1HDT 24v to 12v conversion step by step (5 Viewers)

[Ragnaroek]

I remember around 11..ish years ago I mentioned on here on MUD that I was doing the 24v to 12v conversion, you should have heard (read?) the naysayers and haters, and of course they were the people who knew jack about electrics.

I wonder how long it will be before people take my conversion to cooling the 80 engine with an electric fan done around 12....ish years ago, will also gain popularity?

Funny how it takes so many years for modifications that are beneficial in so many ways to be considered and taken up?

I was also thinking about converting mine to 12v. Then the alternator died on the first day of a holiday weekend trip in my dads 80. Since the 24v starter is happily working down to a voltage of 10,5V on both batteries, we just continued on with the trip for another two or three days, adressing the alternator problem when we got home.

And why in the world should you convert a car like this to an electrical fan? If it decides to give up on you while traveling, youre done. If your fan clutch dies, put a bolt through it and carry on.


Don't get me wrong, i really appreciate your build and enjoyed reading the associated thread, i just don't really get the benefits of called modifications.


Regards, Jona

 

[veiloctane]

I was also thinking about converting mine to 12v. Then the alternator died on the first day of a holiday weekend trip in my dads 80. Since the 24v starter is happily working down to a voltage of 10,5V on both batteries, we just continued on with the trip for another two or three days, adressing the alternator problem when we got home.

And why in the world should you convert a car like this to an electrical fan? If it decides to give up on you while traveling, youre done. If your fan clutch dies, put a bolt through it and carry on.


Don't get me wrong, i really appreciate your build and enjoyed reading the associated thread, i just don't really get the benefits of called modifications.


Regards, Jona

The 24-volt switch-over relay is no longer available for purchase, and many people are experiencing starting issues with their 24-volt systems. If your system is currently working fine, but you know it will eventually fail, what will you do then?

Having a simple setup where you can choose which battery to use, having both a house and starter battery, the ability to boost the battery, and battery isolation is a great advantage!

In your story, it seems that your alternator stopped working, but somehow managed to provide some voltage throughout your entire three-day trip.

Starting at 10.5 volts is not a problem as long as you have a high-amperage cranking battery. In my case, I use a Northstar group 27 battery with 1750 Pulse crank amps, 1080 marine crank amps, 92 amp hours, and a 195-minute reserve capacity.

Consider yourself lucky on that trip. In my opinion, the 24-volt switch-over relay is a potential problem waiting to happen. Additionally, it's much easier to find 12-volt starters compared to 24-volt starters.

 

[veiloctane]

I must have something odd going on as my starter is working without these 3 wires not being connected to anything.

1HDT 24v to 12v conversion step by step

I used a 3way heat shrink butt connector similar to this.

forum.ih8mud.com

 

[Dave 2000]

I was also thinking about converting mine to 12v. Then the alternator died on the first day of a holiday weekend trip in my dads 80. Since the 24v starter is happily working down to a voltage of 10,5V on both batteries, we just continued on with the trip for another two or three days, adressing the alternator problem when we got home.

And why in the world should you convert a car like this to an electrical fan? If it decides to give up on you while traveling, youre done. If your fan clutch dies, put a bolt through it and carry on.


Don't get me wrong, i really appreciate your build and enjoyed reading the associated thread, i just don't really get the benefits of called modifications.


Regards, Jona

@Ragnaroek

LONG!

Hi, I appreciate your comments however, if you had read through my thread (yeh I know a dozen or so years worth), you would have seen why the conversion was done on the 24 volt starter.

When I go off road I need a fridge (diabetic on insulin), so a fridge is not a luxury, it is essential. Running a fridge from a 24 volt parked 80 means the draw is on BOTH batteries as they are in parallel, they only go into series during cranking which means after a couple of days out in the desert there is a risk of the 80 not starting at all. On my vehicle and using decent quality equipment rated way above my 80's requirements the conversion was done. Once parked the fridge runs off of both batteries (both parallel), then a 500 amp Blue Seas VSR separates the batteries when it detects the starter battery has come down to a certain threshold. When this happens depends on weather, how often the fridge is opened and so forth, but generally it is some time during the night or early morning, remember the fridge is not on all the time. So, this leaves plenty of charge to work the 12 volt starter, note the starter battery after supporting the auxiliary battery for whatever hours, once separated the starter battery does just that, start the engine so, that means the starter battery is always protected.

