What is my Engine Bay Missing?

[SteveJ]

Blue, I'm curious - all signs point to your page with and Wayne Monteath as responsible for propagating the notion that what should be 30 amp links are actually 50 amp. From your page - (Thanks to Wayne Monteath for uncovering this rare table!).

Who is Wayne Monteath and how did he determine that the Factory Service Manuals are incorrect? Where did the "rare table" come from?

Honest curiosity. I have only seen the Brown = Red = 50 amp link on the atlanticz site. No where else.

Thanks for any insight you can offer.

We had a good discussion on fusible links just a couple of days ago.

Anyway, the gauge of the wire in the circuit gives a good rule of thumb for the ampacity of a fuse to protect it. Though the 0.03 mm fusible link would translate into about a 20 AWG wire & fusible links tend to be 2 gauges smaller than the wires they protect, I get a feeling that the wires in the circuit are probably around a 14 AWG. You don't want to pump more than about 30 Amps through those wires and only for a very short time. If the gauge of the wire in the circuit is actually larger (I don't have a 280Z.), then my guess would be that there is a component that needs the protection.

As for why it would be different from factory...sometimes factory engineers get things wrong. Also, sometimes standards are revised due to lessons from experience.

[240260280z]

Wayne is a z expert from Ottawa who is a friend and sent me the table ~ 7 years ago in email.

[240260280z]

I did some digging... a lot actually and found this doc online with the so-called "Pacific Table". It does not say that the "fusible element" table applies to fusible links but it does have them in the same section as well as colour matched brown examples. It also says that fusible links are usually 4 wire sizes smaller than the wires they protect.

http://www.autoshop101.com/forms/hweb1.pdf

[SteveJ]

Yeah, that's right. It's 4 gauges. I remember reading that, too. I was thinking 2 when I was typing because you usually don't see the odd number wire gauges. Thanks for catching that, Phil.

[FastWoman]

I'm assuming it's important to you to stick to 100% stock. If not, you might want to install MaxiFuses to replace that fusible link mess. I did it and am still very happy I did. My saga is here:

http://www.classiczcars.com/forums/showthread.php?35588-Upgrade-from-fusible-links-to-circuit-breakers&highlight=

If you do stick with the stock fusible link assemblies, you need to be careful with the bases, as they can break. (Mine were both broken when I bought my car, and the fusible link blocks were hanging off the end of the wiring harness.) There are no new replacements for those, and in fact they are an integral part of the wiring harness. Your only replacement option would be salvage, and I didn't have much luck finding the things. Obviously I gave up.

[Threehz]

Actually I'm not trying to make this a complete stock resto, I'm going to do a lot of performance upgrades and that maxifuse kit looks great. For now my fusible links look fine the only issue is the caps that used to cover them. Thanks for the info FastWoman that'll save me a bunch of time if they do end up breaking or burning out.

[240260280z]

All 77's I have seen have 3 red and 1 black. Any original owners out there with 3 brown and 1 black?

[Zed Head]

All 77's I have seen have 3 red and 1 black. Any original owners out there with 3 brown and 1 black?

The attached picture of page BE-6 from the 1976 FSM shows where the Br (Brown) came from. Notice that it is also the smallest gauge of the three. If your fusible link block has not been too damaged or worn out, there will be a label on the side designating Bl and Br as the fusible link colors. Somewhere over time brown became red or maybe the factory links never did come out brown in color to match the FSM. That may be how a 0.3 square mm brown link turned in to a thicker red link. Color didn't match gauge and someone went with the color code for replacement.

In the big scheme the safety margin that most engineers use probably makes it irrelevant. It's just interesting how some information gets a little warped and propagates.

[Threehz]

Yeah I have three red and one black however the reds actually could easily be mistaken as brown which is interesting.

[240260280z]

Found this on line:

[SteveJ]

Phil, would you post a link to the site where you found that if you remember where it came from?

Edit: From what I could find, the FL series of fusible links are for modern fusible links.

Edited May 24, 2011 by SteveJ
Did some digging

[conedodger]

I changed the heater core on my 78 w/o removing the dash. Not easy but it can be done.

I have also replaced the heater control valve without removing the dash...