Included valve angle on a head

[trd3sg]

Bit of a complex question, but basically, without having a head recast, just wanted to get people's thoughts on any way to have the included valve angle amended in the head of an overhead valve motor.

Theoretically it would seem that the old guides would have to be weld filled and then the new guide retapped\machined and new stems and stem seals sourced. But the only concern would be the shim\bucket or follower arrangement for the valve opening - getting the spacing\angle right to ensure the cam lobe is still working to allow the full motion as per normal of the valve.

What are your thoughts?

[Ben Wilson]

It can be done, but it is a major operation.

You've got most of the basics covered there, but as I'm sure you know, things aren't ever that simple...

[Billzilla]

Bit of a complex question, but basically, without having a head recast, just wanted to get people's thoughts on any way to have the included valve angle amended in the head of an overhead valve motor.

Theoretically it would seem that the old guides would have to be weld filled and then the new guide retapped\machined and new stems and stem seals sourced. But the only concern would be the shim\bucket or follower arrangement for the valve opening - getting the spacing\angle right to ensure the cam lobe is still working to allow the full motion as per normal of the valve.

What are your thoughts?

Way, way, way too hard for the benefit gained.

[takai]

Better and easier to just change the port angle if you are wanting to align the valve with the ports.

[thechuckster]

if hte original head was bucket over/under cam, you would also have to shift the cams and thus the front seals and thus the timing cover and to make matters more difficult, shift the cams in a way that maintains alignment with teeth on the timin belt...etc

ditto for something that used followers...

1853949.3 times easier to change the ports on the head... infact you could probably CNC a new head from billet alloy easier than what you want to do.

One of last year's Race magazine issues had a good article about porting options - including re-alighing the port entry. PM Nero on Performance Forums for detains on back orders.

[terryo]

used to do this on very modified minis. shit of a job. basically as described