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where to start electrics
sgtbrierley901 - 8/1/08 at 06:39 PM

hi there
im new to the forum im building an mk indy with an ford dohc 2ltr engine ,im at the fitting the electric stage now
and as ive never done this before
some stupid questions?
does the the live battery lead go to the starter motor then the alternator and is that?
where does the negative battery lead go to?
thanks
stuart

twybrow - 8/1/08 at 06:42 PM

Have you got a copy of the haynes manual/ a wiring diagram?

zoom - 8/1/08 at 06:45 PM

Negative goes to the engine block, usually through one of the gearbox bellhousing bolts. Dont forget to also earth the chassis to the negative side of the battery as well

jos - 8/1/08 at 06:46 PM

negative goes to the loom (maybe) the chassis and the engine block

sgtbrierley901 - 8/1/08 at 06:58 PM

cheers zoom and jos its a bit clearer now

yes i have got haynes manual and instructions from the loom which is from mk but its like reading mandarin chinese

cheers
stu

twybrow - 8/1/08 at 07:28 PM

Break the whole car down into several seperate circuits. You just cant follow an entire diagram. The battery is a good place to start! Have you got a multimeter/test lamp - very handy for telling what is connected to what on a loom?

bigbird - 8/1/08 at 07:53 PM

make all loom connections before you even think about connecting the battery... you dont want any potentially live circuits touching the chassis with the battery connected......they will heat up like a bar of an electric fire.

Peteff - 8/1/08 at 08:05 PM

While you are working on it live you can clip the lead to the battery with a crocodile clip or mole grip so it can be released quickly if any sparks appear.

RazMan - 9/1/08 at 09:53 AM

I always use a tiny 12v battery from a house alarm until I am confident everything is wired up ok. It will only give a max of 2 Amps so won't hurt if a short is present.

Schrodinger - 9/1/08 at 10:14 AM

You could also temporarlit wire in a low rated fuse to protect everything until you are happy with your efforts.
When I built my Tiger I saton the living room floor for a couple of evenings and labled every connector before taking it out into the garage and installing it in the car, this also gives you a feel for where things go.
Good luck

sgtbrierley901 - 9/1/08 at 11:39 PM

just like to say thanks guts for advice i will take it on board and get cracking at the weekend
cheers stuart

02GF74 - 10/1/08 at 10:26 AM

quote:
Originally posted by sgtbrierley901

some stupid questions?
does the the live battery lead go to the starter motor then the alternator and is that?
where does the negative battery lead go to?
thanks
stuart


no such thing a as stupid question.


although there is some naivety shown here, the thing is we all have got to start and learn sometime! And ofcourse, if you have never involved in electrics, then wiring diagrmas are unintelligible.

A good place to begin would be to llok at a simpe wiring diagram, I would suggest the one in the RC book or series land rover diagram.

bascially you would look at say headlamps, follow the wires to see how the circuit is made.

---oOo----

to answer your question.

does the the live battery lead go to the starter motor then the alternator and is that?

the big fat cable from the battery goes to a solenoid (think of it as an electrically operate swtich of high currents) and then to the starter motor. the solenoid is switched from the ignition. Now the solenoid can be a separate unit (pre-engaged starter motor) or is attached to sdie of starter motor (inertia type) where it also throws the driving cog into the flywheel.

there will be a wire from the alternator output that goes to the battery, usually it goes to the solenoid as it is conventient place to connect it. The other wire from the alternator is for the charge lamp.

the negative battery lead needs to go to other termianl of the starter motor to complete the circuit but the motor does not have a termin, instead using its body as the contact. Hence we onnect it to one of the bolts of the bell housing or engine, e.g. engine mountin plate bolt.. For completeness there should be an earth strap to connect engine and chassis.

sgtbrierley901 - 10/1/08 at 11:26 AM

thanks 02gf74 thats cleared it up for me thanks for the advice


yep i am quite niave when it comes to the more technical areas i was all right doing the suspension and brakes now its scratching my head and look puzzled time and i wish i went for an pinto to begin with not an dohc but hey such is life
yet again thanks