direct injection diesel / huge starter motor

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Guest

Guest
Hi Jeff
had some personal experience with this last week. While replacing the fuel filter on my 60 series, 24v through out (except the radio connections) I must have got a huge air lock in the pump because it took an age to bleed. Predictably the batteries got run down, but luckily we used a 12v tractor to jump onto one of the batteries and we were able to bleed the system through from the power this supplied. I'm sure this isnt exactly good for the batteries but it got everything running again.
As for why 24v on a landcruiser I have no idea. I worked in agriculture for years and nearly all tractors are 12v and they employ some fairly hefty diesels. I only really saw 24v on eastern european tractor, and what a delight they were!
James
hi Christopher
thanks for the explanantion.im sure its been covered before but i must have missed it..you said that the starter uses 24 volt, which i understand, but what about the rest of the electrics in an 80 are they 12 volt, and if so how,
and if i try and jump another (12 volt) car using the left hand battery (as i look into the bonnet) does it deliver 12 volts?
I suspect thats it someting to do with batteries connected in seres or parrallel but ive no idea what that means
regrads
jeff
From: "Christopher Bell" <[Email address removed]>
Reply-To: [Email address removed]
To: <[Email address removed]>
Subject: RE: [ELCO] direct injection diesel / huge starter motor
Date: Tue, 24 Jan 2006 09:47:59 -0000
Jorgen

Apologies if you already know the below, but here is a brief explanation of diesel engine starting.

Diesel engines are "compression ignition", meaning that the heat generated by compressing the air in the cylinders is enough to ignite the diesel when it it injected. You can feel this for yourself if you pump up a bicycle tyre using a hand pump: the end will get hot, and if you do it vigorously enough it can be too hot to touch - the mechanical work of compressing the air is turned into heat. So diesels don't need, and don't have, spark plugs.

Some diesel engines have glow plugs, which literally glow red hot due to electric current, to help with starting when they are cold; but these are usually "indirect injection" engines, in which there is a small cavity above the cylinder where the fuel is injected. Typically they glow for a few seconds before starting to warm things up, and turn off automatically a few seconds after the engine has started.

"Direct injection" engines, in which the fuel is injected straight into the cylinder, don't normally need glow plugs as the heating effect from compressing the air is enough to start the engine. However it does mean that direct injection engines need powerful starter motors, and the Euro spec 80 series diesel has a huge 24 volt starter for this purpose - hence my comment. (I don't know its exact rating, but it is around 2kW which is about 3hp.)


I don't know anything about the D-4D engine other than that it is direct injection, but if yours has a manual gearbox I should think it will bump-start OK. When I had battery trouble I bump-started my 80 series very easily in 2nd gear. If you have an auto box don't even think about it!

Again I don't know about diesel catalysts, but so long as you don't squirt masses of unburnt fuel down the exhaust I don't see that it will be a problem. So as long as it bump-starts reasonably quickly it should be fine.

Christopher Bell
From: [Email address removed] [mailto:[Email address removed]] On Behalf Of Jorgen Gronberg
Sent: 23 January 2006 22:07
To: [Email address removed]
Subject: [ELCO] direct injection diesel / huge starter motor
Hi Folks,

My eye caught the e-mail from CB mentioning direct injection
and a huge starter motor.

Does that also imply that I for example shall be able to bumpstart
my LC3 D-4D 120KDJ ?, does the engine start on the heat generated from
the compression only, and thus ready to fire when the injection happens?

If a bump start is used, will that cause any problems with the catalytic
converter if the engine does not fire-up immediately?

Regards Jorgen KDJ120 UK

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G

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Guest
Hi Jeff
The cruiser only needs the two betteries for the 24v starter after that all
the electrics are 12v. If you use the battery for jumping another vehicle
it will only deliver 12v and not 24v.
cheers
John C
92HDJ 80 1HDT Rep of Ireland
 
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Guest

Guest
Jeff

I assume that you have the twin battery "cold weather" setup that is
standard for Euro spec vehicles.

What happens is this: for all situations except starting the electrical
system is a conventional 12 volt system, and the two batteries are
connected in parallel. "Parallel" means that the positive terminals on
each battery are connected together, and the -ve terminals on each
battery are also connected together. This leave the voltage the same at
12v but doubles the current available.

