Starters and Starter Solenoids ©By: John T. Blair (WA4OHZ) ![]()
Originally written: circa 1994 Lucas has 2 basic types of starters:
The Lucas M418G is used on the +4s with the TR engines. There are 2 types of the M418G, the Eclipse, and the S types. The only visible difference is that the "Eclipse" has a hood over the drive mechanism (Bendix?). The drive mechanism is different for these 2 types of starters. Otherwise, it appears that allot of the parts in the casings are interchangeable, (but not the armatures). Both of these starters also require a remote starter solenoid. The inertial type get their name, because when the solenoid applies power to the starter and it starts to spin, the inertia (no movement) of the Bendix causes it to slide down the spiral grove cut in the end shaft of the starter. The Bendix finally engage to the fly wheel and starts to turn. These starters have been around for years and work well, but they have 2 problems:
This second problem can be caused by a couple of things: The groves in the starter shaft get dirty, which can keep the Bendix from sliding out and engaging the flywheel. This was a constant aggravation on my '67 Spitfire. To fix it, the starter must be taken off the car and the shaft and grove cleaned with varsol or some other solvent. Greg Solow has another cause for the problem. Your starter has a "bonded" rubber drive that connects the drive gear on the starter to the shaft. The rubber inside the coupling comes unbonded from its housing and basically "slips". I have temporarily repaired them by taking them apart and reglueing them together with "superglue" type anaerobic adhesive. This "temporary repair has actually lasted many years. There is a replacement drive available for around $100. 00 that is a good permanent fix. I have seen brain dead electrical rebuilders weld this drive up solid in an attempt to fix it. This doesn't work as the starter needs the cushioning that the rubber provides. Without this cushioning effect, the teeth of the ring gears get sheared off when you try to start the car. Regards, Greg SolowLucas has come out with another starter to over come these problems. This type of starter is called a pre-engagement starter and has the solenoid attached to the starter. When the ignition switch is turned to "start" the solenoid fires. It has a lever attached to the plunger and a fork attached to the Bendix so it pushes the Bendix into position before the starter starts to spin up. These pre-engagement starters are available from Dave Bean Engineering. They bolt right up as did the original starters, but it takes a small modification to the wiring. ![]() Wiring modification for pre-engagement Starter ![]() Most of the Morgans use a Lucas 76446 which is a silver bullet looking thing with a black rubber button on top, mounted on the front of the firewall. The following instructions will allow you to keep this solenoid and add the pre-engagement starter and solenoid.
![]() The other day, I went to replace the power feed cable, and when I removed the nut from the brass stud, the threads came with it. At this point there are 3 options:
The point I'm trying to make here, is that you can replace the contact set. Dave Bean sells a new set for $15. It is a pretty easy job but will require that you have will a soldering gun (140W is fine), and a solder sucker for removing the old solder. (I recommend the plunger kind. It is sort of an over grown pen looking thing. There is a plunger and a spring inside a tube. Once cocked, when the trigger is pressed, the plunger travels rapidly to the top of the cylinder and creates a vacuum, pulling the molten solder off a connection. These are readily at Radio Shack for about $10.)
To remove the solenoid:
Once the solenoid is removed from the starter, the contacts cap will have to be removed. Start by removing the 2 bolts from the contact cap. The solenoid body block "A" can then be removed, but the coil and the block "B" are still attached by 3 wires soldered to the contacts cap. These 3 connections will have to be unsoldered.
For those not initiated it the realm, you heat the gun until you can
When the 3 connections have been unsoldered, the contact cap can be pulled
Now that the solenoid is disassembled, the new movable contact can be
inserted into the coil of wire, the spring set into the hole in the cap,
and cap can slid onto block "B". Be sure that the 3 wires from the solenoid
align with the 3 holes in the contacts cap. Press the two pieces together.
This will require a slight effort due to the little spring inside. (You
didn't forget to put it in, did you?) While holding the block "B" and the
contacts cap together, solder the wires to the eyelet’s on the contacts cap.
Install the block "A" with the 2 bolts, and reattach the solenoid to the
starter. Hook up the power lead and the ignition wire and you're all
done. With any luck the engine will spring to life when you turn on the
ignition switch.
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