[Nightfire]

Many people rev up their cars good before they shut them down......or they shut them down as they shut it down. Is there a reason for this? I've heard its "healthy" for the engine but I cnat really see why or do people just do that to be cool?




Mike

 

[gahi]

Dunno, but sometimes I do it on a poor running motor because I have a theory that it might restart easier, maybe it gives the rockers and bearings more oil. Not sure why, maybe just makes you feel better.

Gary

 

[ponybuster]

revving before shut off

i believe i possibly heard this theory in this forum actually

revving an older pushrod/lifter engine up before cutting it off can keep bad timing from letting preignition or detonation from occuring in a cylinder if you rev it up before you cut it off.

i dunno if this is true.. someone let me know, it'd be a little nit pick thing to know

i do it with my 66 stang.. just cause.. its a hot car, but i dont do it excessively like everytime i cut the car off. plus its just a short pat of the gas just to let you know its there, not to grab attention
heh

 

[poncho62]

One of the worst things you can do to your engine. Rev it up and you are putting a big shot of gas into the cylinders, which you shut off right away, not giving the gas a chance to escape. This washes the oil off of the rings causing a dry condition which accelerates ring wear......
That's my theory anyways........................

 

[mitmaks]

my theory is that it lets oil go up through whole engine so its lubricated when you start it up next time, i guess it makes sense

 

[troy-curt]

The old theory was, it would leave some unburnt fuel in the cyl. for hard to start engines. but like poncho said you then have a wash down and a non lubed cyl. on start up. A rev up will not put any more oil topside. If it did, by the next morn. or next start up it would all be drained back to the pan. Plus the extra fuel will drain into the oil, diluting it. That extra fuel in the cyl. will cause pre ignition. (dieseling)

Troy:nono:

 

[malc]

Way back in history when cars were cranked by hand, it was revved before stopping to put fuel in the cylinders.If you were going to be stopped only a short while this would start the car with the ignition and not have to use the handle.
Today it is better to leave the gas alone and just switch off.

(BTW NightFire, did you learn everything about engine advance ?)

 

[Dubz]

for cars that are hard starters when warm is when i've heard people using it, when they are gonna start the car again in 10-15 min and know it's gonna be hard starting again. Never overnight or for longer periods though, as mentioned that would be really hard.

I belive it originated from the Model T, if you did this trick you could just hit the igntion and it would fire a cylinder and get the motor running without hand cranking

 

[Pony]

In the 50s and 60s it just seemed to be announcing to the crowd at the local hang out " I'm here and my car is Bad" If you we're driving mom & dads car or some other dull car you just coasted in quietly and hoped nobody noticed you. :thumbup:

 

[BillyShope]

With a Hillborn, or, for that matter, with a carbureted engine with a rich idle circuit, you might want to make certain all plugs are clean before you shut down.

With an oval track car, you turn off the ignition while under full power and coast into the pits, so the plug readings will be valid.

But, you can't ignore the "cool" factor, either.

 

[Nightfire]

Allright, seems like there are a lot of theories on this but I'm shootin' for the one that it's bad for the oil rings and generally bad for your car.

(BTW NightFire, did you learn everything about engine advance ?)

Well, sort off. I did read the articles you posted and tried to understand them, though a bit confusing I think I got most of it. Thanks again!








Mike

 

[stepside454]

I Know of two reasons,
1 Like Billy said, to clean unburned fuel from plugs & cylinders.
2 If the guy has an oil accumulator, thats how you can build pressure into the accumulator.

 

[wildman926]

I have seen it the reverse also. As soon as someone turns the key, they already have their foot in it, revving the motor up to almost redline. I hear/see it all the time, and think to myself, what idiots. They just spent all of that money on that bad motor. Then they do that to just impress the crowd. If they knew how to tune their engines, it would start on the first bump.

 

[stepside454]

Wild LOL, I know , thats the worst thing.
We went to the stock car races here earlier this summer. After the race, getting in the car, this kid across from us started his early 90s stang & immediatly revving the piss out of it.
Well, when he let it idle finally, it was just hammering, he shut it off & was pissed off at the car...man I bit my tongue.

 

[wildman926]

We have a "mini" car show every Saturday night here in Houston, at I10/Hwy 6 Sam's Club Parking lot, and I was just talking to the guy in a beautiful 70 Chevelle, $15k in a 496 BBC, 700 hp, and then does the rev thing as he is starting it!!! Nicest guy you ever met, but doing that doesn't show much sense he has. I get to see this every Saturday night.

 

[BillyShope]

I have seen it the reverse also. As soon as someone turns the key, they already have their foot in it, revving the motor up to almost redline. I hear/see it all the time, and think to myself, what idiots. They just spent all of that money on that bad motor. Then they do that to just impress the crowd. If they knew how to tune their engines, it would start on the first bump.

Yeah, I saw that on one of those Speed TV shows. They showed how to build an engine, then the guy jumps in, turns the key, and revs it up!

 

[crazy larry]

most cars with an auto tranny will idle considerably higher when taken out of drive and put in park. this may be some of the revving your hearing.

other than that, i''d contribute it to the sound. I know when i get to work, i found i could set off car alarms on cars parked next to me at an idle.... well I wanted to find out how far away i had to be, it's still an ongoing experiment.... I can be three spaces from this caddy and trip it's alarm,( have to thwap the throttle to do it.) so far, i've only been able to get two spaces away from the little lincoln......:evil:

 

[poncho62]

Why not just ram the Caddy and Lincoln?

That would set the alarm off for sure..............and their owners.......lol

 

[crazy larry]

your cutting into my tool and parts money with that.

besides, any schnook can do it with ramming. how many schnooks you know can do it from 18 feet away and no rock?

how would you type Roscoe P. Coletrains' laugh?

 

[wildman926]

most cars with an auto tranny will idle considerably higher when taken out of drive and put in park. this may be some of the revving your hearing.

I was talking about when they go to leave, and their ride has been sitting for 2-3 hours, and they just turn the key WITH THEIR FOOT IN IT!!! I know it sounds stupid, but I hear/see it all the time.