What is a "reasonable" speed in a Model A for one to get "reasonable" engine life?

[SteveR.]

Just installed a new stock/rebuilt engine in my A from a reputable builder. I asked him if it was OK to drive it 45 to 50 mph, or if that would hurt engine life. He suggested that it would likely last much longer if I typically kept it around 40mph or less. I'm inclined to believe him as he has decades of Model A & T experience, pours his own babbits, etc., but I'm curious what the group's experience is on this. I will probably drive the car 1,000 to 2,000 miles per year, so even 30,000 miles will take a long time. If I get 20 years out of this engine that should be plenty.

[antiquepa]

I Bought my roadster in2002, drove it between 40-45 mph, I had 50,000 miles on the engine when it started loss of power on hills, so i put in a rebuilt one in 2018.
not sure of the miles on the car when i bought it, but it had a re-built engine when i bought it., so i got 16 years out of that engine. sounds to me like you'll get your 20 years..have fun and enjoy!!

[700rpm]

I agree with your builder. If the engine is built like it’s 1929, drive like it’s 1929. If you wanna drive like it’s 2020, buy a car that was built after 1955.

[DBrer]

I don't drive above 45. I guess I'm not in a hurry when I go for a cruise. the car likes that speed and is very smooth.

[Ruth]

There are those that say they drive their Model A 60+mph "all day long". I say let them! My '30 Town Sedan is happy at 45mph and so am I. I know it will go faster but doesn't want to and shows it because she doesn't run as smoothly and quietly when we approach 55mph.

[Patrick L.]

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What Ruth says. These cars were not built for todays speeds, they are 40-45 mph vehicles. In 1930 only 6.8% of roads were 'improved'. My family went in the auto business in 1918 and salesmen taking a client in a Model A at 60 mph on a paved road for short period was a sales gimmick.
But, that said, with todays oils and clean roads these engines will last a long time. Mine was last rebuilt in 1961.

[McMimmcs]

when I am in the A I’m not in a hurry to get anywhere so I routinely travel at 35-40.

[Jordan]

Originally Posted by SteveR.

Just installed a new stock/rebuilt engine in my A from a reputable builder. I asked him if it was OK to drive it 45 to 50 mph, or if that would hurt engine life. He suggested that it would likely last much longer if I typically kept it around 40mph or less. I'm inclined to believe him as he has decades of Model A & T experience, pours his own babbits, etc., but I'm curious what the group's experience is on this. I will probably drive the car 1,000 to 2,000 miles per year, so even 30,000 miles will take a long time. If I get 20 years out of this engine that should be plenty.

Who did your rebuild?

[Ernie Vitucci]

Good Morning...I have been messing with Model A's since 1963, on and off. My experience is that a stock engine in a half way decent car, can be driven at 40 miles an hour for as long as necessary...but no faster...this assumes a 3.78 rear end. Also, keep in mind that the oil should be changed every 500 miles and all 31 or so zurk fittings need to be lubed at the same time...if the car has a 3.54 or 3.27 rear end then the speed can be a bit more. Ernie in Arizona

[Jim M]

40 is pleanty for me. I want to enjoy the scenery and be confident I can avoid any road issues. I stay off 4 lane roads and 65 MPH traffic as much as possible..

[ArtimusGordon]

Welcome to Ford Barn. If you want to drive 45 or over you might consider a Mitchel overdrive. I have a Mitchel OD in my 31 coupe and use it also in slower speeds. GREAT OD for climbing hills in low or second over. Enjoy your A at your comfortable speeds.

[Jeff/Illinois]

Originally Posted by 700rpm

I agree with your builder. If the engine is built like it’s 1929, drive like it’s 1929. If you wanna drive like it’s 2020, buy a car that was built after 1955.

Amen. The sweet spot on a stock Model A Ford is about 40 to 42 MPH on these cars. Listen to the car as you drive it. You will sense and feel it working harder after 42 or 45 MPH or so. Why abuse the car?

That is why it's a smart idea, to keep a 60's muscle car or a 2020 Mustang GT in the garage too so that you can get out and run hard every now and then

[Jordan]

I guess I'm the odd one out. Every stock car around here runs 50 no problem. When mine was stock, it ran 50 no problem for many many years.

[Purdy Swoft]

Same here . I have run mine at 50 MPH for many years with no problem . Momentum is needed to climb the steep hills without needing to down shift . I don't like running at creeping speed and running the risk of getting hit in the back .

[1931 flamingo]

I used to travel to shows on the i/state and state roads 50-55 at least, 1000 mi+ between oil changes, etc. No problems, not sure when or if engine was rebuilt, but acted that way. The "new" to me 40 is a pleasure at 65+ on the highway now.

Paul in CT

[wwirz]

No more than 40 for me. I do not need to look at the speedometer to tell when I am over 40 mph. Get more life out of the car.............

[Mad Mac]

Originally Posted by McMimmcs

when I am in the A I’m not in a hurry to get anywhere so I routinely travel at 35-40.

Me too!

[Kurt in NJ]

The first engine I broke it in slow and easy, rarely over 50, lasted 3000 miles before the rear main crumbled----the engine I have now I knew it would do 67 on the third day of driving, from then on I have driven it trying to break it--- all day at 65, lugged it starting in 3 rd gear, practiced high speed downshifting, ran it on dyno at 3200 rpm, held it in first, second foot to floor to see max speed in each gear

In talking to past owners of model A that drove them to college, they drove as fast as they could to go home to visit girlfriends--over 50 passing every car they could even though they also said they had to put oil in every 100 miles ( used oil)

I was reading in a 1925 Belkin hardware catalog, gears for model T to make car go 55---- people have always gone as fast as they could

[Tom Endy]

I have always been of the opinion that a Model A was designed to run all day long at 45mph with the engine turning over at 2000 rpms (with a 378 ring & pinion). With an overdrive you can travel at a higher speed with the engine still turning over at a lower rate.

