My ’63 Sprite (1098cc) which has less than 3000 miles on a completely rebuilt motor and a recently rodded-out radiator runs on the warm-side when climbing even slight grades. The temperature gauge will climb from 180 to 200-210 degrees. The engine will also begin knocking. I recently installed a VB ten-row oil cooler that has helped a little. The knocking has gone. I thought this modification would have cured the problem. I’m currently running a 180-degree thermostat with Bosch Platinum Spark Plugs. I live in California where the ambient temperature is on the warm side.
What should I try next to cure this problem? Am I running too hot a thermostat? Should I be using a 160-degree thermostat? Are the spark plugs the wrong temperature range? Could it be a timing problem?
A few more questions. Can I install the six bladed fans in the VB catalog on the original water pump hub and still clear the radiator? Would this modification help?
Any suggestions would be greatly appreciated at the point.
From: (Ulix Goettsch)
If your car is running at 200-210 degrees, the thermostat doesn’t make any difference. Both thermostats are fully open at this temperature. The 180 degree one would let your engine heat up a little faster, but under steady state conditions, there would be no difference. You should check your timing to be on the safe side.
When I asked about the six bladed fans in the VB catalog, I got overwhelming response that this is a very worthwhile modification.
From: (Stephen Peter Mirams)
I have a six bladed fan running in my Midget. Never, ever overheats and doesn’t whir. Just out of curiosity, I have a Cooper fan at home that I have not yet tried out. Does anybody out there have experiences with this fan (good or bad) in a Spridget. I’m not really keen on pulling out the radiator again to find out after doing that just 2 weeks ago!
From: (John Haynes)
None of the items you mention seem to get to the heart of your problem. I have three suggestions. Look for steam out the exhaust pipe [after the car has warmed up]. Could be a cracked head but more likely the head nuts need to be re-torqued. Lastly, nobody uses the proper thermostat for the older models. It was make by Smith, and has a sleeve attached to it which moves up when hot to block the by pass hole. A thermostat without this sleeve allows part of the hot water out of the head to pass back into the block uncooled. Stant is said to have a suitable replacement, but I can’t verify that.
From: (Paul D Kile)
Someone on Monday’s digest was considering the possibility of using a Cooper type engine cooling fan on a Sprite. In a word, DON’T TRY IT. The Cooper (mini, Austin America, MG 1100) type fans are designed to blow air out of the engine gay through the side mounted radiator, no to pull air in. Many years ago, I worked on a Bugeye with a cooling problem that got worse the faster you drove. This drove us crazy trying to diagnose it until we walked in front of the car while it was idling…and felt a breeze coming out of the grille! The reverse flow fan would effectively prevent any airflow through the radiator.
The large number of small blades, unlike the four, six, or seven blades on Spridgets can identify many Cooper style fans. If in doubt, hold the fan up against a known Spridget type, if the blade pitch faces the opposite way, don’t use it.
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