Thanks,
The engine isn't a highly tuned one, just a DVA'd 1.6k turning out 155bhp.
The problem I have been having is the car running too cool! The engine has never had a thermostat in and has always run perfectly, then suddenly started running at 40 degrees even on a scorcher! It will heat up to the fan coming on whilst stood and remain at 80. Then any movement and all temp is lost.
I tried a thermostat which seemed to work, but an hour before I was due to visit the ring it started overheating. The only thing to do was quickly drill out the thermostat and jump on the ferry. I have replaced all the hoses with silicone and added a t piece at the heater end. The O rings for the heater matrix are going to be replaced to make sure they're not leaking, as luck would have it I managed to put a hole in the radiator, so will be fitting a new one of those this weekend.
I am now thinking that the "jiggle valve" maybe blocked up, so going to try clean that up.
Has anyone any experience of this? Perhaps causing airlock?