Posted by M Forster on April 09, 1998 at 05:33:53:
In Reply to: WD45 ignition tune-up posted by David S. on April 02, 1998 at 09:04:42:
: I'm still tuning up my WD45, including the ignition system. So far I've replaced plugs, plug wires, coil and distributor cap. Now am replacing points and condensor. How is the point gap set? (I know it should be @ .20). Will it have to be re-timed afterwards and if so, how? What wire should be attached to the coil terminal marked "BAT"? I know these are basic questions, but vehicle mechanics is not my thing and my AC operators manual is rather vague. Thanks for any help.
First let me say that they're are several shop manuals covering the WD-45 and their all useful, however, they assume a general level of "tractor savy". This is a problem for me since my area of mechanical experience is motorcycles. I would buy every manual you can find and make sure you get a copy of "Country General's" (aka Wheelers) tractor parts catalog.
Next lets talk about your coil. It has two terminals and a secondary (high voltage) nipple. The side marked "BAT" is you battery lead, it attaches to the positive battery terminal (assuming that the negitive post is attached to ground). The other terminal attaches to the primary post on your distributer.
Timing is performed as follows:
When installing a distributor the engine must be turned until the number one piston is at top dead center on the compression stroke and the center mark on flywheel is in center of inspection opening, this applies to both WD and CA tractors.
The proper timing of the distributor to the engine is accomplished in the following manner.
Remove spark plug from number one cylinder, and place thumb over plug-hole, crack engine slowly until air is forced past thumb. The center mark on flywheel will be close to inspection opening at this time. Locate center mark in center of inspection opening. Fire mark or F on flywheel will show in opening first, do not use fire mark.
Remove cap, rotor and dust cover from distributor. Check the point setting and adjust point gap .018" to .022" with gap at the widest position, or when breaker arm is on highest side of cam lobe. Install rotor and turn shaft until rotor tip is exactly opposite primary lead terminal. Place distributor in drive housing with primary lead terminal toward rear of engine. Rotate distributor counterclockwise until points just break, and tighten clamps.
Remove rotor, replace dust cover, rotor and distributor cap. Place number one plug wire directly above rotor tip. Proceed around distributor cap clockwise number two, four, three and place coil wire (high tension cable) in center.
The distributor has an automatic spark advance of 30-. This spark advance occurs slowly through a speed range from 400 RPM to 1 000 RPM of engine. Reaching the full 300 at approximately 1,000 RPM
This automatic advance is accomplished by means of a simple centrifugal advance mechanism built into the distributor. This mechanism consists of an advance cam which is integral with the breaker cam. A pair of weights springs, and a weight base which is integral with the distributor shaft at low speeds (below approximately 400 RPM) the springs hold the weights in position so there is no advance and the spark occurs at top dead center of engine. As speed increases the centrifugal force acting on the weights causes them to gradually move out against the spring tension so that the toggles on the weights push the advance cam and thus the breaker cam ahead of the distributor shaft. This causes the breaker cam lobes to open and close the contact points earlier in the compression stroke so that the spark is advanced. The spark is fully advanced at approximately 1,000 RPM of engine.
Since a gradual advance occurs from 400 to 1000 RPM it is necessary if checking with a timing light to check at a speed below 400 or above 1 000 RPK Speed should be set by using a tachometer and it will be found that if it is set below 400 (approximately 350) and the firing checked at this speed, fire will occur at center mark on flywheel and will be easier to see at slow speed. If flywheel marks cannot be easily seen a chalk mark about 1/2" on each side of mark, with mark it-self left dark will help. After timing is checked reset carburetor throttle stop screw so engine will idle at 400 to 500 RPM.
Any more questions, just leave a follow-up.
Mark