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Warming up Apparatus Engines: Is it Necessary?

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  • Warming up Apparatus Engines: Is it Necessary?

    I have heard the argument that it is important to idle the engines before driving them in order to get the oil flowing. This makes sense to me, but I have two questions:

    1) Is it actually necessary? By "necessary," I mean, will it cause damage if you do not do it (assuming above-freezing temperatures)?
    2) If necessary, how long do you have to idle them?

    I have heard some people recommend starting the engine before getting turned out, allowing the engine to warm up while you get dressed for the response. But, there are articles such as that linked below which argue that idling for the purpose of circulating oil is unnecessary after about 30 seconds. (Yes, this is plenty of time to get bunked out, but I see our engines idle for much longer awaiting additional volunteers to show up at the station). I realize that the article is probably aimed more at gas engines than diesel ones, but I feel that the time it takes to warm and circulate oil in a gas engine is probably the same as in a diesel one (same oil, right?), so I tend to believe the article's argument.

    http://autos.yahoo.com/articles/auto...car-in-winter/

    Thoughts?

    Have a great day,
    -Radar

  • #2
    Originally posted by wradar View Post
    I have heard the argument that it is important to idle the engines before driving them in order to get the oil flowing. This makes sense to me, but I have two questions:

    1) Is it actually necessary? By "necessary," I mean, will it cause damage if you do not do it (assuming above-freezing temperatures)?
    2) If necessary, how long do you have to idle them?

    I have heard some people recommend starting the engine before getting turned out, allowing the engine to warm up while you get dressed for the response. But, there are articles such as that linked below which argue that idling for the purpose of circulating oil is unnecessary after about 30 seconds. (Yes, this is plenty of time to get bunked out, but I see our engines idle for much longer awaiting additional volunteers to show up at the station). I realize that the article is probably aimed more at gas engines than diesel ones, but I feel that the time it takes to warm and circulate oil in a gas engine is probably the same as in a diesel one (same oil, right?), so I tend to believe the article's argument.

    http://autos.yahoo.com/articles/auto...car-in-winter/

    Thoughts?

    Have a great day,
    -Radar

    That's a funny question, as per timing. Our local news at noon today had a mechanic on it so people can ask questions. The first one was about "how long should I idle or warm up my car". His answer was "10 seconds". Because of the oil, tighter clearances, yadda-yadda-yadda... it is un-needed to warm up a car.

    Personally, I start the car, buckle up, set whatever, and put it into gear. So give me at least 30 seconds to a minute. No need to just sit there wasting gas. It is warmed up in 5 minutes of driving, if not sooner.

    Fire rigs are fine to start and run. It will take you at least enough time to circulate the fluids before taking off. There is nothing that is going to hurt the engine if you don't let it warm up.

    Get in, start it, buckle up, put it in gear, go to call. Simple as that.

    FM1
    I'm the one Fire and Rescue calls, when they need to be Rescued.

    Originally posted by EastKyFF
    "Firemens gets antsies. Theys wants to goes to fires. Sometimeses they haves to waits."

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    • #3
      To add to FireMech's comments, keep in mind also that at least around here, the apparatus are kept inside and a "room" temperature, so the oils don't get really cold like they might if they were sitting outside.

