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K Series Alternator Upgrade


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It is a little hard to see, mainly because the alternator is polished and you're seeing some reflection of the bracket. 

My bracket is as factory. There's some alloy tube slid over the front of the inside bolt (through original bracket) to bring it out to the front of the alt, then another tube to fill the gap to the back of the bracket on the outside bolt... if that makes sense?

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Hi Si,

        I'm looking at your pic, when you posted it, & thinking; there is a mirror or something in there.  Is the replacement alternator you fitted, a Bosch look-a-like ?

I had another play with it last night.  It is true, as You say; that by fitting the cast pivot bracket upside down, lifts the alternator slightly upwards.  However, if I didn't lift it up, the bottom of my 120A alternator, would touch the front cross member, at the rear.  The position I have mine in, is the only position, where my 120A alternator will clear everything on all sides.  The only issue I have is the belt tension adjustment bracket clearance, under the water pump inlet.  Well I cut down the adjustment bracket, last night, & it clears OK now.  Even though my alternator is cantilevered, off the front of the original cast block mounting bracket; when the pivot bolt is tightened up, the alternator body is "rock solid" with the engine.  I will maybe, fill in some of the unused adjustment slot in the belt adjustment bracket, & weld it in; to give it back, some strength, that I have removed, by narrowing it down.




Just got to pull it all off again, & fit a cable & lug to it's output terminal, then I'll give the engine a run, today, & see how it works dynamically.

Cheers  Banjo

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All went well; & the alternator upgrade, can be ticked off as successful.

The only modification required, was to reshape the fan belt adjustment bracket.  Below is a before & after picture.  I basically flattened the standard bracket, & then sculptured away the topside, & reinforced the bracket, by infilling some of the "unused" slot in the bracket.  I was even able to use the same fan belt, that was used with the old 30-40A Denso alternator.



The following photo clearly shows the mounting bracket & pivot bolt assembly, without the alternator in place.  The original cast "block mounting bracket", is simply inverted, & turned end for end.  The new pivot bolt is 160mm long & 10mm in diameter. (the origin one was also 10mm, so no mods required there).  The spacer & washer allow easy adjustment of the alternators position so the alternator pulley lines up perfectly, with the water-pump & crankshaft pullies.


Here is a picture below, of it all assembled; awaiting the bottom radiator hose to be fitted.


This pic below, displays the clearance at the rear of the alternator, to the engine mount.


The alternator fired up, once I remembered to hook up the +D terminal, with  an "idiot light", & was producing about 14.2 Volts.

This particular Bosch model alternator, has a "W" terminal, which had me doing a quick Google.  It apparently is a tacho output !

A number of European cars, including some VWs, obtain their tacho signal from a Bosch alternator.

Cheers Banjo



Edited by Banjo
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Thanks Si,

                 I can see it very clearly now.   Was the 140A version of the Aeroflow alternator you purchased, the chrome one, & that's why the reflection in your previous picture.

What stops the two little brackets in your pic, drooping under the weight of the alternator ?   



Is the rear pivot bolt through the original cast bracket, tightened up so tight, that the two little flat brackets you made, can't move at all ?

Cheers  Keith

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Yep aeroflow one is polished. 

Yes, I tighten up the inside ones first, then the outer one once the tension is set up top. There is the potential for a little bit of flex in those 2 little plates, so doing them first kind of eliminates the possibility of them being or of square. 

It was always going to be a temporary thing as I planned on making something better, but at the moment it ain't broke! I should really do it now while the car is off the road. 

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All makes perfect sense.   When I first fired my alternator up, with the engine running, I had no 12 volt output.  Then I remembered I hadn't connected the +D terminal to the ignition switch, via an "idiot/charge" light.  Some alternator designs have enough residual magnetism in them, to get them up & away. Not the Bosch system !

It relies on the small current through the charge light, to ground inside the alternator, to create some residual magnetism, to get it up & away.  Once the alternator is producing 12 volts, then it appears on the +D terminal; so effectly, the charge lamp has 12V on either side of it; & turns off.

Normally, the charge lamp in the dashboard, is a small 3W-5W filament bulb.  The only problem with this arrangement, is if the filament bulb filament blows, then there is the possibility that when you start the engine, the alternator will not produce an output.