I have a 23% Ryan overdrive in my Victoria, I also have a tachometer. Attached is a study I did at various speeds.

Tom Endy

[SteveR.]

Originally Posted by Jordan

Who did your rebuild?

Mr. Model T in College Station.

[Synchro909]

Before I installed an O/D, I used to sit the car on 42mph, never more. Both the car and I were happy at that and I did many thousands of miles that way. Since the O/D went in, I drive at 50mph which is slightly lower revs than before and the car is even happier so I am too. We can even talk to each other now as we go. Things are much quieter even though we are going faster.

[Robert/Texas]

Back in the 1950’s I bought a ’28 roadster from the granddaughter of the original owner for $100. It was stock except for 1932 wheels. I drove this car hard for a couple of years and one day I decided to see how fast it would go. It got up to about 65 and threw a rod through the oil pan, damaging the block. Rebuilt Model A short blocks were selling at Sears for $35 without exchange so I scrounged up the money and went there. This was my lucky day. Sears was selling out all their Model A stuff and short blocks were $5. They had three and the manager wanted me to take them all, but I only bought one. He gave me a free after-market carburetor and distributor to boot.

On the next Saturday two friends and I pulled the engine using a 2x4 and rope. We transferred everything from the old engine to the Sears one and reinstalled the engine in the same day. I never used the other parts that Sears gave me.

I drove the car for another year or so without any problems and then sold it to a younger guy. He had a Riley head that he was going to use on it and had cut down {instead of removing), all four fenders. The next time I went to see him he had joined the Navy.

A sad ending for this car, I never found out what happened to it after that. I got another ’28 roadster in 1989, rebuilt the engine some years ago and still have it. I never drive it over 45 MPH.

Robert

[Gene F]

Sometimes a rebuild is not needed. Sometimes all that is needed is a fresh head gasket.

[Curt phillips]

Just purchased a 29 Tudor & have never drove or rode in a model A !
What a experience, steers ok stops good runs great. Got up to 55 twice
On a long empty road and it would go faster. I wouldn’t do that again after
Telling a guy that has a model A about doing that & he said if ya hit a big
Enough hole in the road ya might have to choose if ya going with the frame
Or the body! What gets me is how many cars will pull out in front or me in
Just the 2 months I been driving it! 40 to 45 max for me.

[WHN]

Everything working right, 35 to 40 MPH, car loves it. On up to 45 MPH, car doesn’t mind but starting to breath heavy. Over 45 MPH, you can feel it starting to work. Over 50 MPH, we are both to old!

Enjoy

[40 Deluxe]

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Originally Posted by Curt phillips

Just purchased a 29 Tudor & have never drove or rode in a model A !
What a experience, steers ok stops good runs great. Got up to 55 twice
On a long empty road and it would go faster. I wouldn’t do that again after
Telling a guy that has a model A about doing that & he said if ya hit a big
Enough hole in the road ya might have to choose if ya going with the frame
Or the body! What gets me is how many cars will pull out in front or me in
Just the 2 months I been driving it! 40 to 45 max for me.

So how many documented cases are there of a body separating from the frame after hitting a pothole? Does anyone have pictures?

[Jack Shaft]

I chickened out at 80 with mine,she'll do 62 right comfortable,A engine (modified) mitchell OD..

Id like to see that too,a body being violently removed from the frame I'd say its impossible if all the mount bolts were used.

[Bill G]

Me? 45, sometimes 50 with standard tranny and no OD.

[Curt phillips]

Oh I don’t think that would happen but it was enough to slow me
Down, and with no seat belts & a tank of gas in my lap I’ll hold
Down the rear

[eagle]

Listen to your car. Mine runs easy at 45 to just under 50. Over 50 its starting to feel a bit frantic. Getting close to 60, she's in adrenalin mode. Why not stay in the sweet spot? Ive got lots of country roads all to myself, and I drive my A for enjoyment.

[1928Mik]

I'm with 'eagle' on all counts!

[Bob Bidonde]

Been cruising at 50 to 60 MPH with Model "A" and Model "B" engines on highways with babbitt bearings, 3.78 differential and no overdrive since 1962. No engine failures yet. Slow speeds are unsafe in modern traffic!

The only engine failure I personally experienced was with a freshly rebuilt Model "A" engine. Investigation revealed that the re-builder tied the oil pump into place with a piece of clothesline. The clothesline disintegrated and clogged the oil pump screen. Since then, I never trust an engine re-builder, so I take apart every rebuilt engine. None have been without faults, thankfully minor ones.

[Bob Bidonde]

Been driving 50 to 60 MPH with Model "A" and Model "B" engines on highways with babbitt bearings, 3.78 differential and no overdrive since 1962. No engine failures yet. Slow speeds are unsafe in modern traffic!

The only engine failure I personally experienced was with a freshly rebuilt Model "A" engine. Investigation revealed that the re-builder tied the oil pump into place with a piece of clothesline. The clothesline disintegrated and clogged the oil pump screen. Since then, I never trust an engine re-builder, so I take apart every rebuilt engine. None have been without faults, thankfully minor ones.

[nkaminar]

My just purchased engine has insert bearings and a counterbalanced crank. This is my 6th Model A (all the others were sold, damnit). All the stock ones I drove at 50 or so. This one will go 70 or more and the vibration is low. It is a 1930 Fordor and has an overdrive. I plan to drive it on back roads at 55 or so. What does the group have to say about this?

[JD 1931]

45-50 mph top no mountains here

[Kurt in NJ]

Originally Posted by Bob Bidonde

Been driving 50 to 60 MPH with Model "A" and Model "B" engines on highways with babbitt bearings, 3.78 differential and no overdrive since 1962. No engine failures yet. Slow speeds are unsafe in modern traffic!

