23 replies to this topic

[johnv]

Spinning my engine over before putting it in the car the OP is on the high side, nearly at the top of the gauge .. I’ve got plenty of gauges to try another one but I’m thinking it may be something to do with the relief spring? What should I be looking at? Thanks

[imack]

What kind of relief valve are you using? If ball type you need to shorten the spring.

[johnv]

It's the standard one I re-used it.

[Steve220]

When you say nearly at the top of the gauge, what is it reading?y MPi is almost 100psi on start and drops to 80 after a minute.

[johnv]

Between 75 and 100

[cal844]

Between 75 and 100

Aslong as it doesn't exceed the sweep of the guage it will be ok IME. Anymore than 95psi can cause issues though

[Ethel]

75 isn't bad - more than you need, but it is a new engine. Did you use gear oil etc to get the pump primed? That'd also have an effect. 

[johnv]

I used red line assembly lube to build it and primed the pump with the 20/50 .. good point though, the lube may well be jacking it up a bit, thanks

[mini13]

Yeah if it's not off the gauge leave it until the engines had a run and got the oil hot, see what it's like then

[Tonylamb]

I have an oil pressure issue. I'm running a smiths manual gauge. On start up cold oil pressure is 65\70 psi. Once the engine is up to temp running along at say 2 to 3000 its 50 psi. But as you rev higher up the scale it drops to around 40 to 45. That seems just odd shouldn't it idle around 20 or so hot and then go up with revs. Could it be a problem with the Oil pressure relief valve?

[Tonylamb]

it doesn't drop below 40psi though

[cal844]

Sounds good to me, 40psi hot is healthy. 20psi is the absolute minimum idle oil pressure, any less and I'd be inspecting the relief valve.

My 1275 with 65000 miles fluctuates around 40psi at hot idle then when revved at 3000rpm will sit at 60 psi. Generally when cruising (cold or hot) is a 60-70 psi.

Edited by cal844, 16 April 2020 - 09:39 PM.

[Tonylamb]

So that's not good then because mine is at 40psi at 4000 rpm but goes up to about 50 psi at lower revs? I wonder if the oil gauge isn't primed properly or its a problem with the gauge the engine has only done under 1500 miles. I maybe ran it in badly? I've been using Miller 20w 60 oil maybe that's the problem?

[Tonylamb]

The other thing is that the guage doesn't seem to fluctuate at all. my other classics at idle the oil pressure would drop down to 15 or 20 psi at idle and then increase steadily with revs. The Mini just sort of sits at a minimum even when hot it sits at 40psi but doesn't increase with revs. It did that from the very start. However when the oil is cold its at 60 to 70psi

[nicklouse]

There is no need to prime the gauge.

 

standard spring open the valve at 60/70psi anything else is showing the pressure held by the engine.