1995 Disco 5 speed manual learning curve
- Thread starter joeblack5
- Start date
Thanks, I do not hear anything so I will have to check.
In the mean time with temps dropping to freezing my oil light stays on for 10 seconds.
I experimented with parking the car hit and fire it for a couple of seconds to get oil pressure with cold oil and see if that changes the oil drain back.
No difference. Now I parked the truck with the nose down and see if that makes a difference.
I tried to find a good description of the engine oil system.. if I understand it correctly then the oil pump pumps it thru the oil cooler and then back into the filter. But is the oil pressure relief valve before the oil cooler, after the oil cooler and before the filter or after the filter. The other thing is where does it measure the oil pressure. I would imagine the only proper spot would be after the filter in the main oil gallery. Again I can't find anything on it and don't have a separate engine that I can tear apart.
If oil drains back then I would think that can only happen if air gets in thru the bearings or the relief does not close properly and leaks all the time.
One would think that check valve in before or after the oil cooler would prevent all of this.
Any how questions. All the threads I have read show no definite answers but I feel 10 seconds on every cold start is pretty bad..
Johan
In the mean time with temps dropping to freezing my oil light stays on for 10 seconds.
I experimented with parking the car hit and fire it for a couple of seconds to get oil pressure with cold oil and see if that changes the oil drain back.
No difference. Now I parked the truck with the nose down and see if that makes a difference.
I tried to find a good description of the engine oil system.. if I understand it correctly then the oil pump pumps it thru the oil cooler and then back into the filter. But is the oil pressure relief valve before the oil cooler, after the oil cooler and before the filter or after the filter. The other thing is where does it measure the oil pressure. I would imagine the only proper spot would be after the filter in the main oil gallery. Again I can't find anything on it and don't have a separate engine that I can tear apart.
If oil drains back then I would think that can only happen if air gets in thru the bearings or the relief does not close properly and leaks all the time.
One would think that check valve in before or after the oil cooler would prevent all of this.
Any how questions. All the threads I have read show no definite answers but I feel 10 seconds on every cold start is pretty bad..
Johan
I think some positive pressure is normal. If not both of my gas powered D1s have a problem.
The dummy light switch is above the filter on the starboard side of the front housing (oil/timing cover). You can just see it if you go to the starboard fender and look down behind the alternator and in front of (but lower than) the #2 cylinder exhaust port. If I recall, there is another NPT port just below it that has a plug in it.. that may be useful for an aftermarket pressure gauge (but someone else here needs to check my math on that).
I believe the filter assembly/mount has the bypass in it.
The amsoil full bypass system looks really interesting to me.. that, combined with an electric pre-charge pump would certainly add life to main/rod bearings
High oil pressure in a 3.9 | Rover P5 Club Forum
I am posting this on behalf of a friend who is an experienced engine rebuilder, having done around 500 V8 over a lifetime. He has put together a 3.9 block, and installed a high-volume oil pump (with
The front timing cover (P76...virtually identical...uses longer pump gears as standard)
Note the ports, 3 shown. The bottom port (suction side) receives oil from the oil pickup. The middle port is blanked off by the front engine block face. The top port is outgoing pressure to engine bearings.
The above thread describes the in and outlets of the old style gear oil pump.. I am not sure if the 3.9 that I have has already a larger gear style oil pump or that it can still be upgraded to a large style oil pump with the addition of a plate that allows longer gears to be installed.
I think I will look into an electric oil pump that pre pressures the engine before hitting the starter. Clearly oil is leaking back and has to be sucked up first.
Johan.
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That's a great write up for the old style pump. The 3.9 and up pump is directly on the crank though.
Side note: I just went to grab a pic of the diagram and sadly, it appears frigging TATA (or whoever owns LR now) has removed all the legacy parts diagrams..except for the vaunted Series-Defender :-/ I am holding out hope that its just a newyears server move that went wrong (and will get sorted). Go complain on their contact form if you have a minute.
My oft use disco-1 link:
Now, it's just this:
Side note: I just went to grab a pic of the diagram and sadly, it appears frigging TATA (or whoever owns LR now) has removed all the legacy parts diagrams..except for the vaunted Series-Defender :-/ I am holding out hope that its just a newyears server move that went wrong (and will get sorted). Go complain on their contact form if you have a minute.
