I thought it would be useful to shed some light on the RailBus's challenges on Saturday of the Picnic, since so many were watching and wondering what was keeping it from running.
It was run during the week before with no trouble, and on Saturday AM it started and was run out to the stub switch, where it died. It couldn't be restarted.
Ignition problems were suspected because we couldn't get a consistent spark at the plugs. However, all or our troubleshooting failed to identify the cause. Everything was brand new and seemed to work fine, just no spark when all together and cranked.
This 'T' engine has a distributor and coil added, which is a common (as I understand it) modification. The distributor was familiar to me as similar to the Bosch unit that was on my 1968 Volvo. It was driven from a vertical shaft which was turned by a helical gear set from the camshaft.
After sleeping on it Saturday night, Ric Sisson and I decided to tackle it one more time. After further timing and rearranging of spark plug wires, we got it to start and run well. However, when shut off, it wouldn't start. Then we realized that the position of the rotor in relationship to Top Dead Center of the #1 cylinder seemed to be moving around! Clearly this was a problem. We removed the distributor and were able to manually turn the drive shaft for the distributor when the motor was not turning, so it was now obvious the timing was moving around radically when the engine was stopped because the camshaft gear was turning on the shaft. The lack of spark was because the rotor wasn't aligned with the contact for the plug. We also thought the points in the distributor weren't very consistent, but now we're not sure how much of a problem that was.
This distributor modification required a helical gear to be screwed onto the end of the camshaft at the front of the engine. The instructions were ambiguous about how much to tighten it, and relied on the compression of the engine to hold the camshaft from turning. We think that it really couldn't be tightened sufficiently with that procedure.
The gear was indeed found to need tightening, and after that was done, the timing was reset and it ran and started consistently.
In conclusion it was not really anything that was obviously avoidable, and the real culprit hid itself well until the big day.
The RailCar is truly yet another amazing example of skill and vision and dedication from our members.