1st 6.0 build. wiseco pistonsc4cc dome with big valve reliefs
243 heads. milled .030,
040 head gasket,
custom cam Intake Duration 243
exhaust dur 250
Intake Valve opens 15.5 BTDC (- indicates ATDC)
Intake Valve closes 47.5 ABDC
Lobe Separation Angle 110
Exhaust Valve Opens 59 BBDC
Exhaust Valve Closes 11 ATDC (- indicates BTDC)
intake centwrline 106
Exhaust Centerline 114
Overlap 26.5 degrees

7.375 pushrods, morel lifters, im having piston to valve contact trying to turn over motor by hand,new cloyes chain gears installed dot to dot
any thoughts appreciated

 

My first step here would be to degree the camshaft as installed, to eliminate a grinding error. If that checks out, I would set up a few cylinders with checking springs, and begin the fly cutting process. Go slow and measure very very often.
Of course, you can always change camshafts, going with less duration, and try again. Either way, this is a prime example of how important it is to check for PTV when squeezing the envelope for performance.

 

My first thoughts are that your cam is too big but if you didn't degree or verify the camshaft matches the cam card. My LS370 build has 12cc domes with a 238/246 duration camshaft and I could've went bigger.

 

self inflicted wound, pulled head, to recheck valve clearances, and found a piece of welding chalk on top of the piston, checked clearance, .080 minimum on both valves,

 

Disaster averted..... WHEW!!!

 

Did you backtrack and figure how that piece got in there?

 

.080 is good for intake side, but is concerning for exhaust side. I shoot for .090 absolute bare minimum on exhaust side and feel good at .100
Piston rock by itself can be a wild card.

 

You gave a lot of info, but forgot one BIG thing! LIFT!!! I'd assume its at least .620". Anyway, cutting the heads .030", then installing a long duration cam with a relatively tight 110 LSA, is asking for trouble. IIRC, and I may not be (), your Intake lobe is 4° retarded (?), and youre exhaust is 4° advanced (?). My guess is it's the intakes that are hitting. Also, if you didn't degree the cam, and went only by the dots, it may be OK, but it also may not be. Only by using a degree wheel, and a dial indicator, will you know for sure. Without knowing the lift, I think there are 2 major problems. Number one is the .030" head milling, and number two is combining a tight LSA with the big milling cut. Also, what thickness head gaskets are you running, and what bore are the gaskets? Are you certain it's the valves hitting pistons? It could be too small of head gasket bore, and the pistons are hitting the gaskets. A forum member here recently had this exact issue. You could turn the motor over and it would suddenly hit something, and wouldn't turn any further. However, if you're running a .650", or greater lift cam, with that LSA, and milled heads, that may be what it is. Sorry I can't zero in any closer, but without being there, and not knowing lift, it is extremely difficult to do so. I hope this is a race engine, because with almost 30° overlap, it's not gonna be a grocery getter!!!

 

.630. .617 lift, .045 gasket, i have .050 quench with clay,

biggest problem i found, i reinstallled head, and when i installed rockers, i forgot the rocker stand,,,,,, i couldnt get valves to adjust or even close, i had it installed when i measured for pushrod length,,, dumb move, so , reinstalled correctly , clay in pistons, i have .150. and .130 clearance on ea valve, plenty i think,
its a drag car, hot street car go to church car,

 

ouch I hate those self inflected wounds... I've had many!