Elevation = rough start up..?

[Snobdds]

Diesels do not throttle the air like a gas engine. There should be no noticeable difference between the two altitudes.

You have to run more RPM at altitude for the same power...

 

[SPYDERLK]

Anybody here know anything about diesels at altitude, and with and w/o turbo speak up please.

 

[the old grind]

Just like how a turbo gives more power without more fuel, or how diesels make so much more smoke at altitude for lack of air.

(not to get technical, but I was just warming up... )

 

[SPYDERLK]

The air cleaner on all my diesels keep the butterflies out.

 

[puzlrock]

When it gets cold in Montana I plug in the tank heater, starts and runs great.

 

[DutchInNZ]

Ummmm, pretty sure that's not how math works to get a percentage.

"Air" is also a dangerous assumption. "Air" doesn't cause ignition it's the O2 in the air.

For partial pressure O2 at sea level it's ~20.9 at ~14.7PSI, going to 3,200' it's just less than ~2 PSI lost (about 1.8), so (1.8PSI/14.7PSI)*20.9 PPO2=~2.55PPO2.

So loosing ~2.55PPO2 from sea level that's ~2.55PPO2/20.9PPO2= 12.2% loss of O2 per volume.

Carry on.

etpm is right; that is the diesel physics. A diesel gets to its ignition temperature by adiabatic compression of air to bring it to a high temperature, after which fuel is injected that then burns with the oxygen. Less air in = lower compression = lower temperature, so no ignition or bad irregular burning, which makes the typical diesel knocking sound until the engine is warm.

 

[DutchInNZ]

And it is all dependent on the burning of fuel. Air volume per revolution is the same except in turbo equipped engines where boost has developed.

Less air pressure in equals less volume of air in equals less pressure at TDP equals lower adiabatic ignition temperature equals bad starting when cold.

My Zetor, as all of the old series, does not have glow plugs but a very high compression ratio that makes for problem-less starting.

 

[SPYDERLK]

Filters changed at 48 engine hours in Oregon. Problem started immediately upon arrival in Idaho. Temps in June at start up were in 50˙ range, yesterday 28˙....

It is to be expected with the thinner air and consequently lower compression heat. There will also be a slight?probably unnoticeable loss of power even when warmed because each lungful is a little less air than at sea level. At full load there is more likely to be an excess fuel condition - exceeding the amt burnable in the slightly air starved condition.

A turbo equipped engine will see the same startup issue, but then will pretty quickly come up to a wholly undiminished power capability as the cylinders warm and exhaust heat and boost develops.

 

[JasperFrank]

Interesting reading glow plug times of more than 5 seconds. 15 Seconds? Sat with my stop watch and timed out 15 seconds. I have never held the glow plugs on for more than 5 seconds. 1200 feet, very small 1 liter engine and garage rarely gets below freezing. Wonder if excessive use of glow plugs is in anyway harmful to the engine? What are the recommended glow plug times for larger tractors?

 

[SPYDERLK]

Interesting reading glow plug times of more than 5 seconds. 15 Seconds? Sat with my stop watch and timed out 15 seconds. I have never held the glow plugs on for more than 5 seconds. 1200 feet, very small 1 liter engine and garage rarely gets below freezing. Wonder if excessive use of glow plugs is in anyway harmful to the engine? What are the recommended glow plug times for larger tractors?

Only harmful to the glowplug.