I'd be willing to bet the "EarlyV8" forum on FordBarn.com would have a few who have used that crank.

 

I am as lost as you are, but if your read the link 4tl8ford posted, it sort of explains it - if you can follow what he is saying. What I get is that the flat crank does away with the heavy counter-balance of the normal V8 crank.

It is less smooth a running engine, but, considering its size, still smoother than a 4 cylinder. According to the author, you double the size of the 4 cylinder, but the harmonics only increase 41 percent.

It is a hot-rod engine, and smoothness does not count - as long as the vibration does not tear it apart. The author claims that Ferrari, Lotus and TVR all build flat-plane V8s for their current speedsters.

What I am going to accept (for now) is that the use of the flat cranks in the early flatheads provided a slight edge on acceleration and top RPM. The guys who ran them, and those that ran against them, were very competitive and, as usual, luck and driver skill won the race.

It is a great piece of history from a time when an average guy with a home shop had a chance of taking home the trophy.

 

The historically successful flat-track dirt motorcycles (Harleys and Triumphs) used essentially flat cranks to fire both cylinders at once. This gives twice the torque, which is what those guys want for keeping their rear wheel spinning and coming hard off the corners. The Harleys were made to fire both cylinders in quick succession, while the Triumphs have a essentially single throw, both pistons moving together. Normally they fire 360 degrees apart, but for track racing they fire both at once.

At least that's the way it was explained to me "back in the day"... could be BS

 

Now look what they're doing, making 76 and 90 degree cranks for Triumph's and Norton's. What years you into Norton's?

.....=o&o>.....

 

Guess I am still missing something - you will get the same power out of each cylinder when it fires, right?

Normally you get a power pulse when one cylinder fires, and then a second power pulse 180 degrees later when the other fires. With the flat crank, both cylinders fire at the same time, giving you twice the power pulse, but then you have to wait 360 degrees before they fire again.

Over the entire cycle, the total power produced remains the same - it is only the timing of the power stroke that changes. Why is this better?

On the V8 I can see where getting rid of the counterbalance weight lowers the inertia of the rotating mass, sort of like the new low weight flywheels NASCAR uses. But with a 2 cylinder motor it looks like you would need a larger flywheel to keep the engine spinning during the long wait between power strokes.

What am I missing?

 

With the lighter crank, you can increase the RPM.
If you try to invision the operation in your head, it's too slow, your mind has to be able to run above 5 Grand, and pull like hell through the cornor.

 

I hadn't heard that... is it to make them sound like a Duc or what? To make a little more vibration??

I used to have a '67 Norton-Matchless G15CS, like a fool I sold it for some ridiculous amount like $400 (ex-wife's idea). It would have financed my F-1 project if I'd kept it 15 more years

If I ever finish my F-1, I have a '69 Bonneville in various boxes around my garage...

 

WillyB let me take a shot at it. Normal V8 crank has 1 cylinder firing every 90' of crank rotation. Flat crank has 2 cyl firing every 180'. You still have all 8 fire throughj 2 relotutions of the crank bt the trick part is the flat crank is more balanced and can spin faster. If the engine in your truck right now could spin1000 rpm faster without grenading and have the same horsepower would it be an advantage. Thats why the sprinters and salt racers used the flat crank. Higher sustainable RPM.

 

No Matchless twins but a 500 and 600 Matchless thumpers.
Norton Interstate 74 and Roadsters, total 9 scooters including R90/6 and S BMW's. Sold the T140.
.....=o&o>.....

 

Ok

Lets rewind here a little.

The Nordon/nordion/norden Flat 180 degree Crankshaft used in Flathead Fords primarily for racing has a fireing order of 1-8-3-6-4-5-2-7, it allows one more cyl to fire between the center ports. They are 20 - 30 lbs lighter than stock. Of course you need a matching cam that can be ground in any of the combinations normally available.

As far as Flathead Air Compressors, I've never seen or heard of a Norden/whatever, compressor. The only ones i"ve seen are Schramm comversions for Chrysler Flat six's and Ford Flat four's, six's and the V8's. And I don't recall a Flat crank used in them.

The V8's had two cyl on each bank as power and two as compressor. I think 2 -3 and 5 - 8 were compressor cyl. There were special heads, where the compressor portion had external poppet intake and exhaust valves, the regular internal valve passages were filled in.
Schamm mounted these on everything from a wheelbarrel like device (Needed a Big Sucker) to trailers, self propeled crawlers, to regular Pickups called "60 Specials". The 60 was for 60 cubic feet of air per minute.

Ther are quite a few new cars and trucks running flat cranks, including one of the newer Ford Cars and one of the Ford Trucks (maybe the V-10). A bunch of the exoctics run them as well as some of the crotch rockets, and the can be had for just about any engine.

So ends my current Pontification on the Flat Crank.

Dick

 

Penn Dick, as usual you have done a masterful job of explaining the use of the flat crank. However, I still am curious as to why there would be less vibration on one as compaired to the normal crank. Jag

 

I think we are talking about different things here - specifically, the Nordon crank I was told about fired two cylinders (that shared the same journal, I think) at the same time. It sounded kind of like the Model A 4 cylinder - for that is what it was, two 4-cylinders sharing the same crank.

 

I've read that the "Ford Flathead V8 is Self Balanceing". I've learned that the factory cranks are balanced at grinding, (not assembly) and the rest of the rotating assembly is not. What I think this means is that a stock flathead with stock components will either run, grind its self into balance or blow up.

Anyone building any sort of Modified Flathead better invest in balanceing or have lots of money.

Now for the Flat Crank, I've heard it both ways, it will run smooth as silk or blow up after shaking your brains out.

*****

"I think we are talking about different things here - specifically, the Nordon crank I was told about fired two cylinders (that shared the same journal, I think) at the same time. It sounded kind of like the Model A 4 cylinder - for that is what it was, two 4-cylinders sharing the same crank."

The Flathead has four rod journals, with two rods per journal, 1/5 - 2/6 - 3/7 - 4/8. (Just some basics)

With the Flat crank that puts journals 1/4 and 2/3 180 apart. That is the only configuration that i've ever seen or coul imagine.

With that, pistons 1 - 5 - 4 - 8 are at TDC while 2 - 6 - 3 - 7 are BDC

With a given cam I can fire it as an 8 cyl, 4 cyl or 2 cyl, with the problems being spark and intake volume for the 4 and 2 cyl setups.. The 4 cyl has been done for racing with a special manifold and multi carbs and I've never heard of a two cyl, tho no doubt some one has tried it.

Does this help in what your looking for?

Dick

 

Here is a picture of the Norden 180 Crankshaft

https://www.ford-trucks.com/user_gal...126196&width=2

 

Thanks, 4tl8ford, that is just what I was looking for.