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Discussion Topic:
Too cold in the summer?
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Old Henry |
12-09-2010 @ 8:29 PM
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Senior
Posts: 738
Joined: Apr 2010
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Can the flathead engines get TOO cold in the SUMMER without thermostats? I know this is a weird season to discuss this, but, in light of recent lengthy discussions about not using thermostats in the summer, which is what I've been doing for several years, I've been thinking about the down side of such, even in the hot summer. I've noticed that when climbing over a mountain in the summer without thermostats the engine still gets pretty hot by the top of the mountain, but then, going down the other side, usually coasting or in a gear to prevent excessive speed, the engine quickly cools down to almost no reading on the temperature gauge. That has always looked real good to me after watching the thing climb going up the hill but, after reading a few things lately about the importance of getting the engine up to proper operating temperature and keeping it there I wonder if that's really healthy on the engine and whether I ought to go ahead and keep the thermostats in even in the hot summer to get the engine up to proper operating temperature quicker and keep it from cooling so rapidly under the circumstances I've just described. I've read some comments that such rapid cooling can do damage, even crack the block. And that, at temperatures below ideal, the oil doesn't heat up enough to boil off water and some water born contaminants as well as the internal air space in the engine below the cylinders above the crank - that needs to heat up quickly to evaporate moisture in there. What do you think? Old Henry (The older I get, the better old looks.)
This message was edited by Old Henry on 12-10-10 @ 7:41 AM
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ford38v8 |
12-09-2010 @ 10:15 PM
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Henry, you make some good points. It is true that a flathead will experience a rapid cooling going downhill, but I doubt that extremes would be met in moderate temperatures. Should you have a long downhill run on a cold morning, you might consider using a winterfront if you have no thermostats. I remember one particular winter night driving UP the Grapevine in California that I had to put cardboard in front of my radiator just to keep the engine running. The heater was off, and still had to choke to keep it running steady. Like Johnny Carson asked, "How cold was it?" Headlights frozen to two tiny spots in the middle and ice built up in front of the radio antenna.
Alan
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deuce_roadster |
12-10-2010 @ 7:58 AM
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It sure can, depending on where you live. I have a flathead with aluminum heads, merc crank, Griffin aluminum radiator, cam etc and without thermostats, in the summer here in the Northwest (85 degrees) the engine would NOT get above 110 degrees, even at idle. Not hot enough to run well. Put in 170 stats and it runs like a clock no matter what the air temp is.
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Old Henry |
12-10-2010 @ 4:34 PM
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All things considered, I think I'll give Henry's original engineering a whirl next summer and leave the thermostats in. I have a new engine, new radiator, new higher volume pumps, and new hoses. The system is as close to what Henry engineered for 1947 as it can be, other than the higher volume pumps. I abandon that philosophy that I've had for years that colder is always better for the engine and that the only reason to cause the engine to warm up to any temeperature is for the heater in the winter. I'm convinced now that there are more reasons than just that to get the engine warmed up to at least 160 degrees and keep it there or above. Although 160 degrees may be ideal, nothing wrong with 170, or 180, or 190, or even 200 degrees. If it does get too hot the radiator cap will open and let off some steam to let me know it. (I don't totally trust the temperature gauge since it always seems to read a bit high.) I just don't see that happening with the system all as designed. It will sure save the effort and hassel of draining the water, removing the hoses, and removing/installing thermostats twice a year. Thanks for all who gave input on this issue.
Old Henry (The older I get, the better old looks.)
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BrianCT |
12-11-2010 @ 6:26 AM
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Alan, your climb up Grapevine hill with ice forming on the lights sounds like carb. icing.
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supereal |
12-11-2010 @ 9:44 AM
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If your gauge shows 110 degrees in a warmed up engine, check with a thermometer in the radiator filler. That temperature is too low, unless the ambient is well below freezing. The gauge and/or the sender may be a problem. The sender has a heating element inside, and it it breaks, the reading will be wrong. The thermostats not only provide a quicker warmup that aids driveability and helps reduce sludge, but also provides a bit of system pressure to minimize hot spots in the water jacket ("teakettleing").
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Old Henry |
12-12-2010 @ 9:16 AM
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Here's what Alan may be talking about "Headlights frozen to two tiny spots in the middle." Old Henry (The older I get, the better old looks.)
This message was edited by Old Henry on 12-12-10 @ 11:37 AM
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deuce_roadster |
12-12-2010 @ 10:14 AM
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Supereal, The temp gauge is a mechanical direct reading Stewart Warner, and yes, my first thought was that it was inaccurate. Using a calibrated thermometer (I did medical research for 30 years) the water in the top tank of the radiator was consistantly within a degree or 2 of what the gauge read. I chalk it up to an ultra efficient radiator, it could probably cool a blown big block.
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supereal |
12-12-2010 @ 1:40 PM
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duece: If you can find a way to cool all flatheads with that efficiency, I think you would have the fabled "better mousetrap". The subject of overheating is probably the most posted subject here on the Forum. I've seen some four and five row radiators that could come close, but when a stock radiator is coupled with a system coated with decades of deposits, the operating temperature is more often the cause of some "white knuckle" driving. Thanks for the clarification.
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deuce_roadster |
12-12-2010 @ 2:09 PM
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Super, I can tell from your posts you have a vast wealth of experience and knowledge building flatheads. When building my roadster I had Griffin build me an aluminum radiator that fit in the stock sh*ll with whatever their maximum cooling tube/fin combo was. Also, as you know, a clean block is essential and I had mine Redi-Stripped. It was a real good block, all the cyl walls sonic tested well over .100 after being bored to 3 5/16 so I had a few factors in my favor.
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