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Author Topic: Nothing to do with Listers!  (Read 3777 times)

dieselspanner

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Nothing to do with Listers!
« on: February 20, 2018, 05:32:14 PM »
Hi All

I've spent the last few weeks persuading a a 200 TDI from a Land Rover Discovery into a very nice 1980 Land Rover Series 3 pick up.

It's in, plumbed and wired up and sound great, I have one small problem........

The original motor had a mechanical 'pull to stop', the 200 TDI has an 'energise to run' solenoid, I don't have a spare connection on the Ignition switch that will stay 'live' when the engine cranks.

I've wired the solenoid to the brake light circuit,  the only connection that stays live is to the glow plugs so I've added a link to the solenoid, opened buy a 'momentary on' switch, as you turn the key you press the button and once the motor fires releasing the button stops the 'back feed' to the heater plugs.

My question is (not being 'overly electrically minded') what diode do I replace the momentary switch with, to stop the back feed?

A link to something suitable on Ebay would be greatly appreciated.

Not a Lister query, but I know I'll get a swift and sensible reply on here, the sort of blokes you get on the Landy fora will try to persuade me to go down all sorts of other routes!

Cheers Stef
Tighten 'til it strips, weld nut to chassis, peen stud, adjust with angle grinder.

dax021

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Re: Nothing to do with Listers!
« Reply #1 on: February 20, 2018, 06:55:35 PM »
Try these guys. A good bunch of knowledgable guys, renegades of the usual Landy types

http://braaigrid.org.za/

Ah, sorry, seems like this site is no longer active.  Pity, it was a great site. 

Found them. Name change.

http://landyonline.co.za/landyforum/

















« Last Edit: February 20, 2018, 07:13:15 PM by dax021 »

BruceM

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Re: Nothing to do with Listers!
« Reply #2 on: February 20, 2018, 07:26:00 PM »
Hi Stef,
Tapping into the glow plug circuit which is always live when engine on seems OK, but I don't follow the "back feed" bit.  If you could sketch a circuit diagram I can help more, or write me a PM with more detail. 

There are plenty of sources for a diode to handle a 1 amp or so solenoid if that is what's needed, but I doubt it is needed.

Best Wishes,
Bruce

dieselspanner

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Re: Nothing to do with Listers!
« Reply #3 on: February 21, 2018, 02:21:43 AM »
Hi Guys

I guess I'm nearly as bad at describing my issue as understanding what I want! Writing the post in a rush before going next door for supper probably didn't help, either.........

As the key for the ignition switch is rotated there are 4 positions......

1. Off, no power to any connections. Insert / remove key.

2. Gauges, alternator feed, radio and brake lights ON (run position)

3. Heater plugs ON. Gauges, alt feed, radio and brake lights  OFF.

4. Feed to starter motor ON (engine cranks). Heater plugs ON. Gauges alt feed, radio and brake lights  OFF (Start position)

Positions #3 and #4 are spring loaded with a return to position #2

There is no timer for the heater plugs, once the circuit light comes on, indicating position #3 it's up to the operator to count to 10 before cranking, position #4



I have connected the 'energise to run solenoid' in the injector pump to the brake light feed, once the motor is running, in position #2, it will continue to run until switched off, position #1.

At positions #3 and #4 there is no power to the brake light circuit (and thus the solenoid) and therefor the engine, whilst cranking, will not start.

To overcome this I have fitted a second feed from the heater plugs circuit with a 'momentary on' switch. Pressing this whilst the engine is cranking provides temporary power to the solenoid, allowing it to start and run until the switch is returned to position #2, Run, and the momentary switch released.

Thus starting requires both hands.

Without the momentary switch, the second feed would power the heater plugs from the brake light circuit and burn them out, in no time.

I believe a diode (fitted the right way round) would allow the heater plug circuit to power the solenoid, with the switch in positions #3 and #4 but stop the brake light circuit powering the heater plugs from position #2

I'm happy without a timer for the glow plugs, many years ago, as a baby Bootneck, I was taught to count to 19, I'd just like to be able to start the motor with one hand.......

So, what sort of diode do I use, please?

Bruce,
Is this ok?, drawing and then posting a circuit diagram would severely tax my 'sparky skills'

I worked out and set the whole thing up with a 12v bulb, 2 pieces of wire and 2 crocodile clips, I can use the volts and continuity settings on a multimeter and that's about it.

