Strange JD 4 cyl Diesel Cold Start.

[buickanddeere]

Not enough pre-heat time and possibly waxing fuel.

 

[Industrial Toys]

Just curious. At what point does a traditional (injector pump) diesel fire its injectors? Before TDC, at or after? And is there any variation in this timing, such as vaccume advance in a gasser?

 

[Quebecguy]

I built a simple timer/motor cam driven switch box. It has two positions. Ten minutes on, twenty off, or the other way around.

Cycling a block heater on for ten minutes and then off for twenty minutes sounds like a total waste of electricity to me. The heat built up in the block after only ten minutes will dissipate totally after twenty minutes of below zero temperatures.

 

[doxford jim]

I would be inclined to leave the block/engine heater on for a decent amount of time - a couple of hours. This will allow time for heat to build up properly in the engine. Is your tractor parked outside overnight or through the day ?

 

[jenkinsph]

Cycling a block heater on for ten minutes and then off for twenty minutes sounds like a total waste of electricity to me. The heat built up in the block after only ten minutes will dissipate totally after twenty minutes of below zero temperatures.

It would also seem to increase condensation in the crankcase with all these repeated heating and cooling cycles.

 

[skyhook]

When it's that cold, I would say a "minimum" of 3 hours block heater time.

 

[Agvg]

Just curious. At what point does a traditional (injector pump) diesel fire its injectors? Before TDC, at or after? And is there any variation in this timing, such as vaccume advance in a gasser?

Its injected before TDC, some pumps has a system to alter the timing for easy cold start, my VW Transporter Pickup has a maual solution for that purpose. If you pull it on on a warm engine it starts to run very hard.

 

[Jerry/MT]

It had been around minus 22 C over night. I plugged in the tractor (JD 6200) for around an hour and a half late in the afternoon. It was around minus 10 C all day.

The engine turned over and made a lot of smoke but never fired. It did start to kind of run on it's own with just a little help from the starter motor. It would run for a few seconds after releasing the starter motor.

I have started this tractor under similar cold conditions but you always heard the crack of the detonation. Not this time, although something was clearly causing it to sort of run.

I killed the battery, put a charger on for a few minutes and tried again. Same thing. But then, all of a sudden, she came to life and started.

(Sorry, I have to compose these things a bit at a time, as text just disappears on occassion.)

Anyway, I am just curious what was happening as I have never had a diesel crank so quickly as if half running. Is this possibly harmfull? I did not want to overheat the starter, but then it wasn't under much load.

Cold temperatures are tough on diesel engines starting. At least three things are working against you: it's a compression ignition engine and so the peak temperature in the cylinder is lower, and the cylinder walls are cold, so initiating combustion is made more difficult; starting power requirements go up because of higher oil viscosity at lower ambient temperatures; battery output goes down because of lower ambient temperatures. Further as the tractors get hours on them, the compression drops and the peak temperatures are even lower. So in cold temperatures without starting aids ( and sometimes with starting aids) they clank, and clatter, and shake, etc.


That's why they make cold starting assist devices. A block heater can help warm the cylinders reducing oil viscosity and warming cylinder walls. This reduces starter battery draw. Thermostart systems warm the air charge. Battery warmers maximize battery output, glow plugs help initiate combustion and warm the air charge, etc.
You live in Ontario and I can't imagine your tractor not having at least a block heater because you regularly get cold ambient temperatures in the winter. If you have one plug it in for 3 hrs before you want to use the tractor. If you don't have one they are relatively cheap and are usually easy to install so consider doing so.

 

[Jerry/MT]

Just curious. At what point does a traditional (injector pump) diesel fire its injectors? Before TDC, at or after? And is there any variation in this timing, such as vaccume advance in a gasser?

always before TDC

 

[Industrial Toys]

As far as timing, so it would seem that cranking might be different when fuel is present as to when it is not.

As far as the intermittent block heating goes, I think I am still on to something. A block heater must be high enough in temperature to allow heating in a reasonably short period of time. But beyond that, it is way overkill for starting purposes. My approach ( I believe) is a good compromise. Another good approach would have been to provide a thermostat, some distance from the heater, but this would have been more complicated.

Also, I believe, that there is enough mass in the engine block that cycling the heater would not be much different than reducing heater wattage.

It just seems to me, that people always have a knee jerk aversion to anything that is not the "norm". Must do everything like all the other sheeple.