So, to your 80 with the 24 volt system, your figures are quite frankly wrong, perhaps caused by a faulty meter or procedure in its use? At 10.5 volts your batteries are dead, there is absolutely no way they could crank the engine, 12 volts or 24 volts, they are dead. And to put that sentence into perspective. when the ignition on a diesel 80 is switched on, it immediately starts to heat the glow plugs, each one of the six drawling around 8+ amps, so a 48+ amp load on the batteries, the later versions with the manifold heater perhaps a similar draw, then there is the diesel pump solenoid, this is also circa 8 amps to operate, then there is the various ECU's that power up, dashboard check lights, although not a lot in the whole scheme of things but they are a draw all the same, now you start the engine and this takes a substantial amount of amperage, something around at a guess say 100 - 150 amps? So that will tell you that your reading of 10.5 volts (the pressure if your not electrical savvy?) is not sufficient to push that kind of amperage.

As an aside, my system allows me to press a button on the centre console and allow the two batteries to combine, in effect allowing me to jump start the engine without opening the bonnet, whereas jump starting the 24 volt 80 can lead to some expensive damage, in particular if the donor car battery is not connected to the correct battery on the 80.

So I hope that answers your first question?

Now to the electric engine cooling fan conversion.

This actually brought about a lot of controversy, and to be fair it is understandable, there are vendors who sell modified clutch kits for the 80, so taking that into consideration, the conclusion seems to be the stock fan clutch system is not sufficient to cool the engine.

So, a look at some of the advantages of an all electric system.

First economy, the 80 is not too bad in the diesel versions but pretty poor with the petrol or gasoline versions, fitting an electric fan without doubt does decrease the consumption of fuel, by how much not a lot for sure, but if it is 10% on a vehicle that only gives you say 15 miles to a gallon, then it is an extra 1.5 miles per gallon, that would seem to be obvious but it is not strictly true, there is the load to be considered on the alternator, I will put that aside just for a moment, just to slow down the mathematicians who will go on about using mechanical energy to create electric energy and then use that electricity to turn a fan, these are the people who have no idea about how DC motors work. One member on here quoting something like needing 400 BHP to make the conversion work!

Back to the electric fan, I know that on the typical vehicle moving at around 20 MPH there is sufficient air moving through the radiator to keep the engine cool, this assumes everything is working properly, a properly working fan coupling will be allowing the fan to idle over, so no load on the engine and the same for the alternator with the electric fan being off. The engine starts to heat up as the vehicle speed drops, this is where the engine driven fan starts to lose ground with the electric version. First the sensor controlling the electric fan is far more sensitive than a viscous coupling, so the fan come on earlier keeping under bonnet temperatures down, this does help prolong the life of under bonnet components. Eventually the VC starts to drive the mechanical fan and it will be driven quite hard to get the engine temperature down, this will be noted when the traffic starts to clear, you can hear the fan roaring, this is using more fuel than the electrical fan, manufacturers knew early on that the gains if any were negligible using the electric, just like the mechanical fan they were noisy and used more power from the alternator. The answer to this was to introduce two speed fans, the 4.6 V8 Lincoln fan for example, this was my first choice, it is a two speed fan with a controlled slow and fast speed settings, it needed less amperage from the alternator and was quieter, the second higher speed only needed in extreme conditions, which rarely happened because the engine was not allowed to get too hot. At this point the electric fan was taking the lead, being controlled by sensors which had become more precise now there was no need for the slow reaction of the VC mechanical fan to 'catch up' with cooling the engine.

