Usmts/usra spec head valve guide questions

[speaker56]

Our engines have both had problems with valves sticking which is a problem with these heads because of their design. After it happened the first time the engine builder went in and opened them up more and thought that it should be plenty. But it happened again to an engine that just had 250 laps on the heads with everything new in them.
Running Joe Gibbs oil and VP late model plus fuel.

Does anyone know dimensions of how much bigger the guides need to be compared to the valve?

Thanks

[dirty white boy]

what the manufacturer say?? id try there spec's,...an id use the valves an all thay recamend as well...to much clearance an valves could be shacking an wabblin in the guide an end up gallin an sticking too....ive never run them type heads but hope you figure it out,good luck

[powerslide]

i have an imca spec head (same head) and it locked up solid in the shop a couple days ago. dropped pan expecting a bearing issue, nothing. when i unbolted the rockers then i would roll the motor over. called builder and he says could be same issue you are describing. I will report back once i have more info. If anyone else has had this problem please chime in. i cant believe this would be a manu. problem they have alot of these heads out.

[fast_crew]

What type of guide material? Iron, Bronze? Liners or full guides?

[racin6mod]

don't over look the valve seals some are so (not a nice word)(not a nice word)(not a nice word)(not a nice word) tight you can't get any oil to the valves I've went to using pbm viton seals.some guy's don't even run seals on the intake side.

take an old valve (same brand as your using) mic the stim now heat it 300 degrees in an over (do not use a torch)and mic it while it's hot to see how much it grows at temp add .0015 to that and there's your clearance now just ream the guide tothat number.

[dirty white boy]

don't over look the valve seals some are so (not a nice word)(not a nice word)(not a nice word)(not a nice word) tight you can't get any oil to the valves I've went to using pbm viton seals.some guy's don't even run seals on the intake side.

take an old valve (same brand as your using) mic the stim now heat it 300 degrees in an over (do not use a torch)and mic it while it's hot to see how much it grows at temp add .0015 to that and there's your clearance now just ream the guide tothat number.

i like that idea!!