Head Assembly Prep| Triumph Spitfire Restoration - Part 105 

I’m so glad that you’re replacing all the retainers/keepers! At this point in the game, it’s just not worth taking that chance.

Its always better to do it right the first time!!

Your machinist is correct, if you keep the revs down, you won't have a problem with valve seat recession, it's the high revs for prolonged periods that causes the damage. You have an Overdrive transmission, that will certainly help.

How interesting about that wear on your valve keepers etc, it seems to me that someone kept on using the engine at relatively high RPM after the valve springs were past their best and had started to go soft. The stress then gets passed on to the next part in the system

I don't want to give you the heebie-jeebies, but when I lap in valves, when the sound changes, I lift the valve and stick and turn it 1/4 turn then lap until the sound changes again. Do that until you've made a full circle of the valve in the seat. When you check the grind after washing the valve, the wear pattern should be centered on the valve face and no wider than a 1/3 of the face with a 3-angle cut. The whole point of a 3-angle cut is to center the contact point on the face. Finally, have you taken to heart warnings about buying cheap parts? Two dollars versus 4 dollars for a set of keepers could be the difference between buying chineseium parts and genuine British reproductions. It's one of the reasons I bought exclusively from SpitBits and avoided Victoria British like the plague. Moss Motors bought out Vicky Brit if I'm informed correctly. Beware of Chinese parts from Moss Motors as they do not Quality Control the parts to the level they should and the Chinese manufactures replace imperial screws with metric, etc. Not a problem if you only want to drive the car and have it look good from 10 feet, but definitely not for use on show cars.

Ask the machinist for a guarantee that the seats won't burn for at least 50K miles. This is a known problem for these engines that were not designed for unleaded gas. If you don't want to confront the machinist about his ignorance, look into lead substitute.