4 replies to this topic

[mjpuds]

1380 longman gt7 head..leaded..
1.5 r/r/
webber
all lighten balanced
276 cam

ok just a quick question ...any idea of when you should start to worry when the oil pressure drops .i took my mini out for a run yesturday ..motorway ...then sadly ended up in very bad traffic..crawled for over hour ...presure dropped down to 25...this is oil is new..cant remember what i put in it...engine wasnt running that hot at all but i guess the oil got a bit of a beating..big valve head running leaded with octane booster...should i change my oil just i case again..ran ok this morning bit smokie when starting ...i tink what i might do later is to put some high power pc fans on oil cooler...i think i have some from a old dell server unit...could have them on a switch..

[Big_Adam]

Simplest point first, do you have ENOUGH oil in?

You'd be surprised.

Past that, on my car I have a similar thing. Run for a bit and the pressure drops right down to 20 or so. It stays steady and 20isn't too bad for idle and slow slow traffic shuffling as long as it perks up when you power on a bit.

Slow traffic and idle I'm 20 then a little throttle it perks up to 40+

[Cooperman]

The question is, at what revs did the pressure drop to 25 psi? Another question is what is the pressure at 4000 rpm on a long run with engine coolant temp normal?
When hot the pressure should be around 20 psi at 1000 rpm. At 4000 rpm it should be around 55 to 65 psi.
It's unlikey you'll have 'cooked' the oil.
I assume you have a good quality 20w50 oil like Castrol Classi 20/50, Duckhams 20/50, Halfords, Penrite, Millers or Valvoline Racing.
Do you have an oil ooller? If not, you probably need one. A Mocal 13-row is ideal for higher power Minis.

[miRon]

you 'l have the same pressure if its low on oil or if its on the level.....
the pickip is still in the same place...

[mjpuds]

yer revs must be about 1500+ when at 25..but move back up sharply with revs and stays up until revs drop...yes there is a biggish cooler already ...and oil was 20 -50 ..and on line as well sadly when you run it without any carpet you hear every noise...and there hour in traffic on my first big run after rolling road setup...head off valves done..but sadly we found a small hairline crack in head...from back of rockers to just above number two spark plug...but for all i know might of been there for year ..head dates back to one of downtons/ longman team 27 years ago ...fingers crossed crack hasnt got bigger..was missing all chambers ...