I came across this little circuit on the nett, that eliminates this by using an LED, instead of a filament bulb.  I'll try it out tomorrow.  I have actually read where people have used a 2 Watt filament bulb as an idiot light, & there was not enough current, to create enough magnetism, to get the alternator away.  This circuit, should remove both those possibilities.


Cheers Banjo


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Hey Banjo

It would be handy to know if the new LED headlight lamps draw more current than the old ones. I was thinking of going the same path for my hilux and the Princess' rolla when it comes out of moth balls. It will be interesting to see how long the lamps last. I have read plenty of reviews with people complaining that they fail in a short time some a matter of months. Keep us updated.



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Hi Graeme,  

                  We are about to find out !  I'll certainly keep you posted.  I've got the meters here to mesure the currents, so we can do a direct comparison.


In general though, an LED should always give You more luminoous intensity, for a given power in, than any tungsent fillament bulb.

Once you've driven with that "cool white" light out front, You can never go back to that "yellowie" light, again.


Cheers Banjo



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It is very important, that the 12 volts fed to the alternator "idiot" charging indicator light, is  a switched 12v, from the ignition switch. 


To describe it simply . . . . .


When the engine is not running, the D+ terminal, is effectively at ground or earth potential.   When you turn the ignition on, without placing it in the "start" position, the charge light illuminates, because the charge lamp, has 12 volts on one side (the ignition switch), & ground on the other (D+ terminal). When you start the engine, the alternator turns, & produces +12V.  The D+ terminal basically then becomes the same voltage as the B+ battery terminal.  The charge bulb then has +12 volt on either side of it, & with no volts across it,extinguishes. That's how you know the alternator is working.


Now I have been guilty of this . . . . . . . .   When testing an alternator output, I've simply joined the +D & +B (main battery terminals) together, to get it going.  It works.  But when you are finished, you must remove the link betweeen the +D & +B terminals.  With the alternator off, the +D terminal, does not revert to look like a ground, because it is still connected to the battery +12 volt terminal.  

Internally the alternator, the +D terminal will draw a small magnetising current from the battery, & slowly drain the battery flat.


I've experienced a fully charged battery slowly drain over a week or so, because I failed to remove the link, after testing.


Cheers Banjo



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"Once you've driven with that "cool white" light out front, You can never go back to that "yellowie" light, again."

I'm not so sure..  Having fitted an LED light bar to the KE70 for the 40Km country drive home at night, I find the reflective markers show up much more, the highway signs are blindingly bright and there is a big pool of very white light on the road for about 30M.  What there is NOT, is any illumination 100m and more ahead, which is what I wanted. The LED bar is a 'spotlight' type, not a floodlight type too.

LEDs literally work according to the one inch reflectors behind them, and having 50 one inch reflectors does not throw light a long way. I'm thinking of swapping it for a pair of 6" pencil-beam spotlights.

So, great for close-in lighting, they throw light in all direction, up, down and sideways, but no good for distance.

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Not going to argue over your observations.  After all, you spend a lot of time on country roads in the dark, between Orange & Blaney.   As You well know, I live on the outskirts of Brisbane, in a semi rural area, without a lot of street lights.


I experienced initially, exactly what you describe; as a pool of bright light 30 metres in front of the car, from the bar LED setup.


Now there are a variety of quality, sizes, & prices, of LED bar driving lights for automobiles.


Certainly, if you want to see a mile ahead, & scare the living daylights out of all the sheep in the neighbourhood, then you buy the biggest; brightest; & probably most expensive LED driving lights, & mount them up of the roof, of the vehicle; or at least on the top edge of the bull-bar.


What I am talking about, is the little LED bar driving lights, that are 12-20 inches in length, & mount down on a plate, which fits behind the front number plate. 




1.   By nature, (on a car), they are fairly close to the ground.

2.   They are not very stable, as the number plate is often attached to the body work, & vibrates.

3.   The angle of adjustment is very "finnicky", & a very small angle change will produce a very big difference, in how far the light will travel.

4.    Even the loading of the vehicle, can change the angle of the LED bar light.




If the pool of light is only 30 metres in front of the car, try adjusting the angle of the bar, on a dark night, in an unlit area; & you''ll definitely find their limits. 