The only engine failure I personally experienced was with a freshly rebuilt Model "A" engine. Investigation revealed that the re-builder tied the oil pump into place with a piece of clothesline. The clothesline disintegrated and clogged the oil pump screen. Since then, I never trust an engine re-builder, so I take apart every rebuilt engine. None have been without faults, thankfully minor ones.

After I had the rear main failure I got to look at 2 other engines rebuilt by the same place, neither had been run, one still had wadding in the oil passages to the mains, the other one the oil holes hadn't even been drilled

[Gene F]

Originally Posted by Curt phillips

Just purchased a 29 Tudor & have never drove or rode in a model A !
What a experience, steers ok stops good runs great. Got up to 55 twice
On a long empty road and it would go faster. I wouldn’t do that again after
Telling a guy that has a model A about doing that & he said if ya hit a big
Enough hole in the road ya might have to choose if ya going with the frame
Or the body! What gets me is how many cars will pull out in front or me in
Just the 2 months I been driving it! 40 to 45 max for me.

Curt, you are correct.. My wife sometimes drive our streetrod, and she notices the same thing. People think that they don't want to "get caught behind that old car". In the case of the streetrod, what they don't understand is that old car can often move faster than they can.

[Gene F]

Originally Posted by Kurt in NJ

After I had the rear main failure I got to look at 2 other engines rebuilt by the same place, neither had been run, one still had wadding in the oil passages to the mains, the other one the oil holes hadn't even been drilled

It's amazing isn't it! Years ago we had a guy in our club took his car out with a fresh engine, installed in a shop. Drove it some, and next thing ya know it had to be towed in. Someone forgot to put cotter pins in the rod caps. TORE IT UP!

And if ya say anything the supposed engine rebuilders get mad...

[bdtutton]

I have a 1930 Tudor and it is happy at 45-52 all day long. It will run up to 60 fairly easy, but you can tell it is unhappy spinning that fast. I plan to add an overdrive, but I plan to rebuild the brakes with new cast iron drums first. You need to be able to stop before you think about going fast.

[Jack Shaft]

Originally Posted by Gene F

It's amazing isn't it! Years ago we had a guy in our club took his car out with a fresh engine, installed in a shop. Drove it some, and next thing ya know it had to be towed in. Someone forgot to put cotter pins in the rod caps. TORE IT UP!

And if ya say anything the supposed engine rebuilders get mad...

I yell at my engine builder every morning in the mirror when I shave ..do your own work,you'll have no one to be mad at..


The sweet spot folks describe on here is important to understand,its natures way of telling you your exceeding the limits of harmonic and torsional vibration that occurs with a stock model a crankshaft,the late Herm Kohnke maintained a model a crankshaft will flex at the center bearing .001 when vibrating hard ( picture a tuning fork) pay heed to that uncomfortable feeling you get,you'll save your main bearings..

[Chuck Sea/Tac]

Originally Posted by Gene F

It's amazing isn't it! Years ago we had a guy in our club took his car out with a fresh engine, installed in a shop. Drove it some, and next thing ya know it had to be towed in. Someone forgot to put cotter pins in the rod caps. TORE IT UP!

And if ya say anything the supposed engine rebuilders get mad...

I doubt it was because he forgot cotter pins. I don’t have pin in my rods. No little second lock nuts either. He forgot to torque them!

[40 Deluxe]

Originally Posted by Gene F

It's amazing isn't it! Years ago we had a guy in our club took his car out with a fresh engine, installed in a shop. Drove it some, and next thing ya know it had to be towed in. Someone forgot to put cotter pins in the rod caps. TORE IT UP!

And if ya say anything the supposed engine rebuilders get mad...

I say "misdiagnosis" here. Properly torqued rod nuts don't back off like that! More likely, that shop owner told the new kid to torque the rods and "Don't forget the cotter keys!" When the holes didn't line up, the kid, not having been trained, backed off the nuts until the holes did line up. And no one checked his work!

[Synchro909]

Originally Posted by Chuck Sea/Tac

I doubt it was because he forgot cotter pins. I don’t have pin in my rods. No little second lock nuts either. He forgot to torque them!

IMO, an even more stupid thing to do.

[TerryH]

I have a Mitchell in my 1930 Town Sedan and it cruises nicely at 55 mph., but it is also wonderful to drive it on surface streets at 45 in OD....it is so quiet and almost serene....

[Bruce of MN]

Originally Posted by TerryH

I have a Mitchell in my 1930 Town Sedan and it cruises nicely at 55 mph., but it is also wonderful to drive it on surface streets at 45 in OD....it is so quiet and almost serene....

Same with my Coupe.

[fundytides]

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Back in the late 1950's I bought and sold a few Model A's one summer (kept one which I still have). I sold a 30 sedan to a teenage friend of mine. It was a nice car but the motor was tired. A few days after I sold it he came back to tell me that the car would easily do 60 miles an hour. I had trouble believing him until he explained that he had approached the top of a long local hill as fast as he could go and then put the car in neutral and didn't touch the brakes all the way down the hill (about a mile long) and it was doing over 60 at the bottom. Lucky there wasn't a slow truck or a cow at the crossroads at the bottom. Teenagers!!!

[Pete]

I use my A for a parts chaser and sometimes drive it to town Friday nights for "bench racing and hanging out". It is capable of going easily over 100 mph and I do that quite often on a certain road. I can easily keep up with the fastest freeway traffic. The car has a cage and the seat belts are attached to the frame. I use racing oil in the B engine, have 4 wheel disc brakes and 8 inch rubber. The car looks completely stock from the outside if I put the stock wheels on. (which I do quite often)

The point being, you should not drive at a faster speed than a car is safe at and a stock A was made to go about 60 max. safely.
There is no stigma with driving an A slow. No one has to justify how they drive or the car they drive.