Like pretty much everything these days modern technology moves on, and whilst some resent and reject it, there are others that will in many cases embrace it, I did exactly that, witness the amount of modern vehicles with electric cooling fans these days. So, I purchased the electric fan from a Mercedes Benz, now these use an entirely different system of control, this is called PWM, or Pulse Width Modulation, in other words as the engine starts to heat up the fan comes on very slowly, and if that amount of airflow is not enough it will increase incrementally to keep pace with engine temperatures, the result is minimal load on the alternator, in fact the load is incredibly small, but of course we have talked about energy here but it has proved there are fuel costs to be saved.

Now lets have a look at something else. Your car is outside your house, windows closed on a hot day and your fan is the typical VC unit. If you open the bonnet on a vehicle with a VC fan, you will find it it rotates with little or no resistance, in fact if you know what you are doing you can start the engine and stop the fan, I will not say how, but use some commonsense. So, back to our stinking hot car outside the house, you start the engine and put on the AC however, it is not working? This is because the fan power needed to draw air through the condenser is absent, the viscous clutch drive is not engaging so air is not being pulled through to cool the condenser, now we know this is not speculation it is fact. We also know that the AC condenser is in front of the engine cooling radiator, which at the moment is cold, so even if some of the warm air from the condenser does get drawn towards the engine it gets cooled by the engine radiator, and we already know for the viscous coupling to work it needs warm air, so until the viscous coupling heats up and engages the fan you can just sit in the car getting cooked, here is where the electric fan is a clear winner, the moment the AC is switched on, the PWM electric fan is switched on at around medium speed, so the cooling of the AC condenser is immediate, that is zero delay of getting cold air into your vehicle. It is only when the VC has had enough warm air over it to activate the silicone will the mechanical fan start to engage.

As an aside, people talk about the 'sweet spot' for driving with reasonable economy, in the modified dashboard display I designed and fitted I can say without a doubt that the cooling system on the 80 starts to struggle when approaching speeds of around 75....ish MPH, in particular when climbing hills, whilst I can see that as I have the temperature gauge modification designed by Raventai who I think is no longer a member? The modification shows the needle is starting to climb, I but I am going by the more accurate indication that the electric fan has come on. I am not saying the electric fan on my 80 which is the same size as the mechanical on the 80 is flowing more air than my car doing 70 MPH, but what I am saying is the fan will only run for a minute or so and then go off, if I maintain the speed it will come on and off if I continue over 75 MPH, I know nothing about aerodynamics, although the front of the 80 does resemble a breeze block, I think air is actually 'bouncing' off the front of the car, I would cite that members who have cut vents in the bonnet, or removed the rubber flaps on the chassis rails preventing mud or whatever enter the engine bay have seen decreased engine temperatures when their vehicle is worked hard.

And finally to finish this off and answer your final query about what happens if the electric fan fails, well first I would say I live in southern Spain, so 40* C in summer is not uncommon, so I know it works great, and in the unlikely event of it failing I would do what what anyone else would do, I would let the engine cool down (I do have an overheat warning system) and then continue my journey, but your question is spot on when it comes to being off road out in the desert, I take with me a spare starter, alternator, CV or Birf as they are often called, a drive flange......and yes the mechanical fan is part of my off road spares.

Sorry if there are any spelling or grammar errors.

Regards

Dave

(First car when I was 10 years old, mechanics apprenticeship completed in 1978, so approaching 54 years under a car, currently with my own garage business, which is pretty much dead now (brain surgery to remove cancer tumour), I would be happy to say I have a rough idea what I am talking about.

 

[veiloctane]

2-
you will be left with 1 grey plug with 2 green wires and 1 white wire with a ring terminal. Cut those 3 wires and connect them all together using a heat shrink/crimp connector.

