Author Topic: Help required with loom/harness building  (Read 8038 times)

richard

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Re: Help required with loom/harness building
« Reply #15 on: June 21, 2013, 10:27:23 pm »
expand - barry

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« Last Edit: June 21, 2013, 10:39:51 pm by richard »
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richard

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Re: Help required with loom/harness building
« Reply #16 on: June 21, 2013, 10:43:37 pm »
i meant wi-re you confused  :)

bob it appears that the wires for headlamps and from generator to terminal, terminal to switch and battery to terminal are all 28 / 0.30 cable and the others are 14 /0.30 and that is how cable is sold . if i were you i would take them up on buying cable from AUTO SPARKS Birmingham , make up the harness and then if you wish return your new  harness to them to braid up as original at so much a foot - surprisingly little actually . 
« Last Edit: June 21, 2013, 10:51:56 pm by richard »
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Big Al

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Re: Help required with loom/harness building
« Reply #17 on: June 22, 2013, 08:23:35 am »
If this is for a GRP car it is worth running a set of earth wires in the loom. One of the issues with kit cars using existing loom wiring was earthing. My solution was to run a flat heavy duty copper strap from for to aft and engine then bring things to it. It made fault solving and modification a lot simpler as there was always an earth nearby. That would now be expensive. It solved issues on my Mini Marcos and many later weird monstrosities with half or no chassis or aluminum bits which would corrode if linked to a circuit.

Cars without fuses, or adequate fuses.  Certainly this was popular and ran on late in Britain. Another reason why German cars were better as the had more fused circuits and if the worst came to the worst you could iscolate the duff sub part of a circuit, wire the rest in somewhere else and get home in relative safety. With two or less fuses that starts getting impossible. Also the chances of fire are greater. I have had Isetta, Frogeyed Sprit and TR7 spontaneously combust from a loom fault on unfused or inadequately run wiring. The Heinkel was a failed Siba regulator, which should not even have been there - British quality again, and the Lloyd Bus, a blow back through the carb to a total loss.

So no fuses, do not run an earth wire in the loom as you are offering an overheated wire a short circuit once the insulations failed and then you cannot always turn it of. The same will happen if it finds a lighting wire or something but normally its not a direct short but through a lamp or something which limits damage a bit.

Have we all had a welded car which had a melted loom. Put the wipers on and the left indactor joined or some such. Yep, been there. Schmitts are good for that where the tube wire has been compromised.
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Bob Purton

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Re: Help required with loom/harness building
« Reply #18 on: June 22, 2013, 09:09:45 am »
If this is for a GRP car it is worth running a set of earth wires in the loom. One of the issues with kit cars using existing loom wiring was earthing. My solution was to run a flat heavy duty copper strap from for to aft and engine then bring things to it. It made fault solving and modification a lot simpler as there was always an earth nearby. That would now be expensive. It solved issues on my Mini Marcos and many later weird monstrosities with half or no chassis or aluminum bits which would corrode if linked to a circuit.

Cars without fuses, or adequate fuses.  Certainly this was popular and ran on late in Britain. Another reason why German cars were better as the had more fused circuits and if the worst came to the worst you could isolate the duff sub part of a circuit, wire the rest in somewhere else and get home in relative safety. With two or less fuses that starts getting impossible. Also the chances of fire are greater. I have had Lisetta, Frogeyed Sprit and TR7 spontaneously combust from a loom fault on unfused or inadequately run wiring. The Heinkel was a failed Siba regulator, which should not even have been there - British quality again, and the Lloyd Bus, a blow back through the carb to a total loss.

So no fuses, do not run an earth wire in the loom as you are offering an overheated wire a short circuit once the insulations failed and then you cannot always turn it of. The same will happen if it finds a lighting wire or something but normally its not a direct short but through a lamp or something which limits damage a bit.

Have we all had a welded car which had a melted loom. Put the wipers on and the left indactor joined or some such. Yep, been there. Schmitts are good for that where the tube wire has been compromised.

Yep, good idea about the earth cable, I am going to incorperate a schmitt fuse box to protect as much as I can. Re spontaneous combustion of British cars, I have owned many, I was one of the chumps that bought new BL cars during the 80's to support British industry hoping things would improve and they did a great deal but all too late thanks to motoring journalists, Big Al, Jeremy Clarkson and the British occupation of slagging off everything we make and do. None of the cars ever burst into flames, not even the reliants that my dad owned all his life. Re Isettas, are you sure you didnt do anything as irresponsible as sit in the seat and short out the battery with the seat springs?  I will give you that one, mad but hilarious! The one car I owned that did burst into flames was our old Microcar Virgo, its French you know! Thankfully, the garden hose was adjacent!  Funny how things turn out though, I was recently reading about how German cars have really lost the plot on the reliability stakes and Italian car reliability have improved beyond recognition! Something I can testify to as my Fiat Grand Punto has not developed a single fault in six years of ownership from new.