How long do you glow and crank for?

[Volfandt]

So you are saying that glow plugs can wear out...

I don't know if you're addressing anyone in particular but since it is an open forum I'll throw an answer out
Yes, they'll burn out and also they'll pull more current.
Basic electronics, the hotter the element gets, the higher it's resistance. The higher it's resistance the more current it requires to overcome the greater voltage drop.
They are akin to an oven element and/or in principle to a hot water heater element.

Theres been some postings of the electrical connectors burning open at the glow plugs, no doubt from extended duration applications and a few of the glow plugs being bad. Admittedly the bad glowplugs were mainly on older machines.

Modern glowplugs, like injectors are better than the previous versions but none are impervious to failure.

 

[teg]

Thanks... and yes, when I was addressing "you", I meant all of TBN


.

 

[errandboy]

I park my 80's vintage Kubota L225 outside under a tarp. I installed a lower radiator hose heater last winter. Now I only have to glow the plugs for about 45 seconds to get it to start. I live in Vermont.

Some day I will get a new Kubota and then participate in the debate over whether 6 seconds is needless wear and tear on the glow plugs.

 

[Retlaw 66]

....80's vintage Kubota L225 ...... about 45 seconds to get it to start.

I have a L-275. 30 to 60 seconds is the norm.
It's apart for a rebuild now, so it will be interesting to see if it starts better after it's back together.

 

[texasjohn]

I just twist the key and it starts immediately, and has for 3 years... someday it may actually get below freezing and I'll let it glow for a second or two...

 

[SPYDERLK]

Yes, they'll burn out and also they'll pull more current.
Basic electronics, the hotter the element gets, the higher it's resistance. The higher it's resistance [[[the more current it requires to overcome the greater voltage drop.]]]
They are akin to an oven element and/or in principle to a hot water heater element.

Theres been some postings of the electrical connectors burning open at the glow plugs, no doubt from extended duration applications and a few of the glow plugs being bad. Admittedly the bad glowplugs were mainly on older machines.

Modern glowplugs, like injectors are better than the previous versions but none are impervious to failure.

[[[ That part is a stumble.]]] The higher resistance causes the current to drop. Nevertheless, as you say, the hot glowplug wears by expansion/contraction and oxidation aggravated by its extreme heat. Some glowplugs have a timer circuit that cycles them on and off to prevent the operator from keeping them energized and overheating them.
larry

 

[TalonDancer]

I just twist the key and it starts immediately, and has for 3 years... someday it may actually get below freezing and I'll let it glow for a second or two...

Careful texasjohn! All those folks with snow blowers just might decide to hot rod them and point them at central Texas

And the CFO has steadfastly refused to approve my AFE for a cab

Talon Dancer

 

[Volfandt]

[[[ That part is a stumble.]]]

Stumble eh?
More like a fall and behind bust'n
You are correct, ohms law indicates that with a constant voltage applied to an increasing resistance, the current will decrease. A=V/O. My bad.
From alittle more research,
Most glow plugs will read a constant resistance of about 1 ohm and they maintain this over it's heat range. Over time they can either increase in resistance and produce less heat, decrease in resistance and require more current, burn open and/or short out.
On a BX, there is no timer, temp sensor or any other automatic control. The glow plugs will glow for as long as the key is held in the glow position, that is until the plugs, fuses, wireing or switch burns open or the battery goes dead.
But, in any case, they'll drain the battery down if'n they don't fry 1st

 

[teg]

Ok, Flipside... I have a new tractor, easy to start without using the glow plug, should I NOT use the glow plug if it the outside temp is above 40 (or pick a good temp, which above it, no longer needs the glow plug). Does NOT using the glow plug do any problems???

Inquiring minds want to know (actually, there are a lot of new people to tractors). I know this is beating a dead horse... but I saw it move a little. Could a tractor become a "glow plug junkie" and need it more and more?

 

[SPYDERLK]

From alittle more research,
Most glow plugs will read a constant resistance of about 1 ohm and they maintain this over it's heat range. Over time they can either increase in resistance and produce less heat, decrease in resistance and require more current, burn open and/or short out.
[[[On a BX, there is no timer, temp sensor or any other automatic control.]]] The glow plugs will glow for as long as the key is held in the glow position, that is until the plugs, fuses, wireing or switch burns open or the battery goes dead.
But, in any case, they'll drain the battery down if'n they don't fry 1st

[[[ Hmm. Interesting.]]] On my BX1500 I have been assuming the clicks I hear at about 3s intervals when using the glows, are a timer turning them on and off. Ill have to check.

larry​