Upgrade from fusible links to circuit breakers

[sblake01]

I really don't recall the fusible link colors except for the ones under the two plastic covers. And since I no longer have the car, I can't go look at it to verify them.

[FastWoman]

Well, that wasn't a question to you specifically, but to others in general. I do (very much) appreciate all the information you've given me! Thanks for your help!

[sblake01]

Oh, I know. It's just that the 78 I had was completely stock as far as the fusible links go and I could have accurately answered your question if I still had it.

[wal280z]

I have SIX fusible links in my '78 -- four under cover and two in a double-connector clipped to the side of the relay housing cover.

Hi Sarah - I found what suited my needs at the junkyard - as long as you don't mind a GM logo on the plastic cover...

Found this setup in the Caddy Catera platform - It is a 6 way, I only have 5 connections hooked up - 4 are stock and the 5th is for my headlight relays system. I went as far as sourcing part numbers and distributors for the contacts before giving up and just using a $0.29 butt connector to make the splice inside the cabin. I've got a few spares of these and last I remember, there were two Catera's out at Pick and Pull down here in VB two weeks ago. If anyone else is interested in this setup, I can start a step by step thread on making the conversion, as well as what to look for when getting the donor parts.

Off topic - Stephen - what happened to your Z? Have I been gone that long?

Wayne

[sblake01]

Off topic - Stephen - what happened to your Z? Have I been gone that long?

Wayne

I sold it, end of May this year. In fact, I sold all three of my Datsuns and bought a 2005 Pontiac GTO.

[TomoHawk]

That's a cool setup, Wayne.

[FastWoman]

Hi Wayne,

That's a nice solution! I have my Stinger blocks, though -- more blingish, but I don't think that's a bad thing. I'm going to mount them on an aluminum rail bolted to the relay housing.

I finally unwrapped the wiring harness and extracted the battery-side wiring back to the starter. That's some crazy looking stuff! I had to put it down but will finish the job tomorrow (hopefully). While I was at it, I spray painted the vacuum bottle and bracket with black epoxy spray paint, then gracefully dropping the vacuum bottle in the dirt. After cleaning off the dirt-encrusted spray paint and re-spraying, I think it looks very nice. I'll be spraying the relay bracket too, of course, hopefully without the intermediary step of encrusting it with dirt. I'll post pics when I'm done.

[wal280z]

I have my Stinger blocks, though -- more blingish, but I don't think that's a bad thing. I'm going to mount them on an aluminum rail bolted to the relay housing.

I hope that works for you - I used a similar "Scosche" distribution block setup for about 8 months before the bling got ugly corroded. Of course, she was still parked outside then too....

[FastWoman]

Ouch! Well, I live off the water and park my car outside. The fuse block also sits right under the righthand hood vent. Great combination, eh! On the other hand, all of the connectors are gold plated. (Were yours?) That should help a bit.

I got a couple of Bosch type relays to re-do the headlights, while I'm into the wiring harness. The four headlight wires course right along the same section of harness. I'm going to interrupt the lines to drive two relays (mounted in the relay housing, of course) -- one for low beams, and one for high beams. I'll then use the relays to switch +12VDC to the outbound lines, with the common connectors running to ground, rather than +12. The source of the +12 will of course be the headlight fusible link. This solution won't give me independent fusing for the two sides, but I can't imagine that's so important anyway.

Anyway, I ran out of light and was getting bit by mosquitos. The saga continues tomorrow.

[Langford Chuck]

Well,I like the Catera fuse box: if I can find one local to me so I can check it out in more detail i might go that direction. Otherwise, I might take up Fastwomen on her suggestion to use the Maxi-fuse and just 'de-bling' it a bit. I like the technical davantages of gold, so this route appeals to me.

Otherwise, I might just buy the plain jane $49 6 fuse block from Lordco and 'bling' it up so it is not so, well, ugly. Look forward to seeing what you do Fastwomen: electrical is not just a weak spot for our Z's, it is also a weak spot for me so always like to see what others have done...

[FastWoman]

Hi Chuck,

While you're into the wiring harness, you might want to wire the headlights with relays to offload the high current from the combination switch. To do this, I bought a couple of Bosch-type relays with matching plugs for a total of about $5. Your price might be a bit higher, as I ordered 10 off of Ebay. Here's a somewhat messy diagram of the mod I'll be making. I'll basically be inserting the two relays in the path by cutting the headlight wires in the wiring harness and wiring to relays that I've mounted in the relay housing.

BTW, there's just enough room in the bottom of the relay housing for the two relays, mounted with the plugs extending downwards.

Edited September 3, 2009 by FastWoman

[FastWoman]

Well, I'm not quite finished, but I've made progress. (Life gets in the way.)

I've got the MaxiFuse blocks installed. That was of course the easy part. The harder part is sorting through all the crusty, corroded bits of wiring harness and rebuilding the high-current parts of it. The ground line, which appeared to be about 10 ga and bolted to the block under the front heater hose clamp, was crimped in multiple places to branch lines. I pulled all that apart and replaced the wiring with 10 ga. crimped connections that I've sweetened by soldering.

The alternator wiring looked worse. It, too, was 10 ga, fused at 80A (!!). It had multiple crimp connectors that were crusty, corroded, and burnt. I upgraded to 8 ga, thin-insulated, teflon ensheathed wire, crimped and soldered, with the same wire running from the + post on the alternator all the way to the MaxiFuse block. I found that copper tubing made a great crimp material. Just pinch it with vice grips, and it snugs right up. Then infuse with solder, cool, and tape. I also made the lug at the alternator post out of 3/8" copper tubing. I put the 8 ga main line, a new 16 ga line with a bullet connector on it for the condensor, and the branch line to the field coil connector inside the 3/8 tube. I then crimped, soldered, flattened the end in a vice, and drilled a hole for the post. I finally put a piece of heat shrink around it. It looks great and is 5x beefier than the OEM. With this wiring, I was perfectly comfortable upgrading my fusing back to 80A. (I had previously downgraded to 60A, but upon seeing what horrors were inside the wiring tree, I think the wiring wasn't even competent to handle 40A.)

I took out the 10ga +12 wires and their branches from the starter lug to the fusible link assemblies and from the battery post to the two EFI fusible links, and I replaced it all with a 4 ga cable from the starter to the MaxiFuse block. The branches of the original lines were crimped and crusty, albeit not burnt.

After getting the new fuse blocks put together I went to start the car, and it wouldn't start. I quickly found the problem. The fuel pump wasn't pumping (again!), and the problem was in exactly the same spot. I jiggled the offending wiring harness connector at the firewall, and the fuel pump came to life. Engine runs, and everything is happy. I've decided to break that one wire out of the large connector and to use a bullet connector instead. I don't want to have to be jiggling connectors every time my engine doesn't start!

Along about this time, the mosquitos and gnats were swarming again, so I had to call it quits. I'll do the headlight relays tomorrow and hopefully get the updated wiring tree all taped back together. This project has gotten more involved than I wanted, but at least I've resolved several trouble spots before they had a chance to become trouble. It all looks very nice too, of course.