Head experts on back-cutting valves........

[Skids]

I've got my heads off for a short-block re-build. I'm thinking of doing some light port work (just a clean-up) and lightly back-cutting the exhaust valves 30 degrees...........would this help on these engines or not? The intakes appear to just need a touch to rid them of a small ridge, otherwise they're good.

I don't want to waste my time, but my new metal lathe is crying out for more work!!! Thanks.

 

[sweetv6]

I've got my heads off for a short-block re-build. I'm thinking of doing some light port work (just a clean-up) and lightly back-cutting the exhaust valves 30 degrees...........would this help on these engines or not? The intakes appear to just need a touch to rid them of a small ridge, otherwise they're good.

I don't want to waste my time, but my new metal lathe is crying out for more work!!! Thanks.

reading about 30 deg back cut on intake valve giving some
precious low lift flow but on exhaust dont know.
i try to find the article on gnttype.org but no succes

cp

 

[sweetv6]

i found the article

Ken

cp

 

[turbodave231]

I don't think you would hurt anything by backcutting the exhaust valves, You are better off doing your backcut on a valve re-facer and not a lathe. The refacer won't leave a ridge that you would need to remove.

Cut your seats before you do your backcut so you know exactly where your seal is located.