factory.
This is a highly accurate way of measuring and surely better for your reference when comparing with other shops across the world than relying on someones mic feel.
Your photo's are interesting and seem to indicate that clearance isn't necessarily the problem here.
My theory is that the bearings are different material, hence the price difference between the two. Is it beyond the realms of possibility that some motors have been assembled with the wrong bearings top/bottom ie red top, blue bottom?
Could you check part numbers or colours on a failed set?
I know there have been a few bearing failures but percentage wise across the cars production it's a minute proportion. It's virtually unheard of in the UK.