Took the Nb car down to Wakefield Park today for some testing...
..and seem to be well on the way to sorting the handling.

However the car has taken to blowing water out of the radiator.

First session only a little was blown out into the catch bottle... though a lot of that session was spent dodging high speed Porsches !

Second session only one other vehicle and then the track to myself (Woo Hoo! ) - so able to concentrate on testing and trying to learn the lines etc. and getting a rythm going.

Decided was time to pull in (starting to have too much fun ) and about to start my slow down lap - then noticed water coming into the passenger foot well.
Temp shot up from 70 to 90 and oil pressure dropped from 50 to 25. (75/80 when start up and drops to 50 and constant at that when warm)

On checking the catch bottle (tudor windscreen washer bottle) was practically empty - initially been half full - so had blown the water out under pressure by the looks of the engine bay.
Had to pack up to come home before it cooled down and haven't yet unloaded the trailer - so haven't checked how much water still in the radiator.

I aborted attending a Race meet earlier this year thinking it was a blown head gasket.
I replaced the Head Gasket (BK450) and put in a new Water Pump / fan belt.
(It has no thermostat and uses a blanking sleeve, bypass blanked off etc)

There is no sign of water contanimation in the oil.

Any ideas on the cause of this ? (and how to solve...)
Why should this have started - wasn't doing this in the past ?

Good old Vizard states
"Now strange as it may seem, some S engines suffer with blowing water water out of their cooling system.
Exactly why they should do this I don't know... " etc
His suggestion is an expansion tank.

I have a moke type available - so can rig that in ...
How do you set up the pressure caps ? (eg do you have to change the radiator pressure cap to a special one ? )

Ken.

Ken....have you checked the flatness of the deck and the head??

do you have a heater core still plumbed in??? maybe piss it it off!!!

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"Show me the Mini!"

I'm running expansion tank(plus extra heater core).
The pressure cap(13lbs) goes on the expansion tank and flat cap goes on radiator(as in pic).

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Hi,

It sounds like more than a bad radiator / cooling setup if your oil pressure dropped from 50 - 25 psi. Even at 90 degrees the oil shouldn't heat up that much that it halves the oil pressure. I'd suspect more than the cooling system - bad seal in the engine somewhere - how has it been since replacing the head gasket?

Thanks for the thoughts... all helping !

No heater ...

When head gasket changed only slight indication of a leak between 2 and 3 - and no sign of problems near water jacket... but NO did not get checked professionally.

There is a slight leak of oil - I suspect the Moon Seal to the gearbox - somewhere around there - will get up on ramps and have good look tomorrow.

Had a quick look and appears to have blown out 2 inches worth of water from the radiator.
No mayo in the rocker cover.

Will try and see if I can get a pressure test done over the weekend..... and check for all the usual Head gasket problem indicators.

Car was pulling very well and running fine - cool down lap and run into pits was at lower revs and temp did drop a little - and no feeling of a loss of power.

Ken

Had very similar problems in the Escort tarmac rally car a few years back - no probs during normal road use and transport sections, but radiator would be nearly completely empty by the end of each special stage - just pumped it out the overflow. Changed radiator caps, did every other check, just couldn't work it out. Never lost power or oil pressure, never used oil - just water! It seemed it only happened at sustained high revs and major caning! The thing that puzzled me was not once did a following competitor complain about coolant on the road - weird!
One of life's mysteries.
Peter

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1969 Mini Cooper S MKII (1330)
1972 Honda 750/4 (his),1976 Honda 400/4 (hers)
1982 Honda CB1100RC (ours)

Sounds like a warped head to me you are getting compression near your water jackets causing an airlock that could be forcing water out.
Check to see if there are just bubbles in the radiator when the car is running.