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View Full Version : Why did we rev our motors before we turned them off years ago????


90wreck
01-29-2010, 05:59 PM
I have a few theories.....
To "clear" the plugs?
Because the motors sounded so good...?
:dunno
Why???

jimfog
01-29-2010, 06:02 PM
Yeah...weird one.

I still do it when it's cold out, and I'm shutting Bessie down for the night......which, I'm sure, my neighbors LOVE, as I'm usually getting home @2-3am!

:roll:roll:roll

T.Wesley
01-29-2010, 06:04 PM
I never did it, and I had a bunch of old muscle cars when I was a kid. Well, maybe not a bunch but more than a couple :)

--chiba

aeolian
01-29-2010, 06:07 PM
It's a really bad idea. Especially in a carburated car. What you're doing is creating a huge vacuum that sucks a healthy dose of gas though the carburator into the cylinders, but it doen't get burned because the ignition is off. Nicely washes all the oil off the cylinder walls. So the next time you fire her up and gun it, you're reving unlubricated pistons/bores for the first few until the oil pump/rod splash gets some more up there.

FI shuts off the gas along with the ignition and isn't subject to sucking gas out of a float bowl whenever the manifold is pulling a vacuum.

jimfog
01-29-2010, 06:10 PM
It's a really bad idea. Especially in a carburated car. What you're doing is creating a huge vacuum that sucks a healthy dose of gas though the carburator into the cylinders, but it doen't get burned because the ignition is off. Nicely washes all the oil off the cylinder walls. So the next time you fire her up and gun it, you're reving unlubricated pistons/bores for the first few until the oil pump/rod splash gets some more up there.

FI shuts off the gas along with the ignition and isn't subject to sucking gas out of a float bowl whenever the manifold is pulling a vacuum.

Figures. That would be about right.

If it has to do with something mechanical, and I'M doing it........it's stupid. :wave

90wreck
01-29-2010, 06:17 PM
It's a really bad idea. Especially in a carburated car. What you're doing is creating a huge vacuum that sucks a healthy dose of gas though the carburator into the cylinders, but it doen't get burned because the ignition is off. Nicely washes all the oil off the cylinder walls. So the next time you fire her up and gun it, you're reving unlubricated pistons/bores for the first few until the oil pump/rod splash gets some more up there.

FI shuts off the gas along with the ignition and isn't subject to sucking gas out of a float bowl whenever the manifold is pulling a vacuum.
oh great...now you tell us. :(
But it was so coool.:aok

xntrick
01-29-2010, 06:20 PM
to make sure there was enough oil in the heads...

oldschoolguy
01-29-2010, 06:21 PM
To put an extra little charge on the battery? i can't remember doing it.

FenderBigot
01-29-2010, 06:36 PM
To put an extra little charge on the battery? i can't remember doing it.
I think this is close... it was the old "crank the alternator/generator" thing!

sinner
01-29-2010, 07:23 PM
If my idle is set too low, I sometimes rev up the motor right before shut down thinking it will help start up quicker...pretty dumb I know.

Another one: On your old cars, sometimes you got a few missing teeth on the whatever it's called thing, and you rev it up so it moves beyond those bad teeth so when you start it up the next day it won't be on that bad spot, or something like that!

Another: rev it up while you roll up the power window because for some reason the window goes too slow but when I rev it travels up faster.

GA20T
01-29-2010, 07:24 PM
you were obnoxious teenagers?

joemilitello
01-29-2010, 07:27 PM
My dad used to gun his old '57 Chevy convertible on the highway and get it up to 80 mph or so to "blow the carbon out."

I have since used that excuse many times.

frankencat
01-29-2010, 07:31 PM
I just did it because it was cool :)

dougk
01-29-2010, 07:35 PM
It's a really bad idea. Especially in a carburated car. What you're doing is creating a huge vacuum that sucks a healthy dose of gas though the carburator into the cylinders, but it doen't get burned because the ignition is off. Nicely washes all the oil off the cylinder walls. So the next time you fire her up and gun it, you're reving unlubricated pistons/bores for the first few until the oil pump/rod splash gets some more up there.

FI shuts off the gas along with the ignition and isn't subject to sucking gas out of a float bowl whenever the manifold is pulling a vacuum.

This is the truth.

