Lotus Elan

New starter - wiring woes?

PostPost by: Flying Banana » Thu Oct 15, 2020 8:11 am

Hi, please forgive my electrical ignorance!

I have an S3 Elan with a bulkhead mounted solenoid and until recently a bendix style starter. The car had always turned over very slowly. Even with the plugs out, it wasn't really "spinning" very quickly.

Last night I fitted a hi-toque starter from WOSP, retaining the single power feed from the original solenoid. When I connected the battery I noticed that there was a wisp of smoke coming from the bulkhead solenoid area and also all the main battery cables were getting very warm. I disconnected everything, and removed the battery from the car.

As an aside, I visited WOSP in Aylesbury yesterday prior to fitting the starter to get the pinion swapped for a longer one. Luke @ WOSP could not have been more helpful. After fitting the pinion and bench testing the unit, he wasn't happy with the sound from the internal gears, so stripped the unit to rectify a small clearance issue. Exemplary service.

Tests / readings so far:
1) with the hi-torque starter on the floor with jump leads connected to a battery, the starter fires into life
2) Battery (out of the car) shows a reading of 12.7v
3) Resistance over the 2 bulkhead mounted solenoid terminals = 1 ohm
4) with the battery out of the car, ignition on and the new starter fitted, there is continuity in the circuit between the battery connections and a resistance of 8 ohms
5) on the starter itself, there is continuity between the case (ground) and the power post (this was tested when the starter was out of the car and also when the starter was fitted by checking continuity between the switched contact on bulkhead mounted solenoid and the engine block (ground).
6) there is a rubber boot on top of the power post connection, so it's not touching the engine, but as above, there is continuity between the starter case and the power post anyway
7) pushing the button on the top of the bulkhead solenoid does not active the starter solenoid (as I believe there is a short in the car effectively bypassing the starter)

I'm stuck as to what I should check next. I don't want to connect the battery up again, as I believe I have a short somewhere which is causing the heat build up in the main battery cables.

- What resistance would I expect in a typical circuit per (4) above?
- should the starter have continuity when not powered? I guess so, otherwise the solenoid can't work?

Apologies if I'm missing something basic here. If anyone would be kind enough to give me some step by step pointers (along with expected results if these involve a multi-meter) I would be very grateful.

regards
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PostPost by: nmauduit » Thu Oct 15, 2020 9:43 am

short of a complete reply , I usually figure out better what is going on with the help of a schematic to see what is going on where

https://densoautoparts.com/starters.aspx

the principle being that the solenoid, when activated, moves the pinion so that it will engage the engine flywheel ring, then at the end of its travel makes a contact (often a circular copper washer forced onto 2 copper terminals, one going to the battery and the other one to the starter motor) so that the high current lead brought by the battery can flow through the starter motor.

Under normal circumstances smoke is usually bad from anything electrical.

If in your case, unless you have somehow connected the battery to the motor rather than to the driven terminal or made an other short on the command circuit, I would suspect something has fried (solenoid ? ) and investigate for possible permanent damage. How long was it connected to the battery when it smoked and heated up ? If in doubt I would take it out and test it again out of the car...
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PostPost by: EPA » Thu Oct 15, 2020 9:45 am

If I am understanding your description the solenoid appears to be faulty.If the solenoid isn’t activated there should be an open circuit across the two large terminals and short circuit when it is activated. Measure the voltage at the output of the solenoid with the cable to the starter disconnected and solenoid not activated, It should be zero.
As you don’t really need the solenoid I would leave it out of the circuit to see if the starter then works.The solenoid could be replaced later if required. To remove the solenoid from the circuit you would need to remove the link wire on the starter and connect the starter trigger to the starters in built solenoid. The instructions should explain this
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PostPost by: Donels » Fri Oct 16, 2020 5:35 pm

If you don't already have them here are some fitting instruction for your starter.

Starter Motor Fitting Instructions.pdf
(40.61 KiB) Downloaded 25 times


When you replace the inertia starter there are two/three ways to wire the WOSP.

One requires a link wire from main power connection to the starter to the integral starter solenoid. This way when the bulkhead solenoid is engaged it fires the integral starter solenoid and the starter rotates.

Two, you run the power cable from the bulkhead solenoid to the starter and a wire from either the ignition switch or bulkhead solenoid trigger to the integral solenoid. This way the integral solenoid is fired separately from the main power, but the result is the same.

There is a third way where the starter is powered all the time, bypassing the bulkhead solenoid, and the integral solenoid is powered by the ignition switch.

It sounds like you have the starter wired incorrectly causing a direct short, assuming the bulkhead solenoid is functioning correctly as noted.

Hope this helps.
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PostPost by: Esprit2 » Fri Oct 16, 2020 8:44 pm

WOSP and Gustafson geared starters both start with the Nippondenso geared starter. Then they modify it for use on a variety of British and other cars. "British Starters.com" is a dealer for Gustafson starters, as are all of the 'Lotus' specialist vendors in North America.

I have installed several Gustafson starters in Europas, an Elan, and Esprits, and I'm familiar with them. I've only 'heard' of WOSP starters and have never seen one in person.

I drew the attached alternative schematics for installing the Gustafson. Since WOSP begins with the same basic 'Denso' geared starter, I presume these schematics would also apply to them. However, that's a big assumption... go there at your own risk.

