Article on adding fusible links to pre-67 Corvettes
I am looking for an article that I've seen on adding fusible links to pre-1967 Corvettes. I believe it was written by John Hinckley, but I'm not positive about that. Any help would be appreciated.
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Re: Article on adding fusible links to pre-67 Corvettes
John------
Try this:
In Appreciation of John Hinckley -
Re: Article on adding fusible links to pre-67 Corvettes
Thanks Joe,
I've already seen that thread and many others regarding fusible links. My '64 has a 12 gauge main power feed and I added an 18 gauge fusible link from NAPA about a year ago. However, the battery sense wire on the '64 is 18 gauge, and there are no 22 gauge fusible links at NAPA or anywhere else I can find. I think my best bet is finding a roll of 22 gauge fusible link wire and making my own.
Also, I am wondering why it was recommended to add a fusible link from the horn relay to the ammeter, and not from the solenoid to the ammeter. Any thoughts?
Thanks,
Steve (I go by my middle name but I answer to John also)Comment
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Re: Article on adding fusible links to pre-67 Corvettes
John,
The 1967 model did in fact have a link at both the solenoid feed to one side of the Battery Gauge(IIRC Blk/Wht wire), and a link at the horn relay buss bar to the other side of the Battery Gauge.
I would replicate exactly what was on the 1967 to the 1966, as long as the feed wire gauge sizes are identical.
RichComment
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Re: Article on adding fusible links to pre-67 Corvettes
Rich,
You are absolutely correct. I checked the '67 AIM and it has short 20 gauge links, which I assume are fusible links, at these locations in the wiring diagram. So that answers my question.
Actually, my car is a '64, and the wires in question are one size smaller (18 gauge). So I'm looking for some 22 gauge fusible link wire. I put in a RFP on the internet for 2' of wire from a company named Allied Wire & Cable! The said they will answer in 24 hours. I'll post what I find out.
SteveComment
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Re: Article on adding fusible links to pre-67 Corvettes
Not to change the topic but wouldn't a circuit breaker like for the head lights be a better solution?
I'm assuming the task is to kill battery current in the event of a short while the car is not running.
It may be possible to isolate the alternator but I not sure that would prevent anything.Comment
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Re: Article on adding fusible links to pre-67 Corvettes
Gene, Yes a circuit breaker could be used, but I wouldn't want the self resetting type, ie a thermal breaker like for the headlights built into the headlight switch or the type used for the headlight motors. I'd want something that trips with a reset button. This way if the short was a dead short it wouldn't continually try to reset itself, and cause possible damage.
I'd think GM felt the same protection could be had with the link at a much lower cost. However, if you're on the road they can't be changed easily, warranting a tow truck trip to the dealer, which I guess one could call planned obsolescence with guaranteed returns for their service business income.
The link requires more work than the CB or even a fuse, but replaceable back home. I have one harness here where someone removed the link at the buss bar completely and just crimped a terminal on the remaining wire and reconnected it. Probably to get them going right after they found the short, however they never replaced it.
One more thing, I could never understand why a link was not added in the engine bay at the Ballast Resistor or TI harness if equipped, to specifically protect the IGN circuit. It could have been a Fuse in the Fuse Panel as well. Stories abound about burned up car harnesses and even some cars when the knife-edged distributor shield would cut the Coil + Feed wires.
Maybe it's because GM didn't want a car underway to loose ignition if such a thing happened by blowing a link or a fuse. I guess instead it was better to let the car die on the road or highway without circuit protection, and let it burn to the ground.
RichComment
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Re: Article on adding fusible links to pre-67 Corvettes
Rich, I think you are on to something with a manual reset circuit breaker. Everything is protected with the ability to get on the road again without cutting up the harness. While this would prevent unwanted reset in the event the short is not discovered.Comment
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Re: Article on adding fusible links to pre-67 Corvettes
Gene, It would simply trip again after a manual reset and continue protection if there was a dead short. If the troubleshooter found the problem, let's say a frayed wire or on a C1 the infamous Wiper Cable Saw-blade rub into the IGN wire or something catastrophic like that, he/she could tape up the bare wire, reset the breaker, and drive away.
The important part would be to analyze the circuit and select the appropriate breaker for the task.
I'm in a dilema right now on a 61 fuelie, also with my add-on super-duper John DeGregory Anti Siphon Solenoid.
I have a 30 Amp Fuse on the main feed at the Ammeter. I want to protect the IGN circuit by adding a fuse. I will do that but I need to make some current measurements with everything on and running engine to select the proper fuse and over-rate it a bit.
This is what's on the IGN circuit.
