Vilter cylinder liner discharge valve seats

[RANGER1]

Over the years have noticed Vilter cylinder liners on 440 , 450's with 4 guide pins , have sealing problem on liner / discharge valve seat .
The liners have very thin seat which discharge valve seats on .
When discharge valve guide roll pins are inserted in liners the seat is damaged nearly everytime .
Have pulled brand new machines apart and found poor sealing on these "lapped" faces .
I usually grind side of roll pin and knock it in with ground side facing valve seat to avoid roll pin damaging seat .

Its hard to believe that someone has not bought this to Vilters attention as it makes machine inneficient .

Liners etc have to be removed to correct this seat and modify roll pins .

Has anyone observed this fault and is is still a problem in new compressors out of the factory ?

[NH3LVR]

I have looked at this before, but never had a problem with damaged seats. I am careful installing them and they seal up just fine.
I will admit to being partial to Mycom however, as you get to lap the valve in and they seal well.

[RANGER1]

I worked on 2 x 442 which were relocated from plant in USA .
Both were near new and on inspection found both had this problem where there was slight raised area where pins were installed .
I figure they are all the same .
Many years ago an Ausralian company made them under licence , but they never had guide pins .
There was another offshoot of Vilter ith a few minor differences , probably for patent reasons . They were called Budge and had 2 sidecovers which helped a lot for assy but they used studs instead of bolts on sidecovers and heads so they were also APITA .
Casting of machine guided discharge valve assy in place , seems much simpler to me .

Mycom are good to work on and last few years we just get valve seats surface ground when possible .