Glort
You're quite right about some of the Landy fraternity and I suspect the answers would range from rebuilding the original engine (gotta keep it in factory spec, even to the point of going to Solihull so you can use the same air to pump the tyres up) to changing the solenoid to 'energise to stop' (an option, but if the vehicle rolls away in gear it will start, not good if the keys to the steering lock are still in your hip pocket) or fitting a cable operated 'manual stop' conversion (believed to exist but I can't find one)

Cheers Stef

And that's only the sensible one's!
Tighten 'til it strips, weld nut to chassis, peen stud, adjust with angle grinder.

BruceM

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Re: Nothing to do with Listers!
« Reply #4 on: February 21, 2018, 05:24:16 AM »
OK, much better explanation, Steff.  You were right about needing a diode.

I'd suggest 2 didoes, so that the power to the energize to run solenoid is powered by either the brake light or the glow plug circuits.  Both of the diode's cathodes, the end with band, will be connected together at the solenoid wire.  The anode ends will each connect to the brake or glow plug circuit.  The diodes will block either glow or brake circuit from powering the other.

This is also known as "a wired logical OR"; the diodes allow power to come from either of two sources.

You will need two diodes rated for roughly double the current needed for the energize to run solenoid. 
Voltage rating of 24V or more.   If you need further help with finding suitable diodes or I haven't explained things well enough, please ask again.

If you measure the current drawn by the solenoid when connected that would help you in selecting the smallest suitable diodes, otherwise you'll have to assume something like a 2 amp draw.  You can put more than one diode in parallel to increase the current capacity if needed.

Bruce

PS- something like this would suffice:
https://www.ebay.com/itm/MUR415-DIODE-150V-4A-DO-214AD-AXIAL-5-PER-LOT/152577141774?hash=item23864e6c0e:g:CgQAAOSwiOFZOEqU

You can also use two of the 4 diodes in a bridge diode if that's easier to find.  Each input goes to an AC labeled pin and the run solenoid goes to the + pin.  Don't connect the - pin.

I hope that helps.
« Last Edit: February 21, 2018, 05:34:42 AM by BruceM »

Tom

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Re: Nothing to do with Listers!
« Reply #5 on: February 21, 2018, 06:28:14 AM »
Why not power the fuel solenoid from the starter crank circuit while cranking? No diodeds needed if there are 2 small terminals on the starter solenoid.
Tom
2004 Ashwamegh 6/1 #217 - ST5 just over 3k hours.

dieselspanner

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Re: Nothing to do with Listers!
« Reply #6 on: February 21, 2018, 08:52:46 AM »
Hi Bruce,

Thanks for that, much appreciated, I'm glad my ramblings made sense, I woke up at 2.30am this morning for the usual vist to the toilet and started thinking about it, went downstairs and started typing. I type like a handcuffed mule so it was well gone three before I crawled back under the covers!

I like the bridge diode solution, it would mount neatly on the bulkhead (Firewall in American?) and leave one wire crossing the engine bay to the IP.

One of these, I take it....

http://www.ebay.co.uk/itm/KBPC2506-Bridge-Rectifier-Diode-25A-600V/282555840569?epid=12004559642&hash=item41c9a3f839:g:M7EAAOSwd~RZWsIs

The bridge diode is something I understand, I've used them on British motor bikes, and years back, whilst working in a sewage plant in the UK a friendly sparky showed me how to make a battery charger (which I still use) from a load of bits that were laying around.

Tom,

There;s only one small connection on the Starter motor, so I'd have the same problem, thanks for the thought tho'

Cheers Stef
Tighten 'til it strips, weld nut to chassis, peen stud, adjust with angle grinder.

dieselspanner

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Re: Nothing to do with Listers!
« Reply #7 on: February 21, 2018, 02:09:05 PM »
Hi Glort

I did think of a latching relay, the mate who made my digital rev counter for the Lister briefed me on them when we were talking about making a 'Startomatic' type system, problem is when you go from #2 to #3 and then #4 it would unlatch as the power is off to the gauges ect.

I suppose a timer could be fitted to hold the solenoid circuit open for 20 seconds or so each time the power dropped out, but then you'd need a kill switch to shut it down without a delay.

The ignition switch for the Discovery might fit, as might one from a later diesel Defender but the one on the vehicle would be a bugger to swap out and doubtless the connections would be entirely different.

