S1 Alternator change

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Kinger
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S1 Alternator change

Post by Kinger » Wed May 18, 2022 5:42 pm

I'm thinking about changing my alternator ahead of this years frolic. At Knockhill last Friday I noticed the Alternator/battery light would flash on when the rev's hit 5000rpm. ( checked the belt and it seem quite tight )

There are so many different types available ranging for £90 to £290 and from 100amp to 140amp, don't know whether dearest is best option or just go middle of the road and expect to change it sooner, appreciate your thoughts.

Also appreciate any advice on removal/installation, looks quite tight for getting it in and out, any tips gratefully received.

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s29ttc
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Re: S1 Alternator change

Post by s29ttc » Wed May 18, 2022 7:01 pm

What model of S1 do you have? There were models with misfire detection units installed and one of the lights would flash yellow and force into limp if it detected misfires. The other culprits were coil packs, leads etc that could set it off so may be worth exploring if it is alternator or other factors at play. I can’t for life of me remember what specific light it was but it was yellow and weren’t many on the dash!
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1999 S1 Elise 111S - Fun Spec

2004 Mercedes Benz CLK 200 - Daily Driver Spec

2004 Mitsubishi Shogun- Dog Transport Spec

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Kinger
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Re: S1 Alternator change

Post by Kinger » Wed May 18, 2022 7:48 pm

s29ttc wrote:
Wed May 18, 2022 7:01 pm

What model of S1 do you have? There were models with misfire detection units installed and one of the lights would flash yellow and force into limp if it detected misfires. The other culprits were coil packs, leads etc that could set it off so may be worth exploring if it is alternator or other factors at play. I can’t for life of me remember what specific light it was but it was yellow and weren’t many on the dash!
Its a 118 bhp engine with a few mods, Cams and Emerald. The leads were replaced last year with new Magnecor's and Dist. cap last year and not many miles since. I've just checked the Elise handbook and its the Battery charging Tell tale light. The light only comes on consistently at anything over 5000 revs.

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Stu160
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Re: S1 Alternator change

Post by Stu160 » Wed May 18, 2022 9:55 pm

See if you can fit a volt meter in somewhere to see what's going on.
Don't buy a cheap alternator , they don't last .....I know.
S1 S160
Caterham 310R

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Kinger
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Re: S1 Alternator change

Post by Kinger » Wed May 18, 2022 10:26 pm

Stu160 wrote:
Wed May 18, 2022 9:55 pm
See if you can fit a volt meter in somewhere to see what's going on.
Don't buy a cheap alternator , they don't last .....I know.
The light is only coming on when its getting hammered on track, once rev's pass 5k. I don't see it on spirited road driving ?

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Kinger
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Re: S1 Alternator change

Post by Kinger » Thu May 19, 2022 9:56 am

Stu160 wrote:
Wed May 18, 2022 9:55 pm
See if you can fit a volt meter in somewhere to see what's going on.
Don't buy a cheap alternator , they don't last .....I know.
Stu,
Excuse my electrical ignorance, would I be OK connecting a volt meter directly to the battery or would i need to connect it directly to the alternator ?

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s29ttc
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Re: S1 Alternator change

Post by s29ttc » Thu May 19, 2022 9:43 pm

Just was having flick through this:

https://elise.bidouille.info/docs/Lotus ... Manual.pdf

Page 367 of 624 suggest the battery light is red and will illuminate whilst engine is running indicating battery is not charging which may be broken alternator belt or electrical fault. Must be different to yellow light I was thinking of.

Still think it would be worth having a check over other aspects should the alternator not be the route cause. I remember I had some trouble, replaced alternator and battery and eventually got the the route which was the immobiliser going wonky but was intermittent so took a few months to get to bottom of.
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1999 S1 Elise 111S - Fun Spec

2004 Mercedes Benz CLK 200 - Daily Driver Spec

2004 Mitsubishi Shogun- Dog Transport Spec

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alicrozier
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Re: S1 Alternator change

Post by alicrozier » Fri May 20, 2022 11:29 am

I saw this red light on the old shed S1 at the KH hairpin. I pulled into the pits and just as I turned off the engine the crank pulley fell off....
All characters appearing in this post are fictitious. Any resemblance to real persons, living or dead, is purely coincidental.
Any references to laptimes, speed or driving on the public highway are purely for dramatic effect.

UncleRon
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Re: S1 Alternator change

Post by UncleRon » Fri May 20, 2022 11:47 am

To me it does sound like the most likely cause of the red battery light coming on is alternator related Graham..........

Have to agree with others that there's a lot of mostly Chinese pattern alternators out there now which don't seem to last anytime at all - Even some of the good brands of the past like Hella & Lucas just seem to be pretty rubbish rebadged poor quality stuff now. Even if you spend a wad of cash it's difficult to guarantee a decent life.

When the same thing happened on my S1 a few years ago I did a bit of research at the time and I ended up repairing my own alternator.

I think most S1's are built with Rover sourced Magnetti Marelli units which really are pretty good and for me worth trying to repair & keep especially as all the electronic gubbins is all contained within a replaceable brush box unit which comes with new carbon brushes too and not that difficult to replace.The Magnetti Marelli sticker is quite often still attached to the alternator so you know the type you have. To replace the brush box you just remove the few screws/bolts holding on the end black cover on and then the 3 X 8mm bolts I think that attach the brush box on to the alternator to remove and replace. I sourced a Hitachi branded brush box for mine rather than Chinese but even so was only about £28 delivered and it's worked great ever since.

To remove the alternator itself is a bit of a faff but not too bad in the scheme of things on an S1. You just need to disconnect the battery, lift up the rear of the car, remove the under tray, remove the offside/driver side rear wheel & the wheel arch liner. You can then undo the two wires attached to the alternator from underneath the car and then from within the wheel arch loosen the two 15mm bolts that secure the alternator to the engine block. The alternator is tensioned by an 8mm head bolt but ideally leave loosening that till you have the unit off the car in case it's seized. There is also a 13mm bolt that tightens the tensioner curved slot after setting the tension with 8mm bolt so I can usually just remove the 13mm tensioner bolt completely and maybe the 15mm bolt that secures it to the bottom of the engine block and that releases the tension on the belt to remove then just remove remaining bolts to remove alternator. Once off it's worth using some release oil of your choice and carefully get the 8mm head bolt nice and loose prior to rebuilding on the car. (Worth noting the tension of the alternator belt prior to loosening any bolts so you have better idea of tension required when rebuilding.)

My S1 is still up in the air in the garage with the under tray, rear wheel & wheel arch liner off the car so if you need any other pointers or pics then just let me know. I think I kept the box of the Hitachi brush box I used somewhere in the garage so I had the part number should I ever be back here so if you need me to dig that out for the Hitachi part number then let me know.

Gotta keep the ol' S1's out there - Good luck whatever route you go!

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Stu160
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Re: S1 Alternator change

Post by Stu160 » Sat May 21, 2022 8:33 am

You can connect the meter anywhere really, I bought one from Halford to check the motoerhome as it cooked a battery .think you can get them to fit the cigarette lighter ..
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Kinger
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Re: S1 Alternator change

Post by Kinger » Sat May 21, 2022 8:49 am

Thanks for all the help guys 👍

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