I started and drove my 36 roadster this week that has been sitting for 25 years. It has a 4:11 rear with the original 36 Columbia. For those that don't know the early Columbia rears had a mechanical hand operated vacuum valve on the engine side of the firewall. There is an operation rod slightly off center attached to the bottom of the dash. Attached to the rod under the dash is an arm and another rod over to a mechanical speedometer gear changer to match the speedometer with the gear change. Two hoses run from valve down the firewall and back to vacuum cylinder on the rear that shifts from the stock 4:11 to somewhere around a 3:50 (guess). The hoses go to each side of the vacuum cylinder. When the vacuum is applied to hose toward the right rear wheel it pulls the shift arm in the rear to the right side of the car which I call OUT. When applied to the inside hose toward the center of the rear which I call IN and the cylinder moves the rear shift lever IN towards the center of the rear and the Columbia is engaged and OUT it is back to the stock 4:11 rear. It's easy to remember In is IN and out is OUT. I removed the hoses at the firewall before I ever got the engine running and poured a good shot glass full of MMO in each hose, took an air hose with about 15 lbs of pressure and blew air back to the cylinder and could hear the rear shift each time I changed which hose I blew in. This lubricated and softens the leather cup washers and allows it to shift smoother. The first trip out on the road I pushed the clutch in then switched the lever into high and it smoothly went into Columbia high. Push the clutch when I was coming to a stop and switch the lever to low and it dropped out. The second day on the road was going to turn the switch without pushing the clutch but there was a police car behind me and I wasn't sure what was going to happen so I waited and he turned. I switched without the clutch and nothing happened so I pushed the clutch and it shifted. Driving down the road with the Columbia engaged I turned the lever to low and nothing happened until I was going to stop and I pushed the clutch and it dropped out so that seems like the best way to use it. On the electric shift units you push the clutch, hold it in and push the momentary switch on the dash, leave the clutch out the release the switch. To get out of Columbia you just push the clutch. Every time from the first time I tried it, it switched smooth and crisp both in and out. Spent 4 days getting it running and fixing the small but time consuming problems cleaning the interior, polishing the chrome, polishing the inside and out and cleaning the white walls. Only thing left to do is plug in a loose dash instrument light and fix the gas gauge. Next I'll get on the 35 phaeton which has been sitting about 27 years. Then about a dozen more after that. I have a few months of fun lined up. I got into a lot of commercial properties plus hurricane Charlie in 2006 and had lots to do and haven't done much with the cars, didn't even go to many shows. Skip helped me take care of the cars for years but for the 15 or more years he's been busy with his coils and pumps. He helps me a little if I really need help but I try not to bother him as he stays busy. G.M.
Early Mechanical Shift Columbia
- Thread starter G.M.
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No electrics at all on the early mechanical Columbia's only a clutch operated vacuum switch. The later electric ones have a clutch switch. I made quite a few electric switches for my cars and some for friends that work better than the original Columbia controls. I have the original controls but don't like them. I use a Pollack gas tank fuel valve which has 6 ports for a fuel injected engine with 2 gas tanks. The valve also has a set of contacts to switch the gas gauge. The Pollack valve is 12 volt but has a motor not a solenoid coil and the motor also works on 6 volts. I use the contacts to switch the speedo changer made by SW for 2 speed truck rears. Most of these are 12 volt units and my cars are all 6 volt. I take the coil out of the unit, remove the coil wiring and rewind it with 650 turns of wire 2 sizes larger and it now works on 6 volts. On the first cars I mounted the speedo changer down near the steering box with a short speedo cable to the speedometer. Later I made a thread adaptor for the changer to screw in the back of the speedometer using the original speedo cable. The case of the changer is grounded and has a screw terminal to the other side of the new coil. I run a new wire from the coil screw terminal to one side of the fuel gauge contacts in the fuel valve, the other side of the contacts to ignition switch. I use a double pole spring loaded momentary switch on the bottom edge of the dash held by a clamp on heater switch bracket so I don't have holes in the dash. I also use a mechanical brake light switch mounted to the clutch arm. To go into Columbia I push the clutch, push the momentary dash switch holding it in while letting the clutch out and it go's into OD. When I release the momentary switch the fuel valve changes to put the vacuum to the OUT side of the vacuum cylinder on the rear but there is no vacuum going through the OUT hose until the clutch is pushed. In other words it stays in OD until I come to a stop sign or get on a mountain and need to drop out of OD which it does as soon as I push the clutch. I have used these for 20 years or more with no problems. G.M.
Charlie ny
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GM and Phil,
The Columbia in my '41 1/2 ton is 100% vacuum controlled. A simple
lever valve on the dash, kind of looks like a battery kill switch. 3 ports...#1 engine
vac in, #2 & #3 back to the Columbia for engage & disengage. Admittedly this is
not 'correct' but it does the job. As you mention George the clutch must be
depressed to change the ratio.
Charlie ny
The Columbia in my '41 1/2 ton is 100% vacuum controlled. A simple
lever valve on the dash, kind of looks like a battery kill switch. 3 ports...#1 engine
vac in, #2 & #3 back to the Columbia for engage & disengage. Admittedly this is
not 'correct' but it does the job. As you mention George the clutch must be
depressed to change the ratio.
Charlie ny
Phil your sluggishness may come from the shift cylinder on the rear or smaller pipes or hoses going back to the rear even soft hoses could suck in with vacuum. The leathers in the rear cylinder need to be soaked good with MMO to shift smooth. Any other oils I tried gum up and make shifting sluggish. The other thing on the cylinder where the shaft go's through there is a standard oil seal available from bearing supply houses. If this seal leaks it sucks air in from under the casting where the cylinder bolts to the rear. If this seal is bad rear oil is sucked through the seal into the IN side of the shift cylinder. Remember IN is IN and OUT is OUT of OD I noticed a slightly faster shift on some that I mounted the Pollock fuel valve back nearer the shift cylinder. I did several 46 types with the cylinder under the floor behind the little step up in the floor. On my 33 phaeton I put it behind the rear seat. I think I may have a few pictures in this computer, will post if I do. G.M.
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I just happened to think that to find out if the seal is leaking remove the hose from the cylinder closest to the center of the rear. If it's leaking there will be black gear oil dripping out of the hose. I don't believe in changing parts that aren't bad. While your down there find a way to shoot MMO in both sides of the cylinder. G.M.