Thus (looking forwards from the driving seat, batt #1 on the left, #2 on
the right)

+-----------------+--------------- to vehicle 0v (chassis)
| |
| +-----------------+-------- to vehicle +12v
| | | |
*-|------|-* *-|------|-*
| - + | | - + | PARALLEL wiring (normal use)
| Batt 2 | | Batt 1 |
*----------* *----------*

However when you turn the ignition key to "start" then the batteries are
rewired in series, which means +ve of battery 1 connected to -ve of
battery 2, and the +ve of battery #2 to the starter motor. This doubles
the voltage to 24v, but doesn't increase the current available.
Diagrammatically:

+--------------- to vehicle 0v (chassis)
|
+------------------------+
| +-----+ | |
*-|------|-* | *-|------|-*
| - + | | | - + | SERIES wiring (starting only)
| Batt 2 | | | Batt 1 |
*----------* | *----------*
+-------------------- +24v to starter motor

This is achieved by a changeover relay (circular about 3" diam, 6" high)
that is to the left hand side of the engine with heavy wires coming to
it from both batteries.

As you can see from the diagram the +ve terminal of battery #2 becomes
+24v, and its -ve terminal +12v (both relative to chassis earth) while
starting, which is why you must never connect any extra electrical
equipment to that battery unless you are very, very sure about what you
are doing. In fact its terminal should be shrouded with a warning about
not using it for jump starting. To be on the safe side only ever
connect to a battery if you can see a wire from its -ve post connected
permanently to the chassis.


You can use battery #2 for jump starting so long as you are careful,
because the important words above are "relative to chassis earth". This
is because the voltage across the battery itself is always 12v, so you
are safe as long as
*=09
no part of the bodywork of car A touches that of car B
AND
*=09
you connect both jump leads directly to the relevant terminals
of one battery only
This is because car #1 won't "know" about the chassis voltage of that of
car #2.

This is true whether the LC is starting the other car or even - shock,
horror - the LC has "failed to proceed" (to borrow a phrase from RR)


You might ask why Toyota does it this way, and why not just have a beefy
12v starter motor? The answer is that the energy available from an
electrical system is Volts x Amps (current); but the starter motor
design is easier and smaller with a higher voltage, and also the losses
in wiring rise with current squared. So there comes a point when you are
better off using a higher voltage.

I hope this is clear.

CB
________________________________

From: [Email address removed]
[mailto:[Email address removed]] On Behalf Of jeff watts
Sent: 24 January 2006 10:15
To: [Email address removed]
Subject: RE: [ELCO] direct injection diesel / huge starter motor
=09
=09
hi Christopher
thanks for the explanantion.im sure its been covered before but
i must have missed it..you said that the starter uses 24 volt, which i
understand, but what about the rest of the electrics in an 80 are they
12 volt, and if so how,
and if i try and jump another (12 volt) car using the left hand
battery (as i look into the bonnet) does it deliver 12 volts?
I suspect thats it someting to do with batteries connected in
seres or parrallel but ive no idea what that means
regrads
jeff
=09
=09
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G

Guest

Guest
Hi James,
To save yourself some bother next time, if your 60 is anything like an
80 you should have a priming pump near the fuel filter, failing that it
might be like the older tractors that used to have them on the actual
injector pump.
Also, depending on the injection pump you may have to crack open one or
more of the injector pipes to blead them as well.
--
Regards,
Julian Voelcker
Mobile: 07971 540362
Cirencester, United Kingdom
1994 HDJ80, 2.5" OME Lift
 
G

Guest

Guest
John/Chris,
James has a 60 series and some of them were 24volt throughout, not just
for starting.
--
Regards,
Julian Voelcker
Mobile: 07971 540362
Cirencester, United Kingdom
1994 HDJ80, 2.5" OME Lift
 
