No Oil Pressure

[ukkid35]

At the end of the first day of a two day track day at The Ring the oil pressure was lower than usual, about 50psi, rather than the 60-65psi I'd expect. I put this down to the very hot engine bay, although the coolant temp itself was stable at about 90.

First thing in the morning on cold startup oil pressure was only 45psi, this was concerning, I'd expect it to be 65 minimum, but as the engine warmed up pressure rose to 50psi. This was confusing, but I wondered whether the oil had become degraded somehow.

I decided the car was driveable so took it out for a two lap stint, trying to keep an eye on the pressure gauge which I find is perfectly hidden by the steering wheel. Towards the end of the second lap I saw that oil pressure had dropped to something so low I immediately knocked it in to neutral and started coasting. Then the oil pressure warning lamp came on as the engine idled.

With a little revs the lamp went out, so I limped the car off the track.

At this point I am imagining flying home from Bonn, leaving the car in the hands of ADAC, who might decide to recover the car back to the UK if I'm lucky.

I decided to let the engine cool before doing anything else, and then handed in my transponder knowing I wouldn't be going back out on track.

I asked Jason, who gave me a PAX lap at Rockingham earlier in the year, if I could talk the issue through with him. I said there was a very small chance that the oil bypass valve could be at fault, and I had a new spring that I would try fitting, knowing that if that was at fault it would be like winning the lottery.

Jason kindly helped me retrieve my tools, and Nige lent me a trolley jack. I nearly danced a jig when I found this



So I fitted the new spring



But when I lowered the car and started the engine the oil pressure was 100psi plus

In my excitement I had failed to see that the two pieces of broken spring did not account for a whole spring. So I had to do the job again in order to retrieve the last part of spring that I'd left inside.

Now I get 80psi at cold idle, and 70psi hot in normal use.

I didn't realise the springs were prone to disintegrate, I though they just sagged with age. From now on I will be replacing the spring with every oil/filter change.

I lost three or four hours, but got my transponder back and went back out on track - what a day!

[aide]

Result!
How is the new gearbox?

[ukkid35]

aide said:

Result!
How is the new gearbox?

Faultless - very pleased indeed.

However, each time I changed in to fifth as the change up buzzer sounded, I was imagining the circlip failing and fifth moving up the output shaft...

[Robscim]

Well done Paul!!!

At least you didn't discover the "garage" had put an old bolt inside the spring to take up the slack from the spring losing its springiness (rather than replace the spring), despite me asking many times for them to change it regularly.

Thankfully, that was in the past and I've got a much better garage these days.

Hope you enjoyed the ring again!

Cheers

Rob

[FarmyardPants]

Nice one, lucky you didn't burst the oil filter

[ukkid35]

FarmyardPants said:

Nice one, lucky you didn't burst the oil filter

I use the V8F 8990 from David Brown V8 Filters, which I believe are much higher quality than your average FRAM.

They have much finer synthetic media, rather than paper fibre, and better quality anti drainback valve etc.

I am a big fan - even more so now it stood up to my 100psi plus test...

[ukkid35]

On Saturday about an hour from home, on the way to the most expensive pair of track days ever, I restarted the engine, and while manoeuvring slowly I found I had no Power Steering

Within a few seconds I released I also had No Oil Pressure, so I hit the red button

The only possible explanation is that my car has suffered Auxiliary Drive Shaft Failure, with the sprocket Woodruff key shearing

I had the car recovered, swapped to my backup car, and we headed off for an awesome time at the Ring, while at the back of my mind I knew my Cerb won't run again for months and months

I don't actually know how much damage has been done, the engine was left idling for a couple of minutes before I realised there was no oil pressure, but it wasn't used under load

I know I'm clutching at straws, but I'm hoping there's no metal in the oil, contaminating every part of the engine, destroying every bearing

I haven't even checked the dipstick for sparkles yet...

I knew this AJP8 Achilles heel would get me eventually, I didn't predict that it would happen when the engine was running better than ever before

The car was great at the Ring two months ago, so sad it won't move again, probably until next year

[TwinKam]

Oh no, Paul, I feel your pain!
If it's any comfort, my engine suffered no collateral damage whatsoever when the drive sprocket sheared off the end of the pumps' shaft. But, as you know only too well, it's a huge job just to remove the pump assembly, let alone rectify whatever else you find.
Best of British to you,
Rik

[ukkid35]

TwinKam said:

If it's any comfort, my engine suffered no collateral damage whatsoever when the drive sprocket sheared off the end of the pumps' shaft.

