Oil Pump Removal

[DMT]

Good afternoon Folks

I am planning on removing the Oil Pump as I believe (hope) it is the cause of my oil leak.

I had a quick look and one of the 4 retaining bolts will not come out as the bottom of the Exhaust manifold is in the way. I have 4 into 1 tubular exhaust manifolds and a ZF4 box.

On my MG I used to jack the engine up against the mounts and it gave me enough room to access some of the sump bolts.

Is it possible to do the same with the stag? is there enough movement in the mounts, after removing the down pipe, to give me the room I need to get the last bolt on the oil pump out?

I do not want to remove the manifold unless I have to.

Regards

Dave

[dasadrew]

If you type Oil Pump Removal into the search box you will find at least two other threads with the same title which probably cover your question

[Roy_S]

I have a similar leak, there are oil drips that I can see on the pump and they drop onto the exhaust. One thing to check first is the rocker box because if this leaks at the back it drops down onto the oil pump housing.

Paul at Stag Classics mentioned it to me, if I run my fingers round the back of the rocker box (it's always where you can't see...) there is oil, the rest of the gasket is dry, I'm looking to do this first as parts and access is easier.

[sujitroy]

He has tubular manifolds so those may not apply

[DMT]

I have read all the posts I can. All seem to say that on the tubular systems the down pipe is usually removed and the pump can then be removed ,but on mine one bolt hits the side of the bottom of the manifold.

I have looked for oil everywhere I can think, refitted the pressure take offs, and the highest oil was on the bottom of the pump so decided to remove it. I am not too worried as I would like to check the pump condition and I will fit the correct rated spring as my pressure is a bit lower than I hoped for but is still OK.

It looks like I will have to remove the manifold.

If I can't find the leak I will have Paul at Stag Classics have a look as I will be soon be popping in to see him to collect the Hard Top he has sorted for me.

Dave

[wilf]

Just checking - did you eliminate the oil transfer housing seal as a source of leaks? When it leaks, the drips end up on the pump.

[trunt]

It seemed to me that any oil leak will make it’s way to those pump bolts, it’s very difficult to ascertain exactly where it’s coming from. Like wolf said the transfer housing is always a suspect along with the oil pressure switch. And yes, a right head rear half moon leak will end up there as well! There are even posts saying the pump bolts themselves can leak. Eventually mine was greatly improved by fitting a slightly larger (2mm) O ring to the pressure relief valve. You could try that first and change or shim the spring for pressure at the same time its not an awful job, much easier then removing it.

[DMT]

Thanks, I will have a go at the pressure relief valve.

Thanks for all the help.

Dave

[Richard G]

I have had the same leak and spent a lot of time trying to find where it comes from, done everything, now changed oil pressure switch , its difficult to get a spanner in to remove, trying out tomorrow see if leak has gone. As it drips on to exhaust it soon becomes aparrent!

[jbuckl]

Beware, changing a pump relief valve spring isn’t necessarily a good way to up oil pressure.
Removing bearing wear is though.
Hobourn spring Is about right at 40-45psi on a fresh engine.
Higher rate pressure relief springs can end up with undesirable effects.
The pump generates flow; the small bearing clearances cause pressure.
pumps are sized to be capable of generating more than enough flow.

[MandM]

Thanks, I will have a go at the pressure relief valve.

Thanks for all the help.

Dave

If you are going to have a go at fitting a 2mm O ring (which will cure the leak on this part) do this mod first or you will find it very hard to change this seal again in the future + it also enables you to adjust the pressure slightly by inserting a small washer under the spring if required. got this tip from here

IMG_20190410_173846.jpg

[DMT]

I am planning to change the relief valve spring for a guaranteed standard one. It would be nice to get a higher tick over pressure but I would just like to know I have a recognised base line to compare pressures to,

Dave

[Lingen]

Dave.
A stronger spring will not get you a higher tick over pressure. If that is low, then either the bearings or the pump (or both!) are worn. A stronger spring will only raise the pressure when the pump is delivering more oil than the bearings are releasing, and the release valve is operating..
Mike.

[DMT]

Hi Mike

I seem to have explained my reasons poorly, sorry

I want to change the spring so I have the original correct version. If it means I change to a softer spring then so be it, but it conversely, could mean my existing spring is too soft.

I could not agree more about the best way to have good oil pressure. My engine was rebuild only 5 years ago and has done very few miles.

I have so far (apart from the Weber and header tank) I tried to rebuild everything as factory so I can compare it to all the standard versions around and not get caught out worrying about problems I don't actually have.

Thanks for the post.

Dave

[barkerwilliams]

I note from your post that you may not now be removing your oil pump. If you do remove the pump, and wish to prime the pump before starting the engine, or just pressurise the oil without running the engine are you aware you can spin the oil pump manually?

Buy a hex rod ebay or steel stock holders. for example https://www.ebay.co.uk/itm/274738093...AAAOSwsuNc5Fv3 about £7 and a magnet pen such as this (so useful anyway for retrieving dropped bolts and tools)
HEAVY DUTY MAGNETIC TELESCOPIC PICK UP TOOL 10LBS 4.6KG LIFT REACH EXTENDING PEN | eBay

1 engine to TDC (to reset ignition timing when finished)
2 Remove distributor
3 using magnet withdraw the hex bar that drives the oil pump (bar will drop out when oil pump is removed)
4 fit the longer hex bar you purchased.
5 Attach drill to hex bar above distributor
6 Spin drill in reverse. Oil pump will prime and get to pressure (oil light will go out). If it is going to leak it will do it now!

No chance of starting engine with a dry oil pump that will not prime, a very quick job. Costs a £10'ish

- Don't forget to drop the old hex shaft back in before refitting distributor!!!


Alan