White spots

[Opposedodie]

I am at the point of putting my motor back together and was looking at each of the cylinders and noticed that the 2 rear drivers side pistons had white spots on them . What would do this? The spots rubbed of off the pistons. All the pistons had a little carbon build up but the rear 2 had the spots on top of the carbon.... I should have taken a Pic...

 

[RangerJoe]

What do your plugs from those cylinders look like? Are you running lean on those cylinders?

 

[BlackGT89]

If you are getting extreme detonation it's possible you could be losing tiny flakes of aluminum off the tops of the pistons. Check your plugs and make sure there are no flakes or specs of aluminum on the porcelain part of the plug.

 

[Opposedodie]

My Wide band says that I am running 13-16 under load and at idle I am running way rich 22+... Plugs look good from the two cylinders, lite brownish in color...