Refurbished alternator now reads 16v on idle.

[chrism]

Hmmm, just a furrowed-brow kind of thought - and I don't know if this differs between SEs and S2s...

I know that the O2 sensor on my closed-loop-converted SE 'works off' the alternator warning light circuit, and is provided with a heater circuit (only, I gather) when the light is off.

Does this mean that the SJS-sourced alternator (and this problem has been around for a while...) will be effectively running our m100 Elans on open-loop, since this warning light will be 'permanently on'? (Along with increased emissions, fuel wash-down and consequent higher fuel consumption...?)

Doesn't the current 'freed-up' when the correct voltage value turns off the alt warning light power the heater currents of our O2 sensors? Or have I got it wrong? Confused...

ps I have been pondering this ever since becoming an RA 'convert' (part-and-parcel with this 'red-light-on' problem in mind, I have to say...)

[Tuga2112]

my light was not behaving correctly before the failure, in fact it was off when the alternator had failed.

I Have not driven the car after the instalation to check the alternator light, however if mine is missbehaving. it will be properly addressed eventually, im confident whatever is making it miss behave is within my knowledge to correct, but at the present moment there are a lot of other issues with higher priority to be looked after (starting by the refurbishment of the original one)

[peteoddcar]

https://youtu.be/qlccLGgvIW0

ive watched the video and i am not sure what you meant by the screws.

this is the video of myself doing the work the first time (its been re-done now 3 times with the other 2 regulators, but basically its always been done the same way)

can you elaborate about the screws ?

If the lower screw which secures the reg and brush box is too long it will ground that circuit by mistake and cause max output - your stator is toast ! Pity you did not post a picture before I could have advised you.
Does the warning lamp work properly with the new alternator?

[Tuga2112]

If the lower screw which secures the reg and brush box is too long it will ground that circuit by mistake and cause max output

thats what i needed to know.

i will double check. on the bench if the 3 small screwsa have different sizes. at a glance they sure appeared to be all the same length. but i will be confirming that later today

i just remmebr, i will also check if its grounded with the multimeter. thats a 100% sure way to be sure the screw is not causing any issues

[Rambo]

Tuga - I bought a Alternator from SJ's last year. I was catious to begin with becuase I bought one from SJ's in 2016, which did not work properly (and the batt light remained on all the time)... I sent it back and got a refund; I then had my original one refurbed. It lasted until last year...so I decided to try SJ's again; on speaking to Steve he said that he had sourced his new stock from China! So far it's performing brilliantly (although I do still have the dreaded red light batt on all the time.. there's another thread somewhere on this).. and Steve also provided a new (different length) belt... all fitted really well. Good Luck Mike

Careful with that one Mike as it will be a fail come MOT time.

My NMY did exactly the same for about 4 years so I covered up the dash warning light with black insulating tape. Everything worked OK ie it charged the battery but the light remained on.

The explanation I had from the previous owner was that the diode pack was wrong??? Anyway, all sorted now as I got a brand new Lotus OEM alternater ex Bell and Colville for under £150

[roy666]

Thanks Rambo... car has just passed it's MOT... was a local garage that I know well and they have done lots of easy work on the car. garage owner did mention the red light... but not that it was a show stopper. Is he missing something.. or am I?
ta M

[dapinky]

Red light isn't an MOT failure point - just the amber warning lights (CEL etc).....

..... don't shoot the messenger, I never said it makes any sense.

[muley]

I bought an alternator from RA. (I hand carried the thing back from the USA when I was to-ing and fro-ing for business)

Clearly, the one fitted to an Isuzu Impulse is larger than the one fitted to an M100 Elan

It was too big by a large margin

TVOE

[dapinky]

would be nice if one of the US based owners could purchase one of those 75amp units and take all measurements to compare to this, i certainly would like a 75a one in my car

Well, I'm not US based, but I've ordered one!

Not just because I want to see if it is much different (and if it will fit!), but mainly because I need one for the project car - the one in it is seized solid.

I had the same thing happen with the red car when it had been standing outside for a while - water gets into it and the windings swell, which causes it to seize and in the case of my old one, it caused the metal housing to split.

I haven't taken mine out yet (ran out of time today), but whilst starting on the cambelt job I found the unit to be solid - so I'll get it out tomorrow (maybe!) and see how it compares with the Rockauto one.... if nothing else, and it doesn't fit, I'm sure I can cannibalise some of the internals for future use.

