As I've said on the SVA area, I failed to get to my test because I started to lose oil pressure on the way... now I need to find out why!

Symptoms:

Engine running fine throughout the whole affair, will no loss of poke.

Already done around 25 miles without any sign of problems before starting the journey to the SVA centre. As my journey is down the A12 I just had to travel 40 miles at around 65-70mph or I'd get mowed down by something - it's a very busy road.

I'd done around 35 miles when I had to lift off the throttle due to traffic, and my oil light came on. At the same time the oil gauge reading dropped. When I accelerated again (I had to) the oil light went out and the gauge picked up, but only to around 20psi instead of the 40-50psi I had before.

Managed to get into Chelmsford OK, stopped to check the oil level and top up the fuel tank prior to the test. Oil level was fine (as was everything else) and there were no signs of leaks. I let everything cool down and tried to start the engine but couldn't raise any pressure at all, so gave up and called the rescue man.

This is a totally rebuilt engine that has been running well. My first thought is that the oil pump has failed, possibly the oil relief valve has stuck, or similar. However, I may be grasping at straws...

Could anyone who's experienced in these engines suggest any other cause, given the symptoms? That is: running properly; oil pressure loss on lifting the throttle (pretty much to tick-over); then no pressure at all when trying to restart after cooling the engine down.

Fortunately the engine only ran for a few seconds with zero pressure, and still seems OK.

Help!

David

only seen this once on a x-flow the roll pin securing the screw gear on the shaft shearing giving no drive to the pump.

was it a new pump or a rebuild
if rebuild what are the rotor clearences like

Just a thought, but is it worth checking that the sender and gauge are both OK?

Nick

maybe i'm being a little to obvious here but...

could it not be oil starvation due to oil moving around in the sump ?

the oil pump could possibly then have problems recovering from a 'gulp of air' ?

we used to experience this problem with hydraulic pumps on aircraft when the seals or drives started to get a bit dodgy

[Edited on 10/9/04 by protofj]

seems a bit unlikely that both devices would fail.....

And why a sudden drop to lower, or zilch at tickover, pressure....

Looking at Timf's broken pin idea, I wonder if there was enougth 'drag' by the broken parts to drive the pump for a while, with the drag being too low at tickover.......


atb

steve

[Edited on 10/9/04 by stephen_gusterson]

Well, I've just swapped the oil pump for the original old one - believed to be OK - no sign of oil pressure when I spin the engine over with the plugs out.

I'm beginning to suspect that the oil pickup pipe may be faulty - clutching at straws again...

David

whatever it is David, you are SOOOO close to having a car on the road you should still have a smile on your face whilst looking for the fault.

its better than a whole loada messy grp work!

atb

steve

IIRC Steve of MK had a very similar problem. ISTR he had this problem just before his shells went... but I may be wrong!

When I became a little less peeved I gave this some thought and decided that the engine needs to be hauled out - not such a big task, just a nuisance.

Previously I tried to remove the sump with the engine in the car - front wheels on ramps, engine hauled forward a few inches, and so on. It worked, but I hurt myself in the process: pulled muscles wriggling under the car, bruises, and so on. If it isn't the oil pickup pipe then the engine has to come out anyway, to inspect the bearings.

It'll also give me an opportunity to deal with some annoyances that I've been putting off (such as an oil filter that can't be unscrewed without lifting the engine). Also I will split the metal plate that goes between the engine in the gearbox - one of the reasons working on the sump under the car was such a pain.

This will be a job for tomorrow though - I've got to be nice to my missus today, because I was such a grumpy rat-bag yesterday!

cheers,

David
(who's feeling a little less pee'd off today)

Dave,

Lots of things to consider!

The sump was shortened, but there was an extension that made the oil volume the same. I used the same dipstick and it worked out OK.

The engine hasn't settled at all.

The previous problem I had was down to a user-ability error - I'd screwed the oil pressure switch and gauge sender into the wrong hole! Worked fine when I put it right.

I've tried 2 pumps now and, unless both have stuck valves, it's not likely to be that.

The fact that car ran very well for 50-60 miles of assorted driving suggests that the oil levels & system weren't far wrong.

The engine is now almost ready to come out - at this moment the oil is draining, and then I'll drain the water. It's been relatively simple to disconnect the engine from the rest of the car (X-flows are like Meccano anyway!) and I should have no difficulty separating it from the gearbox, once I remove the alternator to give me some room to move the block forward.

cheers,

David

Hmm wonder what happened? I posted a reply earlier today but it hasn't appeared.

Anyway.

