I bought a spare motor for 200 for my pickup that I am about to start rebuilding. The guy sold it to me as a builder because he heard a slight knock before he pulled it. I bought it, and started tearing it apart. The first thing I noticed was the arp head studs! I was pretty excited about those. next I started getting the pistons out after getting the head off. I found a spun bearing on number 4 cylinder. But the quetion I have is that on the top of each piston, there is a 0.50 stamped on it. What is this number, cause if it were bored 50 over, it would be .050. anyone know what the .50 is?

 

I would assume that it's .5mm over. I believe that's .020 over.
Measure the piston. Should be 92.5mm.

My core was .040 over, 1mm. Had to be taken to .060 1.5mm (93.5mm piston) - probably won't make .080 over, 94mm.

 

Thanks a lot, I didn't even think toyota=metric=mm.