Farmall Cub

A while back, I wrote that my '50 cub was only running about 12 psi oil pressure at mowing rpm (about 1500 rpm) after the engine warmed up both on 15W-40 and 30W HD conventional oil. Some suggested that I try STP Oil Treatment. Others suggested that I try 20W-50 - both conventional and synthetic. I tried the STP, and although it kept the oil pressure around 20 psi, the sticky mess that it made where it dripped on the mower deck made me decide not to continue with that.

Today, I put in Valvoline 20W-50 full synthetic. The oil pressure stayed around 20 psi at mowing rpm and rose to about 28-30 psi at high idle. It stayed there even after the engine got hot. Whoever suggested this to me - many thanks. He was right that the synthetic does not seem to lose as much viscosity as conventional oil. So, synthetic it will be until the motor blows up. I've also decided to go to full synthetic in my Kubota diesel. I've always kind of resisted synthetic, but I think that I am convinced.

Thanks again.

Been using Mobil synthetic for years. I read someplace that new Corvette's come with it from the factory.

there's as many opinions on this as leaves on the trees, but in most all my engines I run synthetic oil, Mobil or Castrol.

Hi Rick,

On that diesel, my wife's VW specifies synthetic and I have had real good luck with Rotella 5w40 synthetic. Whatever you use, I would make sure that it is rated for diesels....
Hope this helps,
Chad

Good to hear you found that the 20W-50 (synthetic) works well. The synthetics do not lose as much viscosity with temperture like normal oils (the isomer chains don't relax and thin out like normal oil).