Bearing pressure loss would usually be accompanied by the death rattle. Is the remaining oil greyish or swirly metallic looking?

Pressure loss at revs change suggests that either pressure relief stayed open or a loss of pump drive. The fact that it then picked up but at lower pressure suggests a sticky spring.
Easier to check on Xflow because it's external pump, although relief valve is in face of pump.

It could be pickup problem of course, hard to tell when ones been modified.

If one bearing has gone then a loss of pressure would occur but it usually can be run up to 10psi or so, not usually zero, without major damage having occured with attendant noises.

Rob,

I didn't hear any obvious noises, apart from the tappets tapping a bit louder than usual due to the lack of oil - but it's a bit hard to hear when you've got a full-face helmet on! Once I knew I had a problem I didn't push my luck, and left the engine switched off.

The oil I've just drained off looked "clean but used" if you know what I mean - no sign of metal particles.

I know what's what tomorrow when I lift the engine out and take the sump off - I still suspect the oil pickup pipe as the oil pump had no oil in it when I took it off - normally there's an appreciable spill when you detach the pump. The chambers looked quite dry.

One problem I have is that I have no idea where the oil pressure relief valve is! I know it's on the mounting face but there's not much to see when you take the pump off. Anyone have a good picture to give me a clue?

Even if the pickup is obviously a problem when I look tomorrow I'll probably still take the bearing caps off to make sure that there's no significant scoring or wear. While the engine's out I might as well make the most of the opportunity...

Incidentally, on reflection I wouldn't be too surprised if it's a bearing failure - from the outset I was concerned about doing a 40-mile thrash with a brand-new engine, as that's no way to run in a newly-assembled engine. I was only doing 3500rpm max to get 70mph, but that requires a fair amount of power so the engine had to work hard. If that is the case, then I hope that just the shells are spoilt, and not the crank surfaces.

Anyone in the Ipswich area know someone with a trailer I can borrow (for a few notes, if necessary). I'll probably hire a van and tow my car on a trailer next time - I can run the engine in properly in varied local driving after the test.

rgds,

David

[Edited on 11/9/04 by David Jenkins]

Hi Dave just a thought could the pickup pipe be to close to the bottom of the sump starving the engine of oil jacko

Thanks, Dave!

How can I tell if it's stuck? Can I prod it with a screwdriver or something?

rgds,

David

Well, the engine's out and on a stand.

- The oil pickup pipe was in place, and intact.
- The pressure relief valve was clean and functional.
- I've checked all the bottom-end bearings: the mains are a nice smooth matt grey, and all but one of the crank bottom bearings were grey with a slight shine. One of the bearings had a copper-coloured stripe, as shown below, but I can't imagine that this would cause a total oil pressure failure (would it?). All crank journals were clean and unmarked.

Apart from replacing the damaged bearing, I can't think what to do next - anyone got any suggestions?

David
Rescued attachment dscf0003.jpg

David, was the oil pick up pipe gasket/seal in place and undamaged with the securing bolts tight?? loose bolts or damaged seal could cause loss of or low oil pressure.and would explain why oil pressure dropped off. Also, I.I.R.C. crossflows should run on 20/50. thinner oil would probably not be suitable, hope this helps, Rusty.

Rusty,

The x-flow oil pickup pipe is just a tube that jams into a hole, with a bolt elsewhere that stops the assembly fall off. There was some sealant around the pipe where it went into the block.

I was using 20-50W - Castrol GTX, in fact.

Anyone know whether the cam bearings often cause trouble? I don't want to get in there unless I have to - it's a fair bit of work to get at it, and it means partially stripping the head to take the pressure off the push-rods.

David

As previously suggested have you checked the pin and gears that drive the pump,if not is there any pin holes in the pikup pipe. Cam bearins dont really drop pressure its definately a bottom end problem,and that shell wont cause a drop either,unless the crank us bad..
DEAN.....

is the pump working?fill it with oil and turn the input gear,oil should come out the hole at quite a rate

david

how far from the bottom of the sump is the pickup. could it be that due to vibration the pick up has dropped towards the sump.

maybe time for the playdo check

tim

The oil pickup was still solidly mounted, so I guess that it was OK.

Just a thought - I was wondering whether my 20-50 oil had overheated due to the A12 thrash, and had become too thin for the old-fashioned engine.

Alternatively, are there any internal oilway plugs on a x-flow that may have come undone? Ones that would let the oil back into the sump, rather than to the outside world.

rgds,

David

surely once the engine is cool again, the oil pressure would rise if due to overheated oil......


atb

steve

quote:

---

Originally posted by David Jenkins
Just a thought - I was wondering whether my 20-50 oil had overheated due to the A12 thrash, and had become too thin for the old-fashioned engine.

