I had a call recently from someone who said their TED had just stopped with a “clatter” at the front of the engine. I was 90% sure what the problem was so , called round to have a look, taking a timing chain and governor parts with me.
Sure enough, no drive to the distributor so broken timing chain. This engine had been professionally overhauled and had not done much work since so, knew what had happened.
Off with the bonnet, tank and radiator, then remove the front axle after placing some blocks underneath the engine. Next remove the timing cover and sure enough, a governor weight had broken away from the mounting plate, got mixed up with the timing chain which then broke. Fortunately the timing cover was not damaged.
Strip out the governor plate and mushroom that are all mounted on the camshaft sprocket then remove the sprocket. Check the new chain is correct then proceed to fit the chain and retime the engine. Forget what’s printed about timing marks and start from scratch as follows:
Remove the rocker cover and turn the crankshaft until the keyway on the end of the crankshaft is at 6-0-clock or bottom. Make sure this is accurate. No.1 and No.4 pistons are now on top dead centre or at the top of their cylinders. No.1 cylinder being on its “firing” position or stroke, No.4 cylinder has just finished its exhaust stroke and is starting it’s inlet stroke.
Now fit the camshaft sprocket to the camshaft and loosely secure with the 2 studs. Turn the camshaft slowly and, watching the position of the rockers, when No.1 exhaust valve is fully depressed, go to No.4 cylinder and set up the exhaust rocker to 0.022 inch clearance. Next turn the camshaft further until the inlet valve on No.1 cylinder is fully depressed then go to the inlet valve on No.4 cylinder and set this to 0.020 inch clearance. Turn the camshaft again and watch the rockers on No.4 cylinder.
Watch closely as the exhaust valve starts to rise because as it gets to the closing position the inlet will start to open. The valves are now “on the rock”. By turning the cam wheel back and forth, use a 0.010 inch feeler gauge and when you can get the gauge to go through both tappets the valve timing position is correct.
Now make sure the crankshaft is in the same correct position, remove camshaft sprocket, fit the chain and turn the sprocket within the chain until 2 of the stud holes line up with 2 in the camshaft. If this can’t be done without moving the camshaft, turn the camshaft sprocket onto its opposite side (this alters the mounting hole by a quarter of a tooth). Repeat the process and you should find 2 holes that line up. Fit the studs and lock them with the locking tabs. It is most important not to cheat at this stage by moving either the camshaft or the crankshaft to find 2 stud holes.
OK, timing done. Next turn the crankshaft and watch the rockers. Reset in reverse the No.4 rockers to 0.010 clearance inlet and 0.012 clearance exhaust. Now rebuild the governors with a new, or very good 2nd hand plate, weight, pins and mushroom. If the mounting plate is 2nd hand do make sure the pin holes are ok and not worn or you could soon have a repeat mishap. Also when you have done the valve timing and before you turn the engine, take off the distributor and the rotor arm should be pointing to no.1 plug hole. Should this not be the case then, as a Club member found out last year, the ignition timing is set incorrectly, however if the tractor was running ok before then the chance of this is remote.
Now to governor setting, this is really too complicated to try to describe so if the governor was working ok before, just do a couple of checks. Go to the adjusting screw on the timing cover, slacken the locknut, and with a screwdriver turn the screw anticlockwise, say a couple of turns, and then screw in until the governor arm moves. Turn screw anti-clockwise a quarter of a turn and tighten the locknut.
Now go to the rod with a fork on the end and with this rod pushed back towards the carbo and the throttle lever set in the tick-over position, the clevis pin should slip in through the fork and the governor arm. If not, the fork can be adjusted until it does and when you can do this, screw the fork onto the rod I full turn to in effect shorten the rod. If the engine is governing ok then leave it at that.
After refitting the tank and before refitting the front axle, have the engine running for a few seconds. There will be those reading this article who will say I have gone over the top with regard to timing the engine but I was taught to time engines from scratch as an apprentice and that still sticks. Engines with timing gears are marked so they can be timed as such but I still get a buzz when I have valve timed a TEF and then spill timed the injector pump but that’s another story.
Published in Journal No.62 Smmer 2009 : Malcolm Rainforth



















