Oil & Fuel 135 Oil Pressure question

[bwarren2]

I just purchased a 70's 135 yesterday and had it serviced. It runs fine but there is some concern with the oil pressure. The pressure was at the top of the gauge after it was serviced for a while and then dropped to half way. it holds steady at the half way mark but drops to 1/4 (just above the red line) at idle when hot. We put it through its paces and it bush hogged fine and the pressure held steady. It preformed very well.

can you tell me where your pressure gauge runs? I have had several people say its just old and thats normal and one other said I need a new crankshaft another said it needs new bearings. I don't know much about tractors and am trying to get some advice on what to do. The tractor will only be used for food plots and bush hogging so it shouldn't see a ton of use.

Another question. Since this tractor hadn't been used for a couple of years, is it possible some junk is blocking the flow causing the pressure to drop? There doesn't appear to be any leaks.

To summarize my questions:

1. Where does your oil pressure run at full speed and idle
2. Does this sound normal
3. My guage does not show PSI, do you know what the PSI range is on a 70"s 135

4. If this isn't normal, any idea what the issue is

I am running rotella 15/40

Thanks

 

[Texas Blues]

Well I dont know what type of motor you have in your 135, but I can tell you that my newly rebuilt perkins 3cyl gas motor in my 135 holds pressure at or over 50psi. When I bought the tractor it had an oil guage that didnt have numbers, just a range. Even as wore out as the motor was it still held pressure at the halfway mark on that guage at operating temp. I would at least hook up a numbered guage temporarily to see how the pressure acts when its cold vs. when its at operating temp. Apparently the Perkins 3cyl gas or diesel (same block) has a very reliable oiling system. Good luck TB

 

[bwarren2]

I forgot to mention it is the Perkins 3 Cyl Diesel engine.

Thanks

 

[Texas Blues]

Well bwarren, my 135 is a 1971 model. Going to be the same block. Oiling system will differ slightly. I think the oil pump is the same, as well as the main bearings, rods and rod bearings. Unless you can hear extra knocking noises or loud rocker arm clatter when warm, the pressure is probably ok. I would still look at the pressure with a more reliable guage though just to be sure. Heres a pic of my guages at almost 190 degrees. Im sure that if I was working it hard the temp would be higher, I havent got that far yet, but it had been running for at least 20 minutes. Both of those guages are new, and not real expensive, but at one day old they should be fairly acurate. Good luck TB

 

[bwarren2]

Texas Blues, thanks for the info. Can you tell me what your psi is at idle when its hot or warm?

When mine is hot its about a quarter of the way up the guage. Thats my real concern is the idling PSI. My gauge doesn't have the numbers like yours.

 

[Texas Blues]

Well that pic is at idle. At a higher rpm, it goes closer to the next mark. It would be normal for a motor to drop pressure some after its warmed up or hot. If your un numbered guage drops that dramatically when its warmed up, I would still start with a different guage. If you get similar results with a new guage, then at least you will have some numbers for reference. Mine hasnt dropped below 50 yet, buts its a fresh build with new pump, rod and main bearings, so its going to be higher. But lower psi than that is probably fine for a more worn motor. I would say if it dropped below 20 psi or so you may have a problem. I thinks its more common for the rings and sleeves to wear out faster that the main bearings. Unless of course you run it out of oil a time or two. I also switched to a spin on oil filter instead of the canister type, I dont know that that would have anything to do with better or worse pressure. TB