---

The copper line is a dirt pickup score mark, this would not cause complete loss of oil pressure on it's own.

Complete loss points to oil pump related problem if shells OK.

The lube progress is as follows:-

Pickup to pump via filter. Pump to galleries feeding mains then through crank drillings to big ends.
Also mains to cam bearings with excess then onto rocker shaft whereby it leaves rockers and drains down drip feeding pushrods and cam lobes on way back to sump.

From above you're left with pickup, filter, pump as main cause other than bearing failure of course.

Any air leak in pickup will cause loss of pressure.

Check the filter, can't remember but it may have a drain spring plate. Prevents oil draining back to sump via filter.


Are you sure gauge is working OK ?
The pressure take off is on the gallery immediately after pump.

I'm puzzled that loss of pressure was not accompanied by bearing noise or such.

Before you stripped it did you start it up on tickover? I don't trust electrical gauges to show anything when cranking. Capillary gauges, yes.

Any gallery plugs missing would result in oil everywhere. One is on block side, one is in block end under timing cover, another in flywheel end of block. They look like ball bearings jammed in.

Good rebuilders of engines remove these and clear out oilways with chemical cleaning follwed by pipe cleaner type brushes.

Rob

i had the same problem, after modifing the sump and tuning the motor,

reason why your oil pressure droped is prob a breathing problem, with to much sump presure the oil doesnt return to the bottom of the motor - it happend to me!

have a look at the little breather tank on the side of the motor, if its not blocked, there is valve in there that you can take out aswell - to just let it breathe

then once the oilpump and the pickup is empty - wany a water needs to run into the sea before it will suck oil up again. U need to fill the pump and the pickup pipe with oil then it will pump again


let me know what happens! i'll find a pic of my breather system.

regards
riaan

Rob,

I think you're right - the shells look OK, apart from the one that's scored. It has to be something to do with the pickup pipe, pump or filter (I hadn't considered that).

The fact that both the pressure switch and the gauge showed a loss of pressure simultaneously suggests that they're OK.

I did spin it over with the plugs out (it got up a fair old speed, as it's running in nicely) but couldn't raise any oil pressure - in the past I have got 10-20psi on the starter only.

As an aside - can I re-use that bearing shell? Instinct says to change it while I'm in there, but that involves time and money! The journal is clean and unmarked, and the bearing surface is now spotless (I'm just "careful with money", as they say!).


Stretch,

I'm not convinced about the oil breather - I had taken it out and cleaned it when I rebuilt the engine - but it won't hurt to take it off and check it while the engine's out!

rgds,

David

[Edited on 13/9/04 by David Jenkins]

i also didnt have any problems, will just
one morning driving to the race track

drove it to a workshop, the guy told me its breathing problem, and i thought - whatever,

Spend R250 for at a day at the workshop, i can drive for hours at 7000rpm without a problem

Breathing also depends on rocker cover and oil filler cap on a xflow.
It's a good point but if it's standard system then the filler is well vented and should breathe in place of crankcase breather. Although not ideal.

Crankcase breather was fitted that way so that fumes could be recirculated and reburnt without smell in car cabin. Not a problem on 7

Xflows in a 7 are prone to throw oil out of crank breather and ideally should have a catch tank/breather or the dreaded oil smoke/oil spill on heavy cornering will occur. Not a problem so much in a saloon car but once in a 7 then cornering forces increase.

As to refitting shell, well I would renew shells if I wanted car to last without any further work. If it's easy to change later then refit by all means temporarily, but change it later as trouble is brewing there.

quote:

---

Originally posted by Rob Lane
As to refitting shell, well I would renew shells if I wanted car to last without any further work. If it's easy to change later then refit by all means temporarily, but change it later as trouble is brewing there.

---

Is it possible the filter element has collapsed internaly? If it's on the low pressure side of the pump then it won't take much to prevent the pump working.

I may well buy a new filter when I get the bearing shells - it's a small cost compared to everything else.

David

David, wasn't there a thread a few weeks ago about oil pressure problems on a cross flow?? I.I.R.C. there was an oil gallery plug missing or loose inside the timing cover, can't remember who had the problem , may be worth a search. Rusty

Hi
I'm thinking along the same lines as timf in particular pump clearances, had a similar problem with a Datsun pump that had been assembled with a thick gasket between the pump body and the cover plate, only takes a couple of thou, and when they get hot the alloy bodies expand a bit as well

Another thought, it wouldn't hurt to check bearing to shaft clearances with plastigauge, just to be sure it's within tolerance

are you saying David that you now have no oil pressure, even when cold..... that looks like something progressively failed, rather than tolerances or whatever....


atb

steve

As I understood it, the engine now has no oil pressure at all, even when just cranking.
This suggests a failure somewhere rather than just bearing wear.
This is a rebuilt engine that only did 65 miles?

