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Where to place plug wires in magneto (392) Success! 5/27/14


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I know what the firing order is for the 392 Hemi but I can't find anything on where to place the plug wires in the magneto in relation to the firing order. The magneto for the dbl dragster 392 shows the wires coming out of the magneto , four each side, so , 'where' do you put the plug wire that goes to the #1 plug? On the same side of the engine as the #1 cylinder? And if so, is it the first wire (front) of the four on that side of the magneto? If I type the word........., no I'm not gonna do it! So that's the question, hope it makes sense :unsure: Thanks.

Edited by Speedfreak
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The mag in that kit represents this style of Vertex / Joe Hunt / Scintilla magneto. hr.htm15.jpg

The wires come out of the back of the cap in 2 groups of 4. Vertex002.jpg

Wire position numbers on the Vertex cap indicate the order of firing of the terminal in the cap. These are not to be interpreted as the engine firing order. Combine the firing order in the post above with the info in this one to arrive at the correct wire layout, although Jeff's illustration is for the 426 later-style Hemi. The 392 has the distributor at the rear of the engine, not the front.

joe_hunt2.jpg

Some engine builders replace the numbered dots to represent CYLINDER number, rather than MAGNETO firing number, but cylinder ONE is usually in the same place on the cap (relative to the hold-down screws) as illustrated, on any engine.

This style mag may be installed in various positions, depending on the needs of the particular car...clearance to firewall being an issue here.

motor001small5dl.jpg

Here's a 392 with that mag installed.

Blown392III.jpg

Edited by Ace-Garageguy
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Bill, So the group of 4 wires that #1 is part of would also contain #2-5-7? And the other group of 4 would be #3-4-6-8? Or, that has no relivance, and there are just two groups of four to keep things neat and orderly on the cap? The blue cap in the second photo: The four wires on the right side are #1-2-5-7? L/R top/bottom? The four wires on the left: #4-8-3-6 L/R top/bottom? I know I'll get this! Bill, thanks for going to all the trouble to illustrate this.

Edited by Speedfreak
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It's a little confusing, I know. When the numbers on the cap are left as 1 2 3 4 5 6 7 8 (firing clockwise as on the black cap) 1 on the cap will go to #1 cylinder, both the first to fire in the mag and the first cylinder to fire. 2 on the cap, the second terminal to fire in the mag, will go to the second cylinder to fire, which is cylinder #8 (going by the 1-8-4-3-6-5-7-2 firing order). 3 on the cap will go to the third cylinder to fire, cylinder #4, and so forth.

On the large black cap shown, mag terminals 7, 8, 1 & 2 will be in the right-hand group of 4, and mag terminals 6,5,4 & 3 will be in the left hand group of 4 wires.

NOTE: The blue cap has had the numbers replaced to correspond with the cylinder firing order. Some engine builders do this to eliminate a source of confusion.

And on a real engine, the mag can be installed with 1 in any position, so long as the rotor internally is pointing to 1 when cylinder #1 is at TDC firing position, and the rest of the wires are oriented correctly to it. In reality, these mags can be installed on any V8 engine (and there are versions for 4 and 6 cylinder engines too) and there are several different firing orders for V8 engines (though 1 8 4 3 6 5 7 2 is the most common). That's why the caps came labeled as 1 2 3 4 5 6 7 8, instead of the specific firing order for a particular engine. The engine builder / mechanic was expected to figure it out, and wire it correctly for the particular application.

Edited by Ace-Garageguy
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Bill, I think I've got it now, just need to do a test run with the parts I'm going to use I guess. Thanks.

I thought you might find this interesting:

http://www.ebay.com/itm/Rare-392-Chrysler-Hemi-Joe-Hunt-Magneto-W-Porcelain-Plug-Ends-Drag-Race-Gasser-/291134500086?pt=Vintage_Car_Truck_Parts_Accessories&hash=item43c8f7ecf6&vxp=mtr

Edited by Speedfreak
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Very interesting. I've never seen those ceramic plug terminals before.

You see on this cap that #1 is in the same place relative to the hold-down screws (and the arrow that indicates rotation) as #1 on the black cap above, but that the subsequent numbering has been changed, again, to reflect the cylinder firing order, and eliminate confusion.

