Alternator wire/ header clearance

[Packer fan]

Where the alternator wires connect is very close to the headers. How close can they be before they melt? The headers are ceramic coated and I will put heat tape over the connector.


Thanks
Jim

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[Packer fan]

I didn’t know if I missed something and should have turned the alternator some how.

Jim

[NAZ]

Wow, that's close -- I would not run a primary wire that close to a header, silicone insulator maybe. I've seen headers run over 1000-degrees on race cars on gasoline and retard the timing and they will get much hotter. I've burned 1200-deg coating off race engine headers before just by running too little ignition lead. These may be extremes but they do happen. I believe automotive primary wire is usually rated to around 250-F or so. Now that's not the temp it actually melts at -- my guess is maybe twice that. I've had wire melt on headers at idle when I accidentally allowed them to touch the headers for a few minutes. If your headers only reach 600-700 degrees that's probably going to damage any wiring that close to the heat source.

And I'm not at all confident you can insulate them enough when they're that close. But if you're going to try my experience is that a heat shield is more effective than insulation at that close distance. The best mitigation is to gain as much distance from the heat source as possible. In physics there is the inverse square law (Google it) that applies to radiant heat energy which will support why I say distance is the best mitigation.

[Packer fan]

Wow, that's close -- I would not run a primary wire that close to a header, silicone insulator maybe. I've seen headers run over 1000-degrees on race cars on gasoline and retard the timing and they will get much hotter. I've burned 1200-deg coating off race engine headers before just by running too little ignition lead. These may be extremes but they do happen. I believe automotive primary wire is usually rated to around 250-F or so. Now that's not the temp it actually melts at -- my guess is maybe twice that. I've had wire melt on headers at idle when I accidentally allowed them to touch the headers for a few minutes. If your headers only reach 600-700 degrees that's probably going to damage any wiring that close to the heat source.

And I'm not at all confident you can insulate them enough when they're that close. But if you're going to try my experience is that a heat shield is more effective than insulation at that close distance. The best mitigation is to gain as much distance from the heat source as possible. In physics there is the inverse square law (Google it) that applies to radiant heat energy which will support why I say distance is the best mitigation.

You did not make me feel any better.
Now, I just have to figure out a way to move the alternator.

[Fixit]

Haven't looked yet, and my experience is with older stuff, but...
Usually an alternator can be "clocked" to a different assembly configuration... The 4 "through-bolts" that keep the case halves & armature assembly together can be removed, and the rear case spun in 90 deg increments to gain clearance(s).

If you choose to try this, don't pull the case halves/armature apart! The brushes will spring out and you'll have a job on your hands reassembling the alternator. Just remove the bolts and try to rotate the case half as needed.

[Packer fan]

Ahhh
When I get home this weekend I will have to look and see if I can do that

Thanks

[edwardb]

There's not a problem. There are dozens (hundreds???) of Coyote builds (mine included) working fine with the alternator hookup as delivered. The main alternator battery cable and control harness from the control pack engine harness should be run around the front of the LH head and back to the alternator. If it helps to sleep at night, wrap the cables with some reflective insulation material like Ford does for some of their wires. I wouldn't try to re-clock the alternator. The Coyote specific Motorcraft alternator has bolt mounting locations as part of the case. If cases pieces were rotated, it would not longer bolt to the block on as designed.

[Fixit]

As mentioned, "re-clocking" may not be an option if the rear case half has a mounting point cast into it. I haven't looked at my setup yet, but will soon be going through the same ordeals. Looks like I'll be pulling the headers out of the attic and mocking up some stuff!!

[edwardb]

Not "if" or "may" the M-8600-M50BALT alternator, standard fare for the Coyote, has a through-bolt in the front and rear castings that bolt to a flange on the block. Plus another mounting point on the front half that clocks to a mounting stud on the block. Any change and it's not going to mount. Even if the case could be clocked (which it can't) the distance of the wiring connections to the header wouldn't be materially changed. Plus would make the locations likely inaccessible since it's very tight to the block.





Honestly, this just isn't an issue, has been used as-is for many builds, and is far from an ordeal. Nothing to see here.