Wiring Cleanup - Ignition Box, EFI etc - Where to route cables?

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TheDude

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I'm finally at a point where I need to deal with my under hood wiring, it's a hot mess and looks like C3PO threw up on my fender. Right now I have a Mallory Ignition box mounted to the shock tower on the passenger side. All the cabling for that and my EFI run across the top / front of the engine and is just ugly and very sketchy. It's basically been a giant wad of cables just zip tied and wrapped for a long time and I need to make it better.  

So easiest thing to do would be to just cut things to the proper lengths, replace some wires like switched power that are spliced 47 times and then dress it better and call it a day. It would look slightly less crappy and hopefully be more reliable long term, but it would still be crappy looking. 

The next thing I'm thinking is to relocate the ignition back behind the shock tower or on the firewall and run everything back there. The thing I don't like about that is heat for the ignition and serviceability. I hate the idea of having to take off the shock tower brace just to take a look at some wiring issues or make small changes. 

Anyway if anyone has some thoughts or pics of how you've run your wiring when you have similar components, I'd appreciate it. Also seems like a distribution block or something might be appropriate for switched and unstitched power, so would be curious to see what you did with that. 

Thanks!

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I have the ignition box also located on the passenger's shock tower and EFI.

Here is an older picture w/o air cleaner. You can see most of my wires run from the ignition box and battery back under the passenger's shock tower braces. Some go back to the coil and EFI along the valve cover. Other wires continue their journey behind the engine and then forward under the driver's side brace to the EFI. I basically used the shock tower braces to hide the mess. I suggest you use wire sheathing to make it look neat. Depending on the sheathing diameter you can run 2, 4 or 6 wires through them.

Note: after this picture was taken I went to a magnetic Duraspark distributor and run the signal wires directly to the ignition box along the front of the engine between the radiator and heater hoses. I did this to reduce the risk of EMI.

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This is a more recent picture. You can see that I have replaced the shock tower braces with a custom Export bar. I am still running the wiring under the bar and along the A/C hoses on the driver's side. With the air cleaner you don't see much.

20210423_000425.jpg

 

TheDude

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Thanks Tony. Sounds like you are setup like I am with the ignition in the same location and EFI, but you ran most of the wiring around back. So EFI etc. all connect around the back of the engine with wires like water temp etc over the top but you left the ignition up front, correct? I had wondered the same about the ignition as it didn't seem like a great idea to make that wire any longer than it needs to be. 

That sounds simpler than what I was thinking at least as far as having the ignition some place I can get to it easy enough. Still have to sort out power distribution as I have I think 5 devices grabbing power from the starter relay. Or I just need to buy a giant air cleaner that covers everything under the hood. 

 

droptop73

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Hemikiller

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Mounted my MSD to the front of the radiator support behind the passenger headlight, since it was a short jump to the starter solenoid and terminal block to pick up power and run the wiring up with the alternator harness. Tach signal wiring follows the accessory feed up the passenger tower brace and goes through the firewall where the AC cars have their vacuum lines. 

 

TheDude

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I'm running an MSD mounted to a bracket inside the car above the glove box. I prefer to keep it away from engine heat. 

To clean up the wiring I used a split mesh from Alextech on Amazon.   https://www.amazon.com/Alex-Tech-10ft-Protector-Sleeving/dp/B07FW3GTXB?ref_=ast_sto_dp&th=1&psc=1     It comes in many sizes with different lengths 
That would be a great location for it. Maybe on round two or three for me on that one for me as I suspect I'll never be happy with the current location. I did pick up some of that sheathing in a few sizes. Need to figure out how to dress the ends of that. My cloth wire look tape doesn't stick right or look good and seems like electrical tape pulled tight could look good, but not sure how it would hold up. 

Mounted my MSD to the front of the radiator support behind the passenger headlight, since it was a short jump to the starter solenoid and terminal block to pick up power and run the wiring up with the alternator harness. Tach signal wiring follows the accessory feed up the passenger tower brace and goes through the firewall where the AC cars have their vacuum lines. 
Oh, I like that spot. Out of the way and still serviceable. At the moment I'm leaving it on the shock tower, but I may rethink that as there is still a mess of wires that all around the battery and starter solenoid and ignition box and it's going to be tough to make that look good. 

For the moment I'm using some magnetic zip tie mounts to hold the looms where I want them. Seem to work very good and can move them all over to get the best fit without drilling a bunch of holes in the car. Also just handy for holding wires in different spots while working on them. 

 

droptop73

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That would be a great location for it. Maybe on round two or three for me on that one for me as I suspect I'll never be happy with the current location. I did pick up some of that sheathing in a few sizes. Need to figure out how to dress the ends of that. My cloth wire look tape doesn't stick right or look good and seems like electrical tape pulled tight could look good, but not sure how it would hold up. 
I burned the ends of the wrap to keep it from unraveling and tied the ends with a small zip tie.

 
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Thanks Tony. Sounds like you are setup like I am with the ignition in the same location and EFI, but you ran most of the wiring around back. So EFI etc. all connect around the back of the engine with wires like water temp etc over the top but you left the ignition up front, correct? I had wondered the same about the ignition as it didn't seem like a great idea to make that wire any longer than it needs to be. 

That sounds simpler than what I was thinking at least as far as having the ignition some place I can get to it easy enough. Still have to sort out power distribution as I have I think 5 devices grabbing power from the starter relay. Or I just need to buy a giant air cleaner that covers everything under the hood. 
I just saw this post almost a month later. Sorry. You are right about the description of my setup. I left the ignition up front to reduce the risk of electronic interference. 

 

cheezsnake

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Mounted my MSD to the front of the radiator support behind the passenger headlight, since it was a short jump to the starter solenoid and terminal block to pick up power and run the wiring up with the alternator harness. Tach signal wiring follows the accessory feed up the passenger tower brace and goes through the firewall where the AC cars have their vacuum lines.
I like this idea. The radiator support is not very flat behind the headlight ... has raised contours. How did you get around that when mounting the MSD? I do notice the headlight box, itself, is very flat on the bottom and wondered about that spot.
 
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