Cutting valve seats by hand

[Tony F]

I have an old 1300 crossflow head, and a decent set of 1600 valves. I intend to cut the 1300 valve seats to match the 1600 valves which is 1.5 mm diameter on the exhaust valve and less on the inlet. Should I do this by hand or send it in to a machine shop where every valve will be cut to exactly the same depth?

[katana]

3 hours ago, Tony F said:

I have an old 1300 crossflow head, and a decent set of 1600 valves. I intend to cut the 1300 valve seats to match the 1600 valves which is 1.5 mm diameter on the exhaust valve and less on the inlet. Should I do this by hand or send it in to a machine shop where every valve will be cut to exactly the same depth?

Depends if you can get your hands on a decent 3 piece, 3 angle carbide cutters! A single 45 degree cutter - sorry in advance - cut it! LOL!

The 30 and 60 degree cutters are used to get the 45 cut seat to the correct width and provide a secondary benefit of nicer transitions.  Assuming all the valves are the same length then spring seat heights may vary (subject to valve recess / projection in the chamber) will give different spring pressures, which could be an issue subject to cam and proposed rpm's?