Low Oil pressure.

[Donels]

I have some skills in failure analysis of aero engines and the rule is always Observe, Deduce, Analyse.

Observing the lead up to your problem. Is no oil pressure, good oil pressure then no oil pressure.

Deduce no initial oil pressure - it’s been shut down since the autumn so needs to fill the system, good oil pressure - it’s filled the system. No oil pressure - it’s not sucking or delivering any oil or the gauge is faulty.

Analyse - it has sucked in some contamination that is preventing the pump from working. Possible causes blocked inlet strainer, blocked filter, stuck relief valve, failed pump or faulty gauge + anything else you can think of. Now do the actions to prove or disprove your deduction.

Crap holding the valve open would mean a lot of crap in the system, so the inlet strainer or filter will also be blocked. So check those first, then so on.

My guess would be a blocked filter so start by draining the oil and see what comes out. If it is full of crap where's it come from? Is it safe to flush. Check the filter is it blocked? Cut in half and have look. A blocked strainer would need considerable contamination and sump off to sort, so that's probably a last resort.

My guess is dirty oil which has settled over winter and the crap has been sucked up blocking the filter. Could be any easy fix.

[512BB]

I have removed an Oil Pump with Engine in Car. Yuo just need to remove the 2 Screws that go through the Engine Mounting and Chassis Lug. With a spreader under the Sump use a Jack to adjust height of Engine on Oil Pump side so the Oil Pump clears the Chassis Flange.
Alan

Agreed, just changed my pump this way, took an hour start to finish, mind you carbs were off...

From the horizontal flange on my Lotus chassis to the top of the oil pump is 1.5". Therefore the engine would have to be lowered by AT LEAST an inch on that side, to enable the oil pump to slide out underneath the flange.

If all the pair of you did was just undo the two bolts on the engine mount on the pump side, and then lower the engine by at least that inch, you must have much more compliant parts fitted to your cars than on mine, as my choke cable, solenoid to starter cable, radiator hoses, exhaust, left hand side engine mount, clutch pipe, carburettor back plate, plus probably a whole host of other things that I have forgotten, certainly could not be moved downwards by that amount.

Lets just hope that its a blocked oil filter on Bills car, or he is in for a lot more work than just removing two bolts, I can assure you.

Leslie

[pharriso]

If all the pair of you did was just undo the two bolts on the engine mount on the pump side, and then lower the engine by at least that inch, you must have much more compliant parts fitted to your cars than on mine, as my choke cable, solenoid to starter cable, radiator hoses, exhaust, left hand side engine mount, clutch pipe, carburettor back plate, plus probably a whole host of other things that I have forgotten, certainly could not be moved downwards by that amount.

Think I raised the engine, but seriously you think a choke cable, starter cable, radiator hose etc can't move an inch? The only thing I was concerned about straining was the exhaust., but if you think about it the engine will rotate about an axis through the gearbox mount & LH engine mount.

If all the pair of you did was just undo the two bolts on the engine mount on the pump side..... certainly could not be moved downwards by that amount.

Oh Leslie, so you're saying Alan & I are lying? As I said I raised the engine to change the pump, but I also dropped it & found I could not remove the pump. Either way it was easy to raise/drop the RH side of the engine an inch or more.

[elanfan1]

Don’t know about Alan but Phil you’re a bleedin liar! How could Lesley be wrong? I mean...

[alan.barker]

I have removed an Oil Pump with Engine in Car. You just need to remove the 2 Screws that go through the Engine Mounting and Chassis Lug. With a spreader under the Sump use a Jack to adjust height of Engine on Oil Pump side so the Oil Pump clears the Chassis Flange.
Alan

I have done this as i said above. It was on my June 1970 +2 S reg APH252H colour Red

No problem you can you can tinker on your Lotus as you like.
So many different ways of doing the same job.
It's like changing the Water Pump on a Twink some people still insist it can be done correctly without removing the Head
Cheers
Alan

[rgh0]

Yes you can change a water pump without removing the head, I did it once and would not do it again

You can also remove the oil pump without disconnecting the mounts for lifting or lowering the engine if you pull the end plate off the pump. I did it once at a race track when I was regularly breaking pump mounting flanges at 9000 rpm until I figured out how to mount them without the paper gasket to stop the failures. Its not easy but at least on my car you could just get the pump past the flange with the end cover removed and a jack under the engine to lift it a little within the practical movement in the mount . I suspect on many cars given the exact engine versus chassis location it would be impossible.

Now if I do change a pump in the car I disconnected the carb side mount and jack up the engine far enough to do it

cheers
Rohan

[gjz30075]

Now if I do change a pump in the car I disconnected the carb side mount and jack up the engine far enough to do it

cheers
Rohan

Does the end plate still have to come off?

[Mazzini]

On my Sprint I had to remove the end plate from the pump and had to do the same when installing the new pump. It's a pain, but it can be done.

[pharriso]

I didn't have to remove the end plate on either the old or new pump... here's a picture of both pumps...

new pump from Sue Miller

Original lotus chassis btw.

[The Veg]

For my Plus 2 recently I had the head and water pump off already so all I did was put a jack under the sump, remove the LHS mount, disconnect the RHS mount, and shove the block about an inch to the left, no problem. Given that with the head off and the exhaust being able to be shoved about as week, I don't know if it would have been so easy with a complete engine, especially since I think the new pump protrudes a little more than the old one. But the job is done so I won't worry about that.

[Mazzini]

I didn't have to remove the end plate on either the old or new pump... here's a picture of both pumps...

IMG_9913.JPG

IMG_9914.JPG

Original lotus chassis btw.

I don't doubt you for one moment...isn't your car LHD? I had a steering column to contend with as well.

[pharriso]

I don't doubt you for one moment...isn't your car LHD? I had a steering column to contend with as well.

Indeed it is.

[alan.barker]

[quote="rgh0"]Yes you can change a water pump without removing the head, I did it once and would not do it again

Rohan,
Was it Oil Tight when you got it back together
Alan

[Mazzini]

I don't doubt you for one moment...isn't your car LHD? I had a steering column to contend with as well.

Indeed it is.

Lovely car by the way.

[rgh0]

Yes you can change a water pump without removing the head, I did it once and would not do it again

Rohan,
Was it Oil Tight when you got it back together
Alan

Yes it was acceptably leak free but the effort to get it all aligned and sealed was more than would have been required to remove the head in the end

cheers
Rohan