Rover V8 Oil Pressure Issues when cold
Discussion
Hi there,
I'm looking for some advice regarding my 3.9 Rover V8 in my Defender.
I have oil pressure issues when starting from cold. in the winter it takes approx 10-12 seconds to get oil pressure from cold start and in summer around 6 seconds. I live in Scotland so winters aren't exactly arctic. I use 20w 50 classic oil.
I have changed the oil pump internals (gears), heavier spring, oil pressure sensor & oil pump casing. (old style external oil pump)
I have also dropped the sump and cleaned the oil pick up pipe and cleaned the sump and replaced sump gasket.
I have a fear it might be the bottom end that is worn but is there anything else I can do to improve the oil pressure on start up?
When the engine is running the light never comes on again.
At the moment I am disconnecting the ECU and turning it over until the oil pressure light goes off then starting it, which isn't ideal.
Thanks in advance.
I'm looking for some advice regarding my 3.9 Rover V8 in my Defender.
I have oil pressure issues when starting from cold. in the winter it takes approx 10-12 seconds to get oil pressure from cold start and in summer around 6 seconds. I live in Scotland so winters aren't exactly arctic. I use 20w 50 classic oil.
I have changed the oil pump internals (gears), heavier spring, oil pressure sensor & oil pump casing. (old style external oil pump)
I have also dropped the sump and cleaned the oil pick up pipe and cleaned the sump and replaced sump gasket.
I have a fear it might be the bottom end that is worn but is there anything else I can do to improve the oil pressure on start up?
When the engine is running the light never comes on again.
At the moment I am disconnecting the ECU and turning it over until the oil pressure light goes off then starting it, which isn't ideal.
Thanks in advance.
A quick look on LRcat suggests there is more than one pressure sensor.
http://new.lrcat.com/
I'd suggest you look into that to be sure you've got the right one AND a good quality one not one of the cheapies.
AND
consider fitting an accurate oil pressure gauge in lieu of the sensor so you can see what the oil pressure actually is.
These aren't a particularly high pressure system but do shift a high volume.
http://new.lrcat.com/
I'd suggest you look into that to be sure you've got the right one AND a good quality one not one of the cheapies.
AND
consider fitting an accurate oil pressure gauge in lieu of the sensor so you can see what the oil pressure actually is.
These aren't a particularly high pressure system but do shift a high volume.
paintman said:
A quick look on LRcat suggests there is more than one pressure sensor.
http://new.lrcat.com/
I'd suggest you look into that to be sure you've got the right one AND a good quality one not one of the cheapies.
AND
consider fitting an accurate oil pressure gauge in lieu of the sensor so you can see what the oil pressure actually is.
These aren't a particularly high pressure system but do shift a high volume.
Paintman,http://new.lrcat.com/
I'd suggest you look into that to be sure you've got the right one AND a good quality one not one of the cheapies.
AND
consider fitting an accurate oil pressure gauge in lieu of the sensor so you can see what the oil pressure actually is.
These aren't a particularly high pressure system but do shift a high volume.
Thanks for your help. I will look into this. I can't remember if I bought a decent quality one or not but I'm sure I bought it off of Rimmer Bros.
But I will try find a genuine one and replace it.
Years years too late and a newbie this late night.
First off these LR engines (push rod) 3.9 (yuck, bored out 3.5's), 4.0, 4.6 (better but without them failing coil packs) all have long delayed oil pressure aka dry start problems.
Oil drain back no matter the brand of oil filter with "anti drain back valve". Some brands better than others but of little help. Let it set a week while on holiday then hear how long the rods rattle at high rpm's on cold start before any oil pressure appears.
Just think how long it takes after an oil change, yikes that hurts, rods rattling spitting babbett a little more each time adds up, then there is none.
These engines are on life support from new especially the cam and lifters eating each other up before and not by 60K miles.
