At least the "general" is consistant! 
A warning for early C4 owners...
Race Director
Joined: Oct 2000
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From: Enter Post Count Here
I think some of the wire in the C4 is Kapton, pronounced "Capped On". 
All of it isn't Kapton, but I believe a lot of it is, at least in my '87.
It's biggest advantage is that it's light as heck, and secondly, flame-resistent. But, it's causing headaches all over the aviation world because it doesn't age well, it splits, it cracks, it stretches. New planes from Mickey-D are coming with a polyvinyl insulation, which weighs more, but in theory should last forever.
I don't know how much a car wire harness is... but a good wire Harness for a Honda Shadow.................$700! For that price, I'll just replace wires as they go bad!
All of it isn't Kapton, but I believe a lot of it is, at least in my '87.It's biggest advantage is that it's light as heck, and secondly, flame-resistent. But, it's causing headaches all over the aviation world because it doesn't age well, it splits, it cracks, it stretches. New planes from Mickey-D are coming with a polyvinyl insulation, which weighs more, but in theory should last forever.
I don't know how much a car wire harness is... but a good wire Harness for a Honda Shadow.................$700!
For that price, I'll just replace wires as they go bad!
Race Director
Joined: Sep 2000
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From: Partying with the Cowboys cheerleaders in Mt. Olive, New Jersey
Originally Posted by bogus
...1984 to about 1990.
somewhere about 1990/1, the Society of Automotive Engineers (SAE) changed the rules regarding the composition of wire insulation.
What this mean is, newer wire is better. It is better able to deal with heat and harsh chemicals found under the hood.
The problem - For those of us who own a pre 1991 Vette, we have a problem. The heat under the hood is slowly eating our wiring away. The insulation starts to get brittle and break, causing possible shorts and grounding conditions.
If you are having a problem with your early C4, and all other logical fixes ain't fixing it, get out a test light and a DDM and commense chasing the harness. It sure isn't pretty, but it might be your only fix.
I so can't wait for the aftermarket to make good fitting harnesses for the earlier cars.
somewhere about 1990/1, the Society of Automotive Engineers (SAE) changed the rules regarding the composition of wire insulation.
What this mean is, newer wire is better. It is better able to deal with heat and harsh chemicals found under the hood.
The problem - For those of us who own a pre 1991 Vette, we have a problem. The heat under the hood is slowly eating our wiring away. The insulation starts to get brittle and break, causing possible shorts and grounding conditions.
If you are having a problem with your early C4, and all other logical fixes ain't fixing it, get out a test light and a DDM and commense chasing the harness. It sure isn't pretty, but it might be your only fix.
I so can't wait for the aftermarket to make good fitting harnesses for the earlier cars.
Oh this is just super... Well, having a fire extinguisher in my '86 doesn't seem so silly anymore. Thanks for the info, bogus.
Melting Slicks
Joined: Jun 2002
Posts: 2,168
Likes: 16
From: Phoenix AZ
Originally Posted by JrRifleCoach
This is why the insulation shrinks and leaves as much as one inch of bare wire exposed at the crimp ends. A classic of this is the fuel pump relay between the wiper motor and brake booster. Just pull the connector out and inspect the wires.
I found the MAF power relay connector wires were exposed. So an evening was spent inspecting every last connector in the engine compartment, and repairing same.....
-JRC-
I found the MAF power relay connector wires were exposed. So an evening was spent inspecting every last connector in the engine compartment, and repairing same.....
-JRC-
Racer
Joined: Jul 2000
Posts: 363
Likes: 11
From: St. Catharines Ontario CANADA
Insulation Shrinkage
Here is a pic of what I am starting to see at connectors. The insulation shrinks back and is likely just a matter of time before conduit shorts... very scary!
This is the MAF relay behind the battery on my 86
I already solved a previous wacky 4+3 OD problem by finding this situation on the OD relay where wires were actually twisted together and shorting with every bump on the road.
This is the MAF relay behind the battery on my 86
I already solved a previous wacky 4+3 OD problem by finding this situation on the OD relay where wires were actually twisted together and shorting with every bump on the road.
Last edited by redvette1986; Aug 25, 2004 at 04:52 PM.
Thread Starter
Team Owner
Joined: Aug 2000
Posts: 40,156
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From: San Pedro CA
Originally Posted by redvette1986
Here is a pic of what I am starting to see at connectors. The insulation shrinks back and is likely just a matter of time before conduit shorts... very scary!
This is the MAF relay behind the battery on my 86
I already solved a previous wacky 4+3 OD problem by finding this situation on the OD relay where wires were actually twisted together and shorting with every bump on the road.
This is the MAF relay behind the battery on my 86
I already solved a previous wacky 4+3 OD problem by finding this situation on the OD relay where wires were actually twisted together and shorting with every bump on the road.
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Team Owner
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From: San Diego , CA Double Yellow DirtBags 1985..Z51..6-speed
I think the risk of my entire Vette going up in flames while I'm going 150 mph is much more exciting than the prospect of swapping out the wiring harness. No thanks! But I do need to get in and do a permanent fix on the fuel pump and OD relays.
Thread Starter
Team Owner
Joined: Aug 2000
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From: San Pedro CA
Originally Posted by CentralCoaster
I think the risk of my entire Vette going up in flames while I'm going 150 mph is much more exciting than the prospect of swapping out the wiring harness. No thanks! But I do need to get in and do a permanent fix on the fuel pump and OD relays.
I donno how hard swapping the harness would actually be. I mean, if done right, the harness should only take a few hours to work through.
Some planning and then some minor wrenching.
Le Mans Master
Joined: Oct 1999
Posts: 6,366
Likes: 34
Originally Posted by mikey whipreck
best wiring was (and still is) cloth wiring... I wonder if its possible to buy that stuff anymore...
I have been wondering where I could find some of that as well. Good stuff!
Thread Starter
Team Owner
Joined: Aug 2000
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From: San Pedro CA
Originally Posted by bill mcdonald
Hmm, I was looking at my old truck and it had some sort of cloth covered wire on the water temp sensor. this wire touches the exhuast manifolds a lot and has never even burned.
I have been wondering where I could find some of that as well. Good stuff!
I have been wondering where I could find some of that as well. Good stuff!
Burning Brakes
Joined: Jul 2002
Posts: 871
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From: Costa Mesa CA
Yeah...
Doing what you can to reduce underhood temps helps a lot as well. I was melting my aftermarket plug wire looms just from normal C4 underhood heat. And I run without a thermo and don't get over 180F much. TB bypass as well.
I bought 4 NACA duct-type scoops, two large and two small that I'm going to install on my hood to let some air in and cool things under there. It's just like an oven with no ventilation at all other than the fan air which is hot already anyway from the radiator.
I'm also think about putting 2-3, 350W peltiers on the TB and see what they can do for cooling the intake air.
BIG JIM
Doing what you can to reduce underhood temps helps a lot as well. I was melting my aftermarket plug wire looms just from normal C4 underhood heat. And I run without a thermo and don't get over 180F much. TB bypass as well.
I bought 4 NACA duct-type scoops, two large and two small that I'm going to install on my hood to let some air in and cool things under there. It's just like an oven with no ventilation at all other than the fan air which is hot already anyway from the radiator.
I'm also think about putting 2-3, 350W peltiers on the TB and see what they can do for cooling the intake air.
BIG JIM
Thread Starter
Team Owner
Joined: Aug 2000
Posts: 40,156
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From: San Pedro CA
There are heat extractors you can get, too.
Another trick, for the earlier vettes, is to remove the piece of foam that seals the hood. There is a piece that runs down the side from the latch, remove that, and air will flow out over the door. This suggestion comes straight from Gordon Killebrew.
Another trick, for the earlier vettes, is to remove the piece of foam that seals the hood. There is a piece that runs down the side from the latch, remove that, and air will flow out over the door. This suggestion comes straight from Gordon Killebrew.
Le Mans Master
Joined: Oct 1999
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Originally Posted by BIG JIM 54
Yeah...
I'm also think about putting 2-3, 350W peltiers on the TB and see what they can do for cooling the intake air.
BIG JIM
I'm also think about putting 2-3, 350W peltiers on the TB and see what they can do for cooling the intake air.
BIG JIM
Advanced
Joined: Aug 2003
Posts: 87
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From: Brisbane QLD
Peltier coolers
Peltier coolers are a semiconductor device which when an electric current is passed through them they will cool the surface dramatically. However like everything else in life, "you can not have a cold surface without a hot one." While there is a cool side of a peltier cooler, the opposite side is a heater which is basically "exhausting" the heat extracted on the "cooler" side.
So if you take out 100W of heat from the air in the intake, then the "heater" side of the peltier will be disappating 100W of heat into the engine bay.
They are used a lot in computers for keeping the processors cool, so thats why you will normally see them refered to that way on the net.
I hope this helps!
A useful reference is http://www.digit-life.com/articles/peltiercoolers/
So if you take out 100W of heat from the air in the intake, then the "heater" side of the peltier will be disappating 100W of heat into the engine bay.
They are used a lot in computers for keeping the processors cool, so thats why you will normally see them refered to that way on the net.
I hope this helps!
A useful reference is http://www.digit-life.com/articles/peltiercoolers/
Race Director
Joined: Oct 2000
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From: Enter Post Count Here
Peltier Coolers have been experimented in refrigerators too, it's a pretty cool theory which I would really like to understand better.
I'd like to second Bogus' recommendation to remove the hood to windshield insulation. George Crouse did it to his car, including cutting off the lip that the insulation sat on. That car makes over 500 rwhp, so a lot of underhood heat, it was pretty cool to feel it RUSHING out of the hood over the windshield, even sitting still.
I'd like to second Bogus' recommendation to remove the hood to windshield insulation. George Crouse did it to his car, including cutting off the lip that the insulation sat on. That car makes over 500 rwhp, so a lot of underhood heat, it was pretty cool to feel it RUSHING out of the hood over the windshield, even sitting still.
Heel & Toe
Joined: Aug 2004
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bogus
I don't know if you read my thread I posted the other day, but I'm having a weird problem with my 1989 Vette. The friggin' thing won't charge properly. Starts up charging normally at around 14.5 volts, then steadily loses it and stays around 11.9 to 12.0 volts at idle. I ohmed all the wiring from the alternator to the block behind the battery, all seems good. I've been all over this thing, you can read all the details in my posting "C4guy1091-car won't charge". Then the car quits on me intermittanly like someone turned the ignition off. Is it possible that when the wiring which runs across the intake manifold is building resistance as the car gets hot? Wadda you think?
Thread Starter
Team Owner
Joined: Aug 2000
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From: San Pedro CA
I can see how resistance would go up as heat rises, but not THAT much! The problem isn't really with the wire, it's with the insulation around the wire.
Has the alternator been tested? I wonder if the voltage regulator is going bad. If anything is going to be effected by heat, it will be the alternator.
You need to find a shop with a load tester. Run the car until it gets hot, then go to the shop and have them run a tests on the hot alternator. Taking a cold unit off and putting it on a machine won't prove anything.
Has the alternator been tested? I wonder if the voltage regulator is going bad. If anything is going to be effected by heat, it will be the alternator.
You need to find a shop with a load tester. Run the car until it gets hot, then go to the shop and have them run a tests on the hot alternator. Taking a cold unit off and putting it on a machine won't prove anything.