16 replies to this topic

[1293gt]

Hello all,

my mini is running over 100 psi of oil pressure even when up to temp.

Is there a way of reducing this or is this not an issue (I think it's far too high compared to other minis I've owned) Engine is a newly built 1293 with the modified engine oil take off like this....

 

https://www.minispar...|Back to search

 

 

Should this have the valve and spring behind it to reduce the pressure?

 

TIA

[nicklouse]

What pressure relief valve have you fitted? That part you have above has no effect on pressure.

[1293gt]

I honestly don't know as I didn't build it. I suppose it's worth removing the pipe from the block and having a look.

Presumable it would be one of these....

 

https://www.minispar...|Back to search

 

 

 

Are these the symptoms I would be seeing without the above fitted?

[whistler]

There's 3 remedies for this that I know of.

Fit an adjustable pressure relief valve.

If you're using a ball and spring then you can shorten the spring a little.

If you're using a ball and spring then replace it with the standard top hat and spring.

[GraemeC]

The pressure relief valve doesn't sit behind the pipe, it is under the domed nut below where the pipe exits the block.

 

It is a common 'upgrade' to fit the Cooper S ball bearing and spring, however in the majority of cases it is actually a backwards step as a) the old style thimble valve is better and b) the supplied Cooper S spring is usually far too strong.

 

This is what is probably in there:

https://www.minispar...IT.aspx|Back to

This is what you want:

https://www.minispar...|Back to search

[Steve220]

I'd be checking the plunger isn't stuck. No way it should be that high when hot. What gauge are you using?

[Spider]

I'd suggest first check what Oil Pressure Relief Valve has been fitted, it's externally accessible, so easy to get to and see.

Then I would suggest checking that it's free and not jammed.

If all appears OK there, then it's mostly the Oil Pressure Relief Valve Vent or Back Vent is blocked. Toy check for that, wen the engine and oil are warmed up, remove the Oil Pressure Relief Valve altogether and screw back in the Cap for it. Remove the Spark Plugs, then crank the engine over on the battery and see what pressure you get then. It should be zero or maybe as much as 5 PSI. Any higher and I'd say almost certainly the Vent or Back Vent is blocked. These are an engine oil fix.
 

[1293gt]

Marvellous!
Thanks all for your input.

So, let's just say the valve is in there and working (not stuck) how much would you take off the spring each time in order to reduce the pressure, and what pressure cold/hot should I be aiming for please?

[sonscar]

Left field thought but is the oil actually circulating?Steve..

[1293gt]

Left field thought but is the oil actually circulating?Steve..

Yes Steve, oil reaching the top of the engine, rockers are oiled.

[croc7]

Marvellous!
Thanks all for your input.
So, let's just say the valve is in there and working (not stuck) how much would you take off the spring each time in order to reduce the pressure, and what pressure cold/hot should I be aiming for please?

Cutting coils from the spring is an option but you could try fitting a lighter spring or increasing the washer stack-up between the block and the domed nut. Reduction of spring tension on the bullet is the intent.

[mini13]

Yep, check theres no ball  replacing the shuttle first,

 

If its still got the shuttle check the outer face for scoring, if there is you can stick a bit of fuel hose up it and a screw / bolt in it to expand it so you can stick it in a drill and polish off any marks only touch the outside cylindrical face, not the tapered bit on the end that seals against the block.

 

then double check the presure against another gauge incase yours is fibbing ( electric ones are especially prone to this)

 

in the unlikely event that you still need to reduce the pressure, go for about 1/2 a coil at a time, to start with, then, start just doing little bits, do it on the thace of a grinder so you get a moothe tapered end if that makes sense. if you go a bit far you can stick a couple of washers in the domed cap to bump it back up a bit.

 

 

 

http://www.reizendem...ne/oilplung.gif

 

there is of course the possibility of sticking an adjuster on there, a bit overkill though

 

https://www.minispar...assic/HPS4.aspx

 

 

[1293gt]

Thanks guys, what PSI should I be aiming to achieve, hot/cold values?

[1293gt]

UPDTATE!!!!!

I removed the dome and spring and yes, it was the ball bearing!

I have replaced that with the correct items and a shorter spring that came with it which has taken the pressure down to about 85psi.

I'm not planning on shortening the spring/packing out the domed nut but what pressures should I be aiming for please?

Guessing around 50PSI hot?

[cal844]

50 psi hot at engine idle would be ideal