|OK, so the workshop manual says this engine
does not need an oil cooler, and the fitted cooling system
is adequate. Well, two successive summers on the WestRun
organised by the Western Vintage Car Club proved otherwise
as far as I was concerned. On a long fastish run, the oil
temperature climbed over the 95C mark, and the oil pressure
understandably dropped accordingly. To top that, we were
stuck in Ballybrit race traffic last summer for a couple of
hours with a boiling radiator. Being twitchy about losing
an engine, and not willing to take out a new mortgage to
have the engine overhauled, I decided to do something about
||Now, you can speculate for as long as you
wish about why the engine overheats. Just to put the usual
issues aside, the timing was set up correctly, carburetion
was perfect, and the standard fan was not slipping. The
radiator seems not to be sludged up, it was (allegedly)
re-cored in the not too distant past.
||Now old engines do sludge up their water
passages (which of us doesn't as we get older). So my
theory is that the heat rejection to coolant was down on
the intended design, throwing an extra thermal load on the
oil. Hence the rise in oil temperature. Conclusion- do
something to take more heat from the oil circuit. And for
good measure, fit an electric fan to deal with the horsey
set in Ballybrit.
I will post more details shortly on the oil cooler
adaptor fitted to the original Bristol engine oil filter
housing. I also fitted a modern full flow filter to
safeguard the engine further.
|The oil cooler is a Mocal 19-row type with
1/2 BSP fittings. The non return valve in the new oil
cooler/filter adaptor prevents the oil draining back into
the sump from the feed lines, but having the connections at
the top of the cooler helps also.
||The fan came from a small Subaru and draws
about 8 amps. It is controlled by a thermostat from the
water temperature at the radiator top hose inlet.
||Any fan installation requires excellent
shrouding if it is to be any way efficient. I was not
entirely happy with the shrouding I fabricated, but it was
the best I could do under the circumstances.