[Icexz]

Hello everyone,
My loved 6640 has decided to test my nerves. After working like a charm for the last 6 years under my ownership, this fall engine oil pressure started to drop as low as 2 bars - no red light on the digital scale when on idle (750 rpm). In the garage it went. Mechanic and I replaced the oil pump with the new one all the bearings on crankshaft (the first one already had some scuffs others were like new). And a bunch of other things.
After the engine overhaul on cold start I get 7 bars of oil pressure. No movement if I apply throttle. Looks good so far.
Now the fun part begins.
When temperature gets to 4 bars oil pressure drops to 5 bars sometimes even 3.
Today I replaced the spring of relief valve on the filter housing (120 eur for a spring...) and I do hope this will solve my problem.
Any idea if it doesnt?
Also I have ordered an gauge to fit on a T piece where the sensor for the light goes so I can see in psi what is going on. What should the oil pressure be? How many bars on the dasg are you getting?
Thanks in advanced for responses and I do apologize for my english as you noticed it is not my native language.

 

[LouNY]

After reading your post a couple of times am I correct that when you are describing your display readings the number of bars are the graphical displays not bar as a pressure unit.
Untill you install a gauge that reads out the actual pressure you have no idea what it actually is.
Oil pressure normally decreases as engine temperature increases especially at low rpm's.
Also the type and weight of the oil used will make a considerable difference in the displayed pressure.

 

[Icexz]

Yes I was talking about bars as on digital display. I admit I did write that a bit confusing. I am using castrol crb 15w-40 (truck&agri oil). Again not cheap.
Oil is on maximum on dipstick.

 

[The 203]

Yes I was talking about bars as on digital display. I admit I did write that a bit confusing. I am using castrol crb 15w-40 (truck&agri oil). Again not cheap.
Oil is on maximum on dipstick.

Like Lou said you need to add a pressure gauge to get a real Idea of what the oil pressure is. There should be allen head plugs on the block on the same side of the block as the oil sender taps into.
Or you can remove the sender and install a gauge or put a T fitting in and have both the dash gauge and oil pressure gauge.
. Electronic gauges aren't dependable when they get old.

 

[The 203]

Here is a fitting that will allow you to add a pressure gauge and keep your dash gauge.

The price is crazy but it would make a less bulky setup than other fittings. Removing a plug and tapping into the cam oil passage is a better option.
Let us know what happens.
$25
1/4 NPT Oil Pressure Gauge Adapter Sensor T-Piece Sender For Ford Falcon 6416867743310 | eBay

 

[LouNY]

That is a fancy run tee, it does have a restriction to reduce pulsations in the system.
Any run tee or branch tee will work also.

 

[Icexz]

Thank you for your replies.
I have fitted a T piece and a gauge for testing purposes so on cold start 7 lights on the dash translates to 4,5 bar (65 psi) of pressure. Waiting for rain to stop so I can go work in the forest to see what will happen when temperature goes up. I should be fine with half that? There is also a small bolt sticking out near oil pressure sender. What is that for? To regulate something or?

I was also playing around with the old relief valve spring. The shop manual says it should be 52mm long with no load and when pushed on with 15.6kgs it should shrink to 38mm. So I put it on a bolt with washers and tighten it until spring was on 38mm I could still pushed it more with two fingers. No way I could squeeze 15kg with 2 fingers.

 

[Icexz]

Ok weather is still not on my side to get engine hot. I replaced the 20bar gauge with a 6 one to get a more accurate reading.
Here are some pictures of my creation. Its not tidy but it works.
If the thermostat is stuck closed because I never get more than 4bars of temp on the digital dash would the pressure drop so much?
I have a probe to measure the oil in sump will try that hoppefully tomorrow.
This is on cold start.

 

[LouNY]

So by my quick conversion you have about 50 PSI at an idle cold?
Hard to say what the value will be warmed up.

 

[Icexz]

Was pulling logs today for 45minutes (too much mud and I dont want to destroy the path) downhill. I only use this tractor for forestry - modified rear end so it runs od idle about 60% of time while I attach logs to winch. Temp on dash came up to 4 lines and oil pressure dropped on 2.2 bar (32psi) while on idle. I hope tomorrow will be better work conditions.
This is what me and my ford do:

 

[pogobill]

That's a pretty good load. It's been a mild winter, but it is best to skid logs before the thaw. Do you mill the logs, or are they for firewood?

 

[Icexz]

Load would be half smaller if I was pulling it uphill. You are right, skidding on frozen ground is like driving on pavement but sadly winters are getting to mild and the ground never freezes. Wood on picture is for firewood. I do this for a living all year round. It depends on tree type. Beech is 90% firewood. Spurce is what we mill. We have some other tree types in my area but this two are main.

 

[Hacke]

Nice setup for skidding.

How is the wild boar situation in your region? Do you have control over their numbers in farming areas?

 

[pogobill]

No frost in the ground in my area either! Very mild winter and it is tough getting the logs out of the woods here, as well. There are three saw mills within a few kilometers of my property.

 

[Icexz]

Nice setup for skidding.

How is the wild boar situation in your region? Do you have control over their numbers in farming areas?

There is not much farming going on in where I live, every house for its own needs. No big farms. Deers are the only ones causing damage on fields. There are some wild boars and they are delicious.

No frost in the ground in my area either! Very mild winter and it is tough getting the logs out of the woods here, as well. There are three saw mills within a few kilometers of my property.

Just for fun. At what price the mills buy wood?
Over here is something like this (logs)
75 eur per tonne for beech firewood
110 eur per m3 for spruce
60 eur per tonne of all other mixed firewood
Back to topic.
After working for 8 hours non stop oil pressure situation is following.
When hot and put od idle drops to 1.6bar (23psi) then within 20 seconds of idling raises to 2.0 bar (29psi) when driving it doesnt matter 1500rpm or full thunder 2500 rpm gauge says 3.0bar (44psi).
Is this all ok?

 

[pogobill]

I don't know what the going rate for logs is around here. The guy I deal with does his own logging and milling. My barn and most of my out buildings are rough lumber from his mill.

 

[HydroTek]

Oil pump may be worn some
How many hours on this engine ?

Still, the pressure you have is sufficient for the engine
Idle pressure in not as important as pressure at high speed
that is where the pressure regulator comes into use

Surprised this tractor uses a gauge , rather than an "idiot light"

 

[The 203]

The pressure gauge was added to this tractor.
Your oil pressure is ok to run your tractor.
We all like 60psi but as bearings wear and clearances increase pressure drops. I have had tractors that at Idle dropped to less than 5psi at idle and 10 psi at 1750 rpms. Thats not good but having Positive pressure means it's getting oil. You replaced the crankshaft bearings and oil pump if I remember right. I wouldn't worry about running it with what you have now.
Watch it and when the oil pressure drops to 5psi at idle I would think about a complete teardown rebuild. I had a Massy Harris 44 that I ran for several years that had ten psi at full throttle and almost 0 at idle and I worked it hard. I couldn't afford a rebuild at the time.
You make your living with your tractor so it's more important to have a solid tractor

 

[Hacke]

Now I get it, there are bars and there are bars (see attached PDF).

 

[HydroTek]

Now I get it, there are bars and there are bars (see attached PDF).

There is a picture of the oil pressure gauge on post #8