I was hoping you'd reply because I couldn't remember what had happened

I will stay positive, thankfully I did get to use the car properly in May, so at least I can remember how good it is when it's working properly

I will have to find a way to work with an engine stand, with the very limited space I have

I will also have to work out whether I will simply try to repair, or do a more comprehensive rebuild

As for the pump assembly

TwinKam said:

I did mine myself, and despite having all the required tools/expertise, still had my heart in my mouth!

Looks like I will be sending the pump assembly to Readman Racing, as I don't have the tools or expertise to try myself

[stickylabels]

Sorry to read this Paul, hope you manage to sort something out that isn't too painful....

Sticky.

[Chimp871]

Sorry to hear this Paul.....

I just pulled the engine out a few weeks ago and disassembled the pump myself, it can be done with a bearing puller and a friendly local garage to press on/off the water vanes. PM me if you'd like to know more.

Did you check the oil pressure relief spring? Iirc that can show almost zero when playing up and increase with the revs.

[Chimp871]

Pulling the engine took me around 14 hours (1st time for me on this lump) to pull. The actual breaking down, bagging, labelling etc is surprisingly quick.

It's also pretty light once stripped. So easy to move around in tight spaces.

Right now I'm measuring gaps, bores etc. Seeing your past posts I'd imagine you might enjoy doing that instead of just sending it off for a £5k rebuild.

[ukkid35]

Sadly I've had the dubious pleasure of removing the heads three times already, and it takes me a lot longer than 14 hours to get anywhere near that point

I'm sure it would be easier if I had a workshop rather than a parking space

What I have not done yet is actually put the engine on a stand and split the block

[Mr Cerbera]

Gutted for you, mate

BUT

Thanks, as ever, for the Oil Spring Tip

Best o' Luxk, Kiddo !

[Chimp871]

ukkid35 said:

Sadly I've had the dubious pleasure of removing the heads three times already, and it takes me a lot longer than 14 hours to get anywhere near that point

I'm sure it would be easier if I had a workshop rather than a parking space

What I have not done yet is actually put the engine on a stand and split the block

Once it out and on a stand it's very easy to tear down. Around 4 to 6 hours. Hardest part was removing main journal caps.

[ukkid35]

This is what I wrote on another car forum about three weeks ago, obviously I had no idea how prescient that thought would be

ukkid35 said:

I have wondered aloud many times why there isn't an ignition cut as soon as oil pressure is lost

People keep telling me that it's a safety issue, except you get an ignition cut if you run out of petrol, so wtf

Stories like yours encourage me to consider how I could incorporate low oil pressure ignition cuts in my cars

Best of luck with your repair or rebuild

[TwinKam]

ukkid35 said:

This is what I wrote on another car forum about three weeks ago, obviously I had no idea how prescient that thought would be

ukkid35 said:

I have wondered aloud many times why there isn't an ignition cut as soon as oil pressure is lost

People keep telling me that it's a safety issue, except you get an ignition cut if you run out of petrol, so wtf

Stories like yours encourage me to consider how I could incorporate low oil pressure ignition cuts in my cars

