If your spark plugs still have the "compression washer" on them from the plug mfg, then that's your cause 9 out of 10 times, the tube is your "compression washer", on a HEMI you remove the plugs compression washer before installing them, if this is the case, you may be able to rework the tube ends, otherwise if they are badly drawn you need a new set of tubes
Why would they be ruined? What is leaving the washer on going to do to them, that a taking it off wouldn't do? If anything, I would expect taking the washers off to have a better chance of ruining the end of the tubes.
Not meant to be an aggressive response just genuinely curious. I'm Running RC12YC Champions with the washers in factory heads with a MP plug tube set. I have to take my covers off a couple times a year to lash valves and I see the tube ends every time. So far so good I guess.
I have a preset valve adjuster torque wrench that I also use to torque the plugs because its convenient. The 22ftlbs preset may be not enough to deform the tubes possibly...
