With a set of valves ready now, it's time to check the valve guides. Shop technique for this is to put a valve through a guide and wiggle it to feel how much play there is. Then put a finger over one end of the guide, insert a valve stem till it hits the finger, then pull the valve out quickly to listen for a pop caused by the suction. After checking all of the ones in my heads we decided the valve guides wouldn't need to be replaced but needed a bit of work to tighten them up a bit. This is done with a "sipraler".
A spiraler cuts a groove into the inside of the guide without removing any metal. By deforming the metal it causes the inside diameter of the guide to be reduced and also allows path for lubrication. After the spiraler is run through the guide a ream which is the correct diameter for the valve being used is then run through the guide. Both tools are run down from the top and drop out the bottom so the head needs to be up on stands.
Pic below is a spiraler bit and a drill with a gear deduction so the work can be done at slow bit speeds. No pressure is used just the weight of the tool is enough. A couple drops of cutting lube are used during spiraling.
In the pic below you can see the grooves cut into the inside the valve guides by the spiraler and the ream being used to make the inside of the guide straight and the correct diameter. No more lube needs to be put in before reaming, whatever's left from spiraling can stay and is fine.
