Top Causes of Corvette Fires

[Stuart F.]

Re: Top Causes of Corvette Fires

Many thanks for the advice from both Duke and Terry. That info is a keeper which I will print for my file as others should do as well. Sooner or later the day will come when we'll all have to make such a change or repair as long as we own one of these precious cars.

Thanks again for the really good information.

Stu Fox

[Frank D.]

Re: Top Causes of Corvette Fires

I Googled your engine, "1963 L76" and found these two images. Were these engines factory equipped with a Carter AFB like these two, or a Holley as you mention?

Each appears to have an in-line filter and an all steel fuel line.

No Holleys in '63 - base motor got a WCFB anything else got an AFB, except of course for the fuelies...

[Mark E.]

Re: Top Causes of Corvette Fires

Brad: I don't have the issue number but the article was entitled: "The Electrical Safety Net For Your Early Corvette" written by Jeff Bernhardt.
Perhaps you can find it in the archives. The fusible link is a 14 gauge wire about 6 to 8 inches long that is wired in to the main wire coming off the solenoid. I found mine at NAPA for a little over $3.
Art

Is this the fusible link I see on my 1970 that's in the harness just behind the starter? I guess GM added these at some point?

[Mark E.]

Re: Top Causes of Corvette Fires

So are we in agreement: The factory used an all steel fuel line (and no rubber hose sections or connections) from the pump to the carb for all years, engines, carbs?

I believe this is true.

And I believe using rubber hose or a clamped-on aftermarket fuel filter in the pressurized segment of the fuel line (downstream from the pump) is a serious fire hazard. The risk of it rupturing, leaking, burning on something hot, or popping loose is too great. I've had it happen on my cars (from my yoot! ) but luckily escaped any fires.

If your car's factory steel fuel line is cut, spliced, crimped or otherwise damaged, make it a priority to replace it with an all-steel line using factory style threaded connections. The reproduction parts stores sell them. And those aftermarket in-line filters are not only unnecessary- they are a fire hazard.

[Jim D.]

Re: Top Causes of Corvette Fires

So are we in agreement: The factory used an all steel fuel line (and no rubber hose sections or connections) from the pump to the carb for all years, engines, carbs?

Nope. The 64-65 L-76 had a rubber hose between the outlet of the fuel filter and the Holley carb.

[John H.]

Re: Top Causes of Corvette Fires

I pulled the photo from Google images, so I don't know the car's vintage. I'm not a C2 expert so I'm going out on a limb here, but as I recall after Corvette phased out Carter carbs in the mid-60s there were two or three model years when all engines had one or more Holleys, even the base engine. Maybe this happened when 300HP became standard? So the photo might be a 300HP base engine from '66 or '67. I'm sure one of the many experts on the Forum can tell us...

But didn't engines with factory in-line fuel filters also feature all steel lines?

Mark -

That Google photo is of my '67 300hp - as with all '66-'67 Corvettes, it has a steel line from the fuel pump to the carburetor inlet; the same was true of all previous midyears EXCEPT the '64 365hp and '65 350hp and 365hp engines, which had a steel line from the fuel pump to the GF-90 fuel filter, but a rubber hose from the fuel filter outlet to the carburetor inlet (terrible design).

See the attached file below for my "Tech Bench" column on the cigarette lighter electrical hazard and cure.

LighterTech.pdf

[Mark E.]

Re: Top Causes of Corvette Fires

Jim, Thanks for catching that. I Googled 1965 Corvette L76 and got this image. I don't know if this is an original configuration, but it looks stock and has a rubber hose between the filter and carb.

So from these photos, it looks like the '63 L76 with an AFB uses steel, while the 64-65 L76 with a Holley uses a rubber hose? And the 66-67 300HP engine, also with a Holley, uses steel? A bit strange.

[Stuart F.]

Re: Top Causes of Corvette Fires

My hose is only about 5" long or just enough to make up the extra 3/8" elevation of the carb. I have no qualms about using it. It is only temporary for as long as I want a good running 63 L-76. I purposely eliminated all steel connections to the carb as part of my program to reduce the temperature of the of the carburetor - which it did by some 30 to 40 degrees. All my mods are temporary until the next fool that owns my car after I'm gone and wonders why he gets fuel percolation while running ethanol laced fuel and all the fun that goes with that. I stand on the fact that if a fuel hose was good enough on the 64 and 65 L-76's running those infamous leaky Holley's, then it can't be too bad on a 63 with an AFB. My fuel hose does not wrap around a leaky Holley. I agree; that is a terrible design.

I still carry a good fire extinguisher, but history shows that most people use them to put out someone else's fire. Not their own.

Stu Fox

[Mark E.]

Re: Top Causes of Corvette Fires

My hose is only about 5" long or just enough to make up the extra 3/8" elevation of the carb. I have no qualms about using it. It is only temporary for as long as I want a good running 63 L-76. I purposely eliminated all steel connections to the carb as part of my program to reduce the temperature of the of the carburetor - which it did by some 30 to 40 degrees. All my mods are temporary until the next fool that owns my car after I'm gone and wonders why he gets fuel percolation while running ethanol laced fuel and all the fun that goes with that. I stand on the fact that if a fuel hose was good enough on the 64 and 65 L-76's running those infamous leaky Holley's, then it can't be too bad on a 63 with an AFB. My fuel hose does not wrap around a leaky Holley. I agree; that is a terrible design.