[Mister Moose]

How would I know if I had a high speed rear end in mine? By modern standards there seems to be a big jump from second to third, is that typical on standard rear ends? My car seems happy at 50 or even 55, I'm just not thrilled about mechanical brakes at 55.

[Ruth]

Originally Posted by Mister Moose

How would I know if I had a high speed rear end in mine? By modern standards there seems to be a big jump from second to third, is that typical on standard rear ends? My car seems happy at 50 or even 55, I'm just not thrilled about mechanical brakes at 55.

Well unfortunately no matter which rear end ratio you have you will still have the big jump between 2nd and 3rd gears.

[Patrick L.]

Originally Posted by Pete

I use my A for a parts chaser and sometimes drive it to town Friday nights for "bench racing and hanging out". It is capable of going easily over 100 mph and I do that quite often on a certain road. I can easily keep up with the fastest freeway traffic. The car has a cage and the seat belts are attached to the frame. I use racing oil in the B engine, have 4 wheel disc brakes and 8 inch rubber. The car looks completely stock from the outside if I put the stock wheels on. (which I do quite often)

The point being, you should not drive at a faster speed than a car is safe at and a stock A was made to go about 60 max. safely.
There is no stigma with driving an A slow. No one has to justify how they drive or the car they drive.

100 mph ! Must be the racing oil !

[Benson]

duplicate

[Benson]

duplicate

[BRENT in 10-uh-C]

Originally Posted by SteveR.

Just installed a new stock/rebuilt engine in my A from a reputable builder. I asked him if it was OK to drive it 45 to 50 mph, or if that would hurt engine life. He suggested that it would likely last much longer if I typically kept it around 40mph or less. I'm inclined to believe him as he has decades of Model A & T experience, pours his own babbits, etc., but I'm curious what the group's experience is on this. I will probably drive the car 1,000 to 2,000 miles per year, so even 30,000 miles will take a long time. If I get 20 years out of this engine that should be plenty.

Russ & Jennifer are great friends of mine, so I am not about to counter anything he has told one of his customers, -but my questions of playing Devil's Advocate is directed to the others as I want to hear from them.

So why won't your Model-A engine reliably 'live' at a reasonable speed of 60 mph?

When you do the math, at around 2,550 rpms with a 30" tall tire and a 3.78 gear ratio, the car should be traveling at 60 mph. At 2,600 rpms, the piston speed is approximately 1,841 feet per minute. The piston that Ford used is good for well over 3,000 fpm, and the crankshaft with 3 main bearings and 7.500 long rod with the original style piston & pin calculates out to be safe to a little over 2,000 fpm, -and add counterweights you you gain another 300-400.

So the truth is, the design of the engine is capable of cruising 60 mph, with spurts of 65 mph not being an issue. So by engineering standards, Ford's advertising of his car being capable of 60 mph is not false-advertising. So if your Model-A engine struggles driving past 45 mph (-just under 2,000 rpms.) then we need to determine where the issue is. So lets look at a list of items that would potentially cause engine failures being operated over 2,000 rpms;

Connecting Rods: Generally speaking, the connecting rod rarely fails on its' own. A broken connecting rod does fail however it is usually from excessive clearance around the crankshaft journal or a wrist pin failure. Based on my own engine rebuilding experiences, I would guess that 1 in maybe 30 connecting rod fails a wet crack test (Magnaflux).

Connecting Rod Bolts: While I have seen connecting rod bolts fail on Model-A rods, it is usually caused by the cap being hammered which loosens the bolt. I don't have a way to test the tensile strength that a pair of Model-A rod bolts will sustain, however I feel fairly sure that a stock Model-A rod should be able to withstand piston speeds of 3,000 fpm which would equate to 4,000 rpms.

Crankshaft: I can probably count on both of my hands the number of broken crankshafts that I have seen in all my years in this hobby. In every one that I have seen fail, it was a craftsmanship error that initiated the cause. Craftsmanship Error includes failure to properly straighten the shaft prior to grinding, failure to grind the proper radii on each end of the journal pin, and/or machining the pin too far creating a lower stage of harmonics that interferes with a cruising rpm.

Flywheel: This is another area where poor craftsmanship and tolerances WAY outside of Ford factory specification cause vibrations that cause issues through-out reciprocating areas of the engine. Crankshafts that have flanges that do not run perpendicular to the crankshaft centerline cause vibrations. Flywheel Housings that are warped cause vibration issues too. Couple those to an improperly dynamically balanced flywheel and you have a mechanical machine that wants to transfer that vulgar energy into areas such as the crankshaft or connecting rod bearings. Sure, we ultimately see the bearings fail however is it really the fault of the bearing, -or shoddy workmanship?

Piston: One thing that is often overlooked is the weight of the piston, ...and/or the wrist pin. When a piston is oversized compared to an original-sized piston (3.8750"), the extra mass equals extra weight unless the rebuilder knows to remove weight to compensate. Next, many pistons used in Model-A/B engine rebuilding today have a wrist pin that is about 100 grams heavier than what the original pin. Think about what this affects as far as reciprocating weight balance and how it affects pistons with regard to travel.

Bearings: A cast bearing (-a.k.a. Babbitted Bearings) when properly poured and machined should have twice the longevity of an inserted bearing. The reason most get a bad reputation is from poor craftsmanship from the engine rebuilder. So often, the engine is being rebuilt on a price-point where steps are omitted and the quality of materials are compromised which affects longevity. This creates a poor reputation for a process that worked well for decades simply because of perception. This list is not about debating whether cast bearings vs. inserts are better, -as both bearings when properly installed should provide many miles of 60 mph driving.

