Does a high compression diesel engine need glow plugs be used to start

[777777]

Hi,

Maybe a silly question but I don't know the answer.

Was looking at an older tractor and was told that the compression in the engine was really good and high so it needed the glow plugs used to aid starting regardless of the outside temp.

So, cold or hot, would have to use the glow plugs to start the tractor or it would be difficult to start.

I always thought that low compression made a diesel difficult to start so was a little perplexed.

Any thoughts ?

Thanks

 

[Egon]

If the engine is hot the glow plugs may not be needed.

Be aware that indirect injection will use a glow plug but direct injection will not.

 

[murphy1244]

My 67 Massey 135 does not have glow plugs nor a key.

 

[777777]

This is a mid to mid 60`s International Harvester BD-154 so don`t think direct injection would be an issue.

 

[Industrial Toys]

I was just messing with a really sweet Isuzu 3LB1 (22:1 compression) for yet another backup generator.

On a warm day, that thing will not start without glow plugs. Even if it has been running (for short periods) within the hour.

Give it less then ten seconds of glow plugs and it will start just about as fast as you can turn the starter on and off. This is much the same as the Little Kubota engine in my Steiner tractor.

On the other hand, our JD 6200 never gets glowed unless it is below freezing. It just jumps to life without.

 

[motownbrowne]

My New Holland will start in warmer temps without glow plugs, but it'd prefer that I use them. During the three cooler seasons, they cease to be optional.

 

[buickanddeere]

I was just messing with a really sweet Isuzu 3LB1 (22:1 compression) for yet another backup generator.

On a warm day, that thing will not start without glow plugs. Even if it has been running (for short periods) within the hour.

Give it less then ten seconds of glow plugs and it will start just about as fast as you can turn the starter on and off. This is much the same as the Little Kubota engine in my Steiner tractor.

On the other hand, our JD 6200 never gets glowed unless it is below freezing. It just jumps to life without.

6200 does not have glow plugs in the combustion chamber . Many people mix up the different heater designs .

 

[Industrial Toys]

Thanks for the tip. That makes sense, but doesn't explain why these little diesels need their plugs.

 

[Sawyer Rob]

The compression ratio of a diesel does NOT determine whether you have/need glow plugs for starting.

SR

 

[Industrial Toys]

I would have thought for sure it would. More compression = more heat, I would have assumed.