Cold weather start, with glow plugs and block heater. Why does my tractor not start at minus 20 C?

[lpakiz]

Egan, I'm not sure if your definition of a block heater is the same as mine, but what I know as a block heater has NO thermostat (nor any other method of interrupting the current) in it. It is a straight, direct circuit as soon as it's plugged in, and keeps on heating until unplugged. Same with lower hose heaters.
Tank heaters, on the other hand, sometimes have a thermostat within them.
And while we are on the subject of cold starting, the first place to look to make it easier to start is to reduce the friction of the piston rings against the cylinder wall! Yes, it helps some to heat the crankshaft, oil pan, transmission, etc. but the biggest draw on your starter is thick oil on the cylinder walls, which a block heater reduces.
Watt for watt, put the heat on the cylinder walls first, with a block heater.

 

[ruffdog]

Back when I worked on medium duty trucks, about the only heater we would install were the Kat's tank heaters that had pumps. They would go in the heater hose and would circulate heat through the block and heater core. One customer had a fleet of propane delivery trucks that demanded a bit more effort to get them running when very cold.

 

[Erik M]

My tractor also has a de-stroking capability for the hydraulic pump which will reduce the load on the crank when starting. A handy feature if starting cold in the field. Not sure if that is standard on most.

 

[Egon]

Egan, I'm not sure if your definition of a block heater is the same as mine, but what I know as a block heater has NO thermostat (nor any other method of interrupting the current) in it. It is a straight, direct circuit as soon as it's plugged in, and keeps on heating until unplugged. Same with lower hose heaters.
Tank heaters, on the other hand, sometimes have a thermostat within them.
And while we are on the subject of cold starting, the first place to look to make it easier to start is to reduce the friction of the piston rings against the cylinder wall! Yes, it helps some to heat the crankshaft, oil pan, transmission, etc. but the biggest draw on your starter is thick oil on the cylinder walls, which a block heater reduces.
Watt for watt, put the heat on the cylinder walls first, with a block heater.

The block heaters work the same as a self regulating heat tape.

 

[LouNY]

The block heaters work the same as a self regulating heat tape.

All the block heaters that I have installed are just pure resistive heating elements,
no control whats so ever. Easiest way to ruin one is run it with no water surrounding it.
Less then 5 minutes to element burnout.

 

[Dmacleo]

The block heaters work the same as a self regulating heat tape.

My Massey brand block heater on gc2400 don't.
There is no thermostatic shut off. And where my cooling system is relatively small I cannot just leave plugged in.

 

[jayhawk238]

I use both a both a block heater and a battery blanket. My tractor will start at the temps your stating every time with no problems. Battery blankets don't cost that much and they work.

 

[CADplans]

My tractor also has a de-stroking capability for the hydraulic pump which will reduce the load on the crank when starting. A handy feature if starting cold in the field. Not sure if that is standard on most.

My 584IH has some sort of fuel limiting on the injection pump that aids cold starting,,
Instead of moving the fuel shut-off to the run position, the lever is only moved 25% of the way to run,,

Crank the engine,, and you get a black, thick, choking exhaust coming out of the engine,,
30 seconds of that,, and the engine is warm enough to run in the normal fuel shut-off lever position.
Maybe the fuel injection timing is changed?? I do not know,,,

 

[Mattsy Fergy]

Direct injection diesel has no pre combustion chamber. Indirect injection engines can make use of a glow plug. Intake manifold heating is different than an in combustion cylinder glow plug.

For our purposes lets ignore pre-combustion chamber engines, which is old technology and not used much these days, and as I stated, intake manifold heaters are often referred to as glowplugs, even though that's not the proper term.

From Wikipedia; https://en.wikipedia.org/wiki/Glowplug

A glowplug (alternatively spelled as glow plug or glow-plug) is a heating device used to aid in starting diesel engines. In cold weather, high-speed diesel engines can be difficult to start because the mass of the cylinder block and cylinder head absorb the heat of compression, preventing ignition. Pre-chambered engines use small glowplugs inside the pre-chambers.
Direct-injected engines have these glowplugs in the combustion chamber.

The glowplug is a pencil-shaped piece of metal with a heating element at the tip. This heating element, when electrified, heats due to its electrical resistance and begins to emit light in the visible spectrum, hence the term glowplug. The visual effect is similar to the heating element in a toaster. The fuel injector spray pattern then impinges directly upon the hot tip of the glow plug during the injection of fuel at top dead center. This ignites the fuel even when the engine is insufficiently hot for normal operation, which reduces the cranking time required to start the engine.

I suspect this is more likely why motors turn over easier with a block heater, since the coolant surrounds and warms the cylinders. Again, there is no coolant near the oil, the oil must be warmed another way.

And while we are on the subject of cold starting, the first place to look to make it easier to start is to reduce the friction of the piston rings against the cylinder wall! Yes, it helps some to heat the crankshaft, oil pan, transmission, etc. but the biggest draw on your starter is thick oil on the cylinder walls, which a block heater reduces.
Watt for watt, put the heat on the cylinder walls first, with a block heater.

