Piston kissing

This is a post about piston to valve clearances.

.022 piston protrusion
.045 valve face depth
No piston reliefs
188/220 cam
Stock thickness head gasket (haisley fire ring)

According to Hamilton’s calculator I’m gtg, with .032 of piston to valve clearance, which is literally on the edge of minimum allowed.

Hamilton’s website also says that .040 is recommended if the engine is going to see more than 4K rpm. Which I would like to see from time to time...

Can I just lash the valvetrain a little looser (.012/.022) to make me feel better, Zach said this was stupid and I agree it’s not optimal, engine is pretty much assembled lol. Opinions? Thanks

What's the exhaust valve clearance? If it's quite a bit larger than the intake clearance, you can simply retard the cam a degree or two and pick up more intake clearance in exchange for less exhaust clearance.

Could have the valves recessed further.

The 188/220 is extremely tight on PTV and has been since it first came out. I went through this and there is a thread on here about my findings on an engine that was within Cummins spec and the valves were way too tight. So much so that they changed the LSA to help them fit. I won't run anything under .040 and like said above your valves could be sunk .010 with a simple valve job and you will be fine. I want to say OEM spec is over .050 deck to valve face. Check the exh valve it's the more important one since the Pistons chasing the exh closed. If it's say .050 PTV the redegree the cam a degree or 2 and see if that frees up the intake. If it's just as tight then sinking the valves, thicker gasket or relief is the only options and the valves would be your easiest solution.