AB oil pump gear?

[uglysteve]

I have been getting paranoid about my oil pump again. :banghead:
Atlantic British sells an oil pump gear for the Disco 2. http://www.roverparts.com/Parts/8979K.cfm
My 03 Disco is about to hit 100k miles. I assume that the pump gear has worn away some of the timing chain cover if it has the alignment issue. I would think that installing a new gear in a worn cover may be a good way to reduce the chance of failure due to a possibly cracked gear, and that stress may be reduced on the new gear because that material may be missing. Any thoughts on this idea? I do have some oil leaks, and may have to change the seal anyway.

 

[listerdiesel]

If the casing is worn away, a new rotor/gear set isn't going to make much difference, as the housing is diecast ali in which the steel rotor runs.

Having said that, if I was in that position, I'd be looking out for a complete front cover assembly, rather than just the rotor.

I never was able to run down with LR Technical exactly what the NAS Spec vehicle oil pump failure was, or what caused it. There doesn't seem to be an equivalent failure mode elsewhere, but nothing seems to come up as to exactly what the problem was.

I've got a brand new cover waiting to go on mine, we fitted a new short engine in 2009 but at the time there were no new covers available, so like you, we fitted a new rotor and it has covered 43K miles with no problems.

I picked up a new and boxed front cover on ebay for little money, nobody else bid for it so it is on the shelf waiting to be used.

We run our V8 on Chevron 10W-40 Diesel oil, semi-synthetic. Has had that in the sump since the day it went on the road after the rebuild and has been good as gold. It also cleaned out a lot of muck from the lifters. We run on gas (LPG) and the oil is still transparent after 8000 miles, which is what our oil changes are scheduled at now.

Peter

 

[uglysteve]

The problem was a misalignment of the dowels that locate the cover. http://www.landroverresource.com/docs/lrna_tsb.pdf

Peter, did you see ware in the cover, any damage to the gear?

I have read posts by Land rover technicians that they would take warranty exchange engines, remove the dowels, and align by hand, for their own use.

The idea behind changing just the gear is that if there was a spot there the cover is rubbing the gear, that spot would now be worn down. So, a new gear would not have the pressure on it, and the new gear would not have cracks. If oil pressure is in spec now, it should be in spec with the new gear. I don’t even know if I have a problem. I need to get a pressure gauge to check it. My truck is in the VIN range that could have the problem, and I have oil leaks to repair. I will be looking at Ebay for a more affordable cover.

I am working on an oil pressure interlock that will kill the fuel pump if oil pressure is lost. Waiting on parts. Will post details when done.
Thanks for the advice.
Steve

 

[listerdiesel]

So the holes in the cover were wrong? They are made by Hobourn-Eaton at Rochester, Kent, you should have their name cast inside the cover. LR part number is LJR000220.

When I changed my rotor, there was some scoring and there was also a fair bit of side clearance where the alloy housing faces had worn away over time.

You could machine the faces again to bring them back to spec, but you'd need a good mill to do it on.

I see that new cover assemblies are £290 + taxes (20%) for 2nd-tier suppliers, or £447 plus taxes (20%) for genuine. By the time it arrives in the USA, that's getting expensive!

I got my new one for £65 plus carriage, nobody else bid, it was on ebay. Genuine LR as well.

Peter

 

[turbodave]

No, it was the dowels in the block that were machined incorrectly.

 

[listerdiesel]

No, it was the dowels in the block that were machined incorrectly.

OK, so do you know what the work-around was, or did they just replace the engine?

I'm only asking out of curiosity, my contacts at LR Technical are very coy about the subject...

Peter

 

[uglysteve]

I believe the holes in the block were drilled wrong. Land Rover was replacing the engine when they failed under warranty. I'm thinking that I may be able to measure the gap between the crankshaft and the timing cover to see if mine is centered. From what I have read, most failed early. I have oil leaks from the timing cover, so I was trying to think of a way to determine if I have the problem, and deal with it in a low cost way. Also, I have read that the gear teeth often crack and brake then they have this problem.

I also do not like the way the oil pressure light is designed. The pressure switch closes when the pressure is low. That switch can fail in either an open or short. An open would seem to be the most likely failure (disconnected). If that happens, I will never know if the pressure is low. I would rather have a false alarm if the switch failed.

I am going to install an oil pressure interlock to protect against catastrophic engine failure.

I still need to determine exactly where the oil is coming from.

Thanks for the information and pictures. They are helping me understand how the pump is designed.

 

[uglysteve]

It would be nice to have some more specific information from Land Rover on the problem. How far are the dowels from there specified location? What direction? When do they fail statistically, min, max, mean? What is the percentage of engines in the S/N range that have the problem? Was there one tool that did all the drilling, or were there 10? What are my chances of this failure? How can I check to see if I am at risk?:banghead:

 

[listerdiesel]

OK, so now I have that information, I can lay out a failure scenario:

The pump gears are sintered steel powder if my memory serves me correctly, they are not machined from solid material.

If the timing cover is offset from where it should be, then the oil pump rotor set will be squeezed tightly on one side and have excess clearance on the other.

