I am putting together a near-stock rebuild for my utility bed, and noticed something I think is odd with piston protrusion.
The right bank measures 0.006-0.008" protrusion, left measures 0.009-0.010" (±0.0005" with the tools we have).
Grade A protrusion spec is 0.0088-0.0108", so the right bank is entirely below the minimum!
But it gets weirder: this is after the machine shop decked 0.005" off the block, so protrusion should have been high, not below spec, right?
The right bank measures 0.006-0.008" protrusion, left measures 0.009-0.010" (±0.0005" with the tools we have).
Grade A protrusion spec is 0.0088-0.0108", so the right bank is entirely below the minimum!
But it gets weirder: this is after the machine shop decked 0.005" off the block, so protrusion should have been high, not below spec, right?
- LB7 block
- Bored 0.020" over
- Decked 0.005" to clean up some corrosion (why do people never change their coolant??)
- New Mahle LB7 race-cast pistons, no valve reliefs, weight matched
- Used LBZ connecting rods, weight matched
- Balanced rotating assembly (external)
- All bearing clearances are in factory spec, measured with bore gauges, not plastigauge
