JD 420

[Anonymous-0]

I have a 1957 JD 420, and I was wondering how to adjust the oil pressure? I was thinking it was the bolt under the filter but I'm not sure.
Thanks,
T. Wall

 

[buickddeere]

What does the gauge indicate? Has the gauge been proven true on a test bench?
What is the oil pressure at idle cold, idle hot, fast cold and fast hot.
What kind of oil is in the engine?

 

[WV2CYL]

I work on a number of the Dubuque engines and if the is an adjustment I am not aware of it. The opld Waterloo tractors have an adjustment screw in the crankcase-block if I remember correctly. I think the only adjustments that could possibly made would have to do with shims in the oil pump. TWS

 

[Rich Duane]

If you check the service manual there is a pressure relief valve that has washers to control the pressure. It is inside the pan at the oil pump. Pressure should be set at 30 PSI hot.

 

[Anonymous-0]

The gauge indicates high at idle cold, idle hot, fast cold and fast hot. The gauge is new, we are restoring the tractor right now, but the old gauge indicated the same. I'm running Penzoil 10W-40 in her. I just wanted to lower the oil pressure a bit. I have JD A's, G's, 60's and there real easy to adjust the oil pressure. I was just wondering about the 420.

 

[buickanddeere]

Time to install gauge that reads psi. If the relief valve is jammed shut, excess pressure could twist or blow something off.

 

[Tennessee Wayne]

The service manual covers this. Adjustment is made by removing or adding washers inside the oil pump. Just remember, if you remove the oil pump, you will have to reset the timing with the distributor.