Lotus Elan

FITTING AN ALTERNATOR

PostPost by: redskatejbf » Tue Feb 06, 2007 9:42 pm

I would like to fit an alternator to my 1970 S4 36/9681 (negative earth) but I am confused with the wiring as my car seems to have part S3 and S4 electrical installation. It is fitted with a RB106 control box but the wiring diag. is for a S4. Could someone confirm the new wiring connections that I need to modify.
Position A1 - brown/blue - feed to dash. light switch/int. light/ig. switch.
Positon A - brown- main feed from solenoid/battery.
Position A - blue-feed to relays, main lights.
All the above to be connected together with the feed output from the new alternator.
Position F - brown/green- not used not required ex. dynamo.
Positon D - brown/yellow- (heavy gauge cable) not required ex. dynamo.
Position D - brown/yellow- ign. switch, connects to alternator.
Could someone confirm these mods to be correct.
Also does the tacho. need altering from the original RV 1 to work correctly.
I have a quote for an alternator from www.alternatormart.co.uk new complete with fan and pulley for ?54.95 inc. vat they have recommended the Lucas A127 unit max output 70 amps but under normal conditions would not produce this as it has a sensing regulator, when the battery is charged or no electrical load it adjusts accordingly. My question now is, is it sensible to fit a fuse on the alternator, if so what would be a safe rating. I am thinking of 35 amps. I do not think the total electrical load on the car is likely to exceed this. But I would appreciate any thoughts, experience and confirmation that I not about to have a pyrotechnic experience. :oops:
Thanks for any help you can give me.
John.
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PostPost by: Frank Howard » Tue Feb 06, 2007 10:36 pm

John,

You pretty much have it. The first wires that go to (A1, A, A, and the alternator output) can be connected together without connecting them to the voltage regulator. When you're through, the only wire attached to the voltage regulator will be the small brown/yellow one at position D. If you connect this wire directly to the Ignition warning light, you will have no wires left at the voltage regulator and you can remove it from the car. Now you have space for a proper fuse box.

The tach will need altering only if you installed electronic ignition.

As far as fitting a fuse on the alternator is concerned, I don't have one on mine but that doesn't mean you shouldn't have one on yours. I would talk to the people you are buying the alternator from.

This is one of the best improvements you will ever make. The indicators will maintain their speed at idle, the windows will run faster, the air will smell fresher, food will taste better.
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PostPost by: iain.hamlton » Wed Feb 07, 2007 12:26 pm

I just did the mod on my positive earth + 2. The wiring as you say. I ran a new heavier cable from the alternator output to battery connection at the solenoid. I have fused this. The new cable bypasses the ammeter. I will fit a voltmeter later this week.

Good luck, best regards, iain
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Positive earth alternator v2.ppt
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PostPost by: redskatejbf » Wed Feb 07, 2007 1:33 pm

Frank........Thanks for the reply and info. confirmation, I am not a purist but I would like to keep it looking like original (cos it is) so my intension was to use the spade connections on the voltage regulator to join the cables up and possibly use the inside of the regulator to house some fuses if I can fit them in.


Ian......Thanks for your reply. What size fuse did you use on the alternator
I am not able to look at your download unfortunately :( as I do not have powerpoint.
Regards, John.
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PostPost by: iain.hamlton » Wed Feb 07, 2007 2:09 pm

John,

I fused the battery cable at 80 Amps, as I am not sure of the rating of my alternator. The AC11 can be either 45A or 60A. I did not want the fuse to blow in normal operation, but I didn't want the alternator to short out the battery either. After all, I have been messing about with the alternator itself.

I connected other alternator outputs for the lights, ignition switch etc again fused, but more modestly.

I am attaching the diagram in another format.

Originality purists are advised to look away.

best regards, iain
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Positive earth alternator.JPG and
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PostPost by: Jason1 » Wed Feb 07, 2007 7:46 pm

Hi Guys

I just saw this on TTR' s site (price list) and thought it may be of interest?

I have considered converting to an alternator but the cost of these brackets on ebay has put me off. I may have to rethink it for ?30 +VAT?

