Tonight, another car rear-ended mine at about 30 mph faster than I was going. Though my two passengers are suffering from pretty sore necks and backs, I and the drunk who hit me seem to be ok. It was really kind of funny, given the results. I was driving my big ol’ '66 Dodge Coronet and he was driving an '87 Olds Delta 88.
The results:
His car: radiator somewhere around where his flywheels (is that what you would call the things the various belts go around?) used to be; hood pretty munched up; bumper pushed well back into the front end.
My car: He bent my trim. Even the tail lamps and bezels are fine! Ok, there’s actually a little bit of damage to one of the caps on the rear fender, but nothing a hammer won’t fix.
But on to the question. As soon as he hit me, my car stalled. Why would it stall? I’m thinking the gasoline flow was interupted by the impact, but wonder if there’s any other good reason.
I’m not an automotive expert, but it seems like a jolt of that magnitude could be enough to momentarily knock things out of whack under your distributor cap, which would mean no electricity was going to your spark plugs. (And that, of course equals no firing of the engine.)
As an aside, those old cars can be tanks. I had a '73 Dodge Dart that was rear-ended three separate times, and twice the other car ended up a lot worse off than mine. (The third and final time was by a fully-loaded tractor-trailer, and needless to say my car lost that round.)
I’d say that it was most likely fuel starvation. The impact swished the fuel around in the carb such that it wasn’t going into the cylinders. Many fuel-injected cars have a motion switch installed in them so that if the car is subjected to either sudden acceleration or decceleration it shuts off the fuel pump. This is to help reduce the likelihood of a fire in a serious collision.
Not to be argumentative, but would an engine really stall that quickly from a brief sloshing of petrol in the bowl? I know that some early carburetted cars that could pull some higher g’s when put into long, hard corners at speed would stall (until baffles were added to the float bowl - this happened with the pre-1981 FIAT X 1/9), but it just seems odd to me that a single impact “slosh” would stall an engine.
Not that I have a better explaination. I’m just trying to visualize a typical American car carburettor to think if this makes sense to me.
Anth, it depends upon on a lot of things. How hard was the impact? At 30 MPH, I’d say it was a pretty nasty bash, since most crash testing is done at about the same speeds. Also, what kind of engine and carb’s in the Dodge? A two barrel carb would be more likely to stall out than a 4 barrel, I’d think. Also the condition of the engine and type of engine play a factor as well. Assuming that it’s the original engine, then it’s nearly 30 years old.
The 1971 Chrysler Newport I had, was equipped with a 383 engine and a 2 barrel carb (so the car was about the same size and weight as the Coronet, IIRC, and potentially could have had the same engine) and when I accidentally did a 180 (wet roads, on a curve, tapped the brakes and suddenly the car decided to swap ends), it didn’t stall, but I was going slightly slower than 30, and once the world began to revolve around me, I pulled my foot off the brakes.
Another factor to consider is that the Coronet was designed to run off of leaded gas (which isn’t available anymore), and depending upon the engine, might be designed to run on higher octane fuel than what’s currently available. This can be compensated for by engine modifications, of course, but we don’t know if those have been done or not.
The level of gas in the tank, and the age of the fuel pumps (along with the last time, if ever, the engine and carb were rebuilt) can play a factor in this as well. If everything in the car was stock, and the carb hadn’t had a rebuild, and the fuel pump was a decade old or more, then it’d be surprising, I think, if the car didn’t stall.
The other thing that might have happened to cause the car to stall, now that I think about it, is that the imact could have jarred some of the wiring loose momentarily. I had a battery cable come loose on my 1984 Honda Accord, and the car died, came back to life a second later, and then totally die as the cable fell completely off.
I don’t know about the mid-Sixties Mopars, but the early 70s had crappy electrical systems due to the aluminum connectors used, and I had frequent stalling problems in mine because of it.
4-V carb is typically operating as a 2-v until the throttle is opened past about 1/2 way. Also, if the floats are adjusted properly, the fuel should not be interrupted by a momentary event.
It’s not a matter of fuel flow into the carb. The thought is that the impact had enough force to slosh the fuel sitting in the float bowl. Put a bowl of water on the floor and kick it to see (I do this all the time with the %&#@* cat’s water bowl). The idle circuit only has to suck air for a second for the engine to die. Alternatively, if the sloshed fuel somehow dumped into the intake, it could kill the engine quickly by flooding.
Gary:
You too with the cats water - well they have a clean eating area from the constant cleaning up
A difference in the carb is that the float bowl is closed and the fuel is drawn from near the bottom. But you still have a better theory than me - none at this time.
I once drove on 2 wheels for about 200 feet before a full rollover. The big block Mustang was still running when I finally landed on all four wheels.
I think some cars have an impact-sensitive switch that cuts off the electrical power so that sparks, etc won’t cause a fire in leaking fuel after the crash. It needs to be manually reset.
Just to be sure, the engine is a 225 slant six with original one barrel Carter carb. No modifications, other than whatever had to be done (if anything) when the catalytic converter came out (IIRC, that’s what was done to switch to unleaded).
