Those of you with long memories may vaguely recall a thread where I enquired about lapping compound I had read about in SEM, in a long forgotten article. This powder mixed with oil has the wonderful characteristic of being very abrasive at first, but breaks down to harmless non-abrasive material when worked for a short time. Anyway, P T-E and John A remembered the stuff and both had used it successfully IIRC. The article I was struggling to remember was Philip's concerning the restoration of a Ransomes Wizard. I obtained a suitable amount for trying (thanks Philip), so I could attempt to get the 4hp Bamford horizontal running better.
With typical Celtic flair, having discussed it, thought about it and obtained the necessary, I then set about not doing the job for ages. In my defence, the engine is stored in my neighbour's poorly lit building, and it was pigging cold at the time. Since then various distractions, procrastination and lambing have kept me from attending to the job.
At long last on Monday night I went down to my neighbour's place and replaced the piston with its new rings in the Bamford. I'd smeared the oily lapping goo around the cylinder first. The friction I needed to overcome to push the piston in was tremendous. Next time I'll put the lapping compound around the upper portion of the cylinder only! The big end was bolted up, and with the inlet valve pushed in a touch to relieve compression, I turned her with the handle. The resistance was strong, in fact driving the piston to TDC was almost as difficult as dragging a dog upstairs for a bath.
A few revolutions later, the resistance lessened, as the compound begain to break down, and the engine turned over reasonably easily with the handle. Now it was time to put in fuel and try to start her. I set the drip oiler to a very generous setting and made sure everything was amply lubricated. A couple of turns on the handle and she started and ran very badly , though I could feel the compression building up. "This wasn't in the plan", I thought, somewhat downcast. In SEM, restarts of engines are glorious affairs, when the engine runs up in speed until the governor takes over and then the old girl proceeds to hit and miss like the day she was tested in the factory.
This was a flatulent, grumpy sort of affair, with the engine stopping a lot and me messing about restarting and adjusting fuel settings. The amount of petrol sloshing about in the cylinder was washing away the lubricant and making the rings squeak. Reluctantly I stopped the engine and headed home, dejected and feeling somewhat out of my depth. I had that familiar feeling that you get with the Haynes Manual. It says "undo the hub and withdraw the half-shaft". A whole night of struggling to get out the reluctant component is boiled down to one sentence.
On further reflection, something about the intermittency of the firing and the amount of spare, unburnt petrol washing about, whispered magneto trouble to me. The fact that the compression was now quite good and there was obviously fuel aplenty in the cylinder backed up my feeling. In the past, I've never had problems with Webster mags, but I remember Richard Bamford saying to me that in his time they were nothing but trouble. The next day at work, various flourescent lamp chokes were found and interesting experiments were conducted with power supply voltages and the best sparking coil was selected from the bunch we had.
That night I revisited my neighbour, wired up the coil and a battery to the igniter, disconnected the mag, oiled up the engine and proceeded to "'ope 'n' crank".
"Putt, tick, tick, tick, tick, putt, tick, tick, tick, tick" said the engine once she gained some speed. She continued in this vein for a few minutes, gaining strength as she went, and chucking out some pretty grim looking metal-loaded oil from the cylinder. A few more minutes and the oil was clean and she then ran for a couple of hours, like the proverbial watch. Swapping the ignition back to the Webster provided the same miss 'n' miss firing pattern as before, despite the engine being nice and warm and the fuel setting being just right.
The Webster mag will now receive some attention when the whiplash from a car altercation yesterday passes off.
Regards, Arthur G