It also has a 'latching' stop pull, the key can't be removed until the pull is out in the stop postion, and locked, meaning the vehicle won't start if it rolls down a slope in gear (ask me how I know this can happen!) When the key is inserted and turned to position #3 it resets, using the spring that holds the stop on the IP in the 'run' position.

I toyed with the idea of setting up a limit switch operated by the stop pull and as a last resort may go that way, first I'll have a play with the bridge rectifier.

Cheers Stef
Tighten 'til it strips, weld nut to chassis, peen stud, adjust with angle grinder.

BruceM

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Re: Nothing to do with Listers!
« Reply #8 on: February 21, 2018, 04:58:16 PM »
Yes, Stef, that bridge diode will do the job nicely. I was thinking the spade terminal types might make it easy wiring it up and it seems you did too. 

A latching relay in EE parlance only requires a brief pulse of current on the coils (often two coils- one for on and one for off- some use reversing polarity on a single coil) to pull it on or off.  It stays in that position (on or off) until the other coil is pulsed (or for a single coil model, a pulse of reversed polarity is applied).  I don't think that's very helpful here-  you would need to generate the pulse to turn off the relay somehow.

A newly created, fused circuit from battery, with a relay controlling the power to the engine run solenoid is a technically polite way of doing it since it draws almost no extra current from existing circuits. This would still take two small diodes feeding the coil from the run and start positions.  I'd try to steal power from existing circuits and use the bridge diode approach myself rather than adding another fused circuit and relay if i could.


dieselspanner

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Re: Nothing to do with Listers!
« Reply #9 on: February 21, 2018, 05:44:03 PM »
Hi Bruce,

Job done!

`
Tighten 'til it strips, weld nut to chassis, peen stud, adjust with angle grinder.

dieselspanner

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Re: Nothing to do with Listers!
« Reply #10 on: February 21, 2018, 05:50:44 PM »
OOPS, the post got away from me!

Job done, just as your last post suggested.

I stole one supply from the brake lights and one from the heater plugs, fed them to the bridge rectifier from my home brewed battery charger and one blown fuse later, careless with the crocodile clip, it all belled out as per plan.

It changes over so swiftly that my 'bulb on a bit of wire' circuit tester didn't even have time to dim.

Thanks a bunch for your time and knowledge.

Cheers Stef
Tighten 'til it strips, weld nut to chassis, peen stud, adjust with angle grinder.

BruceM

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Re: Nothing to do with Listers!
« Reply #11 on: February 21, 2018, 09:43:06 PM »
Glad to help a tiny bit Stef.  Your contributions here have been impressive and enjoyable. 

guest23837

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Re: Nothing to do with Listers!
« Reply #12 on: February 22, 2018, 09:00:11 AM »
The VW relay is easy to wire

dieselspanner

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Re: Nothing to do with Listers!
« Reply #13 on: February 23, 2018, 09:01:04 AM »
Thanks for the 'chuck up' Bruce, I'm not sure how long it's been since a sentence concerning me,with the word impressive, has been used in a positive way!

Using a cheap bridge rectifier to feed one circuit from two supplies without getting them mixed up is a useful addition to my (very) limited electrical arsenal.

Presumably one supply fed into the + terminal would result in two independent supplies at the AC terminals? Not that I can think of a use for it that a 2 pole switch wouldn't accomplish !

Johndoh

Thanks for the VW hint, it's all turned out so well that I suspect I'll leave well alone now.

Cheers Stef
Tighten 'til it strips, weld nut to chassis, peen stud, adjust with angle grinder.

BruceM

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Re: Nothing to do with Listers!
« Reply #14 on: February 23, 2018, 05:16:07 PM »
Stef, to get an "independent" supply in electrical language usually means a separate supply either transformer isolated, battery, or by "swinging capacitor" (sorta like a battery).  An independent supply can have it's level shifted to any new reference voltage, above or below some existing supply. An example is adding batteries in series to increase voltage.  In power circuits, independent supplies are often needed in order to do things like current sensing of higher voltages or to control high voltage power transistors (AKA "high side" power control/sensing.)

Your example of the bridge used to create two supplies will only work if the positive supply was connected to the minus terminal, then both AC terminals will supply positive voltage (minus the diode drop of about half a volt).  There's not much use for it, as it's not much different from just splicing the wire directly to add another wire.

Electronics is one of the many things best learned for most with a lot of hands on experience. I think academia is wrong about how they go about teaching it, so it remains mysterious for most.