How Fast

[Mulletwagon]

Suspect most of us drive our rides around town at about 45 MPH max which seems to be the sweet spot. The question for the cross country travelers is what is the maximum recommended sustained speed on highway driving given the limitations of the non-pressurized engine lubrication system. Back in the day, Ford advertised the Model A will do 60 mph, which it could. Just do not think that fast would be healthy for the old Henrys. Welcome some experienced wisdom on the matter.
Thanx,
Florida Panhandle

 

[nkaminar]

Driving my completely stock 1930 Model A coupe in the 1950's and 60's I would cruise at 50 to 55. It had a 3.78 rear end. That was on the highways and freeways at the time when everyone else was going 60 to 65. Now, with traffic moving at 70 to 80 that would be too slow and unsafe. I now own a Model A with overdrive an a slightly modified engine that will safely cruise at 60 to 65 on the highway. But, and this is a big but, I like to take the back roads where I can safely drive at 55 or less.

If you want to go with traffic you need good brakes and steering and good tires.

 

[Hitman]

60-65 mph on the interstates with an overdrive all days long. The car handles it fine.

People fear the oiling systems, 20's technology and other things. Remember small industrial gas engines in lawnmowers, generators, pumps and similar equipment run 3600 rpm all day long on aluminum rods with no rod bearings, and splash lubrication. Most are flatheads too.

 

[Kurt in NJ]

I drive over 65 if traffic requires it.
Right now the top speed is just short of 70.
Speedometer does have a 75 number
No overdrive no “touring cam” stock head and original zenith carb.
I believe that if I fix the engine balance issue it has I will be able to get closer to the 75 number.
went on a long distance tour to a show in Wisconsin and driving at speeds over 55 I averaged 23 mpg, returning drove the entire length of PA turnpike at 65.
Normal local driving always seems to creep up to over 50

 

[Y-Blockhead]

I
Speedometer does have a 75 number

Haha, And my '55 Ranchwagon has a speedo with 150 mph... Doesn't mean it can or I should drive that fast...

 

[J Franklin]

Fast is great until something lets loose, or you need to stop in a hurry!

 

[Gene F]

Given the scope of the question 55MPH seems to be the standard. However, a lot of variables can move that number to a higher speed in a somewhat safe manor.

I must say the B/W overdrive in my car, with cast iron drums made a huge difference in the cruising experience. Even when cruising ~55MPH with my club on tour, it just so much more pleasurable.

 

[Jim Brierley]

If you are going to drive at highway speeds, get an overdrive, and good brakes, my preference is hydraulic.

 

[updraught]

For those sort of speeds the new dicc brakes would be the go.
Converting a car from drum front brakes to discs gives so much more stopping at speed.
Drums work OK at low speeds.

 

[Ruth]

I have Flat Head Ted's floaters and can easily overcome the traction of my 4.75/5.00 X 19 tires when braking. I think to only way to improve the braking is to put some fat tires on it. I don't see that happening any time soon.

 

[Doug Linden]

I have driven cross-country three times and since we avoid the interstates, unless absolutely necessary, I keep the speed between 45 - 55. On the interstate I will do 60 but stay in the right lane.

 

[ModelA29]

Our Coupe with AER touring engine (6:1, big valves, Tour cam) will run just under 70 with its Mitchell OD - it needs bigger carb.
The question shouldn't be how fast but how good are your brakes? Stuff happens fast at highway speeds and even with my Randy Gross brakes anything past 55-60 is unsafe.
I'm building a hot rod B engine for our Tudor. Brierley head & cam, pair of Strombergs, 4 speed Ford OD trans. It will be a full pressure oil system. It will also get juice brakes (to replace its stock steel ones) & air conditioning.

 

[German guy]

I recently participated in a Model A event in southwest Germany with 13 cars from as far away as Thuringen (about 420 miles) and Hamburg (about 320 miles). The cars from BOTH of those distant areas drove in for the event. Both said that they were doing 70-80 kmph on stretches of the Autobahn, so slightly under 50 MPH. Roughly 6-7 hours. Both said that it was a pretty easy drive. Neither had OD. They just stayed behind the trucks in the right lane. Seemed rather ballsy to me. A blow-out with 4.74x5.0x19 tires at that speed would be a disaster. They were far more experienced with their A's than I so..... I will stick with my 60-70 kmph on farm roads.

 

[nkaminar]

Ruth, I have recently gone to 6.50-19 tires. They have a tread that is wider than the 6.00-16 car tire. This on the advice of my good friend who has 25,000 miles on his 6.50-19 tires and they look like they will go another 25,000 miles. They are about 5% larger in diameter so that give another 5% higher speed at the same rpm. They do not look out of place on my car.

 

[Bob Bidonde]

nkaminar, please post a picture of your "A" with the 6.50x19 tires. I am also considering using this size tire.

 

[Bob Bidonde]

At 63 MPH on a highway, the Model "B" engine in my Victoria threw the #4 connecting rod. One of the studs securing the rod bearing cap broke-off. It was a fatigue failure likely with help from over-tightening. This engine made it home 10 miles from the scene of the failure. The engine was trashed. One of the lessons I learned from this debacle is to have brand new connecting rods in an engine that will be pushed to 3000+ RPMs. Original connecting rods are prone to fatigue.

 

[Kurt in NJ]

Was it insert bearing or babbitt?
From the looks of the crankshaft the bearing burned up first —- the pounding loosening the nut and the single stud wasn’t up to the task of holding it together

 

[katy]

What make of pan gasket is that?

 

[updraught]

That hole in the side of the engine is not original.

 

[nkaminar]

Bob, I will post photos here on Sunday. I am driving to a picnic today, 170 miles each way and I have to leave before sunrise. So no time to post photos today.

Sunday, Bob, here are some photos. The first on is at a rest stop. The second one is a side by side comparison between the 6.50 and 4.50 tires. The last one is a car with 16 inch tires that I don't like the look of.

Because of affordability issues I bought bias ply tires but if you can buy the radial ply tires that are much better quality.