I have lt4 heads with a hyd. roller cam and when the motor was being assembled the pushrod length was check and determined i needed 7.200 pushrods.. Ran it 4500 miles and had pitting in a few valve tips (ferrea valves), so i ground the tips just enough to get rid of the pitting. I checked them now and between the lowest and highest tip there is 30 thousandths. Is this something to worry about? Should I grind the longer valves match the short ones? Any help would be great, thanks

 

How much material did you grind off? How did you grind them?

I would try to find some way to even out the pre-load on all of the lifters, which would either mean a few different length pushrods...or grinding the rest of the valves too...surface finish is pretty important on the tip of the valve, and heat treat might be as well, depending on the material.

 

I ground 5 thousandths off on the tips when I removed the pits with the grinding wheel on my valve grinder.. I checked them today and it seems the lowest is .033 thousandths difference from the high ones.. There are about 4 valves per head that are low and it looks like the locks are lower than others too, like some valves are in the seat further than others..

 

I talked to a Performance Shop thats local and the guy has a good rep, he says it would be ok due to the rockers being adjustable, just use a marker to see where the rocker tip is riding on the valve? And these must have been the same way when I ran them before if I took 5 Thousandths max off them and its still that far off.. Whats some opinions?

 

If the seats were cut on a Serdi machine they'd be all at the same height,unless you had some bad seats. were the valves new ? i've seen some new valves diff. lenght. usually your suppose to check and cut them to match. just make sure your rockers are'nt interfiering with your retainers.
good luck.

 

I guess as long as the rocker has a good contact pattern on the valve when the lifter pre-load is set properly...but it sounds like your installed height from valve to valve is different due to the lock height, which is probably affecting your spring pressure, and could be affecting your clearance when the spring is compressed fully...have you verified the installed height of each spring/valve as well as then clearance at max lift...you might need to start shimming spring seats to get installed height equal...it's sounding like it might be worth it to give the heads back to a different shop to at least check them out, if not replace the seats and valve...I know it's not cheap...but I'd be nervous to run it like that on my car.

 

ok, some valve tips have been ground more than others and some sit further in the seats than others.. The longer valves being the ones that are in the seat farther, so if I have the seats ground on the short ones to make the valves sit even with the long ones, will that work? And ayone know what they would charger to due 4 or 5 valves on each head?

 

I don't know the cost of that work sorry...best bet is probably try to find a local shop that likes working with an enthusiast to make things right...thats usually how they win loyal customers in the future...