Low oil pressure 13/60

[RobPearce]

Hmm... perhaps all my engines are in better condition than glang's but I would usually expect the oil light to extinguish if spun over without the plugs in. As glang says, taking the plugs out gives faster spin-over (because there's no compression) so, with a decent battery, you should be able to get the minimal 3-5psi up on the starter. It can take quite a while, though, especially if the filter is new (and thus empty). My GT6 will happily extinguish the oil light while cranking with the plugs in. I know people who deliberately do this before pulling the choke, to reduce wear (although I think that's probably OTT).

Like glang says, if you just go straight for the "start it up and idle", you are expecting "a few seconds" to fill the oil system. That's at 1000RPM. If you're cranking at 200RPM (which is on the high side, but then you've taken the plugs out) you need to expect at least five times that long. If you can't get the light out after a full minute of cranking (with no plugs) then it might be worth changing the sender - they are known to fail "seriously pessimistic".

[glang]

Interesting, Ive wondered before whether theres actually much benefit in spinning a 'dry' engine on the starter first or if its better just to go straight for a normal start? After all the bearings are turned without an oil supply in both cases although I suppose with the first there isnt the load of the firing strokes but then it does tend to do so for longer.....

[Antonnick]

Ok, many many thanks for the input. I was hoping to get some advice before proceding further. So, I will let the starter run for a full minute - perhaps do this twice with a pause inbetween if the light does not extinguish itself. I cannot imagine that the switch is faulty, it worked fine before I took the sump off. Yesterday I only let the engine turn over  for maximum 20 secs, I would say. Maybe that was the resaon. A minute seems a long time.

After that, plugs back in and wait for the big bang! 

Report later.

[Clive]

I use a battery drill on reverse, fit a gizmo thingy in the chuck chu use that to spin the oil pump (dizzy and drive removed) 

That gets the oil round the engine, then fit dizzy, and go for fire-up.

[Antonnick]

Success!

So I let the engine be turned over but for 45 seconds......the minute seemed such a long time and then put the plugs back. No 4 plug looked a bit oily but that is by the way at the moment.

Then I fired it up. an agonising 5 to 10 seconds before the green light went out and the pressure gauge shot up to 80 PSI. That should not be should it, if the relief valve is working?

Any way, I took it for a short drive to warm it up. At first travelling at 70 km/hr the 80PSI stayed stable making me think the gauge had stuck but I stopped after 3km or so (to put the roof back on as it is a bit cool today) and let the motor tick over. By now it was up to operating temp according to the water gauge and the tickover was just under 30 PSI.

Drover back home and the now that the engine was getting run in so to speak the operating pressure dropped to 60PSI and the tickover to about 20 when I got home.

I will take it for a longar run later today to see what happens then but the signs are good I think. Will now check for any leaks !

Thanks ever so much everybody for your input and help without which I do not think I would have got so far.

[glang]

Congratulations! That does sound good and the pressure will be high with brand new cold oil but soon go down to normal levels. However I suppose we will never know exactly where the problem was: worn bearings, duff oil filter or PRV.......

[Antonnick]

Let us say for the moment that the signs are good - I do need to take it for a longar run first - later today.

[RobPearce]

80 PSI when fully cold is not surprising, and 80 PSI at 70kph before it's warm is also fairly normal. The PRV is a crude device that's sized to handle the needs of a warm engine. If you've got tight tolerances and cold oil, it can't bleed off enough to drop the pressure.

My GT6, now 25 years on from its engine rebuild, still produces 95PSI at 60mph when cold.

My Vitessse, which has had its engine done more recently but not with a new oil pump, gives 85PSI on the first cold (fast) idle after an oil change, dropping to 25 or so when fully hot. Depending on the make of oil, the cold pressure and, to a lesser extent, hot pressure tail off as the miles are accumulated.

As long as you get 40+ at 2000RPM you're fine.

[Clive]

A good result. You should get many thousands of miles of use before needing to put new shells in again! I reckon on average a crank will manage 3 sets of shells before it needs a regrind.

[Clive]

A good result. You should get many thousands of miles of use before needing to put new shells in again! I reckon on average a crank will manage 3 sets of shells before it needs a regrind.

[Nick Jones]

Sounds like a good result.  It's very difficult to tell how worn those aluminium/tin bearings are by eye, the oil pressure improvement says they were well worn!

Now drive the car and enjoy it!

Nick

[Antonnick]

Quoted from RobPearce-

 

 

As long as you get 40+ at 2000RPM you're fine.

I have been trying to calculate the RPM as I do not have a rev counter. Based on a wheel dia of ca. 60cm and a diff ration of 4,11 I reckon that at 2000RPM I am travelling in 4th gear at only 53,2 km/hr.

At that speed the oil Pressure when the engine is warm is only about 30 ish, if that. At 80km/hr, which is 3000 RPM according to my calcs, then I get 40ish plus with a fully warmed up engine.

Does this seem right?

[RobPearce]

My estimate for 2000RPM is about 52kph so close enough. It does sound like your oil pressure is still a little lower than the book specification (Triumph gave only one range - 40 to 60 at 2000RPM - with no specific mention of what operating temperature). If that reading is an improvement on what you had before, I wouldn't worry about it. To be honest, even direct feed oil pressure gauges are not that accurate (electric ones are dismal, in my experience).

