Page 1 of 4 1234 LastLast
Results 1 to 10 of 37
  1. #1
    Gold Member
    Join Date
    May 2002
    Posts
    277
    Location
    Pgh, PA
    Tractor
    Cub Cadet 7360SS, MF1100 & JDx585

    Default bad for glow plugs?

    Is it bad for the glow plugs (or anything else) to start the tractor while they are still "lit"? My Cub Cadet manual says to wait til the glow plug light goes out before turning the engine over. I however am not that patient, as they are still on after a minute or so...

    My old IH656 has the glow plug button, so you could decide when was long enough to run the glow plugs and turn them out before hitting the starter.

    Thanks.

    - G

  2. #2
    Super Star Member RoyJackson's Avatar
    Join Date
    Nov 2001
    Posts
    18,864
    Location
    Bethel, Vermont
    Tractor
    John Deere 4400 MFWD, Deere 855D UTV, Z920A Zero Turn Mower and assorted implements

    Default Re: bad for glow plugs?

    I'd be a little concerned about starting when the glow plugs are hot. I suppose it could be possible to damage a piston (burn a hole in it)...but I am guessing there.
    Has your glow plugs always stayed on that long? Normally 20-30 seconds is about it. Does the glow plug light go off when you crank the engine?
    My Deere is set up so you turn the key counterclockwise to turn on the glow plugs...hold the key in that position and wait 10-20 seconds...then turn the key clockwise to crank the engine. With that system, the plugs are turned off when cranking.
    What does your manual say about starting with the glow plugs?

  3. #3
    Gold Member
    Join Date
    May 2002
    Posts
    277
    Location
    Pgh, PA
    Tractor
    Cub Cadet 7360SS, MF1100 & JDx585

    Default Re: bad for glow plugs?

    I just got it last Sat, so I don't have anything to compare it to. Yes, the light goes out when you crank it, but the glow plug key position is clockwise from stop and clockwise from there is the starter position. I'll have to look at the manual again, but I don't recall any warnings about starting it before the light goes out.

    Thanks.

  4. #4
    Platinum Member
    Join Date
    Jan 2002
    Posts
    856
    Location
    South West Pa/Greene county
    Tractor
    Long/Landtrac360DTC

    Default Re: bad for glow plugs?

    The way my Long works is when you first turn the key on the glow plugs come on for a short time, then go off. When you turn the key to the start posistion, they come back on while you are cranking the engine, then go back off when you let the key go back to the run posistion. In really cold weather you can make them stay on longer by turning the PTO switch on (which prevents the starter from engaging) and then turning the key to the start posistion and holding it there for a little while. When the tractor is already warmed up, like when I have shut it off for a few minutes, I just turn the key on and start it, the glow plugs go out when you let the key go back to the run posistion.

    I don't think the glow plugs actually make contact with the piston, or that they would be hot enough to burn a hole in the piston.

  5. #5
    Silver Member
    Join Date
    Jan 2002
    Posts
    115
    Location
    Upstate NY/north of Syracuse
    Tractor
    Kubota L4610 HST

    Default Re: bad for glow plugs?

    Actually, in theory, it is harder on the engine to start it before the light goes off. The glow plugs (at least in the systems with which I'm familiar) heat for a fixed time (that is, they heat up until the light goes off)--so if you hit the key early, they glow plugs are colder rather than hotter.

    The intent of the plugs is to provide a hot enough environment that the diesel will fire when compressed. If it is too cold, they barely fire, or won't at all.

    In warm weather, it probably makes little difference. As it gets colder, I'd recommend waiting just to make it easier on the engine.

    Just my $.02,

    -Chris

  6. #6
    Super Star Member RoyJackson's Avatar
    Join Date
    Nov 2001
    Posts
    18,864
    Location
    Bethel, Vermont
    Tractor
    John Deere 4400 MFWD, Deere 855D UTV, Z920A Zero Turn Mower and assorted implements

    Default Re: bad for glow plugs?

    "I don't think the glow plugs actually make contact with the piston, or that they would be hot enough to burn a hole in the piston."

    The glow plugs themselves aren't hot enough to burn a hole in a piston. However, the plugs in conjunction with normal combustion, may create a localized hot spot. Especially high compression engines such as diesels.
    Normally, diesel pistons are thicker at the crown then those for gasoline engines and should take more pressures.
    However, there is a reason the glow plugs cycle before starting, and don't continue to operate after the engine does start.
    As I mentioned, I am making an assumption here...

    Still kind of curious why they stay on as long as they do...although I've seen older Mercedes benz diesel glow plugs stay on for more then 30 seconds.

    Let's see what the manual says. By the way, is this a new or used tractor?

  7. #7

    Join Date
    May 2002
    Posts
    1,064
    Tractor
    Yanmar 1500D

    Default Re: bad for glow plugs?

    Yes, it is bad for the glow plugs. The plug has an element that heats when voltage is passed through it. The purpose of that is to warm the combustion chamber. The length of time it is on has been determined by the manufacturer so that the chamber temperature rises to a specific temperature range to aid in ignition of the cold air/fuel mixture.

    If the engine starts to run while the glow plug is still heating, the heat of ignition is added to the heat being produced by voltage flow. This MIGHT cause premature failure of the heating element in the glow plug.

    It will not cause any damage to the engine other than possible excess wear on the starter becasue the chamber temperatire was too law causing more cranking revolutions before starting.

    Let the glow plugs do what they were designed to do for the length of time they were designed to do it. That's why you bought the tractor to begin with wansn't it? To let the equipment do the work?

  8. #8
    Veteran Member
    Join Date
    Feb 2002
    Posts
    1,055
    Location
    WVa
    Tractor
    Kubota L3710, Ford 5600, Case MB4/94, Kubota B6200

    Default Re: bad for glow plugs?

    I doubt that the glow plugs will damage the pistons.Fuel burns evenly in a gas engine. In a diesel it explodes. Although it's an automotive application the glow plug controller in Navistar diesels in Ford trucks cycles the plugs on and off after starting to lower emissions immediately after the start.

    Glow plugs draw enough current to dim the lights on a truck. I suspect the reason for not energizing the plugs during starting is the combined heavy current draws especially in the winter. Both at the same time may make it difficult for the starter to spin fast enough to start the engine.

  9. #9
    Platinum Member
    Join Date
    Mar 2002
    Posts
    718
    Location
    Maine
    Tractor
    Cub Cadet 7360SS & Craftsman GT3000 23 HP w/50

    Default Re: bad for glow plugs?

    G, I have the same tractor... if your glow plug light is really on for that long, you should have the dealer look for a bad plug. At this time of year, the light goes out in 10 seconds on my 7360. During the cold winter it might stay on 20-40 seconds. As has already been said, the issue is not damage, but making sure there is enough heat to ignite the fuel on initial compression. And that should not be a problem at this time of year..... except maybe yesterday when it was only 35 degrees. [img]/w3tcompact/icons/smile.gif[/img]

  10. #10
    Elite Member
    Join Date
    Apr 2000
    Posts
    3,676
    Location
    Grayson County, TX
    Tractor
    Kubota B2710

    Default Re: bad for glow plugs?

    On my kubota B 2710, the glow plug is turned on just by turning the ignition key clockwise. Instructions are to hold in the intermediate position for 2 to 3 seconds then turn the rest of the way to start it. The light goes off immediately when you move on to the crank position.

Page 1 of 4 1234 LastLast

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  
© 2014 TractorByNet.com. TractorByNet is a registered trademark of IMC Digital Universe, Inc. Other trademarks on this page are the property of their respective owners.