My oft use disco-1 link:
Now, it's just this:
It has been a while, haven't driven the disco for a while.. the oil light goes out and comes back on after 10 seconds or so, I dependent of rpm.
Not sure what is going on, I hope a broken oil pressure switch, may be an internal leak?
It also leaks a bit of coolant , I can smell it dripping on the driver side exhaust pipe. Sofar impossible to locate.
Ah well, oil first.
Another amazing design. Getting the oil pressure sensor out. Someone decided it was a great idea to put a bolt on bracket so close that a wrench won't fit. Ultimately with some luck, dirty hands, some cursing it came out. Then if course not a nice handy 1/8 not but 1/2" straight unc thread.
Some searching and I found an adapter out of some scientific machine. It needs an elbow down to get the sensor in because the forementioned bolt. Lowes seems to carry less 1/8 not stuff. Luckily I found one at home Depot.
Ahh not enough space to swing the elbow because of that bolt again.
Need a longer 1/8" npt pipe.
Spend some time on a wiring harness with a "future" oil temp sensor as well. Don't hold my breath. The coolant leak might force me to get rid of this car before that happens. I'm
Not sure what is going on, I hope a broken oil pressure switch, may be an internal leak?
It also leaks a bit of coolant , I can smell it dripping on the driver side exhaust pipe. Sofar impossible to locate.
Ah well, oil first.
Another amazing design. Getting the oil pressure sensor out. Someone decided it was a great idea to put a bolt on bracket so close that a wrench won't fit. Ultimately with some luck, dirty hands, some cursing it came out. Then if course not a nice handy 1/8 not but 1/2" straight unc thread.
Some searching and I found an adapter out of some scientific machine. It needs an elbow down to get the sensor in because the forementioned bolt. Lowes seems to carry less 1/8 not stuff. Luckily I found one at home Depot.
Ahh not enough space to swing the elbow because of that bolt again.
Need a longer 1/8" npt pipe.
Spend some time on a wiring harness with a "future" oil temp sensor as well. Don't hold my breath. The coolant leak might force me to get rid of this car before that happens. I'm
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Thank you Greg, at least I am not the only one that is struggling with seemingly easy tasks.
Well hooked my gauges up, zero pressure,... Hart fluttering...then the G on the vdo sensor is not ground, haha. Wires inverted.. second try, 1 bar.. cold idle or with rpm.
I am not impressed, I would say even mildly stressed. Take the gauge and sensor of the car, back home I test against a adjustable air supply and mechanical gauge.. haha wrong sensor head for this gauge???
But there is hope now. Will try tomorrow again with a mechanical 60psi gauge.
So now a question for the advanced and experienced.
Is the bypass relief valve before or after the filter and oil cooler?
It seems to me that the low pressure sensor port is after all the oils cooler and filter and really measure the pressure in oil gallery.
From the oil pressure sensor down in the casting I end up with a recessed plug with a snap ring. I assume this is the relief valve?
Please comment.
Well hooked my gauges up, zero pressure,... Hart fluttering...then the G on the vdo sensor is not ground, haha. Wires inverted.. second try, 1 bar.. cold idle or with rpm.
I am not impressed, I would say even mildly stressed. Take the gauge and sensor of the car, back home I test against a adjustable air supply and mechanical gauge.. haha wrong sensor head for this gauge???
But there is hope now. Will try tomorrow again with a mechanical 60psi gauge.
So now a question for the advanced and experienced.
Is the bypass relief valve before or after the filter and oil cooler?
It seems to me that the low pressure sensor port is after all the oils cooler and filter and really measure the pressure in oil gallery.
From the oil pressure sensor down in the casting I end up with a recessed plug with a snap ring. I assume this is the relief valve?
Please comment.
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Hooked up a mechanical gauge..
32 psi at idle cold. Dropping down when I rev it up to 30psi and then goes back to 32 when idle again.
Seems to be weird that the pressure does not increase unless it maxes out against the relief valve. Did not have time to run it warm and on the road. I will get a 60 psi gauge or better 40 to see differences better.
