EGR deletes

Is it bad for the engine to have the EGR deleted/turned off?

I have heard that with common rail diesel engines and the cleaner burn of low ash oils that the reducing the carbon build up on the valve seats will accelerate the wear of the valves and cause damage due to the lack of carbon cushioning?

Engine is happy when EGR closed :D but greatly increases emissions. When EGR deleted need advance timing in EGR workinkg zones than you have better fuel consumption.

I've never heard the theory of carbon cushioning, interesting idea though.

One thing to consider, as mentioned above, you may want to alter timing to compensate. Although you may have to retard timing, not advance it in some instances. Large EGR volumes can reduce combustion chamber temps, requiring more timing while EGR is active, so taking EGR away may require less timing, or so the theory goes. Full disclosure, I haven't spent a great deal of time on this personally.

I remove EGR from my car and raise fuel pressure 50 bar in those zones where EGR working. I get better fuel consumtion.