Fire

fire... all caused by a little screw. Thank Heaven for a quick thinking cop with a fire extinguisher.
one of the screws in the distributor cap backed out and when it came out the rotor flung it around until it wedged against the side of the cap and blew a hole thru the cap. the screw wedged in the hole then arced directly to the carb. It promptly ignited... Brad managed to jump out and yank all the pins and get the deck open, he was in the parking lot of the police station and an officer grabbed an extinguisher and doused it getting the flames out. he said there was fire coming out of the scoops, and at the top where the deck meets the back of the tub. it did scorch some paint off the lip, the fiberglass was not damaged but got a good heating up. the air filter melted some. Brad got a few good burns on his hands and arms.
when he ordered a new MSD cap and rotor it came with different screws and washers to hold those screws in. he said they are like lock washers so he has his suspicions that this has happened before and MSD redesigned to prevent it happening again. just suspicion though. check your cap screws, hope it doesnt happen to anyone else.

Wow, what a freak thing! :shocked:

Although I'm sure it doesn't feel this way right now, you guys got lucky--the car was relatively undamaged, and more importantly, nobody got seriously hurt.

I hope his burns heal quickly, and the car as well....thanks for the warning!

WOW, that is strange! I have a halon fire system, you might want to consider one of those. I am glad you came out OK, that is really freaky.

How did a dist. cap screw back out inside the cap??

SPF 2080 said:

How did a dist. cap screw back out inside the cap??

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it was one of the screws that holds the rotor down inside the cap

Mike Drew said:

Wow, what a freak thing! :shocked:

Although I'm sure it doesn't feel this way right now, you guys got lucky--the car was relatively undamaged, and more importantly, nobody got seriously hurt.

I hope his burns heal quickly, and the car as well....thanks for the warning!

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oh we got seriously lucky... some scorch marks and blistered paint is fixable, replacing a melted GT40 is not. the car is fixed and back on the road but if it hadn't been for the quick thinking cop with the extinguisher it would not be. ya'll might want to check your caps and locktight those screws down.

Was it a new never touched distributor or had the rotor been replaced?

MSD sells the replacement cap with 2 sets of screws. One set of screws is longer. If the shorter screw was used it might not have had enough purchase and came loose and out.

See MSD http://www.msdignition.com/uploadedFiles/MSDIgnitioncom/Products/distributors/8467_instructions.pdf

Measure the screw and see what used vs what supposed to be used.

Was the rotor installed by MSD or as a replacement ect.

Steve P2125

steve c said:

Was it a new never touched distributor or had the rotor been replaced?

MSD sells the replacement cap with 2 sets of screws. One set of screws is longer. If the shorter screw was used it might not have had enough purchase and came loose and out.

See MSD http://www.msdignition.com/uploadedFiles/MSDIgnitioncom/Products/distributors/8467_instructions.pdf

Measure the screw and see what used vs what supposed to be used.

Was the rotor installed by MSD or as a replacement ect.

Steve P2125

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I am not sure Steve, this is P2107 one of the first cars shipped here. We have not changed anything on it but will never know if the previous owner changed anything. the replacement cap came with different screws and washers for the screws, the washers, brad said were not flat so the screw head would fit down in them. I will ask him when he gets up (works nights shift) if it looked like they had been replaced or were original.
lol after the fire was put out, he got a ride home, got another cap and rotor, cleaned up the fire extinguisher mess, fired it up and drove it home lol. wicked car...

steve c said:

MSD sells the replacement cap with 2 sets of screws. One set of screws is longer. If the shorter screw was used it might not have had enough purchase and came loose and out.

See MSD http://www.msdignition.com/uploadedFiles/MSDIgnitioncom/Products/distributors/8467_instructions.pdf

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Wow. Here we have an assembly that spins at up to 4,000 RPM retained by two threaded fasteners, and:

• No mention of tightening torque.
• No mention of loctite.
• In the "nut" version is there any locking feature in those captive nuts?
• In the other version they depend on belleville washers????

Hey MSD: did you know that your products are sometimes installed by people who are neither professional race mechanics nor mechanical engineers? :huh:


Story/thought regarding fire extinguishers and systems: I had my "ah-ha" moment about this in 1974 when a (glass-fiber-bodied) Saab Sonnet in the company parking lot went up in flames at least two stories high. A maintenance worker with a 2-foot tall CO2 extinguisher ran towards the car to about 15 feet away, felt the radiant heat, then turned and walked away. Next morning it was a 12" pile of black crap that looked like it was hit in "War of the Worlds." That afternoon I installed a small extinguisher on the floor below my knees in my Lotus Europa.

Even if your car never ignites, you can be the hero when someone else's does.

Anyway, RedReiner, thank you very much for telling the story. I'm going to go check on my MSD rotor right now.

Red,

Alan has some good points but, I have been using MSD distributors for yrs w/o a problem.

