Thread: Crossfire Crank in a ford flathead, question

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First, I want you to know that I do not have one. But, I have a bet for a cup of coffee going. A friend of mine and I were reminiscing about one of the crossfire cranked flathead motors my dad had years ago. My dad and I set it up in a cut down chevelle roll cage, installed cut down big block chevy headers on it, put a 5 gal can of gas along side it with a hose run to the fuel pump. Oh, did I tell you it had a supercharger of some sort on it with 2 duces. When it fired up, it had the sound of a corvair, much like a V6 with a throaty exhaust system. Also, I got to hold a big screw driver against the blower belt to keep the tension on it, we had no tensioner for it. I said all of this to ask; does anyone know what the firing order is on one of these engines with the crossfire crank, 180 degree rod journals. This friend of mine says that it fires 2 cylinder at a time, so it fires 4 times for each turn, much like a 4 cylinder, but using 8. I find that hard to believe, so I am asking the question to you knowledgeable folks. Sure would appreciate the facts in this case. Thank you, Rich rcpowell55@hotmail.com

yes i believe they did fire 2 cylinders at a time but it only fired 2 times per revolution--but then maybe not also--they did have a wierd sound

I think you owe your buddy a cup of coffee. It had something to do with a special crank and possibly cam so that two cylinders fired at one time. These were marginally popular in sprint cars and the idea was that they had more torque coming out of the turns. I've never seen one, but hear that they sound like a couple of 4 cylinder engines instead of a V8.

Hope he doesn't drink that fancy Latte stuff.

Don

I appreciate the info guys. I will try to look respectable while paying off the bet.

Thanks, Rich

Thanks for your input. Looks like it cost me a cup of coffee. The tuition of life never ends, unless we choose to end the learnin'.

Thanks, Rich

Here's link to an antique racing site that has a ton of information on flatheads, and the many different ways people modified them to make them faster. According to the page on Crankshafts, the stock firing order is 15486372 and the crossfire is 18364527. Hit Control-F and enter Crossfire to search - mentioned twice on the crank page, and also on the camshaft page. I did not read far enough to find anything about how the distributor was set up. Flatheads - Crankshafts

I have to say after hearing one years ago at a local dirt track, they have a unique sounding exhaust and for a flathead Ford - a lot more power then that puny 3 main bottom end can handle for long. I did some reading on one a couple years ago, and they were great as long as they stayed together.