[peteoddcar]

I fitted the larger output one from Rock Auto one about 2015 There’s a thread some where detailing what I needed to do but basically it’s too large a diameter it was an absolute pig to get it into the gap.I think I released an engine Mount, it needed a different belt, but once it’s on the brackets it’s fine.. I will post details of the part number of the belt and unit if I can find it , in the receipt box. I got a second belt to add to the spares box as it’s non standard.
I have on my to do list the refurb of my old unit, which suffered a slip ring break up.
Going to do now I’d prefer it to be back on its original.
Warning lamp works properly and it regulates at 14.7 v without lights etc.

[dapinky]

Pete,

It is encouraging to know that it will fit in the gap, and will work!

Getting it into place isn't a big issue - there is so much coming out that I may just whip the engine and box out anyway! (hopefully not, but it wouldn't be impossible).... likewise, I have a selection of belt lengths here that I can try, and then get whichever works and puts the adjustment bolt in the most accessible location! (The engine mount is coming off tomorrow for the cambelt change, so I may leave it only loosely attached until the alternator is done.)

[Tuga2112]

If the lower screw which secures the reg and brush box is too long it will ground that circuit by mistake and cause max output

i will double check. on the bench if the 3 small screwsa have different sizes.

confirmed the 3 screws are exactly the same size. i will check with multimeter when the new stator arrives after instalation. there may be a need to use rubber washers to avoid an unintended ground although when i took the screws apart i didnt see any rubber washers anywhere

[peteoddcar]

Ok that’s good probably ok it’s just that I had an issue like that on a Denso unit I rebuilt for my sons Fiesta race car years ago.

[Tuga2112]

Ok that’s good probably ok it’s just that I had an issue like that on a Denso unit I rebuilt for my sons Fiesta race car years ago.

what you mentioned makes sense and would explain the 16v when i tested.

i cannot understand why a missing winding in the stator would result in a higher voltage output.
in my head, a missing stator winding should have the same voltage output but drastically reduce the current capacity of the alternator.... potentially damaging the voltage regulator by trying to create a higher magnetic field than rated in the core winding.

[peteoddcar]

I think it’s about time we found an alternative to the Denso unit - when I get home I’ll have a measure up and see what’s out there.
I am sure if it were simple though it would have been done by now. Typically the physical size of this alternator are used on fork trucks/ diggers etc, but most are only 35-45 amps output.

[Tuga2112]

I have just ordered a replacement stator. Sounds arrive Wednesday or Thursday.

Hopefully before end of the week I'll have an update

it be frustrating to go through all this effort and find out theres a plug in replacement that is cheaper, but im already far too invlved in this refurbishment process i feel i have to complete it just to prove that alternative is available (and is cheaper than the replacement unit from SJ)

[dapinky]

Pete,

I have been doing some digging on the sizes of units which would physically fit in the limited space (and/or be able to get it in and out!). I started out looking for a 'plug and play' unit that would fit on the current bracket and still align the pulleys - then progressed to 'adapting' the bracketry.....

..... completely inconclusive, as many many units could be adapted to fit the bracket, but most modern stuff is in the 100A+ range due to the requirements of modern cars..... and have the physical size to match.

Maybe a small unit with a 40A rating would suffice - after all, running the car doesn't use anything like that - even with wipers and 4 headlamps on it would be okay - and as many of us have gone down the LED headlamp unit anyway, 30W dipped beams, 3W sidelights and 2W tail lamps (nowt at all for the number plate lights, really!) the output would be pretty similar to the OE 55A unit....

.... so I can have the heated seats on and the stereo loud!

[peteoddcar]

Dave
Agree with the logic on the max output - the 55 amp rating was I think derived from a GM Spec which is something like the ‘ 3 hour traffic jam in winter’ I can’t recall exactly the spec but it asks to test with with blower lights wipers on, obviously with low / idle engine speeds - the low speed output needs to try to balance these loads, generally speaking higher the maximum output the better low speed output ( amps ).
Pulley size can be adjusted to optimise output at idle.
In our 30 year later real world for these cars I am pretty sure a 45 amp unit would not have any issues.
Chinese replicas are available but most have a 3 wire connector so will need a wire mod
I’ll do some digging

[dapinky]

Well, fitting the new one (when it arrives) should be fairly easy....... I've taken the raft out (and the rest of the FOS suspension bits) today - far easier to get to the alternator bolts with all that on the floor!

[bmw02rally]

Its great watching and reading all this useful info on what is such a rare car. My alternator has packed up (11.8ish Volts on the gauge yet I have no Light on the dash).

Being 5 weeks since spinal surgery on my neck I'm still holding off getting under the car to attempt this work.

Keep up the great work gents!!!

Mark