Normal Oil Pressure

[lmichael]

Just wondering if anyone knows the spec for normal oil pressure on a D782 engine? It's now got 1000 hours and been pretty well cared for. I run T-6 5w-40 in it.
Going to be mounting a mechanical gauge on it today. I know I can wade through my Shop Manual but just wondered since I m online not working on it right now.

 

[85Hokie]

Well, I will throw this out at cha -

On my B7100 that has about 1000 hours on it and I run the same oil, I get about 55 ish when starting it cold and it will hold 40 psi plus once hot at high rpms - after a good 30 minutes cutting grass in the heat and pulling back to idle - it will drop to about 15 ish.

 

[lmichael]

Well, I will throw this out at cha -

On my B7100 that has about 1000 hours on it and I run the same oil, I get about 55 ish when starting it cold and it will hold 40 psi plus once hot at high rpms - after a good 30 minutes cutting grass in the heat and pulling back to idle - it will drop to about 15 ish.

OK, oddly I would have expected it to run a touch higher. I am going to disconnect the idiot light and only use the gauge

 

[lmichael]

Hey, another question on this. Is there anyplace else on the engine I can install the mechanical oil pressure line beside where the current sensor is located? Also what size or type of socket does Kubota need to remove that sensor? (assuming it necessary to hook up a mechanical gauge).

 

[D2Cat]

No other place to connect, but you can install a "T" and us both elec and mech. gauge. Need the correct threaded fitting.

 

[lmichael]

No other place to connect, but you can install a "T" and us both elec and mech. gauge. Need the correct threaded fitting.

Does it use a standard sensor socket? I tried a regular deep 30 or 31 mm (actually both) and one was too small and the other felt like it wanted to "round off" so I quit trying. I asked about a secondary pressure pickup point because of that. I really don't feel a need to use the idiot light. Once I have a gauge I'm good. I'd like a do a temp gauge as well, but these machines are kinda stingy with places to mount a gauge. Partly my own fault. I bought a tacho and THOUGHT I was buying a 2.5" one and it's a giant one 3.5" (85MM) and I don't feel like buying another. I had to mount it off to the side. But, it works great now,

 

[GreensvilleJay]

re: I am going to disconnect the idiot light and only use the gauge

hmm, best check the wiring diagram just in case the oil pressure switch is fed into the 'computer' to shut down the engine in case of low oil pressure ??
The 'idiot light' is a GREAT confirmation that the switch works....

 

[GeoHorn]

I ordered/rec’d a BSP to NPT adaptor (plan was to install a gauge parallel to the idiot light)… but the adaptor is so long I fear it will collide with the starter motor and not allow the sensor..OR a “T” fitting.

 

[lmichael]

Well these things are totally oddball LOL. I have the proper oil sending unit socket tried to use it, nope. Dumb thing is 15/16". Thread into the block is British 1/8" Crazy stuff here

 

[TheOldHokie]

Well these things are totally oddball LOL. I have the proper oil sending unit socket tried to use it, nope. Dumb thing is 15/16". Thread into the block is British 1/8" Crazy stuff here

Why is 1/8 BSPT crazy?

BTW - reading through this thread - if you want both a gauge and a light (my preference) the tee does not have to be placed on the port. It can be anywhere in the oil line. It could even be placed on the gauge itself...

Dan

 

[lmichael]

It's a Japanese machine, and ends up having partially SAE size fitting (and at that not even a standard size sending unit. Which is typically a 1" or 1 1/16 size, and then has British pipe threads (Whitworth) in the block. And you don't think the whole thing is "weird" to a point?

Anyway I have it back together. Oil pressure at a "cold start" was right around 45-50 PSI at idle. As I got it hot and running doing yard work today, pressure ran more in the 35 PSI range at 2000 RPM and at idle dropped to 20-25 PSI.
So while I have not looked it up in my WSM I have a feeling that is quite normal. But I think tomorrow I'll check it out in the WSM

 

[TheOldHokie]

BSP has been the pipe standard in most of the world including Asia and Europe for better part of a century and still is.

Are you sure that sender isn't metric as in 24mm?

Dan

 

[lmichael]

Nope. I tried so many different metrics and finally gave up and called the Kubota dealer and spoke to a tech. He said nearly all the Kubotas are 15/16. And BTW I had a Honda before this Kubota and had put a gauge on it. The fitting was 10mm M10x1 IIRC I've never seen British size used on anything but a Triumph (or other British) motorcycle. Never on anything American or Japanese

 

[TheOldHokie]

Nope. I tried so many different metrics and finally gave up and called the Kubota dealer and spoke to a tech. He said nearly all the Kubotas are 15/16. And BTW I had a Honda before this Kubota and had put a gauge on it. The fitting was 10mm M10x1 IIRC I've never seen British size used on anything but a Triumph (or other British) motorcycle. Never on anything American or Japanese

BSP is used by OEMs all over the world. Its incredibly common in Japan, India, Europe, South America, Africa. The Germans are metric centric and hate it.

Japanese Industrial Standard (JIS) hydraulic fittings specify BSP thread forms.

I just helped a guy on an old Ford tractor forum who was struggling with identifying the PS tube fittings in his Ford 1810. Its a mid 80's era machine made for Ford by Shibaura and all the PS fittings are BSP. He was flabbergasted.

You will find Kubota hydraulic systems of all vintages use BSP almost exclusively And if you shop for hydraulic components outside the US BSP will be the most commonly offered thread standard.

Dan

 

[lmichael]

Well I get it. But I still find it so odd. Hell, even the Brits stopped using Whitworth a long time ago and went metric. I guess somewhere there has to be a standard and not sure why that old standard, but so be it

 

[85Hokie]

Well I get it. But I still find it so odd. Hell, even the Brits stopped using Whitworth a long time ago and went metric. I guess somewhere there has to be a standard and not sure why that old standard, but so be it

I will have to say that every damn hydraulic fitting I have run into on my older Kubota's has the BSP fittings - and as mentioned it must be the cats ass everywhere ........ but here

Thank goodness for the hydraulic adaptors that get us from BSP to NPT!

 

[TheOldHokie]

The

Well I get it. But I still find it so odd. Hell, even the Brits stopped using Whitworth a long time ago and went metric. I guess somewhere there has to be a standard and not sure why that old standard, but so be it

The Brits stopped using Whitworth threaded fasteners when they switched to US imperial Unified threads during WWII production.

But today they still use BSP pipe which has imperial Whitworth threads as does much of the world.

You piqued my interest and I did a little checking. it appears that even today Japanese car makers are still using BSP threads on oil pressure sending units, And many DIY gear heads are still f'ing their engines up using metric and NPT adapters.

Dan

 

[lmichael]

Just SMDH. Makes no sense to me but eh, I drive Toyotas only, and this old wrench takes both to the dealer for servicing. Lazy in my old age Hell if I could drive the Kubota to the dealership I would

 

[lmichael]

Not entirely finished but it's working and no leaks

 

[85Hokie]

Not entirely finished but it's working and no leaks
View attachment 131514

is that hot idle? or what rpm vs temp