Wooden Gantry Crane

When I was offered a $300 1998 A8 Quattro parts car (for my 1997) I leapt at the chance. By the time I got it home, though, I thought better of my plan to swap the electrical harness from that car to my car, and decided that I would swap the transmission from the old car into the "parts" car because it was in such better shape. But this presented a problem — how do I pull the engine and transmission out of one car, and put it into the next, given my lack of a perfectly flat and level place to work? The answer as I see it is to build an A-Frame or a gantry.

When presented with the problem of making an engine swap on dirt, the usual approach is to lay down a piece of 3/4" thick plywood so the picker has something to roll upon. Unfortunately, this only really works well when the surface is extremely flat and level. I'm dealing with a somewhat bowl-shaped gravel carport, and I really can't reasonably use that solution. This led to me to the idea of using a gantry which could roll on rails, since it only needs to be able to go forwards and backwards — I can drop the engine and transmission onto a pair of dollies or wagons (which should be an exciting subject itself in the future) and split them up before moving them sideways around the garage.

The big problem then, of course, is finding a proven design. I need to lift some seven hundred pounds of engine and transmission out of the vehicle together. I searched the interwebs avidly until I came across a likely design and then I got to tampering with it. It's worth noting that neither I nor the guy I'm copying is a structural engineer, and this is a dangerous thing to mess with; I should arguably tell you not to use this design. Consider yourself told. I went for a 7' wide design here because I wanted to make it as narrow as possible while still being able to tackle any job I might want it to do; 6' would be wide enough to accommodate my A8, but it's not enough for my F250 which is closer to 7' wide when you account for the width of the wheels and tires.

Having said that, here's the details. All the lumber used in this design is 8' or shorter, the idea being that all the pieces will fit into a minivan. The upright posts which hold the gantry are 4x4s. These are the primary pieces in the design so it might be wise to spring for kiln-dried lumber if it's available. The gantry itself, that's the cross piece(s), is made from two pieces of 2x8, in my case 7' long. The bottom triangle which supports the upright posts is made of two horizontal 2x6s per side, and triangulated with 4x4s. A bracket of 2x6 or 2x8 is used where the triangulating 4x4s meet the upright 4x4s. The chain hoist hangs from a piece of heavy steel pipe which in the original design runs through a pair of 2x4s attached to the top of the gantry as shown here; I will probably use something made of steel to locate the pipe so as to make it lower-clearance since I want this to fit into the carport. The whole thing is held together with bolts, not screws. You can do this on the cheap by buying all-thread, washers, and nuts instead of bolts.

Now... to build it. Once again, do not build this gantry. Or if you do, do not blame me for any injuries incurred. I have not even built this gantry yet, but this is the plan I'm about to use. I'll get back to you when it either falls apart or doesn't.