Hi I'm trying to figure out what these 3 wires do being connected when removing the 24V starter

my 24v starter is removed and the 3 wires are not connected to anything I haven't noticed anything odd unless I'm missing something or its wired differently somehow

 

[Pabloff]

Hi I'm trying to figure out what these 3 wires do being connected when removing the 24V starter

my 24v starter is removed and the 3 wires are not connected to anything I haven't noticed anything odd unless I'm missing something or its wired differently somehow

If understood correctly from another thread those are the for the switching relay timing solenoid, that's why you need to wire them like that to bypass it, because the switching relay has to be removed. If not then you will have to unplug the timing relay in the kick panel and jump the 2 wires.

Pictures taken from:

12 volt starting conversion on a 1997 24 valve manual 80 series LandCruiser

Is this the correct Bosch one? http://www.ebay.co.uk/itm/291025446615?_trksid=p2055119.m1438.l2649&ssPageName=STRK%3AMEBIDX%3AIT

www.landcruiserclub.net

 

[Pabloff]

On that note, I put together a diagram of what I would like my system to be. Appreciate if you legends can opine. 1993 1HDT HDJ81 converted to LHD A442F. Already replaced the alternator, got one from a fj (at least that's what the seller said) just changed the pulley and rewire the plug to the round one. I also got a 12v starter. Just finalizing the design / diagram to see what else to buy.



Saw a post from Dave on that other forum, I'm planning to go a similar way with the blue sea systems automatic charging relay and a 4 position switch to be able to choose what battery to start from or self jump (combine) if needed (I think in my diagram is designed that way, please correct me if wrong)



Here is the diagram appreciate the feedback, special on where to connect the alternator + or if there any more efficient way to wire this around. I'm planning to go the way to jump the wires in the timing solenoid instead of joining the 3 wires as mentioned in this thread (if that's correct).







Or







I understand alternator direct to house battery will have less voltage drops as is a shorter distance



Planning to use 35mm² wire with a 150 amps ANL fuses for the ACR.





Last question, do I need a fuse coming out from alternator? Stock 24v starter goes unfused up to the switch start relay, not sure if there is some protection elsewhere.



Cheers!



PM

 

[urhc2]

Howdy all, I am now in the middle of this project on my 97 1HD-FT and looking for a quick bit of guidance. I have the old 24v wiring out along with the 24v starter. I have one additional grey plug compared to step 2 in the OP, picture below for reference. It has two cables, one black/white and one red/white, and they are taped together with the plug going to the fuel filter. Any idea what these may be and if I need to do something with them? Picture below for reference if it helps. I am asking about the plug my thumb is touching as shown.

Thanks!

 

[urhc2]

Disregard above note, I believe the 3rd plug I was asking about is for the fuel heater, but my truck does not have one. The connector itself is gunked up pretty bad and clearly has not been connected to anything in a very long time.

As an update to my own efforts, I have everything connected but no start. I am hoping this is just due to the battery being low (only reading about 12.5), so not dead, but I will be charging it overnight and trying again tomorrow. If not, multimeter time.

 

[urhc2]

I'm officially out of ideas, I cannot get my cruiser to turn over and I am not getting power to the signal terminal.

I have tried the method of jumping the 12/24v solenoid described in this thread, I have also attempted adding a ground to the white/red cable from the starter relay in the engine bay as described in this thread: 12 volt starting conversion on a 1997 24 valve manual 80 series LandCruiser - https://www.landcruiserclub.net/community/threads/12-volt-starting-conversion-on-a-1997-24-valve-manual-80-series-landcruiser.143513/

I have also tried jumping the 12/24v switchover timer in the passenger footwell.

Anybody have any ideas of things to try or methods to re-try? I am stuck.

 

[mocruiser77]

Isolator and Fuse bracket.

Main

House

I am open to constructive criticism. Please chime in if you see possible improvement.
The whole job took me approximately 24h and cost 1700$ Canadian including batteries and starter.
Big thanks to SHREDWagon for his valuable insight and or allowing me to take a peak at his rig!

