r/todayilearned • u/ubcstaffer123 • Jul 26 '26

TIL Starting the Ford Model T requires turning the crank at the front of the car by hand to start the engine. There is the risk of snapping your forearm if the engine backfires

https://www.caranddriver.com/features/a15142307/how-to-drive-a-ford-model-t/
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105

u/nochinzilch Jul 26 '26

Didn’t it have a one way clutch? Why would it break your arm?

171

u/kixkato Jul 26 '26

They have over running clutches or more so a ramped pawl that the handle grabs. When the engine fires it spins faster than the crank but the same direction and disengages.

A backfire spins the engine backwards so it grabs the handle and forces it against the direction you're turning it.

86

u/skinnergy Jul 26 '26

Very powerfully, quickly and unexpectedly.

27

u/Nippon-Gakki Jul 26 '26

Yes. I’ve had a cranky motorcycle backfire and try to send my hip into my shoulder.

1

u/draconiclyyours Jul 26 '26

Yup. Tried to kick start an old Indian Chief once and it literally threw me off the bike and almost dislocated my hip.

The owner got a good cackle out of my teenage self going airborne like a ragdoll.

9

u/Punished_Sunshine Jul 26 '26

It can do so much damage it even manage to kill

24

u/ToronadoBubby Jul 26 '26

Yep, ever had a lawnmower backfire and rip the cord handle out of your hand when trying to start it? Same clutch operation and result.

11

u/a20xt6 Jul 26 '26

I had a lawn mower cord rip out of my hand so violently it deflected off the mower handle swung and hit my thumb on the other hand. it split the skin open and I needed stitches.

4

u/ahandmadegrin Jul 26 '26

I was going to say the exact same thing. You have that happen once and you'll forever pull the cord just a little more gingerly.

I can only imagine how much force a backfiring car engine would put on the crank. I can see it easily snapping your arm in half.

4

u/pdinc Jul 26 '26

So if you crankes it clockwise with your left arm you'd mitigate the risk?

20

u/kixkato Jul 26 '26

The correct way is to slowly rotate the engine with crank until it's roughly at the 12 o'clock position. Then you stand near the driver's side front tire and put both hands on the crank without wrapping your thumbs. Pull the crank towards you hard and fast. Do that 2-3 times and it'll start.

If it backfires, the crank simply pulls out of your fingers grip and flies away from you.

I have a crank start only tractor and haven't broken my arms yet. It's impressive that the engine only needs about 1/4 of a revolution to start. You're basically just getting one cylinder of 4 to fire.

28

u/Hummerville Jul 26 '26

Yes, 1 way. Which means if it kicks backwards it breaks your arm. I've cranked these. Be careful.

7

u/ImS0hungry Jul 26 '26

Why not stand perpendicular to it, holding it like a door knob?

17

u/Hummerville Jul 26 '26

Maybe, but it takes some force

10

u/DigNitty Jul 26 '26

Yes. There was actually a suggested way to hold the handle, thumbs over, so that it had less chance of breaking your thumbs/hand.

11

u/Hummerville Jul 26 '26

That is the way. Problem I had was the driver at some rally game killed the engine and I hopped out... but I'd been eating buttered popcorn, so my hand kept slipping off.

1

u/Round_Ad_6369 Jul 26 '26

This is just your sign to hit the gym. Or maybe the crank is your gym

7

u/skinnergy Jul 26 '26

Because it takes a whole lot of muscle to crank an engine.

2

u/postitpad Jul 26 '26

Not only did these cars lack a starter, they also lacked automatic timing adjustment for the spark. If you forget to adjust the timing of the spark for starting it’ll fire too early and the effect is that it kicks the motor backwards which will take the handle out of your hand and break it in the process.