The failure will be either at the inner corners of the outer gear, or the drive dogs will shear on the inner gear. Either one will result in oil pump failure, my guess is that the drive dogs fail first. The other option is that the excessive pressure on the alloy housing wears it away to the point where oil pressure falls away dramatically.

In your case, you should be able to do a physical check quite simply by measuring the dimension from the timing oil seal outer housing to the outer diameter of the crankshaft. It should obviously be the same all round.

The other thing to check is for eccentric wear in the timing cover housing for the oil pump rotor.

Peter

 

[listerdiesel]

It would be nice to have some more specific information from Land Rover on the problem. How far are the dowels from there specified location? What direction? When do they fail statistically, min, max, mean? What is the percentage of engines in the S/N range that have the problem? Was there one tool that did all the drilling, or were there 10? What are my chances of this failure? How can I check to see if I am at risk?:banghead:

I can look at a new cover and give you reasonably accurate dimensions for hole positioning, but the simplest thing to do is to check the radial clearance between the oil seal housing outer diameter and the crankshaft nose outer diameter. You could easily make up a test piece that was a close fit in the housing and over the crankshaft nose, that would straightaway give you a 'Go/NoGo' test.

I'd hazard a guess that the whole set of studs and dowels are drilled on an NC machine, so it is likely to be a jig/setup issue. The oil pump rotor does have a fair bit of clearance between the drive dogs and crankshaft, but not that much to allow for the wrong drillings.

If it was just the dowels wrong, the timing cover probably wouldn't have fit and they would have caught it sooner. I'm surprised that the guys doing the assembly didn't catch it it either, it must have been tight.

The complete timing cover and pump are made and sold as one piece, Rover assembly guys would not have had any options about fitting the oil pump separately.

Peter

 

[antichrist]

I am working on an oil pressure interlock that will kill the fuel pump if oil pressure is lost. Waiting on parts. Will post details when done.

That's a dangerous thing to do.
Why install something to intentionally shut off your engine at potentially the worst possible moment?
Consider the consequences if you loose oil pressure as you're pulling out in to heavy traffic, or crossing traffic, say in front of a semi. If someone is that worried, a good oil pressure gauge with a large warning light is far safer. If you're really paranoid add a loud warning buzzer.

 

[listerdiesel]

I'd tend to agree with Tom on this one, just killing the engine is a bit of a hazard, better to have the oil pressure showing up so you can monitor it if you need to.

Satisfy yourself about the alignment of the housing first, then the worry about failure may subside a little.

Peter

 

[turbodave]

http://www.discoweb.org/forums/showthread.php?t=55265

We've been here before.
The "03 block has clearly mis-aligned dowels if you look at the base of the dowels.
I still don't understand why LR didn't make a little more radial clearance. Few other pumps of this design (crank mounted) have such little radial clearance between the annulus and housing as the LR pump. An extra 20 thou diametral clearance would not affect a 13/14 pump set like this at all, yet will all but eliminate the chance of breakage because it wasn't aligned PERFECTLY true against the crank nose

 

[uglysteve]

That's a dangerous thing to do.
Why install something to intentionally shut off your engine at potentially the worst possible moment?
Consider the consequences if you loose oil pressure as you're pulling out in to heavy traffic, or crossing traffic, say in front of a semi. If someone is that worried, a good oil pressure gauge with a large warning light is far safer. If you're really paranoid add a loud warning buzzer.

You do make a good point. A buzzer may be a better option. An interlock like this is common in carbureted engines with aftermarket electric fuel pumps. Pump manufacturers include instructions with the pump. Holley makes a pressure switch just for this purpose.
http://www.holley.com/12-810.asp
Although intended to stop fuel flow in the event of a roll over or collision, not an unreliable oil pump.

I worry that my wife will be driveling and oil pressure will be lost, and she will try and drive home. May be I will add a 5 second time delay relay and a buzzer, to give some time to pull over. Then that would add more components to fail, and cause the truck to shut down.
I will have to think about that some more.

TurboDave, Thanks for the link to your old post, good information.
Steve

 

[antichrist]

I worry that my wife will be driveling and oil pressure will be lost, and she will try and drive home.

Well, I guess you have to decide which is the worse scenario, her trying to drive home with a failed oil pump or getting flattened by a semi.

I think most people, if told, "If this light illuminates and you hear this buzzer, pull over as soon as you can or the engine will be destroyed", would do it.
If they can't understand those instructions, I probably wouldn't let them drive my car.

There are a number of similar systems. There are diesel filters that will shut the fuel off if the water level in the bowl gets too high, but every one I've seen has said don't use them on vehicles that operate on public roads.

 

[listerdiesel]

Stewart-Warner used to make oil gauges (gages) with adjustable pressure trip contacts, they were a US company and may still do that unit.

That would give you visual on the oil pressure and a set of c/o contacts that you can operate an alarm with.

If you set it to alarm at 20psi, that might operate at tickover but would be fine for driving.

Peter

 

[uglysteve]

I don?t have a lot of experience with the cam and valves. Would the engine even run when the lifters have no oil pressure? Will it have any power to get out of the way of a semi? How long before the engine dies with no oil pressure? How long before the bearings are trashed?

I like the buzzer idea, I will hold off on the interlock idea. I have been looking for a gauge with set point contacts, but have not found one.

Steve