Technical Letting an engine idle?

On another forum a guy tried to see if his older car would heat up in a parade by letting it set in the drive way and idle for two hours. I told him is was not good to let any engine idle for , actually, more than necessary, like at a stop light. There was some question about that, there.
So, I come to the HAMB, where I believe is a wealth of knowledge, for answers. What say ye,?



Bones

 

2hr. Seems unnecessary

 

Opinions, like motors, are different. It all depends on the statistics ( idle speed - oil pressure - cooling system efficiency - etc. )

Yes it does.
There should be an answer before two hours buuut the owner for some reason must have his doubts, and needs to know.

 

If cop cars used to do it all the time, I can't see what it'd hurt.

 

It would depend on the engine, but for most engines I don’t see what harm could come to it by just doing what it is designed to do. I suppose some engines could benefit from the additional oil slung around at higher RPMs but most engines don’t need it at low RPM. If the tune up is off it could foul plugs and/or heat up but with everything pretty close it should be no problem.

 

I think newer cars can probably idle for extended periods of time.

But to let a hot rod idle for long periods of time you better have good air flow (fan) and a well made efficient radiator, I have been in situations where you didn't move a mile in a half hour and end up on the side of the road in my old 40 Ford sedan, that will tax any system.

I believe I could let my old Deuce beater idle for a hour but if I don't have to I want. HRP

 

I used to work on ambulances and bucket trucks. The miles were usually low, but they needed engines well before 100,000 miles. The hours running killed them. The older ones that I worked on had seldom had hour meters on them. The new ones mostly do. I never really studied the hour to miles ratio on them.

 

Driving in parades isn't good for old cars, they should be on a race track instead.

 

Love it @squirrel !!!!

I was always taught to not let an engine idle for extended periods , charging system isn’t at optimal rpm for charging , oil pump using at optimum rpm to build pressure , on our carburetor engines your dumping fuel leading to carbon deposits, cooling fan and pump are spinning slow etc etc .


While it might not be a death sentence, it definitely isn’t what a engine was designed for.

 

Yea, but a guy idling his car on the race track might be run over!

 

A mopar automatic will burn up idling in Park because the pump doesn't provide fluid to cool the trans.

 

Truckers do it, and their engines routinely go 300,000+ before a rebuild. What about generators/agricultural water pumps? As long as it doesn't overheat, I see no problem. your talking about low rpm/w no load.

On the other hand, air-cooled engines should not idle any longer than necessary to be able to run w/o choke.

 

When the big trucks park for the night they bump the RPM's up to about 7-8 hundred to keep the cylinder walls from glazing. Also keeps oil pressure up a bit. Been there, done that

 

Modern cars, yes. I once started my wife's daily driver in the late afternoon for some reason and forgot to shut it off. Came out the next morning and it was still sitting there, happily idling... with a lot less gas in the tack.

 

In the 60's& 70's we used to park on the country roads at night with the engine idling for hours , never seemed to affect the car ! Same thing at the drive in movie .

 

I forgot about drive-ins. there were other ways to stay warm, but they didn't keep the windows from fogging up. Doubtful you were watching the movie, anyway.

 

Not real good for air cooled 2-cycle engines.
Liquid cooled four cycle shouldn't be a problem.

I guess he's pretty sure now that it doesn't overheat. LOL

I drove over the road and wasn't aware of drivers ever increasing the idle speed overnight in the big trucks.

 

Diesels are very inefficient at an idle and will often get “ cold” idling, especially in cold weather. Causing poor combustion. The reason over the road drivers could get away with idling all night was most old engines had ring land lubercation and after idling all night the trucker would have that engine on the floor running wide open for eight+ hours the next day cleaning the injectors. These are not factors in most car gas engines.

Also, most modern fire trucks have the high idle function , some come on automaticity after the engine idles so long.









Bones

 

I've idled the shit out of motors running inverters. Longest I remember was three/four days. Didn't hurt it a bit. That old OT 4x4 lasted 20yrs. Body finally fell off, but it was sill running good.

 

When he got older my grandfather would pull his Dodge out of the garage out here where I live now and let it idle with the heater run and just sit in it for hours on end plus the man never broke the speed limit in 65 years of driving. I'd have to take that thing and run a quart of transmission fluid through the carb every couple of months and take off down 97 and up over the first couple of hills until it cleared out and ran right. If you know Rick who has all the old Tin a few miles South of Toppenish he can tell you about Rob filling his yard with the smoke from the trans fluid as I stopped across the road from his place to pour the trans fluid down the carb.

 

But they have Cop Motors, Cop Tires and Cop Brakes !

 

Only if you have a Duntov Cammed 300 horse 327 with dual Smittys why else would you want to hear it Idle...?

 

Those "cop motors" battery-powered?

 

I grew up in South Dakota, and my preferred parking spot was in a pasture by an abandoned gravel pit. Both the old '53 Bel-Air and the '64 Dynamic 88 idled near that pit during the winter "activities" and never missed a beat. I think as long as you have good oil pressure, good carb idle adjustment (not too rich) and a decent cooling system it doesn't hurt them. At least that was my experience in the early 70's.

 

Get on an L.A. freeway at rush hour(s). Millions of cars idling for hours.

 

My '54 Ford Coupe (bored 312 'Y') idled every morning in '67 on my way to work in Van Nuys, CA
L.A. Freeway my a$$!

 

While this isn't a direct answer to the question, maybe it'll provide some additional information to stir into the pot. (I'll let @Dave G in Gansevoort chime in on the diesel side of things.)

When I worked at a fire museum for several years, we tried really hard to not let any of the vehicles (similar vintages to the rods that grace these digital pages) idle for more than 5-10 minutes *once they were at operating temperature*. And that wasn't just coolant temp, that was oil temp as well. Get the oil temp up enough to boil off any water that may have condensed since the last time the engine ran. We heard horror stories of other places that would start up their one ancient fire engine (their pride and joy!), drive it the 15 or 20 feet outside, then shut it down. End of the day, same thing only in reverse. Well, failing to get the engine oil up to temp led to the water jackets rusting out, among other terminal illnesses. These were all gas, no diesel, so YRMV. Also remember that these were purpose-built/designed vehicles, and so often had larger radiators, etc., so that they could "idle" for hours on-end while working a fire. Not so much for your Deuce coupe with a flatty, unless you've upgraded your radiator, etc.

So - any danger in letting your vehicle idle for 2+ hours? Maybe not, other than the transmission issue already raised. I'm sure there's some other gremlin(s) in there that I'm not thinking of, too. Regardless, I'm with @corncobcoupe - just go be in the parade and enjoy yourself!

 

This is funny !

Folks in the cold north (upper Canada / Alaska...where ambient temperatures reach a high...of, say 20 (or less) degrees in the cold months of the year, they leave their engines running ALL NIGHT ! Otherwise, the engine will freeze solid.

Now I fully understand that things have changed somewhat with better block heaters currently available, but when I was in Prudhoe Bay (above the Arctic Circle), back in the 80's, the block heaters of the time were...not so good.

So...they let their engines run, basically 24 hours a day. I asked several, unrelated people about this. They thought I was nuts for asking, and not believing. Like "sure, why not" ...was the basic comment.

So...what seems to be the problem with letting your engine idle for long periods of time ?

Mike

 

You forgot Cop Shocks..