Angle milling head

[bhartley]

Is there any advantage to angle mill a busa head . As opposed to just flat milling it .


B.

[gazza414]

Have heard of 1 guy doing it , although no reasoning , nor justification was at the time supported this decision.

[DarkFalcon]

In the "ole" days they did it alter cumbustion chamber shape and "roll the head over" to change the geometry of the valves in relationship to the bore centerlines...........also to reduce combustion chamber size and increase CR. I think several 1000 SS teams do it today...biasing the cut to the exhaust side.. and I can only think it is a way of reducing combustion chamber size....and increasing compression... without getting too close to the intake seat and keeping piston-to-valve clearances on the intake side in check. At best, this is speculation as I am not that familar with the 1000 head.

[Thomas Lindemann]

You can take more off the head favoring the exhaust side before you get into the seat than you could flat milling.  Used to do it on all 1100 water cooled and oil cooled motors.

[Jay]

On some heads, the intake seat sits higher than the exhaust seats. You can mill a head down until you are getting close to the 45, then that is as far as you can go. In these cases, there is still material above the exhaust seats.

By milling on an angle ( taking more off the exhaust side or the head) you can get it down to where you get both seats at the same time. This gives you the smallest combustion chamber possible without welding.

Jay