There is an oil gallery plug under the timing cover but ISTR that it led to oil leaking if it was out BUT I can't remember now.

It's some time since I messed with the Xflow engine although I know the engine intimately having cut my teeth on them, so to speak. Sometimes it takes a while to recall things. It's an age thing.

Thanks to everyone who's made suggestions! All will be taken into consideration during the rebuild - none will be ignored (including the oil breather, honest!).

At the moment I'm waiting for some replacement big-end bearing shells to arrive before I start the rebuild. I'll check all the clearances using plastigauge while I'm at it.

While waiting, I'm degreasing the oil pickup ready for close examination/rectification. I will also check its seal in the block, and position in the sump. The pump looks OK, but will get a full check before refitting, and there will be a new gasket and filter.

I'll also look at the oil level in relation to the pickup pipe while I'm at it.

Have I forgotten anything?

David

I had a good look at the oil pump while I was fiddling around - all seems OK, apart from a certain 'grittiness' when I turn it.

The main thing that catches the attention is the state of the worm gear, which has significant wear after just 60 miles (it was a reconditioned unit bought when I originally rebuilt the engine). the gear on the original pump is in perfect nick, even though it's probably the original unit fitted by Ford 25 years ago. I've put the old pump back on as it's in good nick and within tolerances, and matches the worm on the cam, which is also original (but reground).

I'm sure that this has nothing to do with my problem, as the pump shaft wouldn't have been able to 'hop over' the canshaft gear, but it shouldn't have worn like this.

Bad materials? Who knows.

David
Rescued attachment dscf0006.jpg

Assuming it's standard materials then it shouldn't have worn that amount. But reconditioners could use any material for the gear.

What's interesting is that it looks like lack of lubrication, given that the cam lobes and that worm gear are 'drip' fed it would suggest that oil wasn't getting to it.
Is the cam gear, lobes etc OK with no wear showing?

David, Rusty might be onto something there.

There are two gallery plugs. One is outside engine, other is in timing cover alongside cam.

It's also the plug that is at end of gallery of pressure switch ! If it was loose in timing cover all oil pressure would dissappear.

Worth removing timing cover to look. I believe it has a hex key end.

Just trying to look logically at the problem.

Rob

[Edited on 15/9/04 by Rob Lane]

I peered into the block with a torch - the pump gear looks OK, and the cam lobes seem to look normal.

If that oilway plug has come loose, where would the oil go? Down to the sump, or the outside world? The reason for asking is that I don't think that I lost any oil outside the engine.

Looks like I have another job for tonight...

David

If that plug was out the oil would leak into timing cover and straight to sump.

Of course it does - there's a squirt of oil that goes onto the timing chain, so it must drain back to the sump...

Silly me...



David

Are you sure the sender is OK?

On my last kit I had F all pressure, changed to capillary gauge and low and behold pressure.

X flows go well even when knackered, I find it difficult to believe that there could be no pressure at all unless the pump is not going around or the pick up pipe is above the oil. This would be obvious. Take the sender off and crank by hand with plugs out. Oil should wee out.

David, Have you had a look inside that oil pump that felt gritty, something must have gone amiss to generate the sort of loads required to destroy that skew gear, another old diagnostic trick is to open up the oil filter and see what it has caught, bearing in mind that whatever you find has come through the pump, I assume you have an effective strainer on the oil pick up pipe

Steve,

It's going to end up being something daft like this!

Had a good go at the engine last night -
- plastigaged some of the bearings and all were 'as new' tolerances (apart from the scored one).
- Took off the timing cover and the oil gallery plug was still screwed in tight.
- The cam surfaces are fine, and its pump drive gear totally unmarked (unlike the pump's gear - see above).
- Oil pickup pipe intact - very slight possibility of an air leak where it is pushed into the block, but it looked (and felt!) tight. I had used some gasket sealant first time round.
- Oil pickup mesh is about 4-5mm off the base of the sump.
- I see no sign of undue wear or oil leaks.

So, I'm left with:

- Not enough oil - but it worked for 60 miles, and the level was right a while after stopping the engine.
- Both oil senders failing simultaneously (but I will check that their t-piece isn't blocked).
- Oil pump pressure valve jammed, but freed itself later, maybe when I took the pump off.
- Oil filter failure (unlikely)
- Something stopping the oil getting back down to the sump quick enough, e.g. oil breather (see earlier discussion).