1- Coil+
2- Wiper Motor
3- FI Electric Choke
4- JD Anti-siphon valve
Sorry if this got a tad Off-Topic but in a way the principle is applicable to any pre 1967 Corvette.
RichComment
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Re: Article on adding fusible links to pre-67 Corvettes
FYI, the 22 gauge fusible link wire was quoted to me at $4.19/ft., 25 ft. minimum. The '63-'65 all have 18 gauge wire to the ammeter. If the recommendation has sound reasoning (are we saying the '67 had fusible links to the ammeter, so pre'67 must need it also?), then someone with a '63-'65 must have run into this issue.
Thanks,
SteveComment
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Re: Article on adding fusible links to pre-67 Corvettes
I'll answer my own question - yes, protecting both leads to the ammeter is very sound reasoning because these wires are hot all the time, bundled with many other wires in the wiring harness, connect to the instrument panel at the firewall connection, remain hot under the dash. So there's some risk of grounding that wire, causing heat, melted wires & connectors, and possibly causing a fire.
The first post suggested by Joe on this thread had a post referring to M.A.D. electronics which apparently sells fusible links, but I didn't see 22 gauge so I never looked into it. But I decided to call the number and ask. I talked to the owner, Mark Hamilton. I was telling him about the issue with the ammeter leads and, before I could ask about the 22 gauge fusible link, he said I needed 5 amp inline fuses. He seemed very knowledgeable about early Chevys and knew exactly what protection was added in the '67 Vette. He also recommended a 15 or 20 amp fuse for the feed to the cigarette lighter, which I also know is hot at all times and unprotected. I think I'm going to go with those recommendations since 22 gauge fusible links are not available (or as someone on this site once said, they must be made of unobtainium.) I think fuses are a better solution anyway.
Thanks,
SteveComment
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Re: Article on adding fusible links to pre-67 Corvettes
Steve,
The 5 Amp fuse sounds like a good idea, and I would add them by creating a mating connector "jumper" pair using the same 2 terminal angled connector types that are used in the harness and on the back of the Battery Gauge.
Adding a 15 Amp fuse for the Lighter is also a good idea, which is a similar recommendation made for the C1 cars which have effectively NO circuit protection for the Lighter, as well as none the Clock, the Horn Relay, the Generator, or the Voltage Regulator. All of these are ALWAYS hot, with key OFF.
Below is a document that Dave Zuber compiled from writings from myself, Dave, Frank Dreano, and others relative to circuit protection, mainly on the C1's but much in principle and connection technology is applicable to the C2's also. You may find this helpful along with John Hinckley's artice.
RichComment
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Re: Article on adding fusible links to pre-67 Corvettes
Rich,
Thanks for the info. Adding fuses at the gauge using jumper wires and existing connectors certainly makes a neat and easily reversible solution. But it protects only a short in the gauge and not the hot wires that feed it. I'm probably going to add the fuses at the source, the horn relay terminal and the solenoid. Although that's not as pretty a solution, it would protect both the wires and the gauge.
Thanks,
SteveComment
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Re: Article on adding fusible links to pre-67 Corvettes
Steve, Yes you're absolutely correct, none of the wiring from the sources to the Battery gauge would actually be protected, so I guess my idea was really not a good one. But it would look pretty.
So actually, the more I think of it, I really wonder if it's worthwhile to fuse those sources anyways. I've never ever heard of a short at those. Usually a short is caused by a IGN path to ground, like the Ignition Shield knife-edge rub and cut to to IGN wire anomaly, and that toaster oven inside the harness would typically melt lots of other wiring inside it.
But, if you do in fact decide to add 5 Amp fuses, I'd be concerned about this. The fuse holder you use down at the starter best be rated at a very high temperature. It could melt from bothe engine heat and in particular exhaust heat, especially if it's a Side Exhaust car. If you're getting AGC glass fuses, there is a Bakelite fuse holder that may be best. I used one recently on a 1957, and it certainly was put up to the task as there was a VR fault that caused the generator field to attain max output, around 20 volts and doing some serious heat build up. I felt the Bakelite fuse holder and it almost burned my hand.
Here it is here. It's a #10 G rated for a 30A fuse, so you'd have to properly splice/solder/shrinkwrap it to that 18G wire. You can just put the 5A fuse in it's place. I think I got it at NAPA. I'm heading there this morning to get a C1 Temperature Sender they ordered for me and will check for the fuse holder as I need one for another Main Fuse I need to install on another car here.
Rich
....it's the Black one laying on the underdash shelf/reinforcement, not the white one which is for the Power pack Radio supply.
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Re: Article on adding fusible links to pre-67 Corvettes
I seem to recall a discussion a few years ago where the need for a "slow blow" / time delay automotive circuit breaker was mentioned as a possible solution.Comment
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