Camshaft: Many Model-A engines still use worn camshafts that affect volumetric efficiency and power bands. Adding to this, many camshafts that have been re-ground to a standard (-sometimes called a touring cam) have been found to have specs that vary from cylinder to cylinder. How do you suppose this affects engine efficiency at higher rpms.

Carburetion: This topic could be a whole chapter in itself but in a nutshell, an aftermarket economy carburetor (-such as a Tillotson) which uses a smaller venturi and jet will never flow the CFMs to keep up with speeds a Model-A engine is capable of. Even when a stock Zenith carburetor has a leaking throttle shaft or poorly flowing venturi, it affects CFM air-flow. A lean fuel mixture at higher rpms definitely makes an engine feel like it is laboring. So at this point, is the problem with the design of the engine, -or poor/faulty maintenance?

Other: This is one of those areas where there a likely a dozen-plus topics that could be discussed as to why a Model-A doesn't feel comfortable traveling over 45 mph. I would be glad to hear your theory too.


Bring this to a close, based on my own experiences it really boils down to a Model-A that is not within the original specifications in one or more areas as to why it struggles to be driven over 45 mph. I would like to hear from someone who feels I am in error in any of the above, but I think this is something that many of us know deep-down is factual however it is easier to make excuses for why it won't (-or shouldn't) do 60 mph instead of making the proper corrections to our vehicle.

[Jack Shaft]

With attention to detail a stock model a engine with the stock drive train will do 60 mph.Dilligent adherence to specification and proper assembly will yield the results Ford advertised.The problem arises when you want 'reasonable engine life..Ford engineering,Lawrence Sheldrick's engine team noted an issue with main bearing wear at high speed and felt a larger crankshaft journal would provide the stability needed to overcome the torsional vibration encountered.Mr Ford overruled them citing flywheel mass was capable of dealing with the issue.
Today,counterbalanced crankshaft and harmonic balancers counteract torsional vibration.At high rpm,the stock model a crankshaft vibrates like a tuning fork,flex has been estimated at .001 at the center main at high rpm (in excess of 2300 rpm). Ever wonder why a front crankshaft pulley cracks and fails? The same rule applies to the uncomfortable feeling you have when you drive the car too fast,its why 45 feels so good

[WHN]

60 MPH is getting to be like “what oil do you use?”.

My father received a new 1931 Model A Sport Coupe as a college (Northeastern) graduation present.

In 1962 when I got my first Model A, also a 1931 Sport Coupe. He told me two things. Stay under 45 MPH, and stay away from big hills, either up or down.

Ford advertised that the car would do 60 MPH. My Volvo will do 120 MPH. I don’t think that either the Model A or the Volvo are/were expected to be driven at those speeds on a regular basis.

I plan on pasting our 1929 Sport Coupe down to my grandson. It’s 100 percent stock. No jewelry or speed parts. It really likes speeds under 45 MPH. It’s 91 years old, has won many show trophies. It is professional maintained mechanically.

60 MPH? This to me is a high school thing. Mine is bigger and better than yours, remember those days.

Enjoy.

[Gene F]

Brent, my A snapped a crank. I saw above where you said "failure to grind the proper radii on each end of the journal pin". He said the radius was the thing that caused the crank to snap. I sent a crank over to that big time shop in central southeast PA that had never been cut. They cut off 10, counterweighted it, balanced it, Then added 30 lbs lightened flywheel, and balanced again, them pressure plate was added, and all balanced as a unit. That's 4 balance steps. Everything was matchmarked with a spray can, disassembled and sent back to me.

In any event it snapped. Please expalin in lay terms what this is.

Thanks,
Gene

[daren007]

If you are in a hurry you are driving the wrong car.

If the machine shop “cut” your crank tell them you do not want it back.

[Kevin in NJ]

You need to read the history of the A to get a better understanding of how it was really driven back when they were just cars to drive.

Quite frankly they drove the hard and fast all the time on crappy roads.

There are also many examples of A's being driven beyond abuse and they kept running. People doing runs as fast as the could all around the country.

If I remember correctly the NY city PD expected 50,000 to 80,000 miles on the engine before a major rebuild. You can bet those cars were not babied.

We have a mental set about and 'old' car braced by a mis-understanding of how the engine was built and how it needs to be rebuilt. As Brent pointed out the engine was built to certain standards. Rarely are these engines or driveline for that matter are actually properly restored to specs. It is about very close attention to details that give you a car that is as good at driving 45 as running 65.

Finally, my experience with people who say the A is only good for 45 is their car did not look safe at 25. This is often surveying the car from 10 feet away.

[WHN]

Originally Posted by Kevin in NJ

You need to read the history of the A to get a better understanding of how it was really driven back when they were just cars to drive.

Quite frankly they drove the hard and fast all the time on crappy roads.

There are also many examples of A's being driven beyond abuse and they kept running. People doing runs as fast as the could all around the country.

If I remember correctly the NY city PD expected 50,000 to 80,000 miles on the engine before a major rebuild. You can bet those cars were not babied.

We have a mental set about and 'old' car braced by a mis-understanding of how the engine was built and how it needs to be rebuilt. As Brent pointed out the engine was built to certain standards. Rarely are these engines or driveline for that matter are actually properly restored to specs. It is about very close attention to details that give you a car that is as good at driving 45 as running 65.

Finally, my experience with people who say the A is only good for 45 is their car did not look safe at 25. This is often surveying the car from 10 feet away.

I am trying to understand what you are saying here.

New York City Police Department Model A’s were driven 50,000 to 80,000 miles at 60 plus MPH, or they were just driven hard? Driving a car hard at 30 MPH doesn’t seem to me to be answering the reasonable speed question.