P.S.  Ultimately, the best solution, would being able to adjust the angle of elevation of the driving light bar, from the drivers seat.  I presume, those products are available; but probably, dearer than the driving lights themselves.







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Earlier on in this thread, I mentioned . . . .



I came across this little circuit on the nett, that eliminates this by using an LED, instead of a filament bulb.  I'll try it out tomorrow.  I have actually read where people have used a 2 Watt filament bulb as an idiot light, & there was not enough current, to create enough magnetism, to get the alternator away.  This circuit, should remove both those possibilities.




I tried it out, & it did not work. 


To create some internal magnetism, to get the "Bosch" design alternator away, you need about 250mA (1/4 Amp).


This circuit below, which I also found on the nett, does however, work well.   Where is says "To Alternator field Terminal"; that is simply connected to the +D terminal on the "Bosch design", alternator.




Cheers  Banjo

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  • 4 weeks later...

The LED  changeover of all lights on my KE-30 has been finally completed, after the last LED bulbs for the rear ‘Number Plate illumination” arrived yesterday, & were fitted last night, with a really good result. 

I thought I would list them all, & their cost, so anyone else contemplating the changeover, will have the LED bulb type/model knowledge, & cost.

There are a total  18 off bulbs involved . . . . .

None of the bulbs required any modifications to connections or wiring.

Headlight Bulbs:

Two (2) off @ 36.57 total.

eBay Description:  4-Sides H4 HB2 9003 LED Headlight Kit Light Bulb Hi-Low 2500W 375000LM 6000K HID



Front Side Guard Indicator Bulbs:

Two (2) off 12V 5W Wedge Bulbs @ $ 2.00 ea.



Front Turn Indicator Bulbs:

Two (2) off

Front Parking Bulbs:

Two (2) off

Rear Stop Bulbs:

Two (2) off

Rear Reversing Bulbs:

Two (2) off

Rear Turn Indicator Bulbs:

Two (2) off

Rear Parking Bulbs:

Two (2) off

Total off 12 bulbs

Three (3) off packs off 4  @ $ 5.99 ea.  Total Cost: $ 17.97

eBay Description:   4 X 1156 BA15S Car While Globe 18 LED Brake Revers Turn Stop Tail Light Bulb 12V



Rear Number Plate Illumination Bulbs:

Four (4) off  @ $ $ 7.48  (note: You only need two, but the pack includes 4 off)





Interior Dome/Ceiling Light:

One (1) off @ $ 6.65 ea. (note: You only need one, but the pack includes 2 off)






You will also need to swap your turn indicator flashing unit, over to a model suitable for LED lamps, as the existing one, (designed for high current bulbs) will “hyper-flash", if used with LED lamps.

LED Flasher Unit:

One (1) off  @ $ 12.99 ea.

ebay Description: 3 Pin LED Flasher Unit Relay Indicators 12V For LED Light Turn Signal 



So all up cost is about $ 100.00, & you get a couple of spare bulbs, to pop in the gove box.

The results were more than pleasing.

There was no mods carried out to the wiring or connections needed.  Obviously, whilst, you've got the "lenses" off to swap over the bulbs, you will give the lenses a good clean.  I found the little rear bumper bar mounted licence plate glass lenses, needed a very good clean.

The flasher unit, is simply a plug out; plug in; requirememt. It is located down behind the plastic panel, next to the drivers accelerator pedal & leg.

The only other advice I can provide, is about the electrical contact points in the car, for all these bulbs.

The existing filament bulbs carry reasonably high currents, that "burn through" slight corrosion on the electical contact points, in the sockets.  However, the LEDs, have very small DC currents, by comparison, & I would suggest giving all the electrical contact points a good clean, before inserting the new LED bulbs.  I found an easy way, was to a bit of steel wool wrapped around the end of a pencil, or similar object worked well. Just make sure to blow out any tiny bits of steel wool, before inserting the new LED bulbs.  For complete safety; this cleaning suggestion, should be carried out, with the negative terminal of the battery isolated.

Probably the best results, I've had on my car, for a $100 spend.

Cheers Banjo 

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