Over heated Ford (Mercury) Engine on my F8

[Jim Price]

My helpers took the F8 out for a spin that other day (it was 100 F (37.8 C)out) and stopped to talk to a neighbor down the street while leaving the motor idling. By the time they arrived back to the house the temp guage was pegged and the radiator overflow pipes were draining anti-freeze fluid. Obviously the engine had overheated. It's a '46 Mercury.

I know that Fords/Mercurys have a problem with this but wonder if the problem lies with the thermostats. (I have new water pumps so this shouldn't be the problem.) Or, with the four-bladed fan blade. I've been advised not to run the engine without the thermostats or restrictors so wonder which would be better, 160 F or 180 F one.

Any thoughts, advice, etc. will be appreciated!

Regards,
Jim

[cletrac (RIP)]

The first thing I'd do is ditch the thermostats. That's an old wives tale about needing them. Those pumps aren't that efficient that you need to slow the water down. If the flattie is running around 120 without them and conditions start it heating up you've got more leeway than if you're starting at 180. If you look at the LRDG pictures the trucks usually had the hoods removed to allow for more air flow in the hot conditions.
Did you do anything to clean the water passages on the engine and rad? If not that can cause problems. If that's the case put some Drano in the rad and run it for half a day then drain and flush. It's amazing what that gets rid of.

[Jim Price]

David,
Thanks for the advice! The engine was clean and the radiator a new one so neither of these contributed to the problem.

Regards,
Jim

[Phil Waterman]

Question for you are the thermostats new? Did you test them to be sure they are actually opening at the rated temperature? I've been doing test on all the thermostats I've put in rebuilding engines last couple of years and discovered a interesting thing. Brand new fresh from the manufacture thermostats are often slow opening the first dozen or so times they open and close. Which will cause and engine to run hot the first few times you bring it up to temperature. There is a big difference in how fast heats the engine pushing the truck down the road than running the engine stationary.

What I do now with new or even old thermostats I test them and cycle them on the stove in a pot of water. Bring the water up to the rated temp 140 180 what ever then dip (using tongs) the thermostat in see how quick in opens. Then dip it into cold water. Do this several times you will be surprised that with a new thermostat it will open a little faster each time.

[cantankrs]

Originally Posted by cletrac

The first thing I'd do is ditch the thermostats. That's an old wives tale about needing them. Those pumps aren't that efficient that you need to slow the water down.

Hi David, I only have experience with a 70's OHV V8 down here in warm WA, and people had told me to ditch the thermostat but I discovered that on a really hot day having no thermostat just seemed to heat the water in the radiator faster until the whole cooling system was way hot. Having a thermostat in it allows the radiator contents to cool a bit more before its demanded. Presumably my situation came about because the water pump was fairly efficient - which perhaps is a vital condition in your statement.

Also with these old vehicles on a stinking hot day you can't even keep the motor running sitting in a drive-thru at McDonalds or wherever without the temp creeping up and up.

Remember that Henry Ford's SV V8 has the exhaust ports running across the block between the cylinders. This contributes to a hot motor thru its design. A clean radiator and functional waterpumps would seem necessary.

Also who's paid good money to have their radiator 'professionally cleaned' only to find it still has blocked cores cos they did it ultrasonically instead of removing the bottom tank and rodding it out like it needed? You only find out after things have gotten hot again! That nice fresh black paint ain't a certification!

Phil, from the same vehicle I can confirm that thermostats certainly can't be trusted from new because I then had to play with a string of thermostats that were opening later than their rated temps. In my situation I settled for a 160 thermostat that tested OK and seemed to resolve the issue with that type of motor.

Regards

Alex
--
M3 Grant, Val, Ferrets, WM20, CMP's

[Mike Kelly]

the idea of having thermostats is to create a temperature difference between the engine block and the radiator ... this temp. difference siphons the coolant around .. hot water rises, like in a home hot water system ... If you remove the thermostats, the whole system is almost at the same temp., and you lose the thermo-syphon effect . Many veteran cars have no water pump at all ...they soley rely on the thermo-syphon thing to circulate the coolant around.

Those SV Ford lumps are HOT motors ,it's a design thing ,the exhaust gas ports are such that the motor runs hotter than it should.

Mike

[cletrac (RIP)]

Way back in the day vehicles didn't have very efficient heaters. Henry Ford took note of this so when the flattie was being designed he insisted that they run the exhaust ports through the block. This would make the motor run hotter and hence a more efficient heater. The rest is history!
Any motors from the fifties and earlier that I've had anything to do with seem to cool better with no thermostats. Those old water pumps don't pump that well at the best of times so you don't want any more restrictions that you can avoid.
Another thing if a motor's running too hot try playing with the spark timing. A few degrees here and there can make quite a difference but on a Cab 11 it's a pain in the butt to do. Sometimes a size bigger on the carbs main jet helps too.

[gjamo]

Back when I was a kid on the farm at Corowa everything that ran ended up being powered by a blitz or carrier motor including ski boats and tractors. The trick we found as long as all other cooling system components were in good condition was to run an extra pint of oil in the sump.
85% of engine heat goes to oil to be disipated. We never suffered with oil foaming or pumping it out and motors ran hot but acceptably ever during harvest in a header.