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Guest

Guest
Julian
hmmm yeah that was the theory any way. we used the pump to fill the new filter and bleed the system as far as the filter. After starting the engine it ran an nearly got through the air blocks but didnt and died. Then started the 1 hour nightmare of having to individually bleed on top of each injector at the engine. I can only assume that some air was still in the new filter somehow and that got into the pump. I spent quite a while looking for a bleed screw on the pump but there isnt one so the starter had to be used to bleed right from the filter. At least it is better to know about these potential problems. It was quite a relief to get it started as I was starting to worry about dirt in the fuel pump.
when replacing the radio on the LC I discovered that the power leads are 12v which was quite a nice suprise. Both the backup power for the memory and the main power from the ignition are 12v so either someone did a proper job in the past or toyota do it. Either way it did make one job straight forward at least!
James

Hi James,
To save yourself some bother next time, if your 60 is anything like an
80 you should have a priming pump near the fuel filter, failing that it
might be like the older tractors that used to have them on the actual
injector pump.
Also, depending on the injection pump you may have to crack open one or
more of the injector pipes to blead them as well.
--
Regards,
Julian Voelcker
Mobile: 07971 540362
Cirencester, United Kingdom
1994 HDJ80, 2.5" OME Lift
 
G

Guest

Guest
Julian
I was replying to Jeff Watts who asked about the 12v vs 24v issue.
CB
|
| James has a 60 series and some of them were 24volt
| throughout, not just for starting.
| --
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G

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Guest
OOPS see what happens when I think I know what you know what I dont know
what you know and you know I dont know what you know and wish I did.
John C
92HDJ 80 1HDT Rep of Ireland
 
G

Guest

Guest
As someone once said to me... =8Cyou think I know damn everything. But
actually I know damn all...=B9
On 24/1/06 13:46, "jeff watts" <[Email address removed]> wrote:
> john
>
> i dont even know what i dont know
>
> jeff
>
>>
>> From: "John Byrne" <[Email address removed]>
>> Reply-To: [Email address removed]
>> To: <[Email address removed]>
>> Subject: Re: [ELCO] direct injection diesel / huge starter motor
>> Date: Tue, 24 Jan 2006 12:23:58 -0000
>>> >OOPS see what happens when I think I know what you know what I dont
>>> >know what you know and you know I dont know what you know and wish
>>> >I did.
>>> >
>>> >John C
>>> >92HDJ 80 1HDT Rep of Ireland
>>> >
>>> >--
>>> >European Land Cruiser Owners Mailing List
>>> >Further Info: http://www.landcruisers.info/lists/
>> -- European Land Cruiser Owners Mailing List Further Info:
>> http://www.landcruisers.info/lists/
 
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Guest

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Jeff
It turns out I do know what I know and now you know what i know because I was correct in responding to your question, so now we know or do we, that is the question.
John C
92HDJ 80 1HDT rep of Ireland
 
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Guest

Guest
John and Jeff,
A hint of paranoia is creeping in here. Console yourselves - you know more today than you did yesterday.
Gareth.
 
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Jeff

Yes, that's safe. You can also use your left hand battery if you want
so long as you connect directly, and only, to its two terminals. But to
be on the safe side use the right hand battery.

Not having the two cars touching is recommended practice for any
vehicle, as otherwise you may complete a circuit unexpectedly ... and
some old cars (minis I seem to recall) used +ve earth.

CB
________________________________
From: [Email address removed]
[mailto:[Email address removed]] On Behalf Of jeff watts
Sent: 24 January 2006 15:51
To: [Email address removed]
Subject: RE: [ELCO] direct injection diesel / huge starter motor
=09
=09
christoper
thanks for the expalnation it makes sence now..so basically i
can jump another 12 volt car providing the cars are not touching and
that i connect +ve and -ve of the LC right hand battery (lookinhg at it
from the drivers seat) to the +ve and -ve of the dud battery
many thnks
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Hi Jeff
what is? what , what we know or what we think we know, or is it what we knew that we forgot we knew untill we knew it again, so know you know what is? or do you. Gareth I wonder somtimes about what I know or think I knew only to find out what I thought I knew but really didn't untill I remembered I knew it in the first place, then of course I knew I knew it and was happy untill I couldn't remember all of what i thought I knew completly, but then thats another story.
John C
92HDJ 80 1HDT rep of Ireland
SNIP
what is?
 
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