Thought I’d swing in and reiterate the facts on the pressure increases by shimming the BX series system reliefs. I’m only talking in thousands of a inch, no millimeter BS. When I searched this topic I kept getting differing information in what 1mm gets you and what .1mm gains were so I did my own test and used a calibrated digital PSI gauge. I’m sure there will be a little variation on each machine but you get the idea.
Shim dia. Of .470
.010 gained 100psi
.020 gained 190psi
.030 gained 275psi
.040 gained 370psi
.050 gained 450psi
.100 gained 900psi
The shim material was wire edm’d from precision stock. I only left the .100 shim in for testing then ground the thickness down to .070 which got me right at 650psi increase and up‘d my BX2230 from a factory 1650 to 2300psi. To say it’s a night and day difference is a understatement and shows no signs of I’ll effects on my little tractor.
Shim dia. Of .470
.010 gained 100psi
.020 gained 190psi
.030 gained 275psi
.040 gained 370psi
.050 gained 450psi
.100 gained 900psi
The shim material was wire edm’d from precision stock. I only left the .100 shim in for testing then ground the thickness down to .070 which got me right at 650psi increase and up‘d my BX2230 from a factory 1650 to 2300psi. To say it’s a night and day difference is a understatement and shows no signs of I’ll effects on my little tractor.