On another note their is not a lot of nice space to put gauges in the car.
I still have to put a fuel pressure gauge and guess a motor oil temp and transmission oil temp. So that is already four.
Later ,j
32 psi at idle cold. Dropping down when I rev it up to 30psi and then goes back to 32 when idle again.
Seems to be weird that the pressure does not increase unless it maxes out against the relief valve. Did not have time to run it warm and on the road. I will get a 60 psi gauge or better 40 to see differences better.
On another note their is not a lot of nice space to put gauges in the car.
I still have to put a fuel pressure gauge and guess a motor oil temp and transmission oil temp. So that is already four.
Later ,j
I'm engaged in the same battle. Need to mount two analog, mechanical, gauges and the options are few.
I have 4 smaller analog needle voltmeters that I could fit left of the steering wheel. From the local scrapyard I got a 3 pin oil sensor from a 99 Jeep Cherokee.. they should be connected to 5 volt ( orange wire) The middle pin is a voltage output. The voltage has an offset of 1 volt at 0 psi but is then linear 3.5 volt at 50 psi.
The voltage is depending on the power supply.
I will get a couple from Chevy engines and see if they behave similar..
Going the diy way I think I can get a better full scale readout then using a 80 or 150 psi gauge for measuring 30 to 40 psi.
Will do the same for the fuel pressure
Johan
The voltage is depending on the power supply.
I will get a couple from Chevy engines and see if they behave similar..
Going the diy way I think I can get a better full scale readout then using a 80 or 150 psi gauge for measuring 30 to 40 psi.
Will do the same for the fuel pressure
Johan
I have thought about popping out a gauge cluster blister to fit above the radio *or* fit onto the top of the main cluster cover. What do you guys thing? and if I do it, will any of you be willing to help offset the cost of popping a few out? It would not really be a "sale" so I am hoping @admin is okay with making the ask here (I can drop it in the classifieds if more appropriate...but I ain't planning on making a biz out of it ;-)
I seem to recall one of the wiser fellas on discoweb went into some detail about the oiling options. I don't recall which post (and am at work..so..keepin it short but sweet).
Hi discoclay,
I am making my gauges to the left of the existing cluster. Like to keep the dash flat for other junk floating around haha.
Yeah,I posted the oil pressure on the technical area but not getting anywhere fast.
The manual is lousy, and seeing the problems with unresolved low oil pressure, slow oil pressure build up it looks like to get to the crux of the problem.might take a while.
I feel the oil cooler lines are way to small to allow oil to flow thru the whole engine?? Unless oil gets partially thru and partially bypasses the oil cooler.
For all that someone would have to study an actual front casting of a d1 3.9 serpentine and describe all the internal oil channels.
Sofar I have not found a thread about that.
Johan
I am making my gauges to the left of the existing cluster. Like to keep the dash flat for other junk floating around haha.
Yeah,I posted the oil pressure on the technical area but not getting anywhere fast.
The manual is lousy, and seeing the problems with unresolved low oil pressure, slow oil pressure build up it looks like to get to the crux of the problem.might take a while.
I feel the oil cooler lines are way to small to allow oil to flow thru the whole engine?? Unless oil gets partially thru and partially bypasses the oil cooler.
For all that someone would have to study an actual front casting of a d1 3.9 serpentine and describe all the internal oil channels.
Sofar I have not found a thread about that.
Johan
I would have been interested but I've started on something simple that will work fine for me.
On a" oil pressure d1" thread in the tech section
Lrdone posted this pic. That explained a lot. So after the relief valve oil still has to go thru the cooler and filter. If the oil is thick that will take some time. Worsened if the oil filter has a bypass valve that has a high setting.
I got a larger filter with a lower psi bypass valve and will see how long it takes before I get oil pressure.
Johan
Lrdone posted this pic. That explained a lot. So after the relief valve oil still has to go thru the cooler and filter. If the oil is thick that will take some time. Worsened if the oil filter has a bypass valve that has a high setting.
I got a larger filter with a lower psi bypass valve and will see how long it takes before I get oil pressure.
Johan
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