I keep spending a little time on my own heads at the machine shop. Funny, but hundreds of heads have passed through my hands at the shop while mine sit on a shelf next to me! I've been there a while now and learned a lot, also realize how much calculating, measuring, machining, parts matching, etc. goes into the building of performance engines. I work on mine an hour or two here and there after I work on other peoples stuff. Kinda like a roofer with a leaky roof. Everybody else comes first. LOL Soooo.... almost all the work on my heads gets done between 11PM and 2 AM! AHAHAHA Last night was no exception and I stopped working on my heads about 1:30 AM. Here's the latest update.
To measure the valve stem height while cutting the valve seats a special gauge is used. The base of the gauge is held against the spring seat and then the valve to be used for that chamber is inserted and pressed tightly against the seat. The valve stem pushes against a plunger in the gauge which measures how far the stem protrudes. As each valve seat is cut the stem height is checked occasionally so the stem heights will be very, very close when done and the seats are cut to a almost equal depth. A procedure later insures all the stem heights are exactly the same.
As a young man I always thought a multi angle valve cut required separate steps for each angle, however they're done in one step. The tool for cutting the valve seats cuts all the angles at the same time. The cutting blade is adjustable and is set for the diameter of the valve, then a pilot is inserted into the valve guide of the seat to be cut. The head has been leveled to the drill press and the pilot keeps the cutting tool straight with the valve guide. There's a spring that gets slid onto the pilot that pushes the cutting tool up away from the valve seat until the drill press pushes it down. The seat is then cut and intermittantly the stem height is checked, once the stem height is correct you're done and move on to the next valve.
Because the cutting tool needs to be moved out of the way to constantly check the stem height etc. the tool is not mounted in the drill chuck but rather an attachment with a notch in it is mounted in the drill press and the tool slides into it as the press is lowered. A small bar on the tool fits in the groove which spins the cutting tool.