Every reason why one "should" is just a BS excuse hiding the fact it just sounded cool.

retrobob
01-29-2010, 07:39 PM
Cuz we saw other people do it, so we thought we were supposed to do it?

sundaypunch
01-29-2010, 08:39 PM
My dad used to gun his old '57 Chevy convertible on the highway and get it up to 80 mph or so to "blow the carbon out."

I have since used that excuse many times.

"The Italian tune-up"

nitehawk55
01-29-2010, 09:31 PM
"The Italian tune-up"


I've always called it a Mexican tune up :aok

Bought a 69 Olds 98 years ago that had been city driven only most of it's life with a big 455 and 4bbl carb. You should have seen the carbon blow out of it when I got it on the highway the first time and nailed it !! It took a while but it ran 100% better after doing that for a time . I know I could have blown the engine doing that but IMHO it was a do or die situation .

Don't recall reving up when shutting down , in fact I usually let my cars idle for a few seconds just to see if they were running smooth .

I see a lot of guys with bikes rev the engines a lot just for the love of the sound .

GAD
01-30-2010, 09:06 AM
I'm going to have to go with "because it sounded cool". Man I haven't done that in years.

Tripower455
01-30-2010, 09:08 AM
It's a really bad idea. Especially in a carburated car. What you're doing is creating a huge vacuum that sucks a healthy dose of gas though the carburator into the cylinders, but it doen't get burned because the ignition is off. Nicely washes all the oil off the cylinder walls. So the next time you fire her up and gun it, you're reving unlubricated pistons/bores for the first few until the oil pump/rod splash gets some more up there.

FI shuts off the gas along with the ignition and isn't subject to sucking gas out of a float bowl whenever the manifold is pulling a vacuum.


Bingo......... I never do it......

Blindspot
01-30-2010, 09:13 AM
I always let an engine idle for a moment before shut-down. Never rev it. Even my lawnmower....

Tripower455
01-30-2010, 09:16 AM
I've always called it a Mexican tune up :aok

Bought a 69 Olds 98 years ago that had been city driven only most of it's life with a big 455 and 4bbl carb. You should have seen the carbon blow out of it when I got it on the highway the first time and nailed it !! It took a while but it ran 100% better after doing that for a time . I know I could have blown the engine doing that but IMHO it was a do or die situation .




I bought a beautiful '69 Grand Prix with a 428 in it from a tenant in my grandma's building in Brooklyn. In 1983, it had 57k on it, and being a city car driven by a middle aged woman, had never been faster than 50 mph in it's entire life. Being an 18 year old kid, I STOOD on it getting on the Belt Parkway, and my friend who was following me disappeared in the black cloud of carbon smoke behind me! Between the valves clattering due to trying to ruyn 10.5:1 cr on the urine gas available, and the sudden revving, it must've shook about 10 lbs of carbon out of the motor! Being older and wiser, I realize that it was a stupid thing to do for a variety of reasons, but it was cool. By the time we got on the Southern State Pkwy, I could stand on it without creating blackout conditions for the car behind me. Still pinged like a sonar though!

Doodad
01-30-2010, 10:13 AM
Cuz it sounds cool and we are about to miss the sound until the next ride.

Baxtercat
01-30-2010, 11:47 AM
I always let an engine idle for a moment before shut-down. Never rev it. Even my lawnmower....
I'm gonna have to rev up my mower and blow the carbon out now.

90wreck
01-30-2010, 12:11 PM
Cuz it sounds cool and we are about to miss the sound until the next ride.
lol I remember that feeling.

jumpnblues
01-30-2010, 01:57 PM
It's a really bad idea. Especially in a carburated car. What you're doing is creating a huge vacuum that sucks a healthy dose of gas though the carburator into the cylinders, but it doen't get burned because the ignition is off. Nicely washes all the oil off the cylinder walls. So the next time you fire her up and gun it, you're reving unlubricated pistons/bores for the first few until the oil pump/rod splash gets some more up there.

FI shuts off the gas along with the ignition and isn't subject to sucking gas out of a float bowl whenever the manifold is pulling a vacuum.


All very true. And if the fuel doesn't ignite upon starting the next time you can "hydraulic" a cylinder and bend a rod...just like you know who did to his big block Chevy engine in his street rod, necessitating a complete rebuild. Expensive lesson. But...the new 496" BB, full roller, Chevy engine is awesome.


Tom