Hope it helps

Jason

Ps

I do not work for TTR or have any association with them :)
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TTR.JPG and
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PostPost by: redskatejbf » Wed Feb 07, 2007 10:03 pm

Ian, Thanks for the pic. I think that would be of great interest to anyone with a positive earth car whose thinking of a alternator mod. I am no spark but I thought a fuse of say 80 amps. would blow at somewhere around double its continuous load, you could be looking at over 130 amp. if that is true. Someone out there may be able to advise.


Jason, Iam lucky in that I have a original set of alternator brackets (there built like a brick outhouse) from a +2 engine that I bought many years ago, it did not come with the alternator, just the brackets.
Brian Bucklands book has photos of them,it should be possible to fabricate them if your handy with a hacksaw and file!!!!!!.
Regards, John.
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PostPost by: iain.hamlton » Thu Feb 08, 2007 6:22 am

I am sure proper brackets are the best solution. Unfortunately I couldn't find any - they may not have worked with my non-standard alternator anyway. I used the standard dynamo pivot bracket with some threaded rod, nuts and washers. I adjusted the steady bracket in the vice. Everything lines up and is strong; so far so good...

One thing everyone seems to agree on, though: be careful not to overatighten the fan belt to aviod stressing the water pump.

It now holds its charge at idle with the electric fan running, and the electric windows work without reving the engine. Result.

best regards, iain
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PostPost by: Frank Howard » Thu Feb 08, 2007 5:04 pm

Jason1 wrote:I have considered converting to an alternator but the cost of these brackets on ebay has put me off. I may have to rethink it for ?30 +VAT?

Jason,

Why limit yourself to the alternator that the TTR bracket is made for? If you pick one up at a scrap yard, you can choose from hundreds of brands, many of which are easily rebuildable and/or replacable.

If you do not have access to a welder, you can always pay a machine shop to make up the brackets for you. I can't believe their charge would be much more than what TTR wants for his brackets. What I do believe is that the junk yard alternator will cost considerably less, even if you pay to take it in and exchange it for a rebuilt unit.
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PostPost by: pereirac » Fri Feb 16, 2007 9:37 am

I gather the alternators conversions coming out of the US (Dave Bean?)use a nice small, efficient Japanese alternator rather than the 'original' Lucas lump. Your local scrap merchant must have loads of these. The only thing I don't understand is why these kits are so expensive for what they are...

Carl
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PostPost by: Frank Howard » Fri Feb 16, 2007 2:58 pm

pereirac wrote:I gather the alternators conversions coming out of the US (Dave Bean?)use a nice small, efficient Japanese alternator rather than the 'original' Lucas lump...The only thing I don't understand is why these kits are so expensive for what they are...

Carl,

I went straight to the junk yard for mine, but in defense of Dave Bean, he has to charge plenty for his alternator conversion because:

1. He has to pay to have the alternator refurbished.
2. He has to pay for packaging.
3. He includes a comprehensive wiring diagram along with instructions.
4. He includes a wiring harness.
5. He includes all brackets including an adjustable length upper arm bracket.
6. He must make a profit.
Frank Howard
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PostPost by: pereirac » Sat Feb 17, 2007 9:00 am

Frank

I know what you mean, everybody has to earn a living...

Compared with some 'modern' cars, most parts for Elans can be reasonably priced. I figure $100 for a single plastic wheeltrim for a modern car expensive.

Carl
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PostPost by: richie666blue » Wed Jul 21, 2010 10:42 am

Has anyone got a wiring diagram for a negative earth alternator set up for and Elan please a picture is worth a thousand words well it is for me as I am thick
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PostPost by: neilsjuke » Wed Jul 21, 2010 10:49 am

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PostPost by: RichardS » Wed Jul 21, 2010 1:06 pm

I bought a 45 amp alternator from here http://www.lukemotorsport.co.uk/lukemotorsportua.html - it was about ?30 a couple of years ago. It has worked fine and I was advised 45 amps was more than enough.

I used this diagram on the Elan.net site and found it easy to understand http://www.lotuselan.net/uploads/elan_m ... wiring.pdf

Richard
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