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      • #4
        Original thinking concerning "Warming up" had to do with low pressure oil pumps and in some cases "dip tube" lubrication of rod bearings. Cold engines (cylinder walls) tend to cause carburetted gasoline to condense on the wall and cause the splashed oil from the crank to be thinned by the gasoline. Running high piston speeds under low cylinder lubrication was thought to be a major cause of seal ring and cylinder wear. Today with Chevy, Toyota, Ford and Chrysler all using oil jets aimed at the underside of the piston skirt, and the oil paths cut into pistons to promote cooling, wear of rings and cylinder walls is nearly eliminated. This little modification of the lubrication has increased fuel economy between 2 and 5%, depending upon the engine design. Cummins is currently doing some research on oil jets (high volume) on an experimental marine engine. This technology is already being used in some O.T.R. tractor trailer engines. As an old OTR driver, I still cringe when someone gets honking on a motor right after starting. It has nothing to do with wear, but everything to do with stresses between engine components that are being heated unevenly, with no chance to stabilize the thermal gradients in the pieces inside the engine. It is useful to consider that cylinder heads and exhaust valves easily see surface temperatures of 1200 to 1600 degrees, while just 3/8" away the coolant circulating through the motor is 220 degrees. Would you take your pyrex baking dish out of a 450 deg. oven and drop it into cold water in the sink? From the consumption of scarce resources and excess pollution generation view point, a zero idle requirement is probably correct. If you are firing up an engine that has been sitting for 2 weeks since it was last run, I think I'd wait 30 seconds until the sleeves and bearings were lubricated. Idling down after working hard is probably more important to allow the temps to stabilize.

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        • #5
          I have always been taught that it is absolutely critical to properly warm up an engine, whether it be a large unit such as an engine or ladder going on a run, or your personal vehicle going to the grocery store. Hell, I even allow my weed wacker or blower to idle for a minute or two before I "get on them." At the firehouse, whenever there was a run, and I was the D/O, the very first thing I did was start the engine. Then I would pull out the map book, and take a quick peek at my routes and hydrant locations. Once the guys were in and buckled, by then the oil had a good chance to get where it needed to go, and things were well on the way to getting warm. I feel it is especially important to do this if you are using a heavier weight oil. The colder an engine is, the more important it is to give it a chance to warm up (i.e. apparatus stored outside, or your personal vehicles...etc...)

          For my personal vehicles (which my wife hates me for) in this beautiful 15 degree weather, I absolutely forbid movement unless the engine has been running at least 5-10 minutes- I or she go outside and start it up, and come back in the house and get the boys ready to go or whatever. She (typical of a woman) wants to jump in, start it and go! (and when SHE goes, it's usually an impression of Danica Patrick.)
          "Loyalty Above all Else. Except Honor."

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          • #6
            Thanks for all of the responses! I'm all for about 30 seconds of warm-up, and that seems to be the sentiment of some of you, as well. FWDBuff, 5-10 minutes of warm-up still seems a bit much to me, but it's not usually 15 degrees down here in The South. ...well, except maybe this week, apparently. Ha!

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            • #7
              We are a volly department so when we get to the station we turn the engines on then open the doors and put turn out pants on. By that time the air brakes are aired up and were ready to go. Plus helps the engines warm alittle.

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              • #8
                Originally posted by FWDbuff View Post
                She (typical of a woman) wants to jump in, start it and go! (and when SHE goes, it's usually an impression of Danica Patrick.)
                Yes, this resembles more than just one example of the fair gender!!

                I seem to remember that the mid to late 90's diesels were automatically not allowed to got to full power until the motor was up to operating temp.

                Not sure if the newer ones are that way with emissions but....

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                • #9
                  I usually let the truck run for a while at the beginning of shift for checkoffs anyways, which of course it will cool down after a bit but you are getting fluids pushing around. As for before a call, as driver, start the truck while everyone is gearing up. When not at the station the whole time you usually have some time for members to show up and after sitting a while the trucks usually need to get the air built back up for breaks and horns. Also their is usually a push to get out the door from the brass, so the sooner you get it started the better off you are. They will run better once they get a little warmed up but a little bit of time is better than none and will still give you most of the lubrication benefits.

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                  • #10
                    I don't think it damages them, especially if you're using modern multi-viscosity oils meeting the appropriate API service grade.

