Morris Minor Owners Club

I was wondering whether there was an adjustable oil pressure fitting that could be installed in my bored out 1100 Problem is, when the engine is newly reco in my opinion the pressure at revs is a wee bit high at circa 80psi. I have clipped the spring a coil, and obviously later on will have to replace it, but an adjuster would be a wizz, as its still a bit high running 15/40 oil

http://www.minispares.com/product/Class ... o%20search

See also:-

https://www.calverst.com/technical-info ... oil-pumps/

Thats my instinct exactly. 50 psi flat out and 25-30 idling. I remember as a kid, the boys boasting about their 40psi at idle, and it kind of sticks. Trick is now, where to cut the spring. Thanks for the link.

Thinking today, that the adjustable oil pressure control may be designed to take the standard length spring and in its unwound adjustment position create somewhat less pressure than the replaced standard plug maintained. We will see.

The adjustable oil pressure cap is exactly the same specification/dimension wise as the standard cap except for the adjuster screw..

You have to shorten the spring by at least one coil to reduce the oil pressure and then you screw the adjuster it in or out to get the oil pressure you want.

If you fit a 5/8" ball bearing instead of the oil pressure relief valve cup you need to take at least two coils off the spring.

There is a difference in length between the Minor and Cooper oil pressure relief valve springs and I would use the standard Minor spring as there is no point in fitting a Cooper spring only to shorten it to get the oil pressure you want.

You can drill and tap the standard cap, fit a bolt and lock nut and you have got an adjustable oil pressure relief valve.

Mmmm!

1380 engine, standard crank journals and >70,000 miles on the same crankshaft, but with ~3 sets of new shells over 20+ years.

I run a standard spring and pressure valve (no ball bearing etc.). The oil is Castrol 10W/60 and on starting from cold the maximum is ~70psi, dropping to ~65psi hot @ >=2500rpm. HOT can be up to 110°C or more on a track day, or high ambient temperatures, such as >30°C in the south part of Europe in the summer, i.e. now!. Idle @1100rpm is ~45psi.

The spring, valve and oil pump all came from Peter May a few years ago, so what is the benefit of changing from the standard set-up?

This is all based on a 1275 engine, so may not be relevant to either a 1098 or 948.

Richard
Changing from the standard set up i.e. spring and cup can be effected on 948cc, 1098cc and 1275cc engines.

I have not changed a 803 oil pressure relief valve set up so will not comment as regards that engine.

The Calvert link explains very well the benefits of controlling the oil pressure which if too high can raise the engine temp & oil temp with subsequent absorption and/or reduction of engine power because it takes power to generate high oil pressure. Also oil at high temperature has a tendency to break down.

The benefit of fitting the 5/8" ball bearing is that there is then very little if any chance of the valve sticking. The cup can stick in the open and/or closed position with a loss of oil pressure or a vast increase in oil pressure.

I have run both the standard Minor and Cooper S oil pressure relief vale springs in my 948cc and 1275cc engine with no adverse effects.

I have also run the ball bearing in both 948cc and 1275cc engines as well again with no adverse effects.

I have a Mini Spares oil pressure adjuster set up on the shelf but have never had the need to fit it to either the 948cc or 1275cc engines as my oil pressure is adequate for my purposes.

For normal motoring the standard Minor oil pressure relief valve spring and valve is more than adequate so long as the oil and filter are changed at the correct service intervals.

Phil

Phil,

'Sticking plunger/valve'. The only time that I have had any problem relating to oil pressure was when a plunger/valve was made from aluminium and started to 'pick up' in its block bore. Not sure who the supplier was, but I would avoid aluminium valves like the plague!

The current one from Peter May is steel and controls the pressure the best I have ever seen.

I did try the 'ball and shorter spring' some while ago, but was never happy with the spring sitting on top of the ball, with no real location, so reverted to the standard 'non-S' design.

Richard
If my memory serves me right the early BMC oil pressure relief valves were made of alloy with the later ones made from steel.

I would agree that the alloy oil pressure relief valve should be avoided as the soft aluminium can easily pick up grit in the oil and jam.

Phil

The only reason I am on the path of adjustability, is that no oil filter should leak under normal conditions and mine was. I changed the spin on filter, as it was not one I generally use, and it also leaked.. I needed to tighten more than a quarter of a turn to stop the drip. I am aware the 948 was not designed for a spin on and the canister filters are much tighter on the lower O ring, but pressure is pressure, so the adjustable is worth an experiment.

The lower 'O' Ring - you will have to explain more.

The canister oil filter has only one seal and that is between the filter canister and filter head.

The seal should be lubricated with engine oil before fitting and the canister tightened by hand.

Is the seat for the seal flat? If it is not the seal may be then ineffective.

The later canister filter heads are not as rigid as the early type and I always fit the earlier type.

Photo of earlier type below and a link to earlier type currently for sale on 'e' bay.
https://www.ebay.co.uk/itm/Mg-Midget-12 ... SwLSZcB94-

Sorry, I cant remember whether the canister faced up or down, as I don't have one. My spin on bracket is new, so no problem there, but as I remember the canister sealing ring was narrower than the ring on the spin on, and the fact that it was spanner tightened means it was probably a tighter fit, the narrower seal as well would have more per square inch pressure than the wider spin on seal. Simple physics.

For clarification.
Currently is your engine fitted with the original type oil filter which has a changeable internal element or the spin on filter.

Which type is or was leaking?

If it was the replaceable element type did you replace all of the seals?

There are two widths of seal fitted into the filter head of the replaceable element type and if the narrow type has been fitted into a wide groove it will invariably leak.

As I said Phil I don't have a canister, and the present filter spin on is a Max filter, and as I said in my last post it leaked as well, and of course I tightened it beyond hand tightness to stop the leak. I fit hundreds of filters mainly on much later cars, no problems. It is the pressure.

Well, suitable in a way. The knob of the piece I purchased was too big to clear the top starter bolt end. Its O.K I can extent the shaft of the bolt so that it is clear, and also I recommend placing an o ring between the adjusting lock nut and the engine plug, as there was some gunk on the withdrawn bolt on this new gadget that was supposed to stop oill leaking, but Im a bit skeptical, so I reckon that's the go, but anyway the cold OP is back to 70 and still holds 40 warm so Im on the right track. The unit I just hind sightedly found was fitted with an allen key socket so that would have been preferable.

Well, suitable in a way. The knob of the piece I purchased was too big to clear the top starter bolt end. Its O.K I can extent the shaft of the bolt so that it is clear, and also I recommend placing an o ring between the adjusting lock nut and the engine plug, as there was some gunk on the withdrawn bolt on this new gadget that was supposed to stop oill leaking, but Im a bit skeptical, so I reckon that's the go, but anyway the cold OP is back to 70 and still holds 40 warm so Im on the right track. The unit I just hind sightedly found was fitted with an allen key socket so that would have been preferable.

Add on oil pressure adjuster is a bit of fun really. I used a self locking nut as a seal on the adjuster thread. I had to turn down the original knob as it was too big to pass the starter lug and bolt.