Oil pressure switch and oil pressure D750

mtec

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B7001
Sep 28, 2014
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Cuxhaven, Germany
Hi,
does anybody know at which level the original oil pressure switch is working?
I have the light coming on with low rpm and want to replace first the switch but i can not see any value on the switch.

Does anybody know the correct oil pressure on a D750 engine?
I have found aprox. 20 PSI in idle and aprox. 40-45 on high rpms if everything is ok!
Is that ok?
 

North Idaho Wolfman

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Those #'s sound a tiny low but good and acceptable for an older motor.
So yes you probably just have a bad switch as it's supposed to trip the light at 7.1lbs.

 

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85Hokie

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"Does anybody know the correct oil pressure on a D750 engine?
I have found aprox. 20 PSI in idle and aprox. 40-45 on high rpms if everything is ok!
Is that ok?"

those numbers are about right.....for an older engine, 1000 hours or so, and hot, hot oil.
At start-up I can hit 50+ psi and idle above 30, once warm, it goes south.

this is with 15-40 synthetic oil too.
 

mtec

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B7001
Sep 28, 2014
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Cuxhaven, Germany
Hi,

i think there is a misunderstanding.
I did not make a measurement on my engine, i have read that 20PSI and 40-45 here anywhere.
I did make the measurement today and found only 5 PSI in idle and 15 with high rpm.
I open the gear case cover and found no plug inside the camshaft!

Ok, i will weld that and that should be fine but i am a little bit worried cause i did not find the old plug anywhere!
I searched everywhere but nothing!

Is that a problem?
 

85Hokie

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Hi,

i think there is a misunderstanding.
I did not make a measurement on my engine, i have read that 20PSI and 40-45 here anywhere.
I did make the measurement today and found only 5 PSI in idle and 15 with high rpm.
I open the gear case cover and found no plug inside the camshaft!

Ok, i will weld that and that should be fine but i am a little bit worried cause i did not find the old plug anywhere!
I searched everywhere but nothing!

Is that a problem?

mmm......it could be that she was opened up and the plug removed not knowing what it was.......

I doubt that the plug went back into the cam hole!:D

I think ONCE you place the plug back in, the PSI will rise up nicely.

How long has it been low on pressure?
 

Daren Todd

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I found the cam plug on my l1501 in the bottom of the oil pan.


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mtec

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B7001
Sep 28, 2014
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Cuxhaven, Germany
mmm......it could be that she was opened up and the plug removed not knowing what it was.......

I doubt that the plug went back into the cam hole!:D

I think ONCE you place the plug back in, the PSI will rise up nicely.

How long has it been low on pressure?
I have that tractor since two years and since that the lamp never goes on during engine run.
Last friday was the first time and i stoped engine asap.

Should i expect any problems if i leave it in the oil pan (if its there)?
 

Daren Todd

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It's too large to be picked up by the oil sump.

Mine had the cam plug out for years before I got a hold of it. Had some blow by for an hour or two after I fixed it, till it worked the moisture out of the top of the engine.

I've put around 100 hours on the tractor since then with out issues. :)


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mtec

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B7001
Sep 28, 2014
10
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0
Cuxhaven, Germany
Hi,
today i weld the hole in the camshaft and put everything together with new gaskets.
I started the engine and had 50 PSI with cold oil (10W30) in idle (may be a little bit high idle), with high rpms i had 62 PSI.
Think that looks good.
After 5 minutes running it goes down to 40-45 in idle and 58 in high rpm.

What are you thinking, is that ok?

I checked also that oil valve with the spring, it works fine.
Dont know why it is so high in idle!:(
 

lugbolt

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Not familiar with that plug, but if it's steel, you can stick a magnet onto the bottom of the oil pan and the plug will just sit near the magnet. Even works on aluminum pans but you have to either glue or epoxy the magnet, and it should be a nice powerful magnet at that.
 

85Hokie

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Hi,
today i weld the hole in the camshaft and put everything together with new gaskets.
I started the engine and had 50 PSI with cold oil (10W30) in idle (may be a little bit high idle), with high rpms i had 62 PSI.
Think that looks good.
After 5 minutes running it goes down to 40-45 in idle and 58 in high rpm.

What are you thinking, is that ok?

I checked also that oil valve with the spring, it works fine.
Dont know why it is so high in idle!:(

Let it run, or run it a while hard and get everything all nice and hot.........I think you'll be 40 psi at 90% WOT and 20 psi ish at low idle, and if so - everything is honkie dorie !