                    I used to drive a 2000 ALF Eagle with a Detroit 60 in it. It behaved poorly when it was cold. During this time, we were running out of a temporary station while the permanent one was under construction next door. The heat in the temporary bay struggled to keep the temp above 40ยบ. The performance of this truck when it was cold left a lot to be desired. It was slow to accelerate, but on the flip side, the cold made the automatic transmission retarder really jerk you when it engaged. This engine would take a really long time to reach operating temperature. Running 1 call wouldn't do it, you needed about two miles of highway to get the thermostat to open.

                    I now drive a 07' Pierce Arrow-XT with a Detroit 60. Same engine, different accessories. This engine has a variable geometry turbo and an cooled EGR valve which heats up the coolant very quick. There is almost no difference between this truck performance when it's cold and when it's warm.
                    The American people will never knowingly adopt Socialism. But under the name of 'liberalism' they will adopt every fragment of the Socialist program, until one day America will be a Socialist nation, without knowing how it happened. --Norman Mattoon Thomas, 6 time presidential candidate for the Socialist Party of America

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                    • #11
                      I will usually start the engine and let it idle for the few secs that it takes for the guys to get their bunkers on. With that said i have noticed that on our 98 [email protected]*#($ saber. When you cut the ignition switch on. You will hear a series of beeps. the speedometer will go all the way up and come back down. Then a solid long beep wll sound until the engine is started. If you start the truck prior to it going through that series of events then the truck is not as quick on the pick-up. My first thought is it is some kind of computer boot up thing. I dont know though.

                      Also I always will let it idle for a bit when we get back before i shut the truck down.

                      At the start of the shift it will usually get warmed up when cheking the pump and ladder. It does seem to run better when it is warmed up and up to operating temp versus when it is cool. After that morning idle time it usually stays warm the rest of the shift with calls, and other stuff.

                      Comment


                      • #12
                        Eh....nevermind....
                        Last edited by BoxAlarm187; 01-12-2011, 08:50 AM.
                        Career Fire Captain
                        Volunteer Chief Officer


                        Never taking for granted that I'm privileged enough to have the greatest job in the world!

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                        • #13
                          And here I thought we were talking about emergency vehicles.

                          You get into it and go.

                          If you can start it and put on your bunker gear, all the better. I question wearing bunker boots while driving but hey, thats me.

                          And Jerkpuke? You are a mutt.

                          Comment


                          • #14
                            Engine Idle

                            Gas engines: With todays modern fuel injection and multi-viscosity oils there is no need to idle more than about 30 secs to get the oil circulating. Don't have a choke on the carburator to warm up to get it to run right and the single viscosity oils that had to warm up to circulate right on a cold day.

                            Diesel Engines: Same issue, with high pressure fuel injection and multiviscosity oils, not as important to idle for long periods. Although the demise of the two cycle engine is a step backwards. The old Detroit 8V-71's and 8V-92's could be started and pedal to the metal in 30 seconds. The big four cycle engines are real tempermental until they get warmed up a bit.

                            More important to idle about two to four minutes after a return from a run to cool the turbo-charger bearings down.

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                            • #15
                              TXGP: The 60 series Detroits run the low pressure fuel through the head, and then split the fuel between the injector pump and with the excess being routed back to the tank through a relief valve thus maintaining the input pressure to the injector pump. The computer is being fed information from the exhaust gas sensor (Oxygen) and it makes adjustments to the fuel, air ratio by comparing the turbo pressure, waste gate position and O2 sensor info along with throttle position sensor. The newer computer programs are doing a much better job of controlling these ratios on a cold engine.
                              RFD21C: The computer check program will hold the engine in the "Limp" mode if you don't wait for it to go through the complete check. Also, some engines will fo into "Limp" if you over rev, like dropping a gear too early. Some will even lock you into that gear until you pull off the road, shot the engine down, wait 30 to 60 seconds, and then go through your normal start-up procedure. Limp can also be activated by low coolant. This sometimes happens if the custom apparatus didn't have a large enough coolant reservoir installed. Running hard warms up these engines, pushes coolant out the overflow, and then after leaving it in the station and things cool off, the coolant level is below the sensor switch.

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