Just a little clarification as I see this pop up from time to time.....
Ether has been around a long time, and has been helping diesel engines start as long as they've been around. It is fine to use, IN MODERATION, and if used properly. The two biggest reasons it has such a bad name are due to improper use. First reason is people spray half a can down the intake and then try to start the engine. This is bad for a few reasons. One, it washes the oil off the cylinder wall, and over time, can lead to scoring. Then when the engine starts, it races and runs away (with no oil on the cylinder walls for a moment) due to the large amount of ether in the intake being fed into the cylinders uncontrolled. This can lead to thrown rods, bent valves, etc. in addidion to the above mentioned scoring. The other main cause for problems is that people usually don't disable the glow plug/intake heater system. The ether hits the glow plugs and goes ka-boom right away. If the piston is on the up-stroke, this can result in a bent rod, etc. If the engine has a intake heater, you could have a small explosion/fire in the intake also. Either way, it's a bad day.
And the whole thing about engines getting "addicted" ether is a myth. What happens is it is used improperly long enough that the cylinder walls get scored and it starts to lose compression. It can also affect the valve seats too. A compression ignition engine that is low on compression = no ignition, so it continues needing help starting.
The proper way to use ether is:
1) Disable any cold start assist the engine may have, i.e. glow plugs, intake heater, etc.
2) WHILE CRANKING the engine over, spray a QUICK whiff of ether in the intake, before the air cleaner.
3) If it doesn't start right away, STOP because you have bigger problems.
Back in the day, most big trucks had a ether injection system built right into them. Most had a lockout so the ether would only be injected while the starter was engaged. They were pretty reliable, safe, and many times the only option available. It's hard to start an engine without glowplugs when it's really cold....
After more than 8 or 10 hours without running in 30 degree weather my truck usually wont start without a quick shot of ether. Is it bad that i always have full oil pressure by the time it starts? lol, i need a place to work on this thing in case the starter burns up