Anyone use Nippon FRM pistons?
01-31-2019, 05:35 AM
#62
The piston to wall was set to 0.0013 without coating. The pistons are to be installed at zero clearance, so I had to lightly sand down the coating to make these fit in the bores.
02-08-2019, 02:54 PM
#63
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since you opted for Line2line coating, would you consider coating OEM std pistons for a diameter increase and hone the bores to 87.08-87.1mm just to freshen up the bores and make them round again? Then use 87.25mm oem piston rings which are still available and set ring gap according to OEM specs. Just a thought.
02-09-2019, 05:56 PM
#64
I thought about this, as there is a white paper floating out there suggesting that the coating can work up to +.25mm clearances, but I'm not sure how the 87.25mm rings would fit on an 87mm piston as it relates to ring groove clearance. I'd love to hear more about this, thanks!
02-11-2019, 03:01 AM
#65
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Rings should be no problem at all (from 87.25mm to 87 is a really minor difference. I have seen this done for 0.5mm and still no problem). I would be concerned for a 1mm difference where spring tension and geometry will be heavily compromised.
02-11-2019, 03:59 AM
#66
Thread Starter
I thought about this, as there is a white paper floating out there suggesting that the coating can work up to +.25mm clearances, but I'm not sure how the 87.25mm rings would fit on an 87mm piston as it relates to ring groove clearance. I'd love to hear more about this, thanks!
02-11-2019, 05:44 AM
#67
Biggest mistake when filing rings is that people file them straight and when the ring is compressed the two ends aren't flat with each other. You always want to file the outer edge of the ring just slightly more than the inner edge so when you put the ring in the bore the two ends have the same face and are flat with each other.
02-11-2019, 12:07 PM
#68
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Still, I wonder how much any clearance-reducing coating would last on a street engine....This is a hugely bigger concern than piston rings filing and installation.
02-12-2019, 06:40 PM
#69
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02-13-2019, 05:37 AM
#70
Based on the technical papers available, the coating is actually quite lasting; in others words, it is a permanent solution and not a sacrificial coating. There are too many unanswered questions and that's why I wanna try to document as much as I can from practical experience. The engine is going in this Saturday, so I will have an update then.