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Will wires fry on my block?
mak - 5/1/06 at 03:06 PM

I'm wondering how much attention I should put into ensuring that any loom wires do not contact my engine. If they touch will the wires melt and subsequently short?
Its a blade engine - not that it makes a difference.

Regards

Mark


mookaloid - 5/1/06 at 03:26 PM

I would have thought that the engine vibration and chafing would damage the cable if the heat didn't.

The consequences of a live wire dead shorting to earth on the wrong side of the fuse box don't bear thinking about in a fibreglass car!

Just my 2p worth

cheers

Mark


DarrenW - 5/1/06 at 03:29 PM

imho i would say that a lot of attention should be paid to routing of everything in car to ensure no contact with hot / chaffing points. This is one area that my SVA guy paid a lot of attention to. You need to think what could possibly (and in some cases impossibly) go wrong and design it out at the build stage.
For example on my exhaust side i made sure that no wires went under the exhaust manifold even if this meant a longer cable run.


mak - 5/1/06 at 03:30 PM

Well its clearly not a good idea to have contact, but just trying to assertain how important it is, as I have wires running very close, and if anyone has any experience of wires being damaged?

Luckily no fibreglass on my car, just good ol fashioned steel and ally.


jimgiblett - 5/1/06 at 03:34 PM

Keep the wires away from the exhaust manifold and wherever possible contain the wires in convoluted tubing or spiral wrap. Keep them from flapping around with either p clips or cable ties and you will be fine.

Make sure any electrics wires with a +ive feed are correctly fused.


mak - 5/1/06 at 03:46 PM

Luckily Cable Ties are my speciality


Yep, ok cheers guys

Think i'm quite safe on the electrical front with everything fused and a battery cut off on the dash.

Mark


RazMan - 5/1/06 at 04:32 PM

If you cannot avoid going close to a heat source, you can always wrap that section of the loom in the heat reflecting cloth that CBS sell.


02GF74 - 5/1/06 at 05:14 PM

the insulation shouldn't melt if it touches the block, only the exhaust.

as mentioned, keep wires away from the exhaust and reasonable distance from the block and secure any wires that may flap about and make contact with either.


Chippy - 5/1/06 at 11:50 PM

Wire will melt on the heat of the engine block, and as somebody has already mentioned, shorting out wires in a GRP car is not a clever idea. Keep the wires away from all forms of heat, fix them securely so that they cannot droop down onto any hot surface, be safe. ATB Ray.


02GF74 - 6/1/06 at 09:00 AM

quote:
Originally posted by Chippy
Wire will melt on the heat of the engine block,


well, I'm surprised by that. The block shouldn't really get much hotter than 110 C, surely cable insulation can take that?


RazMan - 6/1/06 at 09:12 AM

quote:
Originally posted by 02GF74
The block shouldn't really get much hotter than 110 C, surely cable insulation can take that?


Agreed - if you use wire which has insulation with any sort of automotive standard it will stand any amount of heat that a block will produce. But you wouldn't use Chinese bell wire for an engine loom would you?


omega 24 v6 - 6/1/06 at 12:36 PM

most standard automotive cable is only rated at 105 degrees C. Also if it is a heavy cable currying large current then you need to increase the csa to allow for the heat build caused by voltage drop due to cable resistance. This is because the cable will already be hot.( Although this would only be in very extreme circumstances)