Oil & Fuel MF65 too much oil psi!!!

[dmaxwayne]

I've got a 65 that I saved from the scrap pile and restored from the ground up. It didn't have any gauges and the oil filter was broke off and bypassed. I put a new spin on filter kit and gauges on it and now it pegs a 100psi oil prress. gauge and blew out the o ring on the filter. I put a different brand filter on and installed a liquid filled test gauge from work and at idle it runs 130ish psi and will burry the 160psi gauge if you rev it at all. Even once warm at idle it still runs 85-100 psi and will still bury it if I rev it at all. I took the pressure relief valve out and it looked good (didn't seem to be sticking and wasn't scoured up) so I cleaned it with some emory cloth and put it back together with the same results. I can't find a spring part number or tension rating but was wondering if at one time the previous owner had low oil press. and put to stiff of a spring in to solve the problem. I'm about to pull my hair out so any assistance would be appreciated.

Thanks,
Wayne
P.S. I'm running cheap walmart 15w40 right now.

 

[SPYDERLK]

Is that the pressure measured in the main oil gallery? Way high. Sounds like there is a blockage along with a relief problem.
larry

 

[dmaxwayne]

It is tapped in on the lower left side of the block, right in front of the bell housing. I think this is where it is supposed to be measured at. If it were a blockage issue I don't think the oil filter o ring would be blowing out on the right side of the block and still measure that high on the left side of the block?

 

[SPYDERLK]

I dont know -- it depends on how plumbed. The filter is seeing the high pressure - and we need to know whether the gauge is before or after it. The gauge should be on the main gallery after it. I cant conceive how a main gallery could be at such high pressure in a warmed engine; 1] The pump relief should have operated well below that pressure, 2] even if it didnt, the flow from the gallery to the engine main bearings, rods, and head should keep the pressure at lower levels. I think there are at least 2 problems from the below:

1] Stuck relief
2] Pump too large
3] Obstruction in main gallery.

If the last is one of them then ample oil is not getting where it should and your engine will fry.
larry

 

[dmaxwayne]

I don't think blockage is the problem or she would have locked up by now. I raked hay in 90f weather for 5.5 hrs with it and it was at around 25psi oil psi when I was done at operating load. After letting it cool off it still has the same high pressure at idle. Also the pump is original according to my uncle who owned it for 20 years before letting it sit for five or so years.

 

[SPYDERLK]

That sounds healthy hot. Maybe your system does not have a relief or it is stuck shut. If your tractor does not use oil it would be [relatively] cheap insurance to go to Rotella 5w40 or even JD 0w40 so that the oil is not so thick when cold.
larry

 

[Farmwithjunk]

Massey spec-ed oil pumps that were used in the Continental 4-cylinder gas engines, along with both Perkins gas AND diesels have a bit of a history of the relief valve sticking where it takes itself out of the game.... Enough history I'd give it about 90% that's what you're dealing with. The relief valve can be rebuilt to a point but getting the relief adjusted to correct pressure is a hit or miss proposition of sorts. Simple way to deal with that is to replace the oil pump itself. That will have a pre-set relief.

 

[dmaxwayne]

So you are saying that at 16-1700 rpm 25 psi of oil press. is good for this tractor and that I could go to a thinner oil to solve the problem at start up and initial warm ups? If thats the case I'll go buy some different oil and be done with it but won't the oil pressure drop below 25 psi once its hot and I'm working it hard?

 

[SPYDERLK]

So you are saying that at 16-1700 rpm 25 psi of oil press. is good for this tractor and that I could go to a thinner oil to solve the problem at start up and initial warm ups? If thats the case I'll go buy some different oil and be done with it but won't the oil pressure drop below 25 psi once its hot and I'm working it hard?

Yes ... and with a multigrade of the same top # it should not lower hot pressure. ... The 1st # in oil weight indicates the thickness of the oil when cold and the 2nd # tells how it behaves when hot. This leads to a common mistaken conclusion that the oil thickens when hot -- or thins when cold; same idea. All oil thins as it heats. For example - a 40 wt may take minute to pour thru a funnel on a cool day, but take only 10 seconds at the temperature of a fully warm engine. Going to multigrade will change the cool pour time but not the hot pour time. Essentially you have an oil that starts out fairly thin and thins more slowly as it heats, but comes to the same viscosity as a straight weight oil when its hot. The lower the 1st number the easier it will flow cold. You should notice a big drop in cold pressure with a 5W40 ... even bigger with a 0W40. The hot pressure should be darn near the same as youre seeing now. It costs more to get this type of performance from oil because such T stability requires either; a lot of additives, or a very good base stock. Additives arent lubricants. Youll probably pay double for the good stuf [synthetic]. Unfortunately it is the only way to get around the problem in a healthy fashion without fixing it. But the good oil flow when cold and thruout the heat range will make your engine happy, and extend your safe change intervals a bit in the bargain.

Please report back when you try this and give us numbers.
Thanks,
larry

 

[dmaxwayne]

So I put 5w40 rottella in it and it builds about 85-95 psi at idle and then it warms up and drops down fine, at least without working it hard and just getting the temp up. I would have liked to see it drop down into the 60-70 psi range when cold so that in the winter I will not have crazy high press. again but I'm not going to buy any more oil until it needs an oil change but I'll try the 0w40 then and will hopefully be where I want it. Thanks for the help guys.