Cylinder wall problems ( never seen anything like it)

65SignetSweden said

I have assemble all of my engines my self. The only ting I can´t do my self is honing and balance a rotating assembly. I now have an other shop that doing all of my honing and balancing.
And my tune was not off ( no pinging, 12.2-12.7 af. ,plugs ok, timing 35 deg)
I strongly think that all of this damage occured at the last race when the car started to go rich and flooded at the burnout. I have had this engine set up for 7-8 years now and has always tuned with Wideband af meter.

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I am thinking this too. With the high rpms and the associated reciporcating stress on the pistons, plus the sudden heat input of the burnout, it would not take much oil loss on the cylinder walls to do this. The wall discoloration is the clue that I have keyed in on that says gas-washing.

Just one dumb thing to check is to make sure that the piston/cylinder oiling outlets on the rods are pointed in the right direction. I assume this engine has them.....And that the pistons are oriented right and not mounted on the pins/rods 180 degrees out. I saw the 'dents' on the cylinder walls and wondered of the pin offset was backwards. Not that I know it would cause that....just all that came to mind.