Not mine. This is from the FB groups..... It’s a rare thing but I thought it’s important to discuss and learn from it..... incident.... Daily driven 1950 Ford sedan made a 20 minute late afternoon trip. The car was parked for 30 minutes. Upon starting a loud Boom was heard and the engine was on fire. The oil filter canister top blew off and dented the hood. The oil filler cap also blew off. The carburetor was on fire and despite all the oil and flames the owner was able to save the car with a fire extinguisher. The obvious damage.... A blew out oil filter canister, a dented hood with bubbled paint. Specs provided...... No stock fuel pump. Electric pump at the tank 2 week old Speedway 9super7 from Summit Stock distributor hooked to manifold “wiper” vacuum. What went wrong? Go.
Just a guess based on the story only and no pictures. I would start by looking at the new carb. Something was wrong with it and fuel was getting into the crankcase by some mechanism. Could have been washing down the cylinders, could have been a crack or hole in the intake manifold, or something else perhaps related to the electric fuel pump (was it pressure regulated correctly?), but fuel built up and mixed with the oil. Finally got to the point were the mixture reached the right air / fuel ratio and all it took was a spark, which seemed to occur during cranking. One kaboom later, the oil filter canister lid acted as the pressure relief valve and exited the group chat.
Yup. Carb leaked into cylinder and washed past the rings. Then kaboom when the proper vapor combo wafted past a spark. Wonder what spark did it? Maybe in the generator?
Yup. I'd put money on the electric pump (4-5psi) pushing fuel past the carb (needing 2.5psi) and washing the cylinder walls in gasoline. Add a spark and you get combustion, just not in the right place. Buyer beware. I am tired of warning people about the "not a stromberg"
When I taught automotive, a couple of students in another class were working on how to correctly install a distributor and time an engine. We had an Olds V8 on a roll around stand and they would pull the distributor, the instructor would crank the engine with the distributor out and they would have to reinstall it and time the engine. It seem this pair of students was having a really hard time getting the engine to start. They had the distributor in and out multiple times with no success. The last time they pulled the distributor they left the key on. As they were removing it the gas in the oil of the badly flooded engine ignited from a spark and shot the distributor to the very high roof with a loud bang. No one was injured, but it made an exciting day.
I did this not very long ago on my big block Chrysler, no damage other than a massive fireball out of the distributor hole, some singed hair…
Electric fuel pump pushing fuel past the needle valve. Check the wiring too. Some people have been known to wire the pump hot, through a switch. Doesn’t take much of a lapse to forget to turn off the switch. (I might put money on this one).
Had the same thing happen a few years ago, a fellow mechanic was doing a tune up on a sbc powered speed boat in the workshop, flooded the carb and filled the oil pan with gas, next time he hit the key, an almighty BOOM, it was strong enough to blow the alloy Corvette rocker covers off the engine (leaving the securing bolts and the bit of the alloy mount hole behind in the head), both covers hitting the roof about 25 feet above.
Had a PhD neighbor that worked at the National Laboratory here that was an expert on blowing up things with gasoline vapor among the catalysts for destruction....he said "when you got it right..." Someone got it right....
The old way to do this was to just keep running that old mill until it got clogged up with dirt. The road 'draft tube' losing function from various practices, like ditching the air cleaner. and just adding oil rather than changing it. I was treated to the experience, one teenaged day, at my Uncle's Gulf station. The Gulf sat on a hill and mid afternoon an 18 year old Ford was struggling up the hill. A king sized boom and the car stopped dead. A storm of black oil falling beneath the motor, had the mechanics yelling "crankcase explosion". They proceeded to explain the symptom and cause. The guys across the street at 'Ernie's Esso' got to deal with it.
That knock off carb probably siphoned fuel from the tank, and well, then the big boom happened due to the conditions being right inside the engine.
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