Piston kissing - Competition Diesel.Com

Poulina · 01-09-2018, 10:50 PM

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

*Big Blue24* · 01-09-2018, 11:56 PM

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.

Cflanery88 · 01-10-2018, 12:17 AM

Could have the valves recessed further.

DISTURBED · 01-10-2018, 06:24 AM

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.

01-09-2018, 10:50 PM	#1
Poulina Name: Poulina Title: Too Much Time Status: Not Here Join Date: Dec 2015 Location: Norcal Member`s Gallery Posts: 795	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 __________________ 2008 QCLB 6.8 48re Suncoast PCS, DDP supermentals, forcedinductions 467/87, Hamilton 188/220, Carrillos, studded mains w/stock girdle

01-09-2018, 11:56 PM	#2
Big Blue24 Name: Big Blue24 Title: Comp Diesel Sponsor Status: Not Here Join Date: Jan 2008 Location: Cedar City, UT Member`s Gallery Posts: 6,310	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. __________________ 95' 2wd Junker Drag Truck 1502 HP Fuel-Only 12mm P7100 Pump SXE 472 over GTX55 116mm OEM 12v Block

01-10-2018, 12:17 AM	#3
Cflanery88 Name: Cflanery88 Title: Too Much Time Status: Not Here Join Date: Feb 2016 Location: Shelby, MI 49455 Member`s Gallery Posts: 536	Could have the valves recessed further. __________________ 06 Dodge Ram 2500 6.4L, Wagler +.080 rods, Hobbit tuned, Exergy150% injectors,Polished s475/87 1:0 A/R Engineered Turbo Billet Wheel,arp625s,14mm main studs,PPE dual fuelers,Hamilton 188/220,extreme pushrods,Fleece bypass/drains/distribution block,110#springs.

01-10-2018, 06:24 AM	#4
DISTURBED Name: DISTURBED Title: YEA WE RIDE THE SHORT BUS Status: Not Here Join Date: Nov 2007 Location: Winchester, Va Member`s Gallery Posts: 6,417	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. __________________ Thanks, Jeremy 01 CTD Retired sled puller, dedicated "Twin Turbo" tow rig 96 CTD "TOO" Disturbed 3.0 - Built by Disturbed Diesel Performance 96 CTD "The Sickness" 2.6/2.8- Built by Disturbed Diesel Performance