I shouldn't be at all surprised if I put this all back together to find that it works just fine...

rgds,

David

(this is getting like a viking saga)

Is the camshaft correctly fitted/bearings ok? If the camshaft is moving about it could cause a loss of pressure, and it would explain the pump rotor drive wear.

I hope both senders are in a remote T piece!

If they are in side of block the T piece will definitely fail.

Happened to me, oil everywhere. Happened to everyone I've talked too about it.

Rob,

You're just trying to cheer me up!

How did you extend the senders away from the block?

David

[Edited on 16/9/04 by David Jenkins]

Sorry David.

I had just finished a hillclimb run at Olivers Mount, Scarborough and was returning downhill, just before paddock the T piece let go and I was shouted a warning by marshals. I left an oil trail on track for about 6m before I left track, fortunately not on racing line.

It's a commmon problem and the T piece fractures under vibration of engine.

Demon Tweeks and Merlin Motorsport sell a remote 'kit' for something like £13. It has adaptors, piping and joints to take it away from engine.

quote:

---

Originally posted by Rob Lane
It's a commmon problem and the T piece fractures under vibration of engine.

---

quote:

---

Demon Tweeks and Merlin Motorsport sell a remote 'kit' for something like £13. It has adaptors, piping and joints to take it away from engine.

---

David, sorry to hear about your engine troubles.

quote:

---

Oil filter failure (unlikely)

---

Funny you should mention that... I've just about finished rebuilding the engine, after finding absolutely nothing wrong inside (apart from one crank bearing that was probably scored by some dirt). I've plastigage'd every bearing and they're all spot on for clearance.

I'm left with just one suspect, which is the pump and it's accessories. The pump was a bit 'gritty' but OK when I looked inside and cleaned it; now it feels fine. The problem may have been a relief valve that stuck and un-stuck later, as it was OK when I looked. This only leaves the oil filter, which was common to both pumps I tried.

What was the dodgy make? It's always worth knowing these things!

BTW: When I went to get the new bearing shells (Scholar Engines, Suffolk - cheaper than most mail-order companies) I asked about my problems with filter clearance as I have to hoist the engine to remove the filter! They recommend a Renault filter to the Formula Ford folk as it's half the length, so I'm trying one of them. I'll be changing the oil every winter, so it'll only be 3k miles max between changes.

Tell you one thing - it's getting bl**dy hard to find 20W/50 oil now! Halfrauds don't even understand what it is - "not on the shelf? Haven't got it." - and most of the local motor factors only sell cheap rubbish oil or a few Castrol variants, all for modern cars. Eventually I found some "Duckhams Classic", after a LOT of searching.

rgds,

David

[Edited on 18/9/04 by David Jenkins]

They were both Fram filters. I now choose not to use them for the reasons mentioned above. That is from personal experience/choice, and I am in no way saying that the product is actually pants...

I've checked all the engine's giblets, re-assembled it all and put it back in the car. Spun it over with the starter, and at the second spin the oil light went out and I got some pressure on the gauge!

My last guess is that the oil pump's pressure relief valve stuck open, but reset once I took the pump off the engine.

Apart from that I have no idea...
... just hope that I don't lose pressure again!

Thamks to EVERYONE who posted hints and/or advice - all were followed up at some time or other!

rgds,

David


[Edited on 22/9/04 by David Jenkins]

Don't knock it. At least it works!!

Anyway well done and good luck with the SVA

You cant do this to us! All the suspense and hours of thought put into helping you out and NO ANSWER!AAAAARRRGGHH!!

The only funny thing is we all know for the next 200 miles you are going to be watching that oil light like a hawk!
Glad it's sorted,and I think your explanation seems the most logical..
DEAN......

It is an electric one. As for the wiring & components then they're all brand new - and if there is/was a wiring fault then it's all my fault, as I designed the loom!

I was wondering about this, so I revisited my diagrams - and the 2 senders are in totally different parts of the loom, with no common wiring.

Thanks anyway!

David

Well, I connected everything up and tried it out - started almost immediately, and I got oil pressure within a few seconds - 65-70psi! I bought a new high-pressure oil pump, as it only cost a few Pounds more than just buying a new drive gear (don't ask me why!).

The only after-effect of losing oil pressure is that my tappets are distinctly more noisy than they used to be - I think my cam took a beating during the oil shortage. Still, it runs well enough to book a new SVA appointment.

rgds,

David

Nice one,it's frustrating when you get problems but well done.
Good luck with the SVA.
DEAN