No Oil Pressure - AJP8 Auxiliary Drive Shaft Failure

[ukkid35]

A few weeks ago the oil pump drive failed on engine start

This was obvious because I lost power steering and oil pressure at the same time

Although I am nowhere near removing the timing cover, I have now received a new uprated Auxiliary Drive Shaft from TVR-Parts



I was warned by another PHer that the only difference was that the PS Woodruff Key has been changed from 3mm to 4mm width, and in all other respects it remains the same

The failure of the PS Woodruff key is relatively trivial, it can be replaced within a couple of hours, and you can drive the car without power steering in an emergency

If the PS Woodruff key fails, it acts a bit like a fuse, in that it protects the rest of the pump assembly (h/t TwinKam for the fuse metaphor)

So uprating the PS key seems like a poor idea to me, especially as the PS coupling is exposed to foreign debris, as both TwinKam and I have found out

Mine ended up with kitty litter in it after going off the track at Zolder



TwinKam had a bolt from the airbox find it's way in IIRC

Although the PS key is now 4mm, the Oil Pump Woodruff key remains 3mm (long)



As does the sprocket key which is 3mm (short) and hence tiny



This key is just a spare and is most likely too large, despite being the right 3mm width



The Water Pump impellers are a push fit without keys

My engine failure is due to the sprocket key failing, perhaps because the nut securing the sprocket has become lose, perhaps because something has partially jammed the pumps - I have yet to find out

I have never touched the oil pump drive on the several occasions that I had the timing cover off, I think that was a mistake

I probably should have removed the nut/sprocket/key and checked for wear, and retorqued using threadlock - hindsight is a wonderful thing

There was a warning before it failed, the previous couple of times that I started the engine there was a brief squeal which disappeared within a second or two

I guessed this could be an alternator bearing or clutch release bearing complaining, but since the squeal was so brief I assumed investigations could wait until returning from the trip

How wrong could I be!

Edited by ukkid35 on Tuesday 13th August 21:45

[ukkid35]

Chimp871 said:

Feel for you but at least this time it's a final fix.

Sadly not, in fact I would much rather use the original shaft, but I am sure it will have suffered severe corrosion just as your did, so I will have to use the uprated shaft which I believe increases the risk of oil pump failure, even if it decreases the risk of PS failure which is a trivial issue

Fortunately now that I have a PS coupling shield (thanks to TwinKam) the extra risk due to the uprated PS key should be minimised

I would strongly advise anyone fitting an uprated shaft to ensure they use similar protection



I have found your thread and the contributions from Rufus Roughcut absolutely invaluable - thank you

Was there evidence of threadlock on the sprocket nut?

https://www.pistonheads.com/gassing/topic.asp?h=0&...

[ukkid35]

Rufus Roughcut said:

I was thinking if at some time you may have hammered the coupling on you could have damaged the bearings or maybe pushed the shaft through the impellers? The pumps are built from a centre, any tapping on one end without supporting the other could damage it.

On mine the coupling is not a press fit, which is why it could be done easily in situ

The small grub screw in line with the key is to stop the coupling moving up the shaft and releasing from the the PS 'dog clutch' - guess how I found out

[ukkid35]

The Woodruff key is no more, the gear can turn relatively freely, and it appears to have welded itself to the shaft that also turns

However neither the water pump impellers nor the PS pump moves at all

How can that possibly happen?

More importantly how can I remove the gear, so as to remove the pump assembly?

The gear is being significantly distorted by the remover, which I am struggling to tighten further

Any ideas?

[ukkid35]

TwinKam said:

Paul, if the gear and (nose of) the shaft turn freely as one, but do not turn the water pump impellers, then the shaft must be broken just behind the front bearing.
Try not to damage that gear ..they are nla new.

Many thanks for the warning

I have not budged the sprocket at all yet, although I haven't tried heat so far

If the shaft is broken before the wp impellers, might it be easier to pull the shaft out of the bearing, than pull the welded sprocket off the shaft?

Assuming it really has broken, then it would be most likely to happen at the diameter change, so what could be keeping it in place?

[ukkid35]

Perhaps I can find some way to attach a slide hammer to the bearing puller...