Low oil pressure engine design besides the pressure relief valve known to stick half open, weak relief spring, add loose bearings (most the time the rods are already into the brass, babbitt worn away with the mains hanging in there but next to go in short order.
Lookie into those worn rocker shafts as well them rockers bleeding oil excessively hence dropping your oil pressure at between 1,000 rpm's and idle.
Your 20/50 like I run in California but in the summer (up to 90*F tops) I run a blend of 5 quarts 20/50 with 2 1/2 quarts 10/30 wt oil. Winter rarely down to 34*F ten days a year at most with 45-50*F on average, Then run a blend 5 quarts 10/30 with 2 1/2 quarts 20/50 wt oil. Opposite ratios, simple stupid but never forget the additive.
Add 8 ounces of engine break in oil high in zinc and phosphorus additives protecting the cam and lifters as zinc and phosphorus has been removed in oils by the EPA and government in the US of A.
Got ya thinking, what the heck is that 7 quarts 24 ounces engine capacity being way over the LR Discovery's capacity?
This a 95 D1 with 5 speed with a 2002 4.6 plus a Pre-Oiler of 3 quarts capacity I added.
http://www.masterlube.net/classic.htm
When the engine is running 3-4 minutes after startup the Pre-Oiler is slowly recharged, half oil half air ready for the next cold start or anytime beyond two hours next restart.
Also run a 7" long Hastings 426 filter that holds a full quart of oil.
Installing the filter dry no mess, hit the Pre-Oiler switch after refilling the engine and Pre-Oiler, wait 20 seconds then see 38 PSI oil pressure. Electronic timer is set to keep oiling the engine another five seconds longer allowing for a drippy wet engine internally as well now fully pressurized before rotating the crank. This slinging oil up onto the cylinder walls at start up.
Tiny dash switch next to a red / green LED light besides a pressure gauge just in front of the shift lever. Two position switch to read engine oil or Pre-Oil accumulator pressure.
Piper cam & lifters with a RPI "Tornado" chip (Mark Adams), high flow cats, matched pair, distributor mechanical recurved plus vacuum advance unit from Oz. that has more degrees advance than US and California's smog, new 3.9 timing case covering a true double roller timing set with gears, cold ram air intake. A 1 1/2" thick aluminum spacer I machined out and mounted between intake and trumpet base. Port matched intake to heads, exhaust manifolds also port matched with a some minor porting work.
The toughest smog state in the USA, California and I run too clean.
Another secret, toss those pieces of antique garbage Lucas single dribble injectors in the garbage can. They dribble like an old Englishman in a Pub after drinking too many pints that has Prostate problems.
Four hole Bosch injectors made a big improvement in engine operation, heck rock the Disco enough while in 2nd gear to jar the crank a 1/2 of turn it will fire up and idle away from me. Run and jump in then drive away. Clean idle dragging the clutch to below 350 rpm's in 4th idling down clean until a compression stall out.
Restricted the below the throttle heat plate to 110*F max on a cold morning for a dense and cooler air intake charge plus added an adjustable restrictor hidden inside the idle control stepper motor hose preventing cold engine high rpm start up wear.
Went from a slow Disco to a fun Disco to drive the way they should of built it in the first place. Been a fan of these aluminum Buick engines going back to the 1960's General Motors era.
Repowered a 62 P1800 Volvo with a Rover 3.5 litre back in 1971 to the Volvo 4 spd w/ OD.
First post, bet ya thinking i'm some kind of a Yank jerk, nope just a gear head looking how to improve anything mechanical. Electrical also and LR has Mr. Lucas.
......~~=o&o>......
First off these LR engines (push rod) 3.9 (yuck, bored out 3.5's), 4.0, 4.6 (better but without them failing coil packs) all have long delayed oil pressure aka dry start problems.
Oil drain back no matter the brand of oil filter with "anti drain back valve". Some brands better than others but of little help. Let it set a week while on holiday then hear how long the rods rattle at high rpm's on cold start before any oil pressure appears.
