Just completed engine rebuild of D2 5U. On initial start achieved 30 lbs oil pressure continous, regardless of engine RPM. I was happy with that, mains and rods were put at spec of 0.006" clearance. After buttoning up the rest of the tractor and putting oil pressure gauge in place, (it did get dropped in the process), I now have 22 lbs continous. There is a 1 to 1.5 lb change as the engine RPM is changed then goes right back to 22 lbs. I'm concerned now, as I think pressure should be higher. First stop will be to get another gauge to verify that it is a real issue and not a damaged guage. The engine at this point only has a little over an hour of run time, so I can't imagine that I lost 8 lbs overnight without any run time. What pressure would be in the normal range for this engine. Only the main / rod bearings and wrist pin bushing were changed. New rings also installed. Set oil pump out and was rebuilt as well. Comments would be welcome.

Maximum oil pressure is 30 psi.
Nothing wrong with 20-25 psi operating pressure.
Best to check with a good quality gage (psi type) that will have the indicating pressure 50-75% of scale.

OM I thought I read somewhere that a 30's-40's vintage 30wt is closer to a modern 40wt.
Could this affect oil pressures, and should we consider running a 40wt?
Thanks

CS

Hi Carl,
I read that post also.....could be, I haven't looked into it.
I still run straight 30wt in all my tractors, oil pressure not a problem.
Would consider a heavier oil if low oil pressure was a problem (like 10-15psi) but then that is a symptom of bigger problems:D

you used all that slippery Molylube stuff for reassembly and the oil pump was primed by the rebuilder with a thick gooey stuff along with new oil filters. I wouldn't be surprised that the pressure was high at the beginning and the next day seemed lower. All that stuff will cause a slight increase in pressure until all is mixed into your crankcase oil.
OF course I would STILL blame the gauge first!

Could it be that the oil pres control valve has something stuck in it? That oil system is supposed to deliver a constant oil pres and the valve is to choke it down if it gets too high.

Was the pump rebuilt, or did you just clean and inspect it?

Problem solved! Replaced the gauge, easiest thing to do. The gauge didn't like the fall from the track to the hard floor. New gauge reads about 32 to 35 psi at all engine speeds. Ran tractor for 1.5 hours tonight to get heated up, maintained pressure the whole time. Thanks for all of the suggestions. Was kind of down last night, should have known it was going to be the gauge, but I have a tendancy to fear the worst.

Ran into more fuel problems with the poney, looks like carb is full of junk again. Pulled tank, and yes it is rusty. Going to pull entire fuel system apare an clean. Put some clean number 1 stones in the tank and rolled around for about 30 minutes. Simply amazed at all of the junk that came out. I'm going to do this a few more times, then would like to find a tank sealer to put in. I haven't used before so suggestions are welcome. The knowledge that the members of this club have is just wonderful. Sure makes working on the old equipment more fun.

That's good news:)
I know that sinking feeling:rolleyes:
I've had good service from the POR15 tank lining kits......beware there are some out there that set you up with permanent fuel system problems.

www.4secondsflat.com/Fuel_Tank_Sealer.html
Used it on one pony tank a couple years ago, still looks good and is doing fine so far. Gave away my leftovers, now I have to buy some more!

Best results I've had cleaning a gas tank I got from steam cleaning. The heat melts that old varnish out better than any chemical I've tried. I turn it upside down and steam up into the bottom so the stuff can drain out the filler.