Thanks for that idea

[ukkid35]

Once again, thanks for the warning, cracking the block would probably ruin my day

[ukkid35]

There are no obvious signs of oil starvation damage so far, although the lifters look a bit weird, as if they've been etched



There's no sign of anything similar on any other parts, and all the cam caps look fine

I will be removing one of the main bearing caps soon, which one is most vulnerable to starvation?

Presumably the one closest to the oil feed? If so which is that?

[ukkid35]

CerbWill said:

If you're removing the sump you might as well remove and check each bearing one at a time. It's an opportunity to plastigauge them to assess wear vs the as new limits in the build manual too.

I'm assuming that it would be worth replacing mains and big ends as a matter of course

I can't be sure no one has been there before, so how will I be able to tell whether mains are standard or oversize?

[ukkid35]

To my untrained eye it looks like I have dodged a bullet

I can't see any sign of damage due to oil starvation

The one point where you can see copper is directly opposite the cylinder that was pinking, I doubt that is by chance

Do the bearing markings help identify the size

ERR1765 and LA. 7300, Google finds a US Landrover forum, but not much else

The logo looks like they are made by Vandervell, who are part of Mahle who I do rate as premium manufacturer

Edited by ukkid35 on Friday 22 November 08:17

[ukkid35]

CerbWill said:

The cams should be fine as they sit in a bath of oil. If your oil pump stopped it just means fresh oil wont be added to the bath and old oil spilled down the drains front and rear back to the sump.

I agree, so what do you reckon has caused the 'staining'?

To me it looks like there could have been something acidic contaminating the oil that ate in to them while the engine was untouched for months, hence the large contact area patch when the cam was sitting where there are no marks

[ukkid35]

I still can't remove the pump assembly

I've managed to loosen all four bolts, and then sliced off the heads of three of them

I thought this might allow the pump assembly to shift back enough to expose the shaft so I could slice through it

But sadly not

Also, the block has cracked where one of the pump bolts is located

With many of the pump fixings removed I can see that the water pump impellers are not seized

It's the oil pump that is seized, but the oil pickup is fully intact, so where the contamination came from is a mystery to me

[ukkid35]

Since the shaft is broken directly behind the bearing, I don't understand why it won't simply pull out

[ukkid35]

Yes I think I do have the PDF somewhere, but nothing is as it should be because of the failure

Parts are either welded together, seized, or broken, so most disassembly processes aren't going to work

For instance, I can't remove the PS pump, because the shaft is oriented so that I can't undo the grub screw on the coupler

[ukkid35]

notaping said:

The power steering pump will come off without loosening the grub screw - leaving one side of the dog clutch on the shaft.

You're quite right, I have already removed the pump itself, I meant to say the pump carrier

I will need to find a way to removed that rear nut, but even if I can do that I can't remove the coupler because of the grub screw

What might help more is if I can undo the front of the water pump assembly, but those four bolts look very awkward to remove

[ukkid35]

Looking at the new shaft, I am sure it must have broken where it is narrowest immediately after the bearing

Therefore I reckon it should be possible to pull the gear and shaft through the bearing providing I use a suitable bearing puller

Does anyone have any recommendations or suggestions as to what to use?

(I'm not going to try a slide hammer because of the crack in the block)

[ukkid35]

[ukkid35]

Not sure what to do now though

Can't get the PS coupler off because I can't reach either the large or small grub screws which are opposite each other

Perhaps I can double nut the studs, remove them and turn the housing to expose the grub screws?

[ukkid35]

TwinKam said:

Well done Paul!
Did it take a lot of force?
Rik

Not a silly amount, I didn't check but I would guess about 15-20 ftlbs

I was using a 1/2" wrench about 10" long to tighten the M10 bolts

The only thing holding it was the sleeve that you can see in the last pic but one, whose only purpose seems to be to fit in the seal that I've already removed from the front part of the pump assembly

Not sure why it is separate to the shaft itself - it's not part of the water pump seal assembly

https://tvr-parts.com/tvr-parts/part-details/tvr-e...

So what is it, and where do I get one, assuming I need to replace it?

[ukkid35]