guys take a look at his battery cable in his build thread, it explains a lot!

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Bluey-1973 Clubby - 1330, high lift, big cam, 7 port madness in progress..

Gumby-1978 Minivan, British Racing Green - 1310, high lift, mild cam, enlarged porting and chamber shape with big valve head, supercharged build in ever slow progress!

I also have checked out the cable from the Soliniod and the starter.... It wasnt the best either. So I have fitted a new one! Fingers crossed for tonight! Running the new Battery cable front to back

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where should the engine be earthed to? and is there a test to ensure that it is getting a full earth? ie using a multimeter?

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Through the earth strap on the clutch cover to the inner guard.

Clean the threads on the captive nut on the inner guard with a tap. Same with the clutch cover bolt if you can. Sand with a little sandpaper the earth strap contacts until they are shiny. Do the same with the battery connections in the boot.

You test continuity to ground with a multimeter set to Ohms. Short the multimeter leads first and measure the resistance in the leads. Then test from engine to body (at any point on the engine and body will do). Subtract the shorted leads measurement from the new one, and that is the true value of resistance.

It should be basically zero, but you will usually measure 0.1 Ohms or so and that will be fine.

However, if there is any damage or frayed ends on the cables like you have seen, then replace them outright.

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SooperDooperMiniCooperExpertEngineering

All garage work involves equal measures of enthusiasm, ingenuity and a fair degree of irresponsibility.

Another trick to try is to add some addtional earths.

A good pair (not Kmart) jumber cables are ideal.

Just clip them on to the engine and the body.

Bare metal to bare metal is best

Also are use using an up graded battery. say 400 amp hours (new technolgy) then use say a 40 year old battery cable rated for 200 amp per hour the product is heat as the energy has to go some where

So how hot is hot..



Kiwiinwgtn

ok thanks guys,
Ran the new tractor size battery cable ( dont laugh) and managed to get it through the body, around the subframe and mounted it no dramas.

Now, I checked no continuity between the body and the cable so as soon as I pressed the starter button at the solinoid there was continunity..
I then disconnected the battery cable and checked the continunity between the solinoid. Earthing.....
disconnected the solinoid cable to starter motor,
and now the pin that you bolt the cable to, has continuity to the body... so its earthing the cable out at the starter motor..... would this cause my issues? Or is this perfectly normal??

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Just be careful here, starter motors are very low resistance, they are nearly a short when measured on a multimeter. It will seem like its shorted when it is not necessarily so. That's how they get the current through that they do. Ohms law : Volts/Ohms = Current.



Even if a battery is rated for 400 Amperes instantaneously, it doesn't mean it will pump that through the starter motor. It is capable of 400 Amps which is good, but it will only use what the starter motor needs. Once again, it is down to the total resistance. This is the internal resistance of the battery + the cable resistance + the starter resistance. Twelve volts divided by all this will give you the total current through the starter. It will only use what the starter motor allows.

If after all this, the starter turns over slowly, and there is no voltage drop across the solenoid, then the starter motor will need to be looked at by an auto spark.

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SooperDooperMiniCooperExpertEngineering

All garage work involves equal measures of enthusiasm, ingenuity and a fair degree of irresponsibility.

Thats the one thing about electricity that took ages to fully understand, what your trying to power is the determining factor in how many amps are in the circuit.

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Simplify and add lightness

Mini RUNS!!!!!! It was a faulty starter!!! YAY!!

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told ya so

Glad to see you sorted it.

I had an almost identical problem and after trying new solenoid, new battery (I thought the battery was stuffed because it kept going flat) it turned out to be the starter motor.

Sorry I didn't see this thread a couple of days ago or I could have actually had some constructive input.

Cheers,
Watto.