1948 59A; is there such a problem as 'underheating' a flathead? temp only goes to about 140*. also performance wise, cold, it runs good. when the temp gets up to 140*, performance seems to flatten out. thanks john
John, not meaning to be insulting, but have you checked the gauge? That would be the first thing I'd verify. I have a '53 Flathead which was just rebuilt (very clean water p***ages), it has two new water pumps and a Walker high flow radiator and the timing is set dead on and it runs at 170. 140 just doesn't seem possible.
yeah as said double ck the temp in the top tank of the radiator. it is possible for a stock engine if not run hard to be at 140...make sure you have thermostats in it.
Mine runs about 140-150 with a fan and 180 thermostats. Currently I have no fan and it stays at around 160-165. I wouldn't recommend ditching your fan though...
A motor won't run it's best at 140, it needs to be at a higher temp! As the others said, check the temp with something other than the gauge. Didn't anyone tell you that flatheads are supposed to overheat? regards, DJ
Simple way to warm it up some (if you want to) is a piece of cardboard. Or two or three pieces of different sizes, use the one that works best for the day. Looks like it's running a little high, pull over and switch to a smaller one....................
Try a mechanical gauge on one of the heads and see what it reads or use one of the cooking thermometers and put it in the radiator tank. If you're getting your reading off of the original dash gauge you could be way off.
Make sure your running thermostats. When I first put mine on the road I went with the old no thermostat route, bad move, temperature was all over the place. On a 60* morning the temp would barely get over 130 driving and on hot days it would run 190. I put in 170 stats and it really leveled it out. It still seems more subject to outside temps than my overheads but it's much better.
What kind of gauge are you using? Mechanical or electric? If electric, does the sending unit match the gauge? If mechanical, take it out (the wholw gauge and thermal cable), put a pot of water on the stove and suspend the gauge bulb in the water. When water is boiling your gauge should show somewhere near 212* F.On Stwart Warner mechanical gauges, the outer nut can have either of 2 OD sizes and still fit the inner nut. If you have the large OD nut if won't screw into the pipe thread hole beside the water neck in a 59A head. If you reverse a reducing coupling and use a close ******, you can make a watertight hookup, but the gauge will read WAY LOW. We need more info. Dave
Are you sure you're getting a good ground at the sending units? Are you running the stock 6V senders? Flatman
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