Hi im new to all this ive been trying to start a thread but struggling great post btw please if you could help me out i have a pzj77 with a 1hz swap done to it which was converted from 24v to 12 i have wired everything it up but i have very poor power to windows wipers and horn the three power wires at the fusbile link get hot i have replaced the fusible links with midi fuses the alternator its about 10mm wire direct to battery has been upgraded but it does get a little warm near the 100amp midi fuse in between battery/alternator i cant seem to find the cables people crimp the 3wires near passenger wing under bonnet near glow relay or starter relay ( right hand drive vehicle) the ones i have are not the colours in posts iv seen or the wires to jump also the fuel gauge and battery gauge dont work i thought i started a thread but was a conversation what ever that is lol please any help would be great

 

[mocruiser77]

12V STARTER SWAP

The current 24v starting worked great but the need to have an isolated house battery and the safety factor of being able to self jump-start indicated the needed swap. I kept the driver side battery as the Main (start) and the passenger side as the House (aux).
1-
Disconnect and remove all wires attached to the the 24v starter solenoid located behind the passenger side battery.
Remove the starter solenoid.

2-
you will be left with 1 grey plug with 2 green wires and 1 white wire with a ring terminal. Cut those 3 wires and connect them all together using a heat shrink/crimp connector.

3-
Disconnect the starter+ and the small negative connector from the starter. Remove the original starter and replace with 12v version. Connect the negative connector just like the original and run a new cable from starter+ to Main+. (I used 2/0 welding cable for almost all my connections as it was free.)

4-
Ground both batteries to existing body and engine grounds

5-
Connect Main+ to Battery Isolator(I used Battery Doctor 150amp), Battery Isolator to 150amp fuse, Fuse to House+

6-
you will be left with this wire originally connected to passenger side+. Use a heat shrink butt connector and extend it to the Main+ post

7-
make a new wire from alternator to Main+

I think that's it...
I used a Blue Sea 5511e between the Main+ / starter and the House+ / Fuse box. This allows me to shut everything off with one switch and combine both batteries for self jump-start or winching.
I used dual wall heat shrink on the Full length of all wire and wiring loom almost everywhere.
Tin plated cooper lugs were used throughout.
All the small wires connected to the driver side battery+ will remain connected to the Main+
Batteries: Eliminator Ultra XD 34/78 AGM battery for the Main and a Nautilus Ultra XD Group 27 AGM Deep Cycle for the House.

Hi im new to all this ive been trying to start a thread but struggling great post btw please if you could help me out i have a pzj77 with a 1hz swap done to it which was converted from 24v to 12 i have wired everything it up but i have very poor power to windows wipers and horn the three power wires at the fusbile link get hot i have replaced the fusible links with midi fuses the alternator its about 10mm wire direct to battery has been upgraded but it does get a little warm near the 100amp midi fuse in between battery/alternator i cant seem to find the cables people crimp the 3wires near passenger wing under bonnet near glow relay or starter relay ( right hand drive vehicle) the ones i have are not the colours in posts iv seen or the wires to jump also the fuel gauge and battery gauge dont work i thought i started a thread but was a conversation what ever that is lol please any help would be great

 

[mocruiser77]

Hi im new to all this ive been trying to start a thread but struggling great post btw please if you could help me out i have a pzj77 with a 1hz swap done to it which was converted from 24v to 12 i have wired everything it up but i have very poor power to windows wipers and horn the three power wires at the fusbile link get hot i have replaced the fusible links with midi fuses the alternator its about 10mm wire direct to battery has been upgraded but it does get a little warm near the 100amp midi fuse in between battery/alternator i cant seem to find the cables people crimp the 3wires near passenger wing under bonnet near glow relay or starter relay ( right hand drive vehicle) the ones i have are not the colours in posts iv seen or the wires to jump also the fuel gauge and battery gauge dont work i thought i started a thread but was a conversation what ever that is lol please any help would be great

Please help

 

[mocruiser77]

Please help

Help

 

[KaisoCruiser81]

Was the PZJ77 originally 24V accessories? I believe that was the case for the HZJ7x series which probably explains your weak accessories (windows, wipers, horns). The HDJ8x was only 24 volt starter - everything else was 12V when running. That might also be why your gauges don't work.