Sunbeam is running quite well.
I thought one fan-belt has started to wear through where it was rubbing on a thermostat screw. The belt was getting thinner and rubber dust was accumulating in the area.
The screw was been adjusted and it should be ok now.
The fan was a bit noisy as it is running full blast all the time instead of using the viscous coupling. The fan has 8 blades - I think a few less blades and a better electric fan as a backup may be required.
update - A fan-belt shredded yesterday and the other is quite thin. It may be that the fan is causing too much drag so that the cooling pulley is slipping and wearing out the belts. Two blades were removed.
The SPA section fan-belt was replaced by a muscle belt SPZ1120.
On the next run there was no more apparent wear. And the fan noise was quieter.
On the way back one fan blade mangled itself into the radiator. To get home this and its opposite blade was also cut off.
Water Temperature was still maintained at normal - so 4 blades is enough with the electric fan as manual backup. The plan will be to install a more suitable automatic electric fan and fit a twin blade fan just to keep the air under the bonnet moving.
Next time the radiator is removed I will tidy up the cut edges.
On the next run the clutch started make "ticking" noises -so the engine was removed and a new clutch fitted
So while the engine was out the fan blade was trimmed neatly and the chassis rail was dented for the left side exhaust pipe.
After another fan blade failure - at low speed over bumpy ground - it was decided to remove the fan entirely and fit a pair of pusher fans.
The engine must be a little too close to the radiator.
I had fitted an electric backup fan but wasn't convinced it would be totally suitable. So two 9" fans were selected.
The assembly just fits in front of the radiator.
I used a two stage switch to control each fan.
one comes on at 88ºC the other at 97ºC.
it seems to work....