I still carry a good fire extinguisher, but history shows that most people use them to put out someone else's fire. Not their own.

Stu Fox

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?

[Richard M.]

Re: Top Causes of Corvette Fires

Fuse related info. Frank, Dave and I put this together a while ago. Latest pdf here in post#8.

https://www.forums.ncrs.org/showthread.php?106842-1956-to-1962-Ignition-Fuse-Safety&p=714637#post714637

The same can apply to the 1963 to 1967 with respect to the Ignition circuit protection wiring. Remember that even though the 1967 model year includes fusible links at various hot spots, it has no fuse protection for the ignition circuit. If the Ignition feed to the Ballast or the TI Amplifier shorts to ground, commonly at ignition shielding on radio equipped models, a short, harness meltdown, and potential fire could still happen.

Rich

[Stuart F.]

Re: Top Causes of Corvette Fires

Mark;

Q Jets are all made of pot metal with cast bases and have VERY small float chambers that hold a minimal amount of fuel. Several of your cars have fuel evaporation canisters and other such emissions control devices which were designed to address fuel control issues.

If you look closely at the fine photos of the 63 L-76's that you found, you will notice that the fuel filter mounts to the water manifold portion of the aluminum intake manifold (a very obvious source of super heat), and then a steel fuel line connects the filter directly to the carburetor (as you noted) which is an all aluminum Carter AFB. The fuel pump has no return or by pass and therefore acts as a check valve so that any fuel in the line that is heated to the point of expansion can/may overcome the needle/seats of the carburetor. All in all, this design package on the 63 L-76 is a unique recipe for fuel control problems just waiting for the addition of 10% ethanol from the politicians to complete the mix.

That is why this backyard mechanic took it upon himself to reduce the problem (so his wife wouldn't complain so much about the gas stink in the attached garage). I elevated the carb with a 3/8" spacer sandwiched between two unique 63 L-76 base gaskets (which dictated the use of a fuel hose), changed the choke to a thermal controlled electric unit (eliminating the steel HOT fresh air tube to the choke), and installed Tomco fuel control valves in place of the needle/seats (which flow more fuel and provide better control allowing lower float levels). I still get some evaporation which requires me to prime the carb before starting if the engine has been shut down for more than a week. Not much I can do about that without doing some non-reversible modifications.

All in all, I now have a great car to drive year around and the wife doesn't complain any more.

Stu Fox

[Michael J.]

Re: Top Causes of Corvette Fires

Mark;

Q Jets are all made of pot metal with cast bases and have VERY small float chambers that hold a minimal amount of fuel. Several of your cars have fuel evaporation canisters and other such emissions control devices which were designed to address fuel control issues.

If you look closely at the fine photos of the 63 L-76's that you found, you will notice that the fuel filter mounts to the water manifold portion of the aluminum intake manifold (a very obvious source of super heat), and then a steel fuel line connects the filter directly to the carburetor (as you noted) which is an all aluminum Carter AFB. The fuel pump has no return or by pass and therefore acts as a check valve so that any fuel in the line that is heated to the point of expansion can/may overcome the needle/seats of the carburetor. All in all, this design package on the 63 L-76 is a unique recipe for fuel control problems just waiting for the addition of 10% ethanol from the politicians to complete the mix.

That is why this backyard mechanic took it upon himself to reduce the problem (so his wife wouldn't complain so much about the gas stink in the attached garage). I elevated the carb with a 3/8" spacer sandwiched between two unique 63 L-76 base gaskets (which dictated the use of a fuel hose), changed the choke to a thermal controlled electric unit (eliminating the steel HOT fresh air tube to the choke), and installed Tomco fuel control valves in place of the needle/seats (which flow more fuel and provide better control allowing lower float levels). I still get some evaporation which requires me to prime the carb before starting if the engine has been shut down for more than a week. Not much I can do about that without doing some non-reversible modifications.

All in all, I now have a great car to drive year around and the wife doesn't complain any more.

Stu Fox

Stu, those are some great mods for drivability thanks. My '81 Qjet seems to have some internal issue, as after I filled it up with gas (for the first time in many years), it just stopped running about 4 miles later outside my garage. I tried to start it for 30 minutes, but no gas coming through into carb at all. I left it sit for 5 days (I was on a trip), and when I got back, (preparing to check everything from fuel pump on) it started right up immediately, so the float bowl was still full. I am still trying to figure out what happened.

[Mark E.]

Re: Top Causes of Corvette Fires

Stu- That is a creative approach to your percolation problem.

Michael- The no-start occurrence is mysterious. FYI, with 10% ethanol, the fuel in my Q-Jet bowl will evaporate in seven (summer) to 15 (winter) days.

[Michael J.]

Re: Top Causes of Corvette Fires

Michael- The no-start occurrence is mysterious. FYI, with 10% ethanol, the fuel in my Q-Jet bowl will evaporate in seven (summer) to 15 (winter) days.

I am sure the bowl was not empty, since it started so quickly after sitting for 5 days after I tried for a half hour to start it before. There must be some mysterious mechanism in it that Holleys don't have, to make it not squirt fuel in to start when the bowl is full but will do it five days later.

[Mark E.]

Re: Top Causes of Corvette Fires

A Q-Jet has much smaller fuel bowl than a Holley. Maybe that's why their fuel bowl will dry up more quickly.