The last shot is the perfect ref. for your particular engine, as, obviously, wires to cylinders 7,2,1 & 8 are in the right-hand group of 4 (looking forward from the flywheel end of the engine), and that wires to cylinders 4,3,6 & 5 are on the left group of 4...consistent with what you'd get following the numbering procedure in post 7.

Again, remember that the mag can be installed with #1 on the cap in any position relative to the engine (as long as the other wires are in correct orientation to it) to allow for clearance for induction systems or blowers (as in the last shot in post 3) or firewalls, etc.

Edited by Ace-Garageguy
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Ok Bill, so,....Looking at the ebay shot the right group of four, #7-2-1-8, the top left wire (coming out of the cap) is #8, top right is #1, bottom left is #7, bottom right is #2? I have no idea, it just looks like that's how it might be layed out inside the dome of the cap. I'm still working on the left side, it's harder to see. But, top left #3, top right #4, bottom left #6, bottom right #5? If I'm gonna do this I might as well have the wires coming out of the cap in the correct places. Thanks.

Gene

Edited by Speedfreak
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Yes! Where did you find this? Ok, now for the final question,....................... the number #1 hole coming out of the cap, is thart going to the #1 cylinder? Oh, please let it be so, please. And the the hole with #2 goes to cylinder #8 since that's the second cylinder to fire, and, so on? Or, hole (lol) #2 goes to cylinder #2? It's gotta be hole #2 goes to cylinder #8 since that's the second to fire and hole #3 goes to cylinder #4, hole #4/cylinder #3, right? Yes!

Edited by Speedfreak
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Ok, now for the final question,....................... the number #1 hole coming out of the cap, is thart going to the #1 cylinder? Oh, please let it be so, please. And the the hole with #2 goes to cylinder #8 since that's the second cylinder to fire, and, so on? It's gotta be hole #2 goes to cylinder #8 since that's the second to fire and hole #3 goes to cylinder #4, hole #4/cylinder #3, right?

Exactly...as explained in the first paragraph of post #7. You've got it. :)

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WooooooooHooooooo! Thanks Bill! Now, if I can just get this thing to fire on styrene gas!

Ok, one more question: :unsure: This kit engine does not have a valley cover, isn't that where the magneto would be mounted on a 1:1 392 (or, all engines with a blower for that matter?), and , not in a 'hole' in the top of the block the way this kit has it? I have a valley cover from a 'Miss Deal' 392 that I can make work.

Edited by Speedfreak
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The valley cover is just a cover that closes up the lifter gallery on those, and most engines. There is a hole in many aftermarket valley-covers over the distributor-drive opening, where MOST magnetos get their drive from.

BUT, if memory serves correctly today, most 392 Chrysler valley covers have a notch that goes around the hole for the distributor drive, and the mag mounts to the original hole in the block, like this distributor is mounted...

21673601-700-0.jpg?rev=1

In the pic below, notice the blue tape to the REAR of the alloy valley cover. That is the hole in the block where the distributor or the mag will mount. Also notice how the cover is notched to clear it. This is a typical setup. (The round cap is just for oil-fill.)

392.jpg

Edited by Ace-Garageguy
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Great info Bill, for many reasons, thanks much. It looks like at this point because the kit magneto cap is 'so' small I will just have two hole on the back side for the two groupings of wires, at least they'll be on the correct sides and going to the correct cylinders. It's just too small, at least for me, to get eight holes on the back of that cap! I should have been an auto mechanic, I love this stuff!

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  • 4 weeks later...

Believe it, or , not I have the 392 wired correctly. What a job, since I made the mistake of connecting the boots/wires to the valve covers first and 'then' connecting everything to the magneto. I'll post some pics in the next day or so. Gene.

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Ok, here's the engine wired, correct firing order, it should be anyway. Everything is from the kit except the wires, looms and boot material, those are from Detail Master. Thanks to everyone who posted in this thread! Bill, you are the man! This wouldn't have happened without your help, thanks!

post-12459-0-36772200-1401234040_thumb.j

post-12459-0-46998600-1401234063_thumb.j

post-12459-0-77675800-1401234078_thumb.j

Edited by Speedfreak
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