Also, saying a car likes a certain speed range better than a higher speed range, doesn’t necessary mean the car is unsafe.

Owners were being asked for their opinion on a very often talked about question. “What is a reasonable speed”.

Just because a person drives their car fast, doesn’t make it in better condition than the owner who prefers under 45 MPH. Think back to high school again.

Enjoy.

[BRENT in 10-uh-C]

Originally Posted by Gene F

Brent, my A snapped a crank. I saw above where you said "failure to grind the proper radii on each end of the journal pin". He said the radius was the thing that caused the crank to snap. I sent a crank over to that big time shop in central southeast PA that had never been cut. They cut off 10, counterweighted it, balanced it, Then added 30 lbs lightened flywheel, and balanced again, them pressure plate was added, and all balanced as a unit. That's 4 balance steps. Everything was matchmarked with a spray can, disassembled and sent back to me.

In any event it snapped. Please expalin in lay terms what this is.

When you reference "He", exactly who is 'he'?

Personally, I would want to look at the crankshaft. Maybe the grinder missed a stress riser or crack when he Magnafluxed the crank? Maybe he didn't Magnaflux it?? Maybe the crank got inadvertently nicked which set up a stress riser??? I am unsure if you mean the flywheel is 30 pounds, -or whether they removed 30 pounds from the entire assembly (flywheel & pressure plate).

The reason I mentioned what I did above, is many unknowledgeable crankshaft grinders put too small of a radius on the Model-A journals. Ford specified a ⅛" radius to be ground on each pin. For a 20" x 1" (wide) crankshaft grinding stone I am paying nearly $250. If I dress each end to a ⅛" radius, then that leaves about ¾" to grind the journal pin. Many modern engines call for a radius of 0.050 to 0.070 (-vs. 0.125) which means when the grinder finishes a Model-A crankshaft, he must true his wheel removing 0.125" of the diameter of his grinding wheel. Based on useable size of his wheel, that cost him about $10.00 in material expense plus the extra time of truing the wheel. Therefore it is much easier (i.e.: cost effective) to cheat on the radius and use a radius that is much akin to a modern crankshaft.


.
.
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Originally Posted by WHN

I am trying to understand what you are saying here.

New York City Police Department Model A’s were driven 50,000 to 80,000 miles at 60 plus MPH, or they were just driven hard? Driving a car hard at 30 MPH doesn’t seem to me to be answering the reasonable speed question.

Also, saying a car likes a certain speed range better than a higher speed range, doesn’t necessary mean the car is unsafe.

Owners were being asked for their opinion on a very often talked about question. “What is a reasonable speed”.

Just because a person drives their car fast, doesn’t make it in better condition than the owner who prefers under 45 MPH. Think back to high school again.

Enjoy.

I think you are trying to confuse others in your justification. Very few hobbyists have ever driven a very low-mileage Model-A, -or driven a completely restored Model-A that was taken to fine-point status, so they really have no idea of the facts or how they can be driven. For the ones that have, we will tell you that those type of Model-As have no problem driving 60 mph, ...and they feel safe & comfortable doing so. When a Model-A struggles to get to 60 mph, -or if they cause their owner to feel uncomfortable at those speeds, then YES, they are unsafe.



One other quick thing to point out. Unlike today's society where a person's word is often found not to be factual, back during the Model-A era things were vastly different by comparison. Not to imply there were not shysters or con-artists during that time period however you did not find advertising from top-level companies to be as deceiving or misleading as you do today. When Ford offered a statement in their advertising, it was very likely to have been proven factually, ...and especially when their boast or claim was used in multiple years of advertising. So to infer that 45 mph was considered "high speed" back in that era is just not factual. Therefore, a 'restored' Model-A with a properly (-and thoroughly) rebuilt engine should find it to be reasonable to be able to be driven at the same speeds as it was when new. After all, a 'restored' vehicle should be in at least the same mechanical condition and specifications as when it was new. Prove me wrong in what I am saying!!

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[WHN]

Originally Posted by BRENT in 10-uh-C

When you reference "He", exactly who is 'he'?

Personally, I would want to look at the crankshaft. Maybe the grinder missed a stress riser or crack when he Magnafluxed the crank? Maybe he didn't Magnaflux it?? Maybe the crank got inadvertently nicked which set up a stress riser??? I am unsure if you mean the flywheel is 30 pounds, -or whether they removed 30 pounds from the entire assembly (flywheel & pressure plate).

The reason I mentioned what I did above, is many unknowledgeable crankshaft grinders put too small of a radius on the Model-A journals. Ford specified a ⅛" radius to be ground on each pin. For a 20" x 1" (wide) crankshaft grinding stone I am paying nearly $250. If I dress each end to a ⅛" radius, then that leaves about ¾" to grind the journal pin. Many modern engines call for a radius of 0.050 to 0.070 (-vs. 0.125) which means when the grinder finishes a Model-A crankshaft, he must true his wheel removing 0.125" of the diameter of his grinding wheel. Based on useable size of his wheel, that cost him about $10.00 in material expense plus the extra time of truing the wheel. Therefore it is much easier (i.e.: cost effective) to cheat on the radius and use a radius that is much akin to a modern crankshaft.


.
.
.



I think you are trying to confuse others in your justification. Very few hobbyists have ever driven a very low-mileage Model-A, -or driven a completely restored Model-A that was taken to fine-point status, so they really have no idea of the facts or how they can be driven. For the ones that have, we will tell you that those type of Model-As have no problem driving 60 mph, ...and they feel safe & comfortable doing so. When a Model-A struggles to get to 60 mph, -or if they cause their owner to feel uncomfortable at those speeds, then YES, they are unsafe.