Suspect you have the version using (calling for the 3/4" screw and the belleville washer).
The retaining nut used is a type of "captive nut" and in combination with the belleville if the screw is tightned should be OK (always has been for me).

Make sure you look at the instruction link above, install the correct length screw (suspect you may have the shorter screw that won't take designed depth purchase of the nut), belleville washer dome up and tighten untill you get dome deflection (good and tight).

Steve P2125

In all my years working on cars - I've never seen a rotor screw come out of the GM Style rotor...

Glad that you are okay and the car was saved...

Makes me further curious as to how it could have ignited the fuel in the carb - unless it was leaking somewhere...

Apply a spark (volts) to a carb, the spark will find the path of least resistance through the carb body of which is float bowls, chambers, etc, with volital fuel residing and "POOF" it's whats for dinner time!................................Sparky

Brad here. As you guys probably already figured out this had been a gradual thing w/the two stainless phillips head screws backing out. I was obviously extremely lucky in the timing after just taking someone on a "spirited drive". The car has about 3000 street miles on it now and the Roush 427R engine has a moderately radical grind. With the lack of vacuum/lotsa overlap I have gotten used to the gas smell due to the grind. The Edelbrock Air Gap and Holley 770 vac carb as installed by Olthoff make it quite streetable and the open element K&N kept the flames out of the carb itself. The airbox and intake ducting obviously had contained much of the fire though the sides of the carb body are discolored, reflecting that the fire had fully enveloped the area around the carb. Flames had been coming out of the ducting which I noticed in the rear view mirror as I was cranking the engine over to leave. A guy was sitting in his car doing paperwork about 20' away and had a powder type fire extinguisher ready to go. I figure I had about 20-25 seconds of drama before being extinguished within 1-2 seconds. I guess it was murphy's law in that when the loose rotor screw had no where to go the rotor knocked it thru the side of the cap right at one of the plug wire terminals and at a point closest to the carb body.
I was quite amused when the replacement MSD cap and rotor arrived and I found that in addition to the two lengths of screws for the rotor due to design changes that the belleville (sp) washers were included as an update. Seeing that, it was obvious to me that this has happened in MSD distributors w/ GM style internals before. In summary I realize how lucky I was. The cosmetic damage I can live with and simply compare that to the character lines we get in our faces as we get older. I have always been and will continue to be an MSD fan, w/ 6A's on at least 10 of my cars including my Saab Sonett III which has a Pertronix w/ 6A etc. (Had to include that since one was mentioned above). And yes, I have both red and blue locktite which I have no problem using when bolt stretch is not in the equation.

awatkins said:

Hey MSD: did you know that your products are sometimes installed by people who are neither professional race mechanics nor mechanical engineers? :huh

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Im sure they are Alan, just as they are probably painfully aware that those same people are like Tim Taylor and never read the instructions until after the event....

RedReiner said:

Brad here. With the lack of vacuum/lotsa overlap I have gotten used to the gas smell due to the grind.

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The inside photo of the cap seems to show the center electrode broken off. If that didn't happen due to the bolt flying around that would explain your gas smell. My center electrode broke as well and I had a pronounced gas smell from the exhaust of my 427SR due to weak ignition.

Took a look at my MSD distributor and have both good and bad news. (I have the version with belleville washers.)

The plate into which the 10-32 screws thread is around 16 ga, maybe 14 ga. The screw just goes into a tapped hole, so there are only about 2 or 3 turns of thread. So don't be cranking down an that screw too hard.

My washer was no longer from Belleville, that is, it was completely flat; it's now a Kansas washer. This is my experience with those things. I think they're useless or maybe worse than useless in that they give a false sense of security.

Good news: the screw is long enough that, if you wanted to, you could put a nylock or other nut or two on the "extra" length of screw underneath. You'd of course be increasing rotational mass a bit but that screw would NOT be coming out soon.

I chose to just blue loctite the thing and move on.

Yeah, "instructions" derives from a Latin phrase meaning "what I should have done."

Big-Foot said:

Makes me further curious as to how it could have ignited the fuel in the carb - unless it was leaking somewhere...

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If the car just came in from a spirited run and was heat soaking, perhaps there was combustible vapor in the vicinity of the distributor.

happy our experience had a good outcome, and even happier if it prevents anyone else from the same experience lol. I was in the twin cities when this happened, Brad was out giving woman rides in his hotrod while I was gone... dare I say it?? ha! his Karma! ok I am just kidding...sort of.

Good to see things worked out Brad. I'm beginning to think you car may have lost it's Mojo. Brake check at Pacific, disty blows a screw, what's next?

Neal said:

Good to see things worked out Brad. I'm beginning to think you car may have lost it's Mojo. Brake check at Pacific, disty blows a screw, what's next?

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hehe lol the brake check was still fun. going to see you there this year? they have new safety rules in place for the exhibition laps... wonder what prompted that!