I'm hoping someone with WOSP experience will check out the schematics and comment on how appropriate they are for the WOSP. Otherwise, buy a Gustafson geared starter, and these schematic options apply.

Regards,
Tim Engel
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Starter - Gear Reduction Starters from Gustafson - Schematic.pdf
Alternate wiring schematics for Gustafson geared starters... and maybe (?) WOSP.
(126.53 KiB) Downloaded 45 times
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PostPost by: Donels » Sat Oct 17, 2020 3:28 pm

Tim, your wiring diagrams are correct. They are what I was trying to describe.

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PostPost by: Esprit2 » Sat Oct 17, 2020 4:04 pm

I browsed the WOSP website and couldn't find a single schematic anywhere. The written instructions were easy to find, but not a single illustration. One of their customers should rattle their cage about that.

Regards,
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PostPost by: Andy8421 » Sun Oct 18, 2020 7:01 am

All good advice above. Just a couple of points to add:

A number of discussions on here mention a ballast resistor. Neither of my Elans have one, and I haven't seen a resistor on any wiring diagram I have for an Elan, but knowing Lotus I have no doubt some cars were fitted with them. The usual 'Lucas' approach was to have an additional terminal on the solenoid (really a relay) that went live when the solenoid was energised. This bypassed the ballast resistor and supplied full battery voltage to the coil during starting. If you follow the advice above for removing the solenoid and have a ballast resistor fitted, then you will lose this functionality.

You won't be able to measure low resistances reliably with a multi meter. In industry '4 terminal' meters are used for this. Don't put too much faith in low-ohm readings - you are just as likely to be measuring the contact resistance of your test leads than the circuit you think you are testing. There is a lot to be said for a bulb and a couple of bits of wire when circuit testing on an old car.
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PostPost by: Flying Banana » Tue Oct 20, 2020 8:31 am

Thanks for the replies all. I've decided to go belt and braces and have ordered a separate 350A earth lead to run under the chassis from the earth point in the boot floor up to where the starter body grounds. Let's see what happens when this is connected.
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PostPost by: Andy8421 » Tue Oct 20, 2020 11:41 am

Flying Banana wrote:Thanks for the replies all. I've decided to go belt and braces and have ordered a separate 350A earth lead to run under the chassis from the earth point in the boot floor up to where the starter body grounds. Let's see what happens when this is connected.


While it won't hurt (apart from Mr Chapman rolling in his grave), the cross sectional area of the chassis/frame will dwarf the cable, and even taking into account the lower resistance of copper vs steel, the cable in itself isn't going to make much difference. Where it might help is if you have got a dodgy connection from the battery to the frame via the bolt in the boot, or if the engine isn't properly earthed to the frame in the engine compartment.

To be honest, you would do better to check/fix the two connections mentioned above than run a separate earth cable if you think the problem is earth return related. Elans didn't leave the factory needing an additional earth cable.
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PostPost by: 2cams70 » Tue Oct 20, 2020 1:06 pm

Not sure what Elans use but in a Twin Cam Escort that has the battery in the boot as standard specification a real problem is the guage of wire the factory decided to use for the main lead running from battery +ve terminal to the engine compartment mounted starter solenoid. It's exactly the same guage that they used for granny's Escort where the battery is mounted directly under the bonnet close to the starter!

Twin Cam Escorts always crank much more slowly than the standard ones which are never a problem even when fitted with a high compression 1600cc crossflow. The long lead length and insufficient thickness of wire to counter the extra resistance caused by this creates this problem. This design deficiency is usually to blame for poor starting more so than the Lucas inertia starter itself in Twin Cam application
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PostPost by: Flying Banana » Tue Oct 20, 2020 1:19 pm

2cams70 wrote:Not sure what Elans use but in a Twin Cam Escort that has the battery in the boot as standard specification a real problem is the guage of wire the factory decided to use for the main lead running from battery +ve terminal to the engine compartment mounted starter solenoid. It's exactly the same guage that they used for granny's Escort where the battery is mounted directly under the bonnet close to the starter!

Twin Cam Escorts always crank much more slowly than the standard ones which are never a problem even when fitted with a high compression 1600cc crossflow. The long lead length and insufficient thickness of wire to counter the extra resistance caused by this creates this problem. This design deficiency is usually to blame for poor starting more so than the Lucas inertia starter itself in Twin Cam application


Agreed. Where standard battery cable is 16mm2, I'm using 50mm2 flexible welding cable to ensure sufficient current carrying capacity (circa 340A).

Whilst I also agree that the cross sectional area of the chassis is large than any cables available for this purpose, I'm trying to remove as many connection points as possible between the battery and the starter to rule out any connectivity/resistance issues.
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PostPost by: nmauduit » Tue Oct 20, 2020 1:32 pm

well, if you're into that route you might as well take a good pair of jumper cables and test the starter directly from the battery (or the/a battery brought closer to the front if necessary)... if a poor earth connection was the issue the crank would be very slow or even just clicking (due to the amperage reduction because of contact resistance), that is not going to heat up cables rapidly if at all - unlike a short or a full cranking current (e.g. starter motor blocked).

to take things one at a time, I would start from the actual tests and symptoms : what happened in what order then the cables heated up, which cables were hot, if the starter works (still) when out the car... possibly taking photos of connections or starter out of the car for clarifying the discussion...

good luck
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