[Lynn Eades]

what engine oil are you using?
The reason why I ask is because, it is reccomended to use a mono grade oil in the flathead v8, because mono grade oils have better heat transfer qualities.
I would not ditch the thermostats. I would use 160 ones. preferably waxstat ones.( bellows ones fail in the closed position usually) Some engines overheat because the water circulates too fast without thermostats.
They cause your engine to heat up to working temp. quickly, and then maintaining an even temp,which leads to a long service life.
There are quite a few very pertinent comments to this thread that should help.
Lynn.

[Bob Carriere]

... if the thermostat issue does not seem to make a significant improvement...... have you considered using a remote oil filter such as a double spin on PH 8 arrangement..... the two filters will give you an extra 1.5 quart of oil and with the filters remotelly installed inside the frame they will be in the airstream adding some cooling features. The cast aluminium remote filter brackets are usually available at flea markets as left over of the old hot rod days for $10-$20....... and you could also include a engine oil cooler for greater heat dissipation.

Don't forget that you new engine will have more friction has parts slowly settlle in place....

Enjoyed your posting.....good luck.

BooBee

[Bob Moseley (RIP)]

Hi all - I think ditching thermostats is the old wives tale. Go back to the grass roots of engine design where a need was assessed to incorporate thermostats. Sixty three years on the engine is not as efficient through the water flow areas. Fix that and you should have no problems. Ditching thermostats is using the same rationale as to converting to 12v electrics. If you replicate the wiring correctly and not use modern wiring, no problems. Millions of vehicles utilised thermostats and 6v. Modern day restorers should recognise these facts.

Bob

[cletrac (RIP)]

Originally Posted by Bob Moseley

Hi all - I think ditching thermostats is the old wives tale. Go back to the grass roots of engine design where a need was assessed to incorporate thermostats. Sixty three years on the engine is not as efficient through the water flow areas. Fix that and you should have no problems.

The design need for thermostats was to warm the engine up faster in cold weather. This is all well and good with most motors but the flattie suffers with other design problems. If you're running one in cold weather then run the thermostats but in hot weather removing them increases the water flow and helps with the problem. I'd bet money that Fords in the Sahara all had them removed. It's just something that has to be done. The LRDG preferred the Chevs because of the heating and fuel consumption problems they ran into with the Fords.I ran flatties in the 60s in cars and trucks and the only way you could run them was by removing the thermostats. With Chev or IHC 6 bangers it didn't matter. The engine design didn't create the problem. It was accepted practice on the Fords to remove them when you changed to heavier oil in the spring.
Even when flatties were relatively new they were always on the verge of heating and too hot a day or too heavy a load would put them over the top. It's just the nature of the beast. Under these conditions you have to use any trick available to help out and you'll still have to watch the temp gauge.

[Anthony Main]

Jim,
What fan are you using,& did you fit a fan shroud ?

[Jim Price]

Anthony,
The fan is the standard 4-bladed one and no, I don't have a shroud. I have considered a shroud but don't want to contrict the possible air flow around the mainfolds. A 6-bladed fan might be a better addition.

I've considered all that's been said and believe that one of the two thermostats is not working properly. I recalled that when I tested them on the stove in a pot of water awhile back that one of them was slower to open than the other. I'm replacing them both with a pair of 160 F ones that came with the Mercury engine and are new. I also am considering adding an oil cooler to the system. (I am using a mono number weight oil, by the way.)

Thanks to all for your contributions to my thread; keep them coming!

Regards,
Jim

[Chuck Anderson]

Hi Jim,

I had overheating issues with the M20 armored car as well as the C8. In both cases I removed the thermostat and haven't had any problems with overheating or cold weather starting since then. I don't know about which is ultimately better, I just know that it worked for me.

Chuck

[Lynn Eades]

Im not familiar with your vehicle, but the lack of a fan shroud may be part of the problem.
without a shroud, the air may "wash" around the ends of the fan blades, instead of drawing the air through the radiator.

[Bruce Parker (RIP)]

If having thermostats to restrict coolant flow so it stays in the radiator a little longer is desirable, yet there is the possibility they are not opening as designed, would installing theromosts that are jury-rigged to stay open be a possible solution?

[cantankrs]

Hi Bruce,

That sounds like a disc of brass or something, with a hole drilled in it in place of the thermostat. I think I tried that with my engine mentioned above but wasn't happy with the results - non variable to suit changing conditions.

Also while I think of it I spose most people have heard of covering part or all of the radiator frontal area when very cold? You see it in photos, and colder clime people are probably familiar with it. I used to carry a piece of stiff cardboard I'd jam between radiator and grill on my old car when driving long distances on cold nights - so the engine would keep warm and importantly so I could get a bit of that thru the heater! It didn't completely blank off the whole width of the radiator just 2/3rd or so. And a working temp gauge is a useful guide in case you aren't cold enough.

Also some thermostats have a little jiggle device in a hole just nearer the edge and I presume it's to allow trapped air to release during cooling system filling, the jiggle may be to stop it getting blocked up. Some have a little notch pressed into the body such that the valve doesn't seal that tiny portion presumably for the same reason. I think older (or perhaps cheaper) thermostats had no such provision so I'd drill a 1/8" hole to one side. I'm interested in any instructive comments about this.

Regards

Alex
--
M3 Grant, Val, Ferrets, WM20, CMP's