Is it too cold to start my tractor?

[Daronspicher]

I was reading this thread and noticed a post or two where the owner was under the impression that the glow plugs warm up the cylinder.

That's not how I thought glow plugs worked so I thought I would ask around about it.

I was under the impression, diesel cold start is a matter of the compressed fuel/air mix not combusting at the top of stroke because it's too cold and doesn't ignite.

When you run the glow plugs, you heat up a little bitty (think nail head) at the top of the cylinder, hot enough it glows red (glow plug).

Then, when the compression stroke happens, the mix is compressed against that hot thing at the top and combusts. The first hot actual combustion leads to the next one being successful and the engine is started.

Is that how it works, or are we really "heating the cylinders"? I would think actual heat in the cylinder to be minimal.

That would make the idea of bumping the starter to reposition the crank not that effectual.

Anyone know how it really goes? I'm open to learning something.

Thanks.

 

[oldpilgrim]

it would seem that since cycling the plugs several times, works better than just letting the plugs go thru their heat cycle once, then they're heating the combustion chamber.

 

[jonnmero]

I was reading this thread and noticed a post or two where the owner was under the impression that the glow plugs warm up the cylinder.

That's not how I thought glow plugs worked so I thought I would ask around about it.

I was under the impression, diesel cold start is a matter of the compressed fuel/air mix not combusting at the top of stroke because it's too cold and doesn't ignite.

When you run the glow plugs, you heat up a little bitty (think nail head) at the top of the cylinder, hot enough it glows red (glow plug).

Then, when the compression stroke happens, the mix is compressed against that hot thing at the top and combusts. The first hot actual combustion leads to the next one being successful and the engine is started.

Is that how it works, or are we really "heating the cylinders"? I would think actual heat in the cylinder to be minimal.

That would make the idea of bumping the starter to reposition the crank not that effectual.

Anyone know how it really goes? I'm open to learning something.

Thanks.

Basically you are right. There is also a system where a plug in the head is heated (hot bulb engine), as with the famous Lanz Bulldog: Starting a Lanz Bulldog (in German) They were reversed by rocking the engine: Rocking the Lanz
Single cylinder motor, 10 or so HP motor, 6 - 700 ci. Had a similar one in a boat once, and they are fascinating. Flywheel weighed in at nearly 600 pounds for a 10 HP motor.

 

[vtsnowedin]

Hard saying not knowing. But if your glow plugs get "red hot"that is 1400 degrees F. So it would at least melt the frost off the top of a piston that was close to top dead center. maybe not the whole surface of the piston top but the area that comes close to the glow plug. That maybe all it needs to make the start easier and getting all the pistons defrosted maybe all it takes.

 

[Mike Tipton]

My diesel tractor is stored under an awning. Hard to start when cold so I got an engine block heater and run an extention cord to supply power. Not expensive and helps tractor start.

I have read all the comments till now and I read some great ideas. For people who live in a lot more cold areas than I do, I like your methods for warming your tractor..

 

[BarnieTrk]

Somebody suggested to run the PTO while the engine is warming. I've been doing that and the hydraulics warm up much faster.

Just a quick reminder note about running the PTO to warm the hydraulics...... First off, yes, it does help warm the hydraulics.
BUT - don't forget to disengage the PTO before shutting down your tractor.

Reason being, if you don't disengage the PTO, when you go to start your tractor the next time, the tractor engine won't start because there is likely a safety device that prevents the engine from starting BECAUSE THE PTO IS ENGAGED........ After looking in my manual and reading that the starting process is disabled when the PTO in engaged, I then disengaged my PTO and,, lo & behold,,,the tractor started right up! :thumbsup:

BarnieTrk :cool2:

 

[Mike Tipton]

Thanks for passing on this information--good to know.

 

[buickanddeere]

Combustion chamber glow plugs are placed in "pre-combustion" chambers outside of the swept volume area. The engine starts because diesel fuel is sprayed on a hot electrical element and bursts into flame . Instead of being ignited from hot air .

 

[oldpilgrim]

Combustion chamber glow plugs are placed in "pre-combustion" chambers outside of the swept volume area. The engine starts because diesel fuel is sprayed on a hot electrical element and bursts into flame . Instead of being ignited from hot air .

that makes sense except for why cycling the plugs multiple times works better than just letting them glow once.

 

[vtsnowedin]

Dose anyone have a picture of a head from a diesel engine that has glow plugs looking at it from the pistons point of view. IE looking up from the block? We should see; intake and exhaust valves plus a fuel injector port or nozzle and the glow plug end with whatever pre combustion chamber is around it. I cant imagine this pre combustion chamber being very large as that would take away from the compression ratio.