29-06-2019, 11:01 AM
(This post was last modified: 29-06-2019, 08:44 PM by Bob Culver.)
I used an electric drill with wheel in it clamped to the toolpost. Doesnt have to be on horizontal centre but feed must stop 3/4 from centre.. Work out exactly where the centre corres 3/4 radius with minimum removal is and mark. Pack out from and clamp to faceplate. Arrange centre exactly on centre. Hand rock back and forth whilst advancing and traversing the drill. Finish on oilstone but beware as removes metal rapidly and easy to lose squareness etc.
It provides a more "full" lift and slightly extends opening. For a car not intended for racing revs the exh duration is already quite adequate and the valves large so probably only the inlets worth doing. The accelerations are much increased which is why it not done by Herbert.
With care and patience camshafts can also be home modified with similar basic gear.
Angle grinders are too fast for hard stones and the usual discs not intended for hard steel.
It provides a more "full" lift and slightly extends opening. For a car not intended for racing revs the exh duration is already quite adequate and the valves large so probably only the inlets worth doing. The accelerations are much increased which is why it not done by Herbert.
With care and patience camshafts can also be home modified with similar basic gear.
Angle grinders are too fast for hard stones and the usual discs not intended for hard steel.