Thread: my disco problems, help!

Originally Posted by glenn82

what causes low presure? oil pump stuffed??

Yes, oil pump could be on it's way out or bypass valve (if the rover oil pumps have them) may have been blown open and now is jammed bypassing oil back to the sump.

Or a blockage on the oil pick up or in the filter as I said before, you didnt happen to bend the sump or anything silly like that as if the sump is bent under the pickup it can cause cavitation and suck air which can cause a drop in oil pressure.

Without looking at it I couldnt tell you much more, take it to a Landrover speciallist, check the recomended repairers section on this forum for one near you.

Originally Posted by glenn82

REAR MAIN WAS REPLACED COS DURING HIGH REVS THE CRANK HAD MOVED THE SEAL.. ETC ETC

That doesnt sound right, I used to have Datto engines running standard oil seals spinning at 10000 RPM and never spat one out.

I would suggest you have a look at the head gasket thing that PeterM I think it was suggested as that really doesnt sit right with me.

By the way, can you please turn you caps lock off.........Im going deaf with all the yelling

OKOK every 1's telling me that, sorry.

yeah its booked in for a cheach on sat, a real LR mech is looking at it .

so nothing wrong with sump. had the sump seal replaced also, well so i was told.....

do you have brain 1 about mechanicing stuff? (thats not a go at you, so far you seem to be doing all the right things)

if you do...

take a rocker cover off and start it up if your getting good oil flow its not the pump,

take the supply lead to the coil off and crank it on the starter, if the oil pressure light goes out, its not the relief valve jammed wide open.

you could still have oil delivery problems from a blocked gallery but youd pick that by the no messing around crunching and grinding noises.

I can buy the rear seal failing from a sudden over rev providing some other conditions were present (some are in older engines in most cases) but the over rev would have only been a contributing factor and not the cause.

with no other info my money is on a worn lifter/rod or a damaged cam along with the other general wear that will be in the valve train. if all of those have actually been checked and replaced then it may be a bearing on the rockers.

Originally Posted by Blknight.aus

do you have brain 1 about mechanicing stuff? (thats not a go at you, so far you seem to be doing all the right things)Your not having a go at him

if you do...

take a rocker cover off and start it up if your getting good oil flow its not the pump,

take the supply lead to the coil off and crank it on the starter, if the oil pressure light goes out, its not the relief valve jammed wide open.

you could still have oil delivery problems from a blocked gallery but youd pick that by the no messing around crunching and grinding noises.

But this makes me think you are at me over it

I can buy the rear seal failing from a sudden over rev providing some other conditions were present (some are in older engines in most cases) but the over rev would have only been a contributing factor and not the cause.

with no other info my money is on a worn lifter/rod or a damaged cam along with the other general wear that will be in the valve train. if all of those have actually been checked and replaced then it may be a bearing on the rockers.

I just made a couple of suggestions and I suggested a dead easy way to check it......as did you but I have had oil pressure switches open circuit at 3psi so I dont rely on an oil pressure switch as a diagnostic tool when you have an engine knock that could be an oil feed problem.

Popping a rocker cover off will take longer and cost more than whacking a pressure guage into where the switch is and checking your getting pressure.

But your spot on, if it's getting to the top then it should have pressure.

It could also be a pumped up lifter which is geting stuck on a bit of gum from the over rev which may be coming loose as it heats up and then maybe getting stuck again intermittantly now that it has moved past that point.

This is comon in 253 and 308 V8s and I suppose anything with hydro lifters would be the same when they get old.

If it is a stuck lifter then it will chew out the cam before long so you do want to sort it asap.

Ive changed my mind since typing this, my money is deffinatly on the lifter.

hi
i am 90% sure it is a lifter,
a i have spoken to many more knowledeable pppl than myself.
being a lifter is it a big job to rectify? i think i got qutoed around $6-7 each( + labour of course) with a total of 16??
i dont know if this is right. im so confuse

Remove :

Rocker covers,
rockers,
Intake manifold,
Valley cover

Pick out 1 at a time (I use an O ring pick) either just removing the push rod for the lifter your working on or taking them out and keeping them all in order.

Take note of any imperfections in the pushrods or on the surface of the camshaft as you may need to replace them.

Again, that is general V8, Rover stuff may be a little different.

Imsure someone will pipe up If im wrong.

wasnt having a go or dig at you about the seal thing as theres no way just over revving an engine will cause the seal to fail. BUT..... With some other contributing factors an over-rev (ok revving beyond the normal range the engine runs at) can be the straw that breaks the camels back.

let say the engine normally only revs to say 3000 rpm just to pick a number because of the drivers driving style

lets also say that for some reason the guy who machined the crank goofed and the rear main seal section has a 10 thou eccentricity

Lets also say that theres been some very slight weapage of oil and its picked up some contamination which is sitting right next to the seals running surface

lets also say that at some point some idiots put some stop leak in to condition the seal and stop it from leaking just so it can be sold and then whoever bought it didnt put the stop leak back in on the next service.


the end effect is you wind up with a seal with a soft bit and a hard bit that runs fine with the slight eccentric of the crank and because its been running with seal softner the bit that does the flexing still flexes and the bit that just sits there gets harder... when you take the engine up past the normal rev range the seal stresses and fails.

OR

with the extra revs that little bit of crud that was happily running along side the seal shifts and picks itself up into the seal and with the slight eccentric of the crank it then works its way around the seal destroying it...

take any of the other caveats out of the picture and yep you could rev that puppy till the pistons made for the ISS and the seal would hold up right to the point that the crank decides to go somewhere else.

thats what I ment when i said

Originally Posted by me

I can buy the rear seal failing from a sudden over rev providing some other conditions were present (some are in older engines in most cases) [color=blue]but the over rev would have only been a contributing factor and not the cause.