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

[Sawyer Rob]

There were glow plugs in indirect injection diesels before EPA.

Some common rail direct injection now use the injectors for the pump.

Yes there were... BUT, tractors like the smaller Kubota's were direct injection then, and would start without glow plugs...

Then along comes the EPA, not liking a little start up smoke ect... SO all the smaller tractors went indirect injection/prechambers and needed glow plugs. AND everything that comes along with them.

I liked those older Kubota diesels much better than todays.

SR

 

[Egon]

Yes there were... BUT, tractors like the smaller Kubota's were direct injection then, and would start without glow plugs...

Then along comes the EPA, not liking a little start up smoke ect... SO all the smaller tractors went indirect injection/prechambers and needed glow plugs. AND everything that comes along with them.

I liked those older Kubota diesels much better than todays.

SR

My 1995 Kubota had indirect injection with a glow plug.

Direct injection did not really get going for small engines till the injection systems got better. Most new engines, common rail, are direct injection.

 

[Egon]

Thanks. That link in post 16 showed me what I wanted to see. So the glow plug in a indirect injection motor is presumably in the pre-injection chamber. And, can one have a heater element in the intake manifold in both styles of engines?

Check out this site:
[video]https://en.m.wikipedia.org/wiki/Diesel_engine[/video]

Inlet air can be heated externally for both types.

 

[sd455dan]

My 1995 Kubota had indirect injection with a glow plug.

Direct injection did not really get going for small engines till the injection systems got better. Most new engines, common rail, