Top Causes of Corvette Fires

[Pete P.]

Re: Top Causes of Corvette Fires

I want to share this experience because it goes along with what Brad described above. Back in the '80's, when I used to drive my 1960 more frequently, even to work, I had been checking the spark plugs the night before taking the car to work the next day. The next day I started off to work and got about 2 miles from my house when white smoke started coming from under the dash. It smelled like electrical wiring and I quickly pulled over. I looked under the dash and could hardly see through the smoke. Finally, I got a glimpse of the red wire glowing red. To protect my hands, I used a hat I had in the car and grabbed the wire to pull it off. Little did I recall that the red wire is attached to the ammeter with a nut. Well, the result was the wire burning through my hat and into my hands. I was in state of panic to keep the car from catching fire that I didn't even know my hands were burned. I unlatched the convertible top and put it down to clear the smoke. Then, I popped the hood and saw the glowing red that runs from the ammeter to the regulator. The adrenaline was now flowing and I managed to get the battery cable off somehow. The wire cooled down with almost all its insulation melted. It's a miracle that the glowing red hot wire, which goes through the firewall grommet, didn't cause a fire. Now, with my hands starting to really hurt, I wasn't sure if I should leave my car on the side of road. So, I decided to push the car by myself about 200 feet into a nearby cemetery so the car would be somewhat safe. It's amazing what you can do when you need to. I was fortunate that a good Samaritan watched all this happening and gave me a ride to the nearest police station. Needless to say, I got my first ambulance ride during rush-hour traffic to the hospital. I had to call the local police station to let them know my vintage car was resting in the cemetery for a few days. What was the cause of all this? In my rush the night before to get the car ready to drive to work the next day, I caught the RED wire behind the spark plug shield when putting the shield back on. The wire got shorted against the exhaust manifold. When my hands healed (about 2 months) and I was able to fix the wiring, I checked each and every wire on the car and made sure that the RED wire was in those u-shaped holders up near the fender. Oh yeah, I supervised a few of my buddies with my hands wrapped like boxing gloves, to get my car back home from the cemetery. Thank the Lord that my car didn't catch on fire, my hands healed, and the car wasn't stolen from the cemetery. Sorry for writing a book.

[Joe R.]

Re: Top Causes of Corvette Fires

Pete,

Wowsa, that is quite a story! You showed a great deal of bravery in saving your car!!! My 66 is down for a paint job. It has the factory radio option, but I have been toying with the idea of making it "radio delete." You just may have swayed me in that direction for the long haul.

Joe

[Mark E.]

Re: Top Causes of Corvette Fires

Thanks guys! This thread contains some valuable advice for preventing a fire from damaging your Corvette.

Summarizing the key points (let me know if I missed something):

Electrical:

• Replace antique, frayed, spliced wiring
• Add a fusible link to the main wire coming from the solenoid (C1 and early C2)
• Add a 30 amp ATC blade-type fuse in the black wire from the ammeter to the battery, and add a fuse to the clock (if it’s original) and cigarette lighter power leads. (C1)
• Install a fuse in the cigarette lighter hot wire (pre-’67)
• Add a fuse to the ignition circuit (C2)
• Make sure the battery is externally vented (C3)

Other:

• Avoid fuel line modifications
• Diligently inspect all rubber fuel hoses and connections throughout the car
• Make sure the PCV, air cleaner, flame arrestor are properly installed and working
• Make sure wheel bearings are properly adjusted and lubed
• Diligently inspect the catalytic converter; replace if plugged or restricted ('75 and newer)

[Ian G.]

Re: Top Causes of Corvette Fires

Would the "30 amp ATC blade-type fuse in the black wire from the ammeter to the battery" be in place or in addition to the "The 14 gauge wire fusible link wire about 6 to 8 inches long that is wired in to the main wire coming off the solenoid." ? I've also read 16 gauge wire on this one in previous posts of other threads.

[Frank D.]

Re: Top Causes of Corvette Fires

It's odd how some engines suffer from percolation while others do not. For some reason, even though I live in Dallas (hot) which has 10% alcohol, none of my vintage cars experienced percolation (including '70 LS5, '73 L82, '69 Caddy 472, '72 El Camino SS 350- all with AC).

Maybe Q-Jets handle heat better?

It is indeed peculiar - I fabricated my own phenolic 1/4" spacers under my '61s dual carbs to deal with the problem. After the carbs were rebuilt by Bob Kunz no more perc withOUT the spacers. The float levels are identical to what I ran so I have no idea how it got fixed. But I can now take the car on a smokin' run in Orlando heat and leave it sit for 45 minutes with the hood closed and still no issue. I'm mystified...

[Mark E.]

Re: Top Causes of Corvette Fires

Would the "30 amp ATC blade-type fuse in the black wire from the ammeter to the battery" be in place or in addition to the "The 14 gauge wire fusible link wire about 6 to 8 inches long that is wired in to the main wire coming off the solenoid." ? I've also read 16 gauge wire on this one in previous posts of other threads.

Ian,

I'm not the expert so maybe others will chime in, but my thoughts:

- If your car doesn't have one, add a fusible link in the harness's main power lead that connects to the solenoid.

- If your car has a real ammeter (one that's wired so a significant current load goes through the gauge, unlike a more modern "battery" gauge that measures voltage drop) then you may want to protect this circuit separately with its own fuse.

But instead of using a blade type fuse as originally suggested, consider a period correct SFE (glass tube type) fuse for a more original look.

Regarding wire gauge, I would use the same gauge used in the circuit you're protecting.

[John H.]

Re: Top Causes of Corvette Fires

Regarding wire gauge, I would use the same gauge used in the circuit you're protecting.

Mark -

You DON'T want to do that. A fusible link is ALWAYS two wire sizes smaller than the circuit it's protecting - that allows the fusible link to fail before the excess current fries the harness. Wire sizes are only even numbers, and a larger number means a smaller wire. For example, if your main power circuit is a 10-gauge wire, you'd protect it with a 14-gauge fusible link.

[Brad K.]

Re: Top Causes of Corvette Fires

This response is for Mark Edmondson.....I totally missed your inquiry earlier....it is only when I re-read the entire link that I caught your question. Yes....the fire happened to my Triple Crown winner in the early 80's, when it was my daily driver and long before I restored the car. I shudder to think that I came within seconds of the car being a total loss. That's why I ALWAYS carry a halon fire extinguisher directly accessible between the seats! I never needed it since....but it is still there.

[Walter F.]

Re: Top Causes of Corvette Fires

Owning and 84 I have been told that the Crossfire design was more prown to fires then other corvettes. Personally I think this is pure myth. I don't see how the design makes it any more likely to go on fire then any other Corvette. For some reason the 84 seems to be the wipping boy of all Corvettes.If it not the ride it the spinning out. If its not the spinning out its the poor electronics. Its the one Corvette we should all avoid. Even some Corvette publications have hinted such.

[Mark E.]

Re: Top Causes of Corvette Fires

Owning and 84 I have been told that the Crossfire design was more prown to fires then other corvettes. Personally I think this is pure myth. I don't see how the design makes it any more likely to go on fire then any other Corvette. For some reason the 84 seems to be the wipping boy of all Corvettes.If it not the ride it the spinning out. If its not the spinning out its the poor electronics. Its the one Corvette we should all avoid. Even some Corvette publications have hinted such.

It's easy to forget what a sensation the new '84 Corvette created when it was introduced. What a media frenzy! Corvette's first completely new chassis, body and drive train in 21 years brought Corvette into the modern age. It seemed like it was continuously on the cover of at least one car magazine for months before and after its introduction. Chevy tapped into the excitement with some of the coolest Corvette TV commercials, print ads and sales brochures.

I consider the C4 the first Corvette that offered all-around performance. When ordering, no longer did we have to choose between equipping the car for hot rodding or grand touring- the C4 offered both. I remember being in a cross-country Corvette caravan in the summer of '92. I was sweating in my '73 while listening to the engine drone at 3,000 rpm on the highway. Meanwhile, my C4 buddies were riding in AC comfort, listening to their Bose and getting almost 30 mpg. The humbling part is that their cars were also quicker and faster than my L82.

The 1984 is overshadowed by the subsequent model years which offered better performance, refinement, and comfort. The same can be said for 1968 and 1997. In my mind, that doesn't take away from its role as being the new world-class leader in its day.

And more good news: Clean, original, low-mileage C4s are absolute bargains right now.

I haven't heard about fire risks with the cross-fire induction.

[Richard M.]

Re: Top Causes of Corvette Fires

I install a 30 AMP glass fuse at the Ammeter from the solenoid battery terminal. This doesn't protect the wire from the solenoid up to the Ammeter but most catastrophic shorts afterward.

It saved a new harness once when I dropped a screwdriver down at the Voltage Regulator when I was polarizing the generator on a new build. The blade hit the Red wire and lodged on to the ground shield of the generator harness. The fresh air hose was in the way and took some time to reach down and yank it out.

The 30 AMP fuse immediately blew and saved the engine harness.

fuses.jpg

[Mark E.]

Re: Top Causes of Corvette Fires

Thanks for the correction, John.

[Richard M.]

Re: Top Causes of Corvette Fires

This response is for Mark Edmondson.....I totally missed your inquiry earlier....it is only when I re-read the entire link that I caught your question. Yes....the fire happened to my Triple Crown winner in the early 80's, when it was my daily driver and long before I restored the car. I shudder to think that I came within seconds of the car being a total loss. That's why I ALWAYS carry a halon fire extinguisher directly accessible between the seats! I never needed it since....but it is still there.

Reminds me of this story which happened to me years ago.....(copy paste from another site I wrote several years ago talking about broken hood release cables. this happened in the late 80's/early 90's IIRC)

BTW, Halon will not work when it's windy. If that happens, spray the Halon under the engine bay, this to remove the oxygen from the fire from below. A Fireman taught me that.

Go get a soda and a bag of chips for this one.........

Arghhh!!!! Reminds me of an episode about 10 years ago when my wife and I left a downhill parking lot on a hot summer day in NH. My 59 had a hot start problem then. Car has dual fours, old wcfbs. I made the stupid mistake of flooring the throttle, you know, to open the throttle plates to get more air, to start. But I should've only half throttled, to get the primary carb open. Flooring to start a hot engine with dual fours dumps lots of fuel into the front carb too. You know where I'm heading with this don't you. So we go to leave the lot, downhill, waiting for traffic to go by to turn left to get on the highway for a 2 hr journey for an overnight stay in the mountains, top down, beautiful day with my lovely bride of many years.

Finally traffic passes by, I turn left, shift into second, and "BANG", I thought, s__t, backfire, it'll be alright. Next thing, I smell it, that horrible feeling set in. Oh my God, FIRE! Yes, the engine was on fire!
Pulled over just before the on ramp. Wife tried to get out, her sneaker laces got caught on the window crank, she panicked. I tried to keep my cool, OK Rich, stay calm, we can fix this, had to get wife out first, then just reach under the dash, pop the hood. I prayed, Please God, don't let the hood release cable break on me, just this once, I promise I'll go to church this Sunday, really, honest. The hood popped open, I saw smoke coming out towards the windshield. I figured the car was doomed. 10 years of hard work gone.....no, had my mini Halon extinguisher in the center glovebox, and a full size in the trunk. Grab the Halon stupid, no time for the trunk!

Got out.....wife was screaming, I was starting to panic. Opened the hood and there it was, a round cone of fire completely surrounding the beautiful 2x4 air cleaner she got me for Christmas 10 years earlier from Ecklers. The flames were about 2 feet high......Ok, how does this Halon thing work....pulled the pin and in one circular motion around the air cleaner I shot the yellow & black flames. What seemed like forever, but actually seconds.......OUT! No flames, nothing, gone, poof. I stood there looking for more, ready with my handy dandy fireman's friend to kill anything that even blinked yellow. Nothing. We looked at each other, sighed, said a few explatives, and sat on the curb hugging each other. She was crying. I was shaking my head, wow, that was cool! These Halons really do work!

After a little while, I let the air cleaner cool off, took my Mothers polish out of the trunk. Cleaned off the black soot from the edges of the air cleaner(came out like new), put it back on and started the engine. All's ok. Got in the car, took a right onto the onramp and had a beautiful ride to the mountains for the weekend. Car was fine.

Morale here......make sure you check those cables often, they will let you down when you least expect it. AND, carry a fire extiguisher close to you in the car for those sudden emergencies. We were lucky. Also make sure those throttle shafts on your old wcfbs are not worn so badly that they let unspent fuel leak out onto those hot intake and exhaust manifolds. That was the reason for my episode. When we went downhill out of the lot, the fuel in the front carb leaked out the shafts as the carb was not sucking fuel as it was not being told to with less than half throttle. Fixed that with new ones and a rebuild when we got home.

Rich
ps Went to Church twice that weekend. Second time to cover us for the ride back home.
====

[Mark E.]

Re: Top Causes of Corvette Fires

Wow. I'm glad neither of you were hurt. And you just continued to drive the car on your trip?!?!

So the cause of the fire was gasoline from the accelerator pumps leaking through the throttle shafts and onto the manifolds? I understand that, but never heard of it happening before. Those dual WCFBs must squirt a lot of gas... And I thought Quadrajets were dangerous.

Wasn't the hood or other nearby stuff damaged? Did the fire create a unique hood scoop or paint mural for you? :-}

It sounds like the halon extinguisher you kept in the console saved your bacon. How large was it? My understanding is that small halon extinguishers can handle surprisingly large fires as long as the air is still or in a confined area. It certainly did a big job for you.

[Richard M.]

Re: Top Causes of Corvette Fires

Wow. I'm glad neither of you were hurt. And you just continued to drive the car on your trip?!?!

So the cause of the fire was gasoline from the accelerator pumps leaking through the throttle shafts and onto the manifolds? I understand that, but never heard of it happening before. Those dual WCFBs must squirt a lot of gas... And I thought Quadrajets were dangerous.

Wasn't the hood or other nearby stuff damaged? Did the fire create a unique hood scoop or paint mural for you? :-}

It sounds like the halon extinguisher you kept in the console saved your bacon. How large was it? My understanding is that small halon extinguishers can handle surprisingly large fires as long as the air is still or in a confined area. It certainly did a big job for you.

Mark, Yes car was fine after that. It was my own fault. Very lucky I didn't loose it then.

The problem with dual fours is that the progressive linkage prevents the secondary carburetor(front) throttle plates from opening until more than half throttle at the pedal. The rear(primary) carburetor does all the work until then.

Sequence is like this. At half throttle, rear carb is at half throttle, primaries open. Past that, the front carb begins to open primaries, and rear carb begins to open secondaries. As the pedal throttle lever "progresses", near 3/4 throttle, the front carburetor secondaries open. From then on all 8 throttles on both are open.

When a WCFB, like most carburetors, is first throttled, the accelerator pump pumps high volume fuel into the bores. Because the front carb never was told to open, i.e. the pedal never went past half way when I got the engine started, the fuel from my "flooring on hot restart" dumped raw fuel in the front carb from the accelerator pump, which I recall I may have floored it repeatedly on several attempts to start. It had nowhere to go because when it finally started only the rear carburetor was drawing fuel via vacuum, i.e. less than half throttle. Front bores had much fuel sitting there.

When I was downhill waiting for traffic to pass, I had to feather the throttle to keep it running. Engine was very hot. All that time the front carb had fuel sitting at the throttle plates. When I turned left it likely came out then. The fuel leaked out the shafts and onto the hot manifold. The fire also burned the black paint on my generator, so it started on the right side of the engine.

No other damage than that. The underside of the hood got some new black coating. It may still be there. The black soot on the air cleaner came right off. The Halon was a small 8" or so high Sears unit. I still have it as a remembrance and may still have a charge. I keep it in the same place, along with a larger Halon in the trunk.

Rich