September-October - RROC - Rolls Royce and Bentley Owners of ...

TECHNICAL: Cool Cloud by Mike Faircloth
When I got my 1958 Silver Cloud (SFE 423) several years ago, it came from a gentleman in the southern
Midwest that we here in San Diego might affectionately refer to as a “Redneck”. It had some interesting
engineering refinements. One of those refinements is the subject of this article.
The Cloud 6 cylinder engine uses a radiator that has a small cap on the right side that is essentially open to
the atmosphere and connected to a down tube that runs down the side of the radiator to the road below. When
the car overheats water and or coolant simply blows out of this tube to the ground. When I rebuilt the engine on
this car, I cleaned out the block. It was evident that this car had done plenty of
“overflowing” since the block was about half full of mud, grunge, rust, gloop,
goo, and some things unidentifiable. The afore mentioned owner had decided
to fix this incontinence problem by attaching a radiator overflow tank.
See figure 1 : Redneck overflow tank
This refinement consisted of a rubber hose going to an old drinking flask that
once held about a cup of booze.
Since the previous owner had cut the overflow tube to attach his refinement
to the system, I thought maybe I could use this to do some of my own re-engineering.
It is well known that putting pressure in the cooling system will raise
the boiling point of the coolant at approximately 3 degrees for every pound
of pressure. There are limits to this, as you will eventually blowout the hoses and/or the radiator itself. Modern
cars run pressure caps of 18 to 20 psi, thus raising the boiling point quite a bit.
I had seen early Clouds with pressure caps that had been put in place of the original screwdown cap, but didn’t
like the look. I wanted something a little less conspicuous. A search through the Mcmaster-Carr catalog showed a
brass and stainless steel “adjustable” pressure relief valve that was very small (part # 48935K25 at a cost of $5.85
ea.). This valve could also be reversed to work as a vacuum relief valve with adjustablility from 0 to 20 PSI and
0 to 30 inches of mercury. I ordered 2 of these and attached them in tandem. One is set for 8 pounds pressure;
the other is set to 2 inches of vacuum. The entire affair was
then connected to the down tube where the previous owner
had already cut the tube. See figure 2
The pressure valve raises the boiling point from 212 degrees
to about 236 degrees. Both valves are in an overflow tank set
on the frame under the generator. Should the car overheat, the
coolant would be caught in the tank, not on the road. When
the system cooled back down the vacuum valve would open
and draw the expelled coolant back into the radiator.
To keep track of the temperature I made a small bracket that
mounts to the inside of the open cubby hole in front of the driver (right-hand car). This holds a temperature gauge
and oil pressure gauge. These can easily be seen even at night. I have heard of cloud owners carrying a flashlight
to be able to see the dash gauges at night. These modern
gauges are out of the way and don’t prevent me from getting
the things in the cubby… papers, tire pressure gauge, small
flashlight. etc. etc. See figure 3
Since this adaptation the car has run great for the last year
and a half on the outskirts of San Diego California where the
summer temp is in the 100 degree range and winter in the 20’s
… never over heats… and doesn’t leave “puddles”.
Mike Faircloth
September-October 2007
Finis
Page 8 Volume 35 Issue 5
Photos by Mike Faircloth