[nang]

You won't find a perfect, cheap gauge . You know the light works, so would suggest you put a bit of masking tape over the gauge, go for a long drive and don't worry unduly. 😆 😳

Tony.

[Bitumen Boy]

Did you fit a decent oil filter in the end? If not I suspect there may be a greater improvement in oil pressure to be had for negligible extra work. However, I wouldn't worry unduly about oil pressure that's on the low side but steady, the time to panic is when you see a sudden loss of pressure at speed.

[Clive]

Which oil are you using now? 

[Antonnick]

I have fitted a Mann filter with Liqui Moli öl

[Antonnick]

The oil is 20/50 of course.

I am not too worried about the pressure at the moment. I do not intend to go on any long jounies just yet and perhaps during the winter lay-up I will take off the head and check that over - perhaps fit a recon one for unleaded. Will have a think.

[Antonnick]

I have returned to this thread.

Having ordered some things from Rimmers I decided to add a new oil pump to the list - it is not that expensive and I was uncertain that I had properly checked the old one. Certainly the oil pressure had not improved as per the gauge.

So with some help, we removed the sump, replaced the old pump with the new. The new one has a mesh fitted and then put the sump back and refilled with new oil. I then started the engine and let it run for maybe 2 minutes - no oil pressure at all shows on the gauge and the green light does not even flicker.

What have we done wrong?

[RobPearce]

It is possible to fit the pump wrong but it takes some ingenuity. It's possible the pump is a dud or the mesh is hiding a blockage. It's also possible it just needs a more aggressive priming regime, as those pumps are not designed to work dry.

When fitting the new pump, did you pull it apart and pack with Vaseline (petroleum jelly) first?

I would be tempted, with a new pump, to prime it in situ before starting the engine. Remove the distributor and its drive gear, making a careful note of the orientation for re-fit (note the angle when it disengages the cam gear as that's where you need to re-fit it). Then take a long bolt and modify the head to engage on the oil pump drive. Fit the shaft in a reversible electric drill, set for anti-clockwise, and use it to spin the pump until you see oil flow. You probably won't get any pressure with the drive gear missing but you'll see oil.

[glang]

Yes the 6 cylinder pump has a 'tongue' on the end of its drive shaft while the Herald one has a slot so obviously if you did manage to bolt in the wrong type it wouldnt rotate....

[Antonnick]

If there is a 50% chance of doing it wrong, then it is a 99% certainty that I have. In between times I have removed the spark plugs and turned the engine over for a full minute - that is a long time when you are counting. Then restarted it hoping for the best. Ran it for 30 secs with no improvement so turned the engine off.

No, we did not pack it with vaseline.

I have rechecked the pump spec which is ref GLP145, suitable for all Herald Models. The sketch does show a slot - it is possible that the slot is not engaged?

REmoving the distributer to sping the pump with a drill I have heard of and seen in Utube videos. I am worried however of upsetting the timing. Perhaps it should first be set to TDC?

Where will you see the oil come out once it is primed?

[RobPearce]

To avoid upsetting the timing, you should take a couple of precautions:

- remove the distributor by unbolting the pedestal from the block, don't disturb the clamp

- make a careful note, as I said, of the angle of the drive gear as you remove it

You shouldn't need to rotate the crank at all while it's apart, at least until reassembly. Setting it to TDC beforehand isn't a bad idea but not necessary. On re-assembly, you will find the drive gear doesn't want to engage in the oil pump and the easiest way to get round that is to turn the engine over a few times, but make sure you've slotted the gear in correctly first. Once engaged, the motion of the cam will pull it down and keep it in mesh.

The bottom of the distributor sits in an oil passage, so as you spin the pump over there will be oil flowing into the hole you've stuck your drill / screwdriver / special tool down.

The packing with Vaseline is to pre-prime the pump. Engine oil would not stay in place and grease contains things you don't want in the sump. Vaseline will dissolve in oil and evaporate in use. You don't actually need to completely pack it but make sure all the working surfaces are coated thick enough to seal the gaps between the rotors.

[Antonnick]

Thankyou Rob for the very quick answer.

I see I have two choices - either remove the sump again after draining the oil and then removing the oil pump to pack it is vaseline.

Second choice is cleaner but risky, ( because of the timing problem) the removal of the Distributor. Am a bit worried about the drive gear meshing  - I am trying to find a picture in the manual.

[Antonnick]

So, I am taking the distributor off and as predicted, getting myself confused.

I removed the nuts from the vertical bolts at the base of the distributor, This looks like there are two studs which hold the flange but this does not move at all. I can see the all important clamp bolt which I have loosened in the past to adjust the timing. This should not be touched. There is however another horizontal bolt and having removed this one, the distributor body comes easily out. I hope this is right.

Now when I look down into the shaft I see the slotted driving dog ( this is what the manual calls it ) and there is a shaft in the middle of it. I was expecting to see the slot of the oil pump but there is no slot. 

I suspect this "flange" which I cannot get off is hiding the oil pump shaft and that I have undone a bolt too many.

Is this right?