Just think how long it takes after an oil change, yikes that hurts, rods rattling spitting babbett a little more each time adds up, then there is none.
These engines are on life support from new especially the cam and lifters eating each other up before and not by 60K miles.
Low oil pressure engine design besides the pressure relief valve known to stick half open, weak relief spring, add loose bearings (most the time the rods are already into the brass, babbitt worn away with the mains hanging in there but next to go in short order.
Lookie into those worn rocker shafts as well them rockers bleeding oil excessively hence dropping your oil pressure at between 1,000 rpm's and idle.
Your 20/50 like I run in California but in the summer (up to 90*F tops) I run a blend of 5 quarts 20/50 with 2 1/2 quarts 10/30 wt oil. Winter rarely down to 34*F ten days a year at most with 45-50*F on average, Then run a blend 5 quarts 10/30 with 2 1/2 quarts 20/50 wt oil. Opposite ratios, simple stupid but never forget the additive.
Add 8 ounces of engine break in oil high in zinc and phosphorus additives protecting the cam and lifters as zinc and phosphorus has been removed in oils by the EPA and government in the US of A.
Got ya thinking, what the heck is that 7 quarts 24 ounces engine capacity being way over the LR Discovery's capacity?
This a 95 D1 with 5 speed with a 2002 4.6 plus a Pre-Oiler of 3 quarts capacity I added.
http://www.masterlube.net/classic.htm
When the engine is running 3-4 minutes after startup the Pre-Oiler is slowly recharged, half oil half air ready for the next cold start or anytime beyond two hours next restart.
Also run a 7" long Hastings 426 filter that holds a full quart of oil.
Installing the filter dry no mess, hit the Pre-Oiler switch after refilling the engine and Pre-Oiler, wait 20 seconds then see 38 PSI oil pressure. Electronic timer is set to keep oiling the engine another five seconds longer allowing for a drippy wet engine internally as well now fully pressurized before rotating the crank. This slinging oil up onto the cylinder walls at start up.
Tiny dash switch next to a red / green LED light besides a pressure gauge just in front of the shift lever. Two position switch to read engine oil or Pre-Oil accumulator pressure.
Piper cam & lifters with a RPI "Tornado" chip (Mark Adams), high flow cats, matched pair, distributor mechanical recurved plus vacuum advance unit from Oz. that has more degrees advance than US and California's smog, new 3.9 timing case covering a true double roller timing set with gears, cold ram air intake. A 1 1/2" thick aluminum spacer I machined out and mounted between intake and trumpet base. Port matched intake to heads, exhaust manifolds also port matched with a some minor porting work.
The toughest smog state in the USA, California and I run too clean.
Another secret, toss those pieces of antique garbage Lucas single dribble injectors in the garbage can. They dribble like an old Englishman in a Pub after drinking too many pints that has Prostate problems.
Four hole Bosch injectors made a big improvement in engine operation, heck rock the Disco enough while in 2nd gear to jar the crank a 1/2 of turn it will fire up and idle away from me. Run and jump in then drive away. Clean idle dragging the clutch to below 350 rpm's in 4th idling down clean until a compression stall out.
Restricted the below the throttle heat plate to 110*F max on a cold morning for a dense and cooler air intake charge plus added an adjustable restrictor hidden inside the idle control stepper motor hose preventing cold engine high rpm start up wear.
Went from a slow Disco to a fun Disco to drive the way they should of built it in the first place. Been a fan of these aluminum Buick engines going back to the 1960's General Motors era.
Repowered a 62 P1800 Volvo with a Rover 3.5 litre back in 1971 to the Volvo 4 spd w/ OD.
First post, bet ya thinking i'm some kind of a Yank jerk, nope just a gear head looking how to improve anything mechanical. Electrical also and LR has Mr. Lucas.
......~~=o&o>......
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