Comfortable speed

[46woodyman]

Hello,

I am brand new to the forum and have a question for the members.

I am seriously considering purchasing a 1946 Super Deluxe wagon that has a 239 c.i. V8 motor. The specs on it state that it has a 3 speed transmission with the 3.78 gears in it. The tires are bias ply 6x16". Standard hydraulic drum brakes all around

My question is this: what would be a reasonable expectation for a comfortable and safe cruising speed? Most of the driving will be on roads that have a speed limit of 55 mph.

Thank you for any insights

[deuce_roadster]

When all the systems, steering, brakes etc are in top notch shape 55 is a safe speed. Keep in mind the old brakes are less efficient then new ones which self energize. I myself have a 40 wagon and keep those things in mind while driving by leaving extra room to stop. The wagons I believe are heavier then other passenger cars.

[41ford1]

At 55 it should feel comfortable. 65 to 70 will sound like it's being pushed. . My pickup with 3:54s runs good at 60 to 65 comfortably. My 53 at 65 feels like it's being pushed. It's got 4:10 gears. It all depends on the rear end gear ratio and if you have OD. None of mine have OD.

[rheltzel]

I daily drive my '35 with 3.78 at 65, when safe, allowing extra stopping distance between me and the car in front of me. As has been intimated, the critical element in modern traffic is the ability to stop when you are surrounded by ABS 4-wheel disc-equipped cars that can stop in half the distance you can.

[mrtexas]

Put front disc brakes on and get a mitchell OD. Then 70 is no problem. That is what I did with my 36 woodie. Without the OD it feels strained at 50mph.

[4t8v8]

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I have a F1 with the 239 8BA and S10 T5 transmission and 3.78 gears. 20% overdrive. Cruise it at 70 -75 MPH all the time. Back in the day I had a '50 Custom 2 door 3 speed that I used to run 80 -85 on the flat open highways of Nevada (no speed limits in those days). 55 will be a breeze for that flattie.

[scooder]

It may feel "strained" at 70 if you compare it to modern 87 speed trans cars. But it ain't. It'll cruise at 70 all day in good condition. Sure overdrives or 3.54 gear sets make it less busy, mechanicaly though there not necessary. You won't break it doing 70.
70 mph with a 28" tire and 3.78:1 rear gear is circa 3175 rpm. That won't hurt a thing. The flathead is a very well lubricated engine full of stout parts, not made out of bananas.
Martin.

[FrankWest]

With un restored antique cars it is never a good idea to push them to their limits.
It seems that 55 should be ok...But upon just receiving it, drive it around town at 40 max to get a feel for the thing.
Remember as an un restored car and thing can give out at any time, so you don;t want to be traveling at 65 mph when a wheel falls off or something.

[JM 35 Sedan]

With the experience of driving my 35 fordor sedan ~ 26,000 miles in the last 9 years, here's what I think....

● Starting with a freshly rebuilt 221ci, 21 stud engine, all mechanicals in good condition, radial tires, rebuilt shocks, 4.11:1 gears, on a car with 41,000 original miles back in 2007, I could cruse all day at 50 mph on good roads, and at 55 I was probably pushing the limits of a car that was 72 yo at that point in time.

● While keeping all things as stated above, and changing rear tires to 750 x 16 radials, I could easily incease the stated numbers above by 2 or 3 mph.

● Then in 2013, after changing rear gear ratio to 3.78:1, I could easily cruise all day long at 60 mph, but was pushing a bit at 65 to 70. Also, when cruising at 65 to 70 mph, I begin loosing some small amount of coolant, causing engine temperature to increase at a slight, but steady, amount until I had to stop and add coolant to get engine temperatures back to a more normal reading.

[G.M.]

Originally Posted by JM 35 Sedan

With the experience of driving my 35 fordor sedan ~ 26,000 miles in the last 9 years, here's what I think....

● Starting with a freshly rebuilt 221ci, 21 stud engine, all mechanicals in good condition, radial tires, rebuilt shocks, 4.11:1 gears, on a car with 41,000 original miles back in 2007, I could cruse all day at 50 mph on good roads, and at 55 I was probably pushing the limits of a car that was 72 yo at that point in time.

● While keeping all things as stated above, and changing rear tires to 750 x 16 radials, I could easily incease the stated numbers above by 2 or 3 mph.

● Then in 2013, after changing rear gear ratio to 3.78:1, I could easily cruise all day long at 60 mph, but was pushing a bit at 65 to 70. Also, when cruising at 65 to 70 mph, I begin loosing some small amount of coolant, causing engine temperature to increase at a slight, but steady, amount until I had to stop and add coolant to get engine temperatures back to a more normal reading.