The only block heater thermostat I was able to find was on some GM and Ford vehicles, which would only permit operation below a certain temp, not to shut it off at a certain temp. Can you direct us to that other type?

This is an interesting conversation and I'd like to see research done on whether a block heater warms the oil. I will be surprised, but admit it if I'm wrong. 2 similar motors 1 with block heater 1 without, with temp sensors in multiple places, oil pan, rods and crank, pistons, and inside cylinders, just to see how much heat transfers, and where it goes, from the coolant with a block heater. The only way a block heater would heat the oil is if you're running an oil cooler, and I think it would take an immense amount of heat to make a difference there.

 

[North to Alaska]

I may also change the oil to a 10-40 instead of a 15-40. The tractor is in a barn, but it is not heated.

I strongly recommend changing your oil to at least a 5w40 if not 0w40. Your battery will turn it over much easier and the engine will thank you it.

 

[Egon]

All the block heaters that I have installed are just pure resistive heating elements,
no control whats so ever. Easiest way to ruin one is run it with no water surrounding it.
Less then 5 minutes to element burnout.

They look like that but they are temperature regulated by the way the element is made. The element has to properly oriented when installing for it to work.

 

[lpakiz]

I still doubt that.
Procure a block heater and immerse it in a small container of water (a soup can, small cooking pan) and plug it in. Pretty sure it will boil the water, and boil it hard, until it evaporates enough water to expose some part of the element, then the element will burn out.

 

[Egon]

I still doubt that.
Procure a block heater and immerse it in a small container of water (a soup can, small cooking pan) and plug it in. Pretty sure it will boil the water, and boil it hard, until it evaporates enough water to expose some part of the element, then the element will burn out.

I still doubt that.
Procure a block heater and immerse it in a small container of water (a soup can, small cooking pan) and plug it in. Pretty sure it will boil the water, and boil it hard, until it evaporates enough water to expose some part of the element, then the element will burn out.

Give that a try and let us know what happened. Make sure the heater is immersed in the proper orientation.

There are many misconceptions on how a block heater works including non transfer of heat to the oil in the oil tank.

 

[lpakiz]

I tried to edit to add another paragraph and lost the whole thing!
I wanted to add that the element position has more to do with hot water rising (element loop should not face down) and especially, the element cannot touch any metal engine parts. That's why there are dozens of element shapes-to clear internal engine parts.
I still stand by the "full on or full off" part of my previous post. If there is added resistance when the water gets hot, a clamp-on ammeter on one of the supply legs would indicate less amps.

And if that were the case, an electric water heater wouldn't need a thermostat-just design the element to kick out at 130 degrees. They don't. When the thermostat fails "ON", the water gets so hot the pressure relief valve starts to emit steam.
Now, the block heater will never get so hot as to boil, because the heater is probably 800 watts or so for a big one. (I was shop foreman for a trucking company and we used 1500 watt heaters in our 855 CID Cummins. In Wisconsin).
The element in a very well insulated water heater tank is 4500 watts, if I remember correctly. Not much heat escapes, so the water heater boils if not shut off by the thermostat or the increasing resistance of a heated element.
The blocks on our tractors loose heat much faster, so fast that it's doubtful if the exterior of the block gets warmer than 100 degrees, more than a few inches from the location of the heater. But even 80 degrees around the cylinders equates to a warm summer day, when my tractor starts very well without heat.

 

[LouNY]

Heaters by Kat's
No place in their literature will you find any information on self regulating block heaters.
You can find thermo cubes which are temperature switches, you can find timers, but no mention of regulated.
Block heaters are on/off.

 

[lpakiz]

I do believe there are some models of TANK heaters that incorporate an internal thermostatic switch which will turn the element ON or OFF, but it doesn't regulate (vary) the current flow.

 

[Egon]

Well, tell me how a self regulating heat tape works.

 

[Mattsy Fergy]

 

[CalG]

Just to add a couple of deviations to the "Cold starting" issue.

Firstly

The Kubota B7200 has a compression release that is sometimes described as an aid to cold starting.
Presumably the benefit is getting the pistons all moving at a good clip prior to a need to do the real work of compressing air and making heat.
My own experience hasn't drawn conclusions on this idea. The engine is a hard starter when cold without the glow plugs, starts right up with glow, and the battery condition is key . Either way! ;-)

Second

Injected fuel is cold, with any vaporizing fuel chilling the intake charge even more. Countering the heat produced via compression.

Cranking the cold engine while holding the fuel cut off closed may offer some "accumulated" chamber wall heating that could benefit the combustion once fuel is allowed to be injected.

desperate times take desperate measures ;-)

 

[Mattsy Fergy]

With a block heater, if the temp gets above the motors thermostat setting, it will open and allow the hotter water to go to the radiator, pulling cooler water into the block thus cooling it. So the coolant will never go above whatever the thermostat setting is.
This is not likely to happen since the mass of cast iron will bleed heat off faster than the block heater can heat it.