Rpm

johnbuckley

johnbuckley

Well-known member
Did Ford quote a max rpm for the stock A.
Jim Schild's book says 40 hp at 2200rpm. Were these the the correct maixima?
 
That is the speed at which max HP is achieved with a stock engine. The engine will rev beyond that. With modifications, max HP will be at a different rpm.
 
The small bore AF engine (3" bore) was rated at 14.9 HP and produced 28 BHP at 2600 RPM. The bottom half of the engine is the same as the 24 HP,Same crank and bearings etc etc.So Ford was happy with that RPM however the pistons were a little lighter but not by much 3 7/8" verses 3" also the wrist pins were shorter so slightly less rotating weight. The rear end was 4.55 to 1 so needed the extra RPM. A fully loaded town sedan with the small bore was not the first choice of bank robbers needing a quick getaway !!!

John in partly cloudy warm early afternoon England
 
What is it about us limeys that we're interested in max rpm. What were your source for rpm figures for the 14.9 and the 40 hp .Was it offficial period Ford info or is it from a knowledgable guru?
 
Last edited:
johnbuckley said:
What is it about us limeys that we're interested in max rpm. What were your source for rpm figures for the 14.9 and the 40 hp .Was it offficial period Ford info or is it from a knowledgable guru?
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John, this is off the subject but I have a question about the use of the word "limey." I was never really sure if that is a derogatory term or not but figured it probably is having heard people say things like "that limey s.o.b." etc..

As a kid I was told that people from England were sometimes called "limeys" because years and years ago, English sailors ate a lot of limes while out at sea. The limes would keep a long time and not spoil.

Is this the truth? ..... just curious.

Sounds like to me there was nothing dumb about English sailors. My ancestors came over from England in 1640.

Thanks


Larry B.
 
quote
As a kid I was told that people from England were sometimes called "limeys" because years and years ago, English sailors ate a lot of limes while out at sea. The limes would keep a long time and not spoil.

Is this the truth? ..... just curious.
quote


I am not English, but I believe the limes were taken on ocean journeys to be eaten to prevent berri berri.
 
Bob Johnson said:
Limes were a source of vitamin C. Which prevents Scurvy.
Click to expand...

If you add the limes to a little tonic and gin it goes down better and the tonic helps with preventing malaria...carefully following this medical advice I have never suffered with a bout of malaria! LOL
 
I don't think anyone here is upset by being called a limey. Quite the reverse it sounds friendly .The Aussies call Brits "pommies" or "poms". even "pommie bastards". The french who we call frogs call us " Les Rost bif" all nice fun you Yanks. Derivation as stated previously..supposedly from limes being caarried on long voyages to ward off scurvy ( vitamin c deficiency). Discovery attibuted to Captain Cook but a previous sea-dog had initially introduced it. Berri berri vitamin defeiciency supposedly common if diet is primarily dehusked rice . Now what about rpm?
 
The relatve BHP/RPM were in English Ford publications of the period. I have it somewhere but I know not where right now (its my age)

Still John in the land of the guys with the funny hats ( Thanksgiving,we were pleased they got there too !!!)England
 
¿Is anyone up for some real help for a chap where Model A info may not be too plenteous? I'm a newbie lusting for a '29 RPU for a Driver. I'd like to feel confident of 400 mile runs in 9 hours or so, so I've been occupied with calculating engine speeds for various road speeds and gearing combinations. A source for data like performance curves for the engine would be great. Some aftermarket modifications raise HP, some increase available RPM, some improve breathing and cooling, some reduce engine RPM for given road speed. A improvement spread sheet with expectations of results here would be useful. It can't be that everybody that comes to this hobby has to start at zero and make all his own mistakes.
 
400 miles in 9 hours with an hour off for miscellaneous rest
stops would require an average speed of 50 mph.
This would be a challenge to maintain for both car and driver
over a nine hour period, even with good roads, in a stock Model A.
Add some traffic, the usual hills and curves and a reasonable
safety margin for you, the car and others using the road and
. . . . well good luck, you will need it.
And yes I know it can and likely has been done, but why???
 
johnbuckley said:
Did Ford quote a max rpm for the stock A.
Jim Schild's book says 40 hp at 2200rpm. Were these the the correct maixima?
Click to expand...

I've never found anything in Ford records or publications indicating an answer to your question. That means all we can do is come up with a small range based on facts.

Those of us that have been playing with these cars since the days when unmolested cars were not uncommon know with certainly that any ORIGINAL Model A with 3.78 gears will do 65 mph MINIMUM on flat ground. When I was a kid we drove the daylights out of a '30 Murray Town Sedan that did 70 mph and it was not uncommon for us to do so. Speedometer accuracy was not an issue.

Based on a '30-31 car with 19" wheels and a rolling tire diameter of 28.25" the calculated engine speeds are as follows:

65 mph = 2922 rpm
70 mph = 3147 rpm


 
Mustang said:
400 miles in 9 hours with an hour off for miscellaneous rest
stops would require an average speed of 50 mph.
This would be a challenge to maintain for both car and driver
over a nine hour period, even with good roads, in a stock Model A.
Add some traffic, the usual hills and curves and a reasonable
safety margin for you, the car and others using the road and
. . . . well good luck, you will need it.
And yes I know it can and likely has been done, but why???
Click to expand...


Well, no need to jump on the limey ******* ...... LOL

That was his first post.


Larry B.
 
Ahh Larry – it was just a gentle explanation explaining
that a Model A wide open for 400 miles could result in
a “Last Post” <@^@>
 
My grandfather sold A's new.The only new car he bought in his life was a 30 Phaeton.That car would reach 72 MPH,at least on the speedo.That one was used to take prospective buyers for a ride,as they had to order the cars as needed.They were just a repair garage with a Ford sign out front.No dealers around then.They were instructed by the Ford rep to show people what the car would do,but NOT to sustain over 50 MPH or so for long periods of time.It was not an issue here,you had to drive 50 miles to get to a road that you could go 50 for more than a minute or two.They nearly lost the agency about 1930,new cars there were losing the engines in just a few hundred miles.My uncles sawmill was within a stones throw of my other uncles garage/agency,and cars would come in from Somerville Mass,three to a flatcar.There was a siding at the mill,but when the cars came in the forklift operator unloaded them like a load of logs.Drive the forks under,pick up,and back out.Not good for the running boards and splash shields.They decided to let the cars go to Manchester,another 20 miles up the rails.There was a drive off platform there.Then My uncle would recruit three boys to drive the cars back.Everybody wanted to drive an A then,so they did it for free.It took about 6 months to figure out the guys were leaving the station and holding their feet right to the floor for the 21 mile ride back.They would race all the way back,then tool up to the garage at 25MPH.I think everybody knows of an A that would hold up at high speeds.A man here in town had one that he ran between Freeport and Portland Maine daily,65 MPH on the Maine pike.He ran it until the mid 70's until he retired.My pickup would run 72,but I would not do it for sustained periods of time,it would spit oil out of the exhaust when I did it,and I really didn't want to blow it up.When I tore it down,it had .020 pistons in it,and had to go to .125 to get the bores straight again.I have only had it up to 64 since I went through it.It just feels tight.With the BF head,old B cam,Aries exhaust,and a B dist.cam with 3.54 gears I can run right up hills at 45-50 without lugging.Just step down and go.
 
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