You can hear the engine roaring when going to fast with whatever rear
you have. I have put hundreds of thousands of miles on old Fords with
a lot of turnpike driving at 70 to 75 MPH for 10 or 12 hour stretches.
Of course for this type of driving the car must be in excellent mechanical
condition. I also never follow other cars very close and let the engine
slow me down rather than heat the brakes up. My cars are fitted with
3:78 rears, 28 1/2% Columbia overdrive rears and 600/16 tires. Front
ends are tight and can leave go of the steering wheels at any speed
and the car continues straight down the road. I also balance all wheels
with the drums on a spin balance machine. All of these early Fords with
an overflow tube off the radiator push water out the overflow as you
describe at almost all speeds and as you found low coolant causes high
engine temperatures. You can correct this problem by having the
radiator converted to have a pressure cap or with Skip Haney's 3 lb
pressure valve mounted on the bottom of the overflow tube. You can
now fill the radiator up to the filler neck and not loose coolant. When
the engine runs cool it is cooler in the cab of the car or truck. G.M.

[bobH]

Ditto what's being posted here. My 34, 3.78's, no od, and factory everything else, is like said here. Using Skip's 3-lb valve. If I push it, it wants to throw water. If I keep it below 60-65, it's fine. My other car, a 47, with factory pressure cap, and 3.54's, runs all day at 65, never tosses water, year in and year out. My limiting factor is the rest of the car, not the engine. Anything above the speeds posted, I don't like the feel of the steering, suspension, brakes. And, like the other posts, I leave LOTS of room in front of me.

[Vic Piano]

I usually let the Flathead I'm driving let me know what speed it wants to cruise at. I do a lot of highway driving with my Flatheads and each one exhibits its own comfort zone where speed is concerned. I try not to be in too big of a hurry when cruisin' in a Flathead however, it's nice to know that power is there if and when you need it... I have been accused of having a heavy right foot sometimes.

[G.M.]

Originally Posted by bobH

Ditto what's being posted here. My 34, 3.78's, no od, and factory everything else, is like said here. Using Skip's 3-lb valve. If I push it, it wants to throw water. If I keep it below 60-65, it's fine. My other car, a 47, with factory pressure cap, and 3.54's, runs all day at 65, never tosses water, year in and year out. My limiting factor is the rest of the car, not the engine. Anything above the speeds posted, I don't like the feel of the steering, suspension, brakes. And, like the other posts, I leave LOTS of room in front of me.

Bob, If your pushing water out with Skips 3 lb valve there is a reason.
I would take the valve off and flush it good in the sink. It may have dirt
in it and be in and be leaking. Or you may have a slight compression
leak putting pressure in the system for this try a bottle of Bars stop leak.
G.M.

[Kurt in NJ]

I used to run the big truck(46) with a 2 ton load at 60, it had the 2 speed rear -- when it was sold it was driven to California in 4 days, with the 15 gallon tank they must have been going faster to make up for the fuel stops

[bobH]

Originally Posted by G.M.

Bob, If your pushing water out with Skips 3 lb valve there is a reason.
I would take the valve off and flush it good in the sink. It may have dirt
in it and be in and be leaking. Or you may have a slight compression
leak putting pressure in the system for this try a bottle of Bars stop leak.
G.M.

GM... I'm pretty sure (nearly positive) the radiator is plugged, not allowing 'free-flow'. And, yes, there is a good chance of contamination in the 3-lb valve. The valve has been there for a few 'seasons', and easily could have accumulated 'stuff'. I've done the usual tests for compression leaks - found nothing.
Thanks for the suggestions.

[dude]

In the car you mentioned, I'd keep it at 50-55. If you have a need to run 65-70 -take the Caddy.

[G.M.]

Originally Posted by bobH

GM... I'm pretty sure (nearly positive) the radiator is plugged, not allowing 'free-flow'. And, yes, there is a good chance of contamination in the 3-lb valve. The valve has been there for a few 'seasons', and easily could have accumulated 'stuff'. I've done the usual tests for compression leaks - found nothing.
Thanks for the suggestions.

I wouldn't be so sure the radiator is plugged. There is a BIG restriction
in ALL old Ford radiators. There are 144 tubes in most of the old
radiators. These are about two feet long and have a small layer of
dirt on all sides inside the tubes. Also if you add the inside area of
the two top hoses dumping water in the radiator it's as I remember
4.5 square inches, add the area of the 144 tubes and it 3.5 square
inches. This is like putting 3 lbs of whatever into a 2 lb bag. The
coolant don't free flow through the radiator, it has to be forced
through. The restriction causes coolant to back up in the top tank
and out the over flow tube. I don't think Ford added a 4 lb pressure
cap to raise the boiling point, it was added to keep the coolant from
going out the overflow. G.M.

[37 Coupe]

The 1946 Ford V8 was originally equipped with the 3:54 rear axle not the 3:78.Any gear ratio other than the 3:54 in 1946 would have been an option or special order.

[1934]

When I had my '34 roadster I took it up to 70 mph. It started spraying prestone out of the rad cap so I took it home and spent the next hour cleaning the windshield and hood! After that I never took it over 60, but 50 to 55 was comfortable for that car. Doug.

[JSeery]

Originally Posted by G.M.

I don't think Ford added a 4 lb pressure
cap to raise the boiling point, it was added to keep the coolant from
going out the overflow. G.M.

While this may be true, it is not what Ford claims! Their claim was because of the benefits of running the engine at a higher temperature.