Stock valves in a 1mm oversized spot??

[Paulice]

Ok I need some help here, I have a head that is cut for oversized valves, 1mm over, and a friend of mine is rebuilding the head for me, and is putting stock sized valves in it, it is on a 4g63T...Can anyone tell me if this will be ok or if it will have problems?

 

[GVR4592]

Try lapping one of the valves to see where the contact point is. If it isn't making full contact on the 45 degree angle then that's a problem. I think that it won't seal and will most likely cause damage to the seat and the valve.

 

[mjarrell20]

It won't seal, you need the over-sized valves.