Do any of the Finns mess with them? I know they are several different types that the Cummins crowd uses and they can make a big HP change.

What I have discussed there is some guys, which have put the bigger delivery valves and it has been a good solution specially with the bored cylinder head and special cam profile. Haven't done it to my own OM603 yet.

What several of us 617 guys (me included) are going to try is removing the collar entirely since it is already very thin as-is.

Well, we tried it and the idle went to crap and EGTs went through the roof but there was a huge jump in power.

The idle would have torn up the mounts in no time and it was terrible as a daily driver so I went back to the stock delivery valves.

Forced_Induction kirjoitti:Well, we tried it and the idle went to crap and EGTs went through the roof but there was a huge jump in power.

The idle would have torn up the mounts in no time and it was terrible as a daily driver so I went back to the stock delivery valves.

Very interesting....

I think I can explain Why you found an increase in power, the idle went crap and EGT high--Plus (I'm guessing) Smoky exhaust....

The stock del. valve is designed to allow a specific residual pressure in the line, controlled by the collar and its movement back into the valve, thus extracting a specific volume of fuel from the line.....

We'll say the residual pressure on a good, stock valve is 50 bar--It Probably Isnt though, but we'll say it is....

If you grind off the collar, What happens...? There is no retraction action by the collar-it no longer exists- So--The valve snaps shut leaving near full pressure in the line...

The Injector is still open at this point, the instant the 'spill-port' opens in the elements so the last amount of fuel 'dribbles' in over a unspecified period of time....

This causes smoke, uneven idling etc.

The reason for extra power is the fact that the lines are at a much higher 'between pumps' residual-pressure, controlled by the final closing of the injector....

So--What we would like to find are Del.Valves whose collar is Closer to the tapered seal surface, this will allow a higher residual pressure and a greater overall delivery Quantity Should equal more power, but without the problems you have found.....