oil pressure question

[areger23]

i have a 1950 cub that i rebuilt the engine over the winter. i have 10w30 oil in it right now due to using it over winter. i had it at plow days over the weekend and the oil pressure was between 1/4 and 1/2 on the gauge all day. today i mowed my grass with it and the oil pressure was almost in the red at full throttle and dipped into the red at idle. my question is what does everyone elses oil pressure sit at and do you think the 10w30 is causing it. my theory is a 10w30 is suppose to act like a 10w when cold and a 30wt when warm but i may be wrong

[tst]

when you say rebuilt were new bearings used, was the crankshaft machined, clearances measured?, I rebuild a lot of cub motors and most will run at 3/4 to almost peg the gauge, I have found many aftermarket gasket sets use a oil pump gasket that is to thick which causes low pressure issues also

[areger23]

it had a cheap rebuild, new rings, rod bearings, measured main bearing clearances all were within spec. i did not pull the oil pump out. during plow days it was about 30 degrees cooler out than what it was today.

[Glen]

Hi,
You could try using a thicker oil in the warm weather.

Below is a page from a Cub owner's manual, showing the oil recommendations. This manual was printed after multi weight oils began being made. It says 20W 40 motor oil can be used above 32 degrees F.

http://farmallcub.com/rudi_cub/www.clea ... e%2063.jpg

[tst]

oil pressure for the most part is good main bearings, good crank journals and correct clearance, doubt that the oil is a problem

[pickerandsinger]

Talked to a fellow who works as a mechanic for a semi truck firm...He maintains multi viscosity oil has a tendency to flow not far from the lower number..In other words 10/30 is not ever going to be as thick as 30...He maintained to use lucas oil treatment with the oil...He says it quiets and protects old engines and raises oil pressure and its 100% petroleum based..I been using it in my loader tractor and it raised my oil pressure and quieted the engine considerably...Just my own experience...Dave

[Sailor]

Did you pull the oil pressure limiting piston/spring? One of the reasons for my rebuilding my engine was low oil pressure. When I got it back from the machinist, the oil gauge still read low. One of the guys here recommended that I pull the piston and take a look at it. The piston was rusted on one side and been stuck for some time. I replaced the piston and the spring and now my gauge reads close to max.

[BigBill]

The P.O. of my 52 fcub rebuilt it. I can see new gaskets with sealer on them. My oil pressure is all the way up. I’m using Mobil delvac the million mile oil 15/40wt for hd gas engines and Diesel engines. I talked with a Mobil engineer and he said to stay with it.

[BigBill]

i have a 1950 cub that i rebuilt the engine over the winter. i have 10w30 oil in it right now due to using it over winter. i had it at plow days over the weekend and the oil pressure was between 1/4 and 1/2 on the gauge all day. today i mowed my grass with it and the oil pressure was almost in the red at full throttle and dipped into the red at idle. my question is what does everyone elses oil pressure sit at and do you think the 10w30 is causing it. my theory is a 10w30 is suppose to act like a 10w when cold and a 30wt when warm but i may be wrong

Yes your correct. 10w30 has the 10wt viscosity when cold and when hot it has the lubricating qualities of a 30wt when hot.