Best of luck with your repair or rebuild

Paul, this has often been mooted in car circles and particularly following cases of expensive engine damage, or fear of same.
I recall one owner of a DB5 wanting me to wire the fuel pump to cut in the event of no oil pressure... I pointed out that he'd probably seize before the float bowls emptied! So you are on the right track with cutting the ignition, and I have done this on a number of 'competition' cars but I wouldn't recommend it for the road (unless possibly there was an accessible over-ride).
And this is why, from personal experience, it also ties in with an answer I meant to give you earlier about the risks of running the engine after oil pump failure.
My pumps stalled and snapped the drive sprocket clean off the forward end of the pumps' shaft when an air box bolt dropped into the area of the triangular PAS pump drive flange. Instant loss of PAS, oil pressure and coolant circulation. I was exiting a roundabout onto a fast stretch of dual carriageway at the time; I noticed the lack of PAS first, then the lack of oil pressure. I knew that there was a layby in approx quarter of a mile, so I cut the engine and coasted... but was losing momentum fast. This was on a left hand sweep with traffic possibly trucks etc coming up fast from behind, I had to take the decision to fire it up and drive to the layby, using as few revs as I could. When I reached it, the engine was also overheating...
For those who know the area and want to relive my nightmare, this was leaving Chichester's Tesco roundabout on the A27 ... it's the start of an 8 mile sprint to Emsworth... there is no hard shoulder and I had visions of being rear ended, or even being driven over!
Had my ignition been automatically cut, I would not have been able to drive to safety. Yes, I could have run out of petrol or broken down for many other reasons in similarly awkward spots, but this is an instance where I was glad to have the option to drive on. This doesn't apply to track use, where you can just pull off and are probably not being followed by artics. In addition then to my hatred of 'smart' motorways is a hatred of Mway standard roads with no hard- shoulders either.
Having taken the agonising decision to fire up an engine with no oil pressure (even if only to confirm that there really is no oil pressure!), you then have to be prepared to see collateral damage when you strip it. Happily in my case there was none, not even from the errant drive sprocket inside the timing cover. Actually the episode did me a massive favour as I discovered hitherto unknown issues within the engine that would have raised their ugly heads in the very near future, namely failing head gaskets and a collapsed crank nose needle bearing... but there was no bearing or journal damage. I was able to 'simply' refresh the engine with no more than a crank polish, bore hone, and reassemble with all new bearings, rings and seals. And a rebuilt pump assy with new shaft of course.
I write this to give you hope, you may be as fortunate as I was, and give thanks to the gods of retained oil memory.
But of course it's still a right royal PITA and wallet.
Rik

Edited by TwinKam on Monday 29th July 10:54

[ukkid35]

TwinKam said:

Actually the episode did me a massive favour as I discovered hitherto unknown issues within the engine that would have raised their ugly heads in the very near future, namely failing head gaskets and a collapsed crank nose needle bearing... but there was no bearing or journal damage.

Thanks Rik, I really appreciate the encouraging words, and I am eternally grateful for the PS pump cover that you sent to me

I had to pull the heads a couple of years ago because they weren't sealing, and I was lucky that I did because it meant I found the loose valve guide - had that not been found I could have ended up with a broken valve stem and the major failure that would have resulted

Nevertheless I don't enjoy pulling the engine apart, as I am very slow, and don't really have anywhere practical or secure to work

That's why it was 18 months before I was able to get the car to an MOT centre and get a ticket

I am curious as to why the pump mechanism appears to have seized, perhaps there was some debris in the cooling system?

I am also wondering what to do about the Aux Shaft, as I have been told that although the uprated shaft has a larger Woodruff key at the PS end, the Sprocket end is exactly as before - that doesn't seem very well thought through!

One option might be to add an extra Woodruff key 180degs opposite, that would mean just two fairly simple modifications, to the shaft and to the sprocket, both beyond my capabilities but I'm sure I could get it done somewhere

Any thoughts?

[TwinKam]

Personally I wouldn't worry about the forward end... cutting an extra key way there will further weaken the shaft in an alreaady critical area. Fitting a brand new latest spec shaft is the best you can do.
If the pumps stall/seize for any reason, something has to give; I understand that in some cases that is the key, although in my case it was the shaft. Toughen up the weak point and you pass the grenade up the line... would you rather it snaps the crank? Think of it as a fuse...
I will be interested to learn where and why yours has failed, but in any case whilst rebuilding your pumps I would advise the fitting of a brand new shaft. The sprocket is not supported in the timing cover, and I would suggest that there could be an element of whip fatigue in the neck of the shaft immediately behind the sprocket.
As far as the other end and the PAS drive is concerned, I drilled and tapped the drive flange for a grubscrew immediately opposite to the keyway as others have advised.
Good luck and don't forget to post pics!

[ukkid35]

I have now found out what the ultimate cost of this failure would be

I managed to leave a spring fragment in the oil pump feed tube that runs from the sump to the pump

In fact there is nothing to stop the fragment failing by gravity in to the tube so that there is no chance to retrieve it

It sat there in the pump feed tube like a ticking time bomb, while I was totally unaware

And exactly two years later it managed to find it's way in to the oil pump body

This caused the pump to seize and has made things very difficult indeed



My advice is to change the £6 spring as often as you change the oil

The consequences of one failing are not good at all