Engine Hoist design

[andysredmini]

Im toying with the idea of building an engine hoist at work. I don't really need one at the moment but have plenty of time and material so thought i may as well.

I'm thinking along the lines of an A Frame gantry on wheels that fits over the width of the car. one that comes apart with corner joints holding a box 25x25x25 shs frame together with a 50mm tube for the crossbar.

Has anyone got any links to anything similar for me to look at. i have had a Google but not really found anything like what i have in mind.

Also how high should i make it above the build table and top of chassis?
my shed roof may be the limiting factor on that one though!

Cheers

Andy