I build classic Mini engines and transmissions in my little shop, and I decided it would be a good idea to be able to start them and run them before sending it off to it's owner. This way I can check for oil leaks, proper oil pressure, water leaks and temperature, set the timing and adjust the carbs a bit. I built it pretty much out of scrap, I found an old treadmill on a neighbor's curb and another had an old weight machine, I cut and welded it all up and added a "dashboard" with some cheap gauges off Amazon. Since I built it I've run about 5 engines in it - one had been sitting for about 15 years and the owner just wanted me to see if I could get it to run - which I did. I also found a pretty good oil leak from the front crank pulley.... Today I fired up an engine I had just built, I haven't done anything with the carbs yet but it sounded pretty good!
Yesterday I went ahead and adjusted the carbs on the hot rod motor - this is a pretty special motor, a little over 10:1 compression, 266* cam, a Keith Calver stage 2 cylinder head, twin HS4 SU Carbs and a few other of my own tricks - it should make between 90-100HP, pretty good for an engine that originally was stressed to make 55HP. To set the carbs, first you disconnect the linkage between the cabs so you can adjust them individually. Next you set the throttle openings so they draw the same amount of air, then you can set the mixture - you do that by raising or lowering the main jet with the brass nut under the carb. I had given them an initial adjustment of two full turns down, but had to go quite a bit further to get it into the right mix....we may have to get some richer needles but for the first 500 break in miles these will be fine. Further refinements will come after it's in the car as the owner will install a wide band O2 sensor that will give him a much more accurate picture of what the carbs are doing. Once I had it dialed in I shut off the fuel pump and let it run the gas out of the carbs. I think the owner will be pretty happy with this one.
I love the engine test stand.. would love to see more of that (and the engines you are building). I must say, great job on essentially doubling the HP on that engine. Tuning carbs to me is a little bit of black magic. Had to do it on motorcycles.. but I can’t say I was great at it. I could get them to about 95%.. but then would take it to a guy that always could get a little more and clean up either power curve or overall running.
Over the past few years I've run a bunch of engines in my little cobbled together stand, and I've learned a lot about how I should have built it....enough so that I may build another one in the near future. Improvements to include making it easier to get the motor in and out of the stand, moving the dashboard up to a raised panel on one end of the stand and making a removable cover for the wiring. Finding room to install a small fuel cell and an easily accessible place for the battery to sit. I might even see if I can make the dash panel rotate so I can easily see it from any location around the stand? Just ideas at this point after using this one for a while now......it works just fine as it is, but as my old boss used to say "You don't have to be bad to get better" Right now I have a 1098 mounted in there to do my EFI research and work, and it has brought up a few shortcomings with this design. It will do for now but I think a new one is on the horizon.