A Single pulley retains the 1:1 mechanical advantage ratio but does allow the operator to change the direction of the winch pulley.
Teaching the Ropes
Every four-wheel-drive magazine I've ever read has, at one time or another, made the same statement you did in your article in the Dec. '05 issue entitled "Building an Off-Road Recovery Vehicle." This time I felt I had to respond. The statement in question is on page 48: "initial outfitting included... a 17,500-pound pulley block to double the winch load capacity."
Gentlemen, a single block affords a mechanical advantage of 1:1 and therefore makes no change to the winch capacity. It only allows you to alter the direction of the pull.You can verify this for yourselves very simply. Lift a bucket of broken U-joints (or whatever) straight up with a spring scale (like you find in the grocery store). Now hang a pulley from a rafter in the garage and fasten one end of a line to the bucket. Loop the line through the pulley and back down. Fasten the other end of the line to the scale. Now, pull on the scale again (you're the winch). The weight reading will be the same: no mechanical advantage. You need more than one block to gain mechanical advantage.
Two or more pulleys must be used to gaim mechanical advantage.
I bring this to your attention so the next time someone says they will double their winch capacity with a single block, you can set them straight. Otherwise, people could believe it, miscalculate, and find themselves in trouble someday by introducing too much load into an already bad situation.
Mark Jenkins, Fernandina, Florida
Mark,
You caught us, along with all of the other publications who have printed similar information in the past. Thanks for the illustrations you sent with your letter.
Blank Canvas
I don't know much about four-wheel drive, but I have a '55 Willys wagon that my grandfather gave me last January. I pulled the 226ci Super Hurricane I-6 out of it and was wondering if you had any suggestions for what drivetrain I should put in it.
Andy Kidwell, Palermo, California
Hey Andy,
With the age of your Willys, you can install any drivetrain that will fit and not worry about keeping the drivetrain conversion smog legal. Even though your truck can legally run any engine, we'd recommend a small-block Chevy V-8 with throttle-body injection (TBI). This engine is a common, good performer, and is well supported by the aftermarket industry. You didn't say whether you plan to keep the stock transmission in your Willys, but you have the option to use a Chevy transmission adapted to your original transfer case or to use your original transmission and transfer case adapted to the Chevy engine. We'd recommend the TBI over carburetion because this type of fuel injection is easy to work with and offers all the advantages of fuel injection, namely the ability to run at any angle, temperature, or altitude. Check out www.advanceadapters.com and www.painlessperformance.com for more swapping info. Good luck. Let us know how it turns out.