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MG MGB Technical - Running wiring inside the car

What have people done as an alternative to running the wiring loom under the bottom of the car? When my car is back from being painted I have a brand new, Advance Autowire loom to install. I would prefer not to install it under the car though. Is there enough space to run the wires to the back of the car along the transmission tunnel or along the sill on the right hand side? Or even inside the inner sill?

I figure there are about 7 wire. Tail lights, brake lights, reverse lights, left blinker, right blinker, fuel pump and fuel sender. I think the number plate lights run off the tail lights? Plus 1 for an alarm switch in the boot probably. The main power to the fuse/relay panel I can run underneath alongside the starter cable I guess.

Any thoughts?
Simon Jansen

Simon Thats where the loom normally runs. At least on the early Aus roadsters. I could take a pic if you like but the GT may be a little different. The loom on the RDSTR goes through a grommet up into the boot just in front of the fuel tank. If I run any exposed wiring that may be subject to damage or weather I run it through 1/2" low pressure irrigation hose. I pull it through with thin HT wire. It looks OK and makes me feel better. You must be getting close now, will be great.
Denis
D M HILL

Simon, I removed the innermost rear plug from the drivers floor (RHD)& fitted a suitable grommet in it's place. Then I routed the original loom through the hole & ran it along the right side of the trans tunnel & up behind the centre console. The carpet & driver's seat mounting keeps it in place along the floor. Barrie E
Barrie Egerton

Simon
Any particular reason for not running it underneath the car?

John
John Minchin

Presumably Simon doesn't like the thought of the harness being exposed to the elements but quite frankly I don't see the problem as the whole section is wrapped in self amalgamating loom tape so is impervious to water ingress. Besides these cars have survived for over forty years so far so there does not seem to be a problem
Iain MacKintosh

Simon,What year is your roadster?
rich osterhout

It's a 78 but heavily modified.

The loom I have isn't wrapped in any way. It's just loose wires and they are also much thicker gauge than stock so they do make up quite a bundle! It just seemed more sensible to route them somewhere safer/less exposed but as Iain says they seem to do well on cars 40 years+ (aside from being covered in muck) so maybe the stock, under car position will be OK.

I am not yet sure what I will wrap the loom in but my preference was for spiral wrap in the areas where the loom is exposed like in the engine bay. I also have some loom tape which is different to normal electrical tape in that it isn't very sticky.

I could use that ribbed split tubing under the car perhaps with tie wraps at intervals to hole it nice and tightly closed so it doesn't fill up with rubbish?

Simon
Simon Jansen

I've used the ribbed split tubing for my Auto Advance wiring and it makes a nice job. Looks good and keeps it tidy. Where have you put the power board Simon? I fitted mine vertically behind the glove box (see picture). The wires then fall neatly either for crossing behind the dash, or down beside the tunnel to go aft. The silver box below the board is the ECU mounting for the fuel injection.

I ran the cables inside along the passenger's side of the tunnel at floor level, then across the heel board still at floor level, then up and through the hole in the side structure so they can go over the rear wheel arch. Once all the carpets and trim are in, you can't see them at all.



Mike Howlett

I fitted mine in the engine bay near where the fuses would normally be. I wanted to put it inside somewhere and didn't even think of putting it where you have!

I made a special bracket and an aluminium cover to go over mine since it is is int engine bay.

I can move mine easily though as the bracket uses existing holes for mounting and it is easy to remove.

Here are some pictures of it in place.




Simon Jansen

And with the cover. I want to get a small plastic cover to go over the fuses too.




Simon Jansen

Whoa Simon.....What do you do for a living(job)? You have to be an Engineer or the such.Regards,Rich
rich osterhout

I am just finishing up my Advanced Auto Wire job on a US model 78 Roadster. I routed my wires to the after part of the car as Mike Howlett has done. I mounted the main panel inside of the passenger footwell map pocket, which I remounted with hook and loop fasteners for quick and easy access in case of blown fuses or relays.
The part going forward of the firewall is enclosed in ribbed split wire loom, large diameter to go through one of the rectangular plugs into the engine bay, and then branching off into smaller diameter sections as various wires leave the main loom. It terminates just forward of the radiator bulkhead with the headlight and side position light wires running off to either side and through the inner wing panels, and the horn and fan leads going to their respective locations.
All and all, I am quite pleased with the system. It looks good, and I really appreciate the heavier diameter wire for the lower resistance and the increased mechanical integrity.
John Campbell

The downside of my location for the board is that it is a bit of a fiddle if a fuse should blow, but hopefully I will be spared that. I couldn't agree more with John about the quality of the cables used in the Auto Advance kit. They are top notch and give a real feeling of confidence. Since my fuel pumps are run by the ECU through their own remote relay, I didn't need the fuel pump relay on the board, so wired it to the rear hatch heated window instead, a high capacity component that the designer of the board forgot.
Mike Howlett

Yes, the Advance wiring setup is really, really good. The wires are much thicker than stock.

Rich, I am a software quality assurance manager. A good job for a perfectionist!
Simon Jansen

This thread was discussed between 27/08/2009 and 29/08/2009

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