Oil & Fuel "compression" start for a diesel

[simonmeridew]

Just a theoretical question: is there any reason a diesel engine can't be started using a compression start-- turning on the key, putting the gearshift in 4th gear and popping the clutch? Of course a HST won't do it.
simonmeridew

 

[638]

It would help if it was moving at the time you 'popped' the clutch.

 

[number two]

Glow plugs,if applicable,would help it start easier on a push start.

 

[BotaBigot]

Theoretically, it'll start.

Practically, it depends on tractor weight (tire slippage), gear ratio (engine spin speed), grade, and engine temperature. Depending on temperature, distance could become a factor...

 

[aczlan]

it can be done for a diesel, at one time my dad ran diesel VW rabbits and Jettas, after working on them instead of wearing out a battery to get them primed (the only fuel pump was in the injection pump) we would push it out of the shop and to the "big hill" and he would take it down, put it in gear and pop the clutch... they generally started by the time they got to the bottom.
now that might get exiting on a tractor... but YMMV.

Aaron Z

 

[rScotty]

It works fine on diesel tractors. The trick is to put it in the highest gear you have and to pop the clutch while the tractor is moving slowly. Too fast and the tires will just skid.
rScotty

 

[rbargeron]

My L3600's starter solenoid stopped working earlier this summer - we could get it rolling by hand in the driveway and pop the clutch in high gear - lit up right away.

 

[simonmeridew]

thanks for the replies!
I'm most interested in making sure it's ok for the tractor--oil pressure issues on startup, injector pressures etc.
simonmeridew

 

[KubotaSam]

thanks for the replies!
I'm most interested in making sure it's ok for the tractor--oil pressure issues on startup, injector pressures etc.
simonmeridew

Turning the engine is the same if from an electric motor, a pony (gas engine) or rolling down a hill. You need to rotate the diesel engine to get it to run. I remember rolling a 3020 John Deere down a hill and popping the clutch when I was a kid to see if it would start. It did start very easily. However it was warmed up from running about 1 hour so the lack of using glow plugs was not an issue. It does not make any difference how you get the diesel to turn. You just need to get it to turn to start. If you had a totally dead battery (or no battery) one of the new diesels with a an electric fuel shut off would not start because of no fuel delivery.

 

[Ob1kubota]

My L3600's starter solenoid stopped working earlier this summer - we could get it rolling by hand in the driveway and pop the clutch in high gear - lit up right away.

Ain't Auto ignition great Dick!!!!!!! I've done the same thing with my L2600 dead batteries to light her off.

 

[Wombat125]

There is a rumor that some of my Unimog friends got a mind to try to pull start a 125 hp Unimog. I suspect malted refreshments were involved. The process goes as such:

Block front tires.
Jack up one rear tire.
Place Mog in high gear.
Turn key to 'run' position.
Wrap tow strap around rear tire, recoil style.
Put several grown men on the other end of the strap.
PULL!!!

Rumor has it that this worked.

 

[rbargeron]

There is a rumor that some of my Unimog friends got a mind to try to pull start a 125 hp Unimog. I suspect malted refreshments were involved. The process goes as such:

Block front tires.
Jack up one rear tire.
Place Mog in high gear.
Turn key to 'run' position.
Wrap tow strap around rear tire, recoil style.
Put several grown men on the other end of the strap.
PULL!!!

Rumor has it that this worked.

This is off-topic because it wasn't a diesel - but I had a wood splitter for my old Ford 8n (whose battery was always dead) so one winter I left it near the wood pile with one rear wheel lifted off the ground. In high gear it started easily with some choke and a pull on the tire rib.

Back on topic, the fuel cut-off solenoid only activates for a few seconds after shutting down with the key. After it de-activates, fuel is again injected whenever the engine turns. (assuming the hand fuel-stop is not pulled out)