Now that Winter is coming, I want to get to grips with the engine and cooling system of my 16/70. Its basic problem is that although it runs pretty well generally, with temperature guage reading about 75 deg C, when you go up a long hill, the temperature reading rapidly rises to as much as 100 deg. At the same time, the engine can lose power and start to spit back through the carbs. I have checked the guage, which reads about right.
I have checked the plugs and carried out tests on the mixture (both by using a colortune, and using the old technique of raising the piston in the carbs with a screw driver). All these indicate the rear most carb to be running lean and the forward one running rich (the one in the middle being about right so far as I can tell). I have adjusted these by unscrewing (to richen) the big spring loaded nut on the bottom of the carbs. I have not tested the car on the road since, but was surprised at the fact that I had to move the 'weak' carb as much as 8 'flats' on the nut (i.e. more than a turn). I thought the mixture control would be more sensitive than that.
Issues/ questions:
1. The water pump is driven off a pulley attached to the fan, via a split pin. Is that really all that should connect the pulley to the water pump?
2. My radiator shows pretty even temperature across its width, although on the o/s one or two inches the temperature is much lower whe the engine is hot. I am going to try some radiator flushing liquid to see if it clears the blockage, but even with this I am surprised that the temperature of the outlet from the radiator is only 5 deg less than the input. Does this imply that the fan is not doing its job? It appears OK to me, and it looks like water is circulating if you remove the filler cap, but I am aware that the fan belt is a modern rubber item rather than the period leather jobbie so could be slipping I guess.
3. Using an infra red thermometer, I have checked the temperature at rest of the block (because if there are any blockages I guess I would see local over heating?) Anyway, as far as I can tell, the temeratures are pretty even.
4. There appears to be some wear in the carb linkage. The centre and rear carbs open together, but there is slack causing the front carb to open later. This looks to me to be a result of the throttle butterfly bearings on the centre carb being worn. Is that right/ does it matter in that the car runs well except for the over heating/ spitting back problems?
5. Is there anyone in the Surrey/Kent area experienced with these engines that I can take it to who would be able to tune it properly and tell me what is normal? That is one of my key problems: I am experienced in modern cars and do not really know what I should expect in a pre-war car.