Electrical Q and starter push button - S2a

[Cap]

In the process of wiring the series 2a (1963) which was originally a positive earth (I believe). With the S3 diesel engine and alternator, I am wanting to keep it as a negative earth. I am using the original starter button setp and also another starter button to be used for the glow plugs.

A few things have cropped up that I am unsure of:
1) there is continuity between the positive and negative battery terminals (battery not installed). This would indicate a short somewhere or can continuity occur due to other items (like the starter button)
2) starter button, how does it work in terms of ignition key? I have the two wires that go on the two spade terminals on the starter button, and that terminal goes to the +tive and the other terminal goes to the starter solenoid on the starter motor.

However, when I test continuity between the two terminals on the button, there is continuity. So how does the button work?

Hope the above makes sense...

[123rover50]

sounds like the button is faulty. Should not get a circuit if not pressing the button, should get one when pressing.

[JohnboyLandy]

Hi Carlos,

As for your continuity between batt +ve and -ve, that could be your alternator. Try disconnecting the charge and sense wires from the alternator and see if you still have continuity.

In your case for a diesel, the ignition switch "ON" position ought to power the glow plugs. I don't know much about diesels, but I thought the glow plugs don't need to be powered once the engine is running, so you should be able to turn the ignition switch off when the engine is running, and have the engine remain running. How many positions does your ignition switch have ? ACC - OFF - ON ?? On a petrol engine you need the ignition switch on all the time to power the coil. On both Diesel and Petrol, the ignition switch ON position would normally power things like indicators and wipers.

It does sound like your starter button is misbehaving.

HTH

Cheers,
John

[bemm52]

Cap if you unscrew button ....(button switch and assembly out of car) it is possible to prise around the cover of the starter guts and have a look inside.
My button stuck on which was quiet interesting, exiting car, lifting bonnet with spare on and ripping of negative battery lead quickly.
Once you get inside starter unit there are parts that are insulated from others, on the end o f the starter push rod is a metal (copper?) washer insulated from but attached to the rod that gives the electrical contact.
In my case the insulation had broken down, I disassembled and drilled washer then filled hole with epoxy and redrilled to attached rod that was then insulated by the epoxy resin.
Once you get it apart prise metal lip on terminal end the workings are quiet straight forward if you can do an ignition switch you can do this
Good Luck
Cheers Paul
,

[Blknight.aus]

turf the push button, you're not using that for a diesel starter motor.

now dont worry about too much else from the 2a side of starting stuff.

the extra wires are the bypass wires for the ignition coil that bypass the ballast resistor so that the coil gets everything it can on a petrol to try for a start.


what you can just use that push button start from the 2/2a is for the glow plugs on the diesel, they draw between 80/120 amp they are normally wired in series and have a honking great chunk of coiled resistance wire in series with them as well, theres several aftermarket 12v glow plugs that will work and can be wired up in parallel so if you loose one you dont loose em all, and trust me, you're going to need them if it starts heading south of about 5 degrees.

[Cap]

Thanks all for the replies. A couple of things... I am keeping the 'original' series setup which includes the push button starter as I dont want to use the later ignition switch that has the glow plug option.

So what I have done is basically run the +tive to the starter motor (something the button did before), but now I use the button to activate the starter solenoid. I did this when starting the engine with just a wire between the starter battery feed and the solenoid so I know that system works.

The other button for the glow plugs will only activate when key is on as with the starter push button. Yes I can press the glow plug button anytime when running, but so can the starter button.

From what you describe I do have an issue with the button as I get continuity between the two poles without pressing the button... so ill check both buttons first.

Yes my electrcial schema is a hack but I do love the old style push button setup and keeps with the '63 era

[goingbush]

What Bk said, the starter push button wont have enough capacity to crank a diesel . use a solenoid .

[Blknight.aus]

what you do if you want to keep the starter "button"

use it in place of the AUX relay that is normally used to drive the starter solenoid, that will give you the old push button start, it only has to handle about 25Amps.

to drive the glow plugs, use a timed relay and hang the earth off of a 60 degree make/break switch and bolt it to the head (I would go along side the alternator under the exhaust manifold that way they wont come on if the engine is already hot, you can get 40 degree switches and if you can get one use it instead but set it up on the thermostat housing.

[Cap]

Good news and embarrassing news. No fault at all on the buttons because.... there was a wire that was left dangling and earthing out, how damn silly of me not to pick that up. Im clearly no electrician but this is a very novice mistake. Did retest the buttons so all good. Again thanks for all your wisdom.

Cheers,