I am swapping from a XE262H to a XE284H. My heads have 1.90 1.60 valves. I have the stock pistons with stock valve nothces. Do you think I will run into any piston to valve issues. I dont want to pull the heads off to check piston to valve clearance.
well....just a quick, insuffecient way to check would be to go ahead and put the cam in, setup up the valvetrain and turn the motor over by hand and make you cant feel the valves pushing on the pistons.
if the lift at the valve is more than about 0.540" (which is too damn close anyway), then you probably will have p/v issues...just a guess though, clay it and find out for sure.
I have 2.02 1.60 valves in my Canfield heads and run a .566/.566 lift 218/224 duration @.050 FTI cam with stock pistons and had just enough clearance.
Duration plays a bigger roll than lift when determining valve clearance. You have to use solid lifters to check valve clearance cause the hydraulic lifters will bleed down. It is not enough that the valves dont hit the pistons when turning the motor over. You have to have 15-20 thousanths of clearance on top of that or you will have high RPM interferance.
There are ways to check piston to valve clearance with the heads on. You can install some weak springs and when the rocker is all the way down push the valve till it hits the piston and measure the distance with a dial indicater.
This is not a place where you want to take shortcuts.