There is another alternative. Instead of removing the cast iron guide and replacing with new (I cracked a head once removing an old one so I don't remove them any longer), you can have your machinist install a bronze liner in the old guide, then cut the top part of the guide for a Teflon seal, often times referred to as a PC seal (Perfect Circle but lots of companies now make them). I do not use them with just plain cast iron guides, but always with the bronze liners. Between the little bit of lubricant and the bronze which itself is a lubricant, the combination works pretty well. Used on plain cast iron, might be too little lubricant getting to the guide and stem leading to a seizure of the valve stem to the guide. Your machinist has to know what he is doing with these Teflon seals because the valve stem and guide does need a little bit of lubricant so sometimes a valve stem has to be polished just a bit to get the right clearance. Its not hard but the Teflon seals are much more durable then the rubber seals.
Last edited by Dragsix; 06/30/2020 8:59 PM.
