Calling all engine builders with PTV experience. I am currently bulding a new 5.4 engine for my F150 Lightning. Forged steel crank, h-beam rods, manley 18cc coated spherical dish pistons, stage II 102600 comp cams, ARP head studs, ARP main studs, new 2003 production 5.4 block bored +.020", and patriot performance stage II heads. I installed the heads and timed the engine and that is where I ran into a big problem. I even triple checked my timing to make sure it was right. I have PTV issues even though the deck is .120" thick stock? I had .008" machined off the deck and +/-.005" off the heads. I installed a solid valve lash adjuster to verify piston to valve clearance and noticed that the valve is not even seating when the round of the lobe is contacting the rocker arm? I contacted JDM to get some insight on the problem and they said the valves are sunk too far into the head or the valves are the wrong length. I measured the distance form the top of the valve to the top of the retainer and got different results every time! whats going on here? Measurements were .412", .425", .441", and so on... These should all be the same? Has anyone else run into this problem? Should I just return the heads and get a different brand? Please help asap as I already had to reschedule my dyno appointment due to this problem... Thanks a bunch!

 

patriot heads a JUNK. send them back.

 

yeap. send them back and look into some other heads.