One other quick thing to point out. Unlike today's society where a person's word is often found not to be factual, back during the Model-A era things were vastly different by comparison. Not to imply there were not shysters or con-artists during that time period however you did not find advertising from top-level companies to be as deceiving or misleading as you do today. When Ford offered a statement in their advertising, it was very likely to have been proven factually, ...and especially when their boast or claim was used in multiple years of advertising. So to infer that 45 mph was considered "high speed" back in that era is just not factual. Therefore, a 'restored' Model-A with a properly (-and thoroughly) rebuilt engine should find it to be reasonable to be able to be driven at the same speeds as it was when new. After all, a 'restored' vehicle should be in at least the same mechanical condition and specifications as when it was new. Prove me wrong in what I am saying!!

.
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Confuse others?

Someone asked for members views. Which, on this same subject, a number of times over the years people have given. The general consensus seems to be that around 45 MPH a lot of Model A owners think their cars run very nicely. Having said that. I don’t believe those same people are saying their cars will not run faster. Just that at that speed things seem very good.

I would ask everyone to please remember the original question that we were asked. “What is a reasonable speed in a Model A for one to get reasonable engine life”.

I have no idea what level his car has been brought to. Nor do I know the quality of the engine rebuild. I do know that at 45 MPH or less, even a worn engine will last longer than one driven faster.

Enjoy.

[BRENT in 10-uh-C]

Originally Posted by WHN

Confuse others?

Someone asked for members views. Which, on this same subject, a number of times over the years people have given. The general consensus seems to be that around 45 MPH a lot of Model A owners think their cars run very nicely. Having said that. I don’t believe those same people are saying their cars will not run faster. Just that at that speed things seem very good.

I would ask everyone to please remember the original question that we were asked. “What is a reasonable speed in a Model A for one to get reasonable engine life”.

I have no idea what level his car has been brought to. Nor do I know the quality of the engine rebuild. I do know that at 45 MPH or less, even a worn engine will last longer than one driven faster.

Enjoy.

Yes, I do think your comment is very confusing. My modern daily driver drives nicely at 45mph, ...however equally as well at 55, 65, and 75 mph. You still have not answered my question as to what fails. If I drive a Model-A with stock tires and gear ratio at 30 mph, the engine internals rotate at 1,270 rpm. If I drive the same vehicle at 60 mph, the rpms are 2,540. So the engine turns the same amount of revolutions to cover the same distance however one speed causes the engine reciprocating parts to rotate for twice the length of time. Outside of that, there really should not be any difference in my view. So again, what internally fails, ...and why does the component(s) fail? Is the engine failures at these higher speeds due to engineering design flaws, -or due to faulty craftsmanship?



As for a worn engine, how is this applicable to the original poster's question as he clearly stated it was a freshly rebuilt (i.e.: not worn ) engine. Commenting about a worn engine lasting longer is kinda confusing to the original question.

[Terry Burtz, Calif]

The Model A engine has several engineering design flaws including small diameter poured bearings and not enough main bearings.
A contemporary engine like the 1927/1928 Dodge "Fast 4" has larger bearings that use replaceable inserts and a 5 main crankshaft.
No amount of craftsmanship can make up for an inadequate design.

[WHN]

Originally Posted by BRENT in 10-uh-C

Yes, I do think your comment is very confusing. My modern daily driver drives nicely at 45mph, ...however equally as well at 55, 65, and 75 mph. You still have not answered my question as to what fails. If I drive a Model-A with stock tires and gear ratio at 30 mph, the engine internals rotate at 1,270 rpm. If I drive the same vehicle at 60 mph, the rpms are 2,540. So the engine turns the same amount of revolutions to cover the same distance however one speed causes the engine reciprocating parts to rotate for twice the length of time. Outside of that, there really should not be any difference in my view. So again, what internally fails, ...and why does the component(s) fail? Is the engine failures at these higher speeds due to engineering design flaws, -or due to faulty craftsmanship?



As for a worn engine, how is this applicable to the original poster's question as he clearly stated it was a freshly rebuilt (i.e.: not worn ) engine. Commenting about a worn engine lasting longer is kinda confusing to the original question.

Brent, your just looking for someone to argue with.

Have fun.

[BRENT in 10-uh-C]

Originally Posted by WHN

Brent, your just looking for someone to argue with.

Have fun.

I am having fun. I repeatedly asked a simple question that no one can seem to give an answer to.

Originally Posted by Terry Burtz, Calif

The Model A engine has several engineering design flaws including small diameter poured bearings and not enough main bearings. A contemporary engine like the 1927/1928 Dodge "Fast 4" has larger bearings that use replaceable inserts and a 5 main crankshaft. No amount of craftsmanship can make up for an inadequate design.

Terry, define "inadequate design" please? Inadequate by today's standards -or inadequate in the Model-A manufactured time era??

While I agree there were design advancements/improvements that came subsequent to the Model-A (i.e: Model-B engine with larger crankshaft journals, counterweights, higher compression, better carburetion, pressurized oiling system), but exactly what consistently failed on a Model-A engine that caused it to be deemed as an "inadequate design"?

Maybe another way to ask this is; -you mention poured bearings and not enough main bearings as being 'engineering design flaws' however did these two items create longevity issues during the era of the vehicle?

I guess my way of looking at this entire thread is what is a 'reasonable expectation' of a Model-A engine back then. It has been stated over & over that Ford proved their engines could be driven 60 mph for periods without their engines failing. While the engines may have not been developed to their maximum potential, it sure seems to me they were engineered well enough for the class of car they were intended to be sold in, and they lasted well enough during their era to be around today in large numbers.

[Jack Shaft]

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It appears that was Mr Fords point as well,when his engineers in 1927 pointed out the center main bearing/crankshaft diameter issue..the first case of design obsolescence? Perhaps..

