Some wiring help needed

[Lippyp]

I put this in the electrical section but got no replies and I was hoping to do this today so I've moved it here.

I have a new M&H engine wiring loom for my 67. It came pre modified for HEI but now I'm having to use a pertronix ignitor conversion in my Mallory as the HEI dizzy don't fit. As a result I have a question. The loom came with a pink and yellow wire crimped to one terminal block which I'm guessing would have gone to the + terminal on the HEI. Does this now go to the + terminal on the coil? I'm guessing as I'm also running a mini starter that the yellow wire is no longer required so when I connect it up can I just tape that out of the way at both ends?

Also, my wiring was so hacked about all I had coming from the original terminal block at the back of the fusebox was two wires, the big purple one and a green one (which I had to trace and unwrap as it then became red and finally blue via two bodged taped connections and ended up at the oil pressure sender! It seems the main pink power feed had been pulled out of the back in the cab and connected to another odd wire that fed out to the coil.

I'm pretty sure I know where the other wires go (purple and yellow to the starter, brown to the brakes, one green to the oil pressure switch) but I have a round connector with a light and dark green wire going to it and I have absolutely no idea where it goes as I don't have one of those! I have attached a picture of it and any (clean!) suggestions welcomed. EDIT: looking at the wiring diagram I think its the connector for the backup light switch on the tranny, am I right?

The other problem I have is how do I get the damn plug out of the fusebox/firewall? I've found a bolt head in the middle but it just spins. Do I have to drop the fusebox off inside the cab to get to the back of this bolt to undo it? I'm guessing I'll need to do that anyway to refit the big fat pink wire into the connector from where the previous owner "re-wired" it. It thankfully does look to be intact so should just push back in.

Damn I hate vehicle wiring, just looking under the dash is scary as theres 43 years of assorted bodges with some stuff seemingly re-wired or bypassed for no apaprent reason like the neutral safety switch that works fine but has been bypassed so it now starts in gear.

The offending extra connector.

[Billhilly]

Not a lot of help Lippy, but yes, my wiring diagrams show light green/dark green as 'backing lamp switch'.
I'm wondering if the bolt in the middle of the bulkhead plug is just spinning, means it is loose, and the plug is just 'glued' to the fusebox side with old sealer and sticky pins! Try gently levering it and see what hapens. I'm far enough away that if it breaks I won't be able to hear you yell! Well I guess you are replacing it anyway.
Couple of colour diagrams for your confusion.

Bill.

[Lippyp]

Thanks, I might try removing the fusebox first anyway as I need access to the back of it. Not many 67 Chevys in junkyards over here if I bust anything! Whats the weather like down there, must be mid winter now. We have a south east/north wets split at the moment, down south its hitting 31C and sunny, up here its high teens and raining so I might not be working on it today unless it stops. Plus its the British Grand Prix today so this afternoon is booked for time in front of the telly.

[Billhilly]

Yeah same down here, no Chevy's in the wreaking yards at all.
A couple of small screws hold the fuse box on from memory. Pay to get the bulkhead plug off first either way.
Pretty grim down here the last few days with a Southerly storm keeping temps around seven to eight degrees somedays.
I see on the news tonight Vettel/Webber at the front of qualifying. I say go McLaren!

[dwcsr]

The loom came with a pink and yellow wire crimped to one terminal block which I'm guessing would have gone to the + terminal on the HEI. Does this now go to the + terminal on the coil? I'm guessing as I'm also running a mini starter that the yellow wire is no longer required so when I connect it up can I just tape that out of the way at both ends?

The HEI wire is a 12 volt wire. The original was a resistor wire @ 9 volts to the + coil terminal. 12 volts to the coil will work but would eventually burn out the coil and points. I would follow the Pertronics directions for the install and see if they need 12 volt or 9 volt input. The yellow (20Y) wire is not used on a mini starter so tape it off.

I have a round connector with a light and dark green wire going to it and I have absolutely no idea where it goes as I don't have one of those! I have attached a picture of it and any (clean!) suggestions welcomed

Yes backup light switch, but it may be a switch for standard transmission

Not sure on the fuse box issue. good luck.

[Lippyp]

The Pertronix coil is internally resisted and needs 12V.

[dwcsr]

Originally Posted by Lippyp

The Pertronix coil is internally resisted and needs 12V.

The HEI wire will work then.

[Lippyp]

Can anyone help me with getting the damn plug out of the firewall? the 1/2" bolt in the middle of the block just spins round and doesn't seem to come undone at all but I can't pull it out. Does this go into a captive thread or is it a loose nut the other side in which case do I need to remove the fusebox. I'm now stuck and don't want to destroy anything by prising and pulling at it. I'm going to have to drop the fusebox anyway as the main pink power wire has been pulled out of the terminal so I need to refit it.

[Billhilly]

Like I said it might just be 'glued on'. There is a seal around the bulkhead plug, which on one of mine, wouldn't separate. Had to prise it off. The bolt is 'retained' in the plug. It won't come out as such. Nut is 'captured' in the back of the base. Bottom pic shows plug with seal/gasket destroyed to get it apart.

[Lippyp]

Thanks, that makes things much clearer, I'll drop the fuse box out and then carefully lever the plug off the firewall. Like I said the previous owner has removed the big pink wire from the block so its all got to come out so I can re-insert it.

[Lippyp]

Aaargh! I've had to drill the bolt head off the plug as it was just spinning, I think 43 years of rust on the thread versus 43 year old plastic meant that the retained/captive nut part was justy spinning inside the block. Of course then you can't get anything onto it to hold it still so my only option was to drill the head off. Now I've butchered it I'm left with the remains of the bolt still stuck in the back half of the bulkhead plug/socket (the top picture above) so I think I need to replace it. Can this part be bought seperately from the loom and can the existing connectors be prised out of the plastic block and re-inserted in a new one?

Does anyone know where I can either get a new part or a good used one shipped to the UK? I'll buy a whole fusebox assembly if thats what it takes. I'm guessing I can just use an appropriately sized bolt to bolt the plugs back on into a new block.

I've also got to contend with the backup light wiring not being there. I guess when the previous owner converted the backup lights to UK spec turn signals he removed the wires too, not a huge problem as at the moment theres noth to switch anyway so I may just leave it until I get around to fitting some oher backup lights into the rear step bumper.

The other problem I have is how to route the new loom. Its an M&H engine wiring loom pre converted for HEI. I can't see how to route it so that everything reaches the right components. The wire for the oil pressure sender seems to be too short, almost as if they expect it to be on the passenger side of the block not the drivers side. Obviously I could extend it but if its just me not knowing how the loom is supposed to be routed that would be plain daft. Does anyone have a good picture of the engine bay showing how the loom should be run? I want to get it right and not start hacking stuff around.

[Lippyp]

Anyone? I'm pretty stuck until I can sort this out.

[Billhilly]

Ring Wes Hepp, Lippy. If he hasn't got it in stock, he will certainly be able to get something. Ships every where as well. Find him here - http://www.classicheartbeat.com/ Ain't it fun when you can't just go to the 'bone yard' and get some more parts! The things we do huh.

[Lippyp]

I know Wes, he's helped me out on various occasions. In fact the new loom came from Wes originally a good few years ago, when I was over in the USA on holiday. He shipped me a load of stuff including a full carpet set that came home with me in my suitcase (ok, I had to buy a second case!)