Question for diesel mechanics re glowpugs

[..]

On my school bus I have to wait for the engine warm light to go out before cranking the engine.

Why don't you have to do that in a modern diesel car or pick up? You just turn the key and crank 'er up.

[R J]

Easiest way to explain it is:

1957 Chevy to a 2008 Chevy engine.
Carb vs Fuel injection.   Both Diesel engines have fuel injection, one just needs more heat to fire.

At the shop we call them the red hot's in your style.....
Cause that is all your glow plug is doing, is getting the hole hot so the fuel will burn and get the piston going up and down.......

OR:

The newer ones have later technologies in them.

[sandy]

Britboy: If you recall, I've been driving Scottsdale kids for 5 years now. We have Internationals (01-05's) that require the "Wait to Start" key switch. Our newer busses are Thomas built and don't have the glow plug system for cold startup.

[Daniel Meyer]

A lot of the newer diesels have a preheater in the intake manifold instead of glow plugs. It heats the air-charge going into the cylinder and takes much less to no time to "preheat".

Also, do NOT use ether or starting fluid on one of these engines (Cummins in Dodge trucks are like this).

[roboto65]

Still wonder why some use heater coils heck my boat has 2 stroke Detroits 16 cyl and uhhhh no heaters here LOL gets pretty cold in that engine room LOL

[Pete]

As stated earlier, today most use air intake heaters.

One that was not mentioned was some use ether or another flammable gas inject during start up only to get it going.

[Daniel Meyer]

Still wonder why some use heater coils heck my boat has 2 stroke Detroits 16 cyl and uhhhh no heaters here LOL gets pretty cold in that engine room LOL

Typically not much below freezing though (just guessing?). Boats don't punch through that solid water all that well...

My Dodge would start on the first turnover down to about -10...below that you had to wait for the intake heaters to kick in.

[..]

I believe my question has been answered in full.

[Madmike]

There are two basic styles of cylinder preheat, glow plugs and intake heaters. Some use a combination of both.  Preheat systems can be either manually or automatically controlled.  

Manual systems such as those found on older equipment usually have a combination preheat switch that you manually hold to that position to energise the heaters and then turn to another position to crank the engine.   Some operators will go back to the preheat position once the engine starts and give it some more heat if the engine has cold cylinders that are missing and use the preheat until it is firing on all holes.

Engines equipped with auto systems will usually crank regardless of whether the glow plugs are on or not.  Most of these systems will continue to cycle the glow plugs or intake heaters after the engine is running dependent on sensor status.

Intake heaters are not a new thing.  I have an early 60's vintage Cockshutt tractor that has a Waukesha Diesel in it that is equipped with an intake heater.  

None of the 2-cycle Detroits regardless of displacement or cylinder size were equipped with glow plugs and I have never seen one fitted with an Intake heater but they may exist somewhere.  They utilise other means of heating the engine so that it will have a warm air charge to help starting.  Methods that I have seen are electrical, diesel or fuel gas heaters that heat jacket water.  Some are fittted with ether injection systems to help with starting.

Some fellows use a hook up that allows them to connect their pickup to the cooling system on the piece of equipment with quick couplers and heat the equipment engine that way.  Most have quit doing this as they were cracking pickup blocks because of teh thermal shock caused by the cold water.

If it gets real nippley sometimes all you can do is pull a parachute over the piece of equipment and use a Herman Nelson to thaw it out and get it started.

http://www.herman-nelson.com/

[Patrick]

The boys covered it pretty well.. I've got a cold weather diesel story.. We got a 'no-start' call one cold-ass wintry day years ago.. I show up at the truck, an 8V-71 Detroit, only to find a former employee[which I fired months previous] had beat me to the call and was stealing the service call.. The mouth on the truck was open and a big-ass bottle of ether was bolted to the firewall [common in those days] and it could be smelled.. This clown is in the process of firing up a torch [with a rose-bud tip] and is waving it along the engine block/base to warm the engine.. I back off about in time with the explosion which blew him into the middle of the street, blew the tire off the wheel and broke his arm in 3 places.. So much for his stealing that service call and I think you can tell why I previously fired him..

[Skinhead]

You guys missed one other method I have seen which is along the line of the Herman-Nelson and rosebud method.  When I was in Korea back in '76 they had a curfew from midnight until 0400.  At about 0500, the truck driver or his helper would go out and start a small fire under the engine of the truck, then go have breakfast.  Come back an hour later and fire that sucker up.  They were probably thrilled when they got glow plug technology.

[Patrick]

Start a fire under the vehicle ??!! Funny you mention that.. This isn't about a diesel,but, its about a fire.. Way back when in our college days I built a SBC 327 for a friend that we stuck in his Jeepster.. Between 13/1 pistons, roller cam, hilborn injection and COLD weather that critter just wouldn't start.. So Tommy 'the torque wrench' went to lighting fire's under his monster to get it started.. He is the same fella that used a can of ether to blow down our dormitory door,walls and windows which set everything in the next 3 rooms on fire just to get some fellas that decided to raid our floor and had locked themselves in our room..

[Sludge]

Out in the stix, I have actually built small fires under diesel engines in sub zero weather to warm them as well.  It worked.  Now, it took a while and you had to keep the flame SMALL so as not to risk burning wiring or air lines etc.. but it worked when nothing else would.  I only had to do it once to 3 trucks many years ago.

[Pete]

Years ago when farmers were using Butane in there tractors, it was not unusual on very cold days to pass a tractor with a fire under the Butane tank!!!!!  Seems that butane tanks had insufficient pressure at low temps to vaporize. Often wondered how many exploded before they learned the error of there ways. Pete.