[Ernie Vitucci]

Good afternoon...I said this way back at the beginning of this discussion....I've had Model A Fords on and off...since 1963...at that time...we were told...'If you want the car to last, Engine and running gear...drive it at 40 miles an hour'. Most of us don't drive our A's more than a 1000 or 2000 miles a year. So driving too fast might not show up for a number of
years...but if you are using the old girl daily...and I often do...then 5000 or 6000 miles a year become normal...and hard use will show up much quicker...Keep in mind that the 'Old Guys' giving us youngers these instructions...in 1963...were from the Model A Era...and knew what they were talking about...I believe more than we sometimes do. Ernie in Arizona

PS...If you have a Mitchell or some other overdrive...then you can go faster without engine damage...but the running gear will still absorb additional punishment...

[Bruce of MN]

As I understand it, there weren't many long, straight paved roads back then to drive at 60 mph for an hour or more. How smooth was US 30 in Nebraska in 1928?

[shew01]

Brent,

I’m curious. Your shop puts a lot of effort into an engine rebuild. How long (in terms of miles) does one your rebuilds typically last, regardless of whether is driven at 45 or 60?

Also, how does that compare to how long an original engine would last when new? (I presume lower quality oil and dustier roads would cause the original engines to need rebuilds sooner than today’s rebuilds.)


Sent from my iPhone using Tapatalk

[BRENT in 10-uh-C]

Originally Posted by shew01

Brent,

I’m curious. Your shop puts a lot of effort into an engine rebuild. How long (in terms of miles) does one your rebuilds typically last, regardless of whether is driven at 45 or 60?

Also, how does that compare to how long an original engine would last when new? (I presume lower quality oil and dustier roads would cause the original engines to need rebuilds sooner than today’s rebuilds.)


Sent from my iPhone using Tapatalk

Mr. S, I honestly do not know how long they go as many of them likely still have less than 30k-40k miles. I would however, expect them to get to the 50k mark at a minimum. I offer a lifetime warranty on our engines as long as the bearings are kept within factory specs, and the oil is properly changed. If something comes apart (such as the bearings) I will replace it under warranty. If the engine simply wears out or is improperly maintenanced, then the repair is on them.

With that said about the 50+k expectancy, I know of a couple A/B engine rebuilders that have inserts in their Model-A engines that have that kind of mileage too. I know Dave G. from here is one that has been all over the country with his engines and at higher speeds. Any issue he has had has been in areas above the pistons and not below.

Again, the Model-A hobby went thru some sloppy craftsmen back in the 50s thru the 00s where methods and materials used gave casting bearings a bad reputation. Now that better equipment is being used by some, -and materials & procedures being used are much superior, then longevity, reliability, and performance has increased substantially. Unfortunately, old notions & opinions from yesteryear are sometimes hard to put aside by some.

[johnneilson]

Originally Posted by Terry Burtz, Calif

The Model A engine has several engineering design flaws including small diameter poured bearings and not enough main bearings.

No amount of craftsmanship can make up for an inadequate design.

There is truth in that statement, at least by today's standards. Given the roads and conditions back then, it made sense.

The '32 "B" motor was a big step in the right direction, but still too little too late.

J

[DHZIEMAN]

On this original question, we all have a view. The safety item on these cars that varies by car and owner, are the ability of the brakes to stop the darn thing.
Now that I have redone my brakes, to me, keeping the old girl not much more than 45 MPH seems to feel right. Along with that, I have only owned this car for maybe 3 of its 90 years and I venture for the number of owners and the fact the engine gets the car up to 45, I am happy to drive at that speed.

[Synchro909]

I'm sure everybody has been asked "How fast will it go?" My answer to that is "I don't know. I've never tried it." (And I haven't)
I love the confused looks on people's faces when I say that, especially younger ones.

[shew01]

Originally Posted by Synchro909

I'm sure everybody has been asked "How fast will it go?" My answer to that is "I don't know. I've never tried it." (And I haven't)
I love the confused looks on people's faces when I say that, especially younger ones.

Someone asked me the same question the other day, and I gave the same answer you gave, “I’ve never tried it.” I got a confused look too. [emoji23]


Sent from my iPhone using Tapatalk

[wwirz]

I am retired and worked with reciprocating engines and compressors my entire 40 year career. Slower RPMs is always better. Your forces are increased by the square of the rotative speed. I guy in my club says if you drive an A at 35 - 40 mph they will last forever. Enjoy the ride....there is no need to drive an A over 40 mph. Why would you drive faster in a car with mechanical brakes and no protection in case of an accident? If you need to get to a destination and drive at highway speeds, take another car.

[Jack Shaft]

First thing that happens in an accident at speed is the doors fly open,next on front impact is the rigid steering column to impale you..oh,and there is a gas tank in your lap..40mph or 60 mph its about as dangerous as riding a motorcycle..5

[Bruce of MN]

That's a relief, I've been riding motorcycles since 1970!

[Ernie Vitucci]

Good Morning....Agree with wwirz...and said so early in this thread! However, we seem to be in minority...Ernie in Arizona

[woofa.express]

Some people tell fibs.
I often speak of the greatest lies ever told.
The yield of crops. The size of fish caught especially the ones that got away and thirdly the speed of Model A’s.
Why doesn’t mine go fast just like others I read about? Well now I feel informed. Some have overdrives or highspeed difs. I figure they’d need upgraded breaks to accommodate. Some have modified engines and some clearly some meet category 3 above. They tell fibs.
I found it pleasing the speed of my A’s was comparable to many who have responded to this thread. Made my day.

[Greg Jones]

Brent's posting (#53) is a very very useful list of engine rebuilding considerations. Now, I won't get into the "how fast can a Model A go" argument but I very much commend Brent for his posting.