The Stovebolt Site Forums The Shop Area The Tool Chest Ignition Scopes

This year I picked up a Heathkit Ignition Scope at a swap meet. It was their first model. While looking online for information I found their next model on Ebay for cheap, so I bought it too. They now work perfectly and are fascinating tools. With the IO-20 I had to make my own cables up. Just lately there has been a bunch posted for sale on Ebay. There is an IO-20 complete with cables for around $65. If anyone was looking for one of these, it is a real bargain.

Went to a consignment auction last spring and they had one of the very large 5’ tall X 6’ long Sun machines. Tested everything back in the day. It rained the night before the sale and nothing was covered. It sold for $25 because there was no way to test it and it had been wet. Would have been great for an automotive related man cave.

Those Sun machines with the distributor tester were quite the beast. I understand that with some of the dual point distributors, a machine like that was the only or best way to set them up.

Like anything else, the experienced guys knew some tricks, like setting up dual points with nothing but a dwell meter and a business card, but the Sun tester made it profitable for the pros to make a living. I watched Dad make V-12 Lincoln Zephyr distributors work on flathead Ford V8 race engines all through the early 1950's. That was quite an education for a pre-teen kid. I did something similar with HEI distributors in the late 1980's on small block Chevy race engines.
Jerry

Hotrod,
so I understand the dwell meter and card trick. Could you use that on the Zepher V12? My neighbour used to have a beautiful 37 Lincoln Zepher.

Nope- - - -the Zephyr distributor is actually two distributors in one housing, with two coils integrated into one case sitting on top of it. That one runs 6 cylinders on one coil, and the remaining six on the other. Once the dwell is set on each set of points individually, then they must be synchronized so all 12 cylinders have the same initial timing and centrifugal advance. Ford also uses a "vacuum brake" system to retard the timing during acceleration when the manifold vacuum drops below a certain point. There's a reason there were Ford mechanics back in the 40's and 50's, and "everything else" guys!

Dad would install an 8 cylinder cam into the Zephyr distributor with 4 lobes ground off, so each set of points ran 4 cylinders. He also had to modify the rotor, and pick out 8 of the 12 plug wire terminals to wire for the V8 engine. The end result was about 50 degrees of dwell for each firing impulse, and a fat blue spark about 3/4" long even on 6 volts. On his own car, he added a little sneaky Pete trick- - - -he used an 8 volt battery! Since they didn't run generators, late in the racing program he still had a hot spark when everybody else's battery was getting a little weak! The starter also cranked that 11:1 compression engine better with 8 volts instead of 6. That's probably the only time I've ever seen a good reason to run an 8V battery, BTW!
Jerry

Wow, I knew it was different but not that different! My neighbour used to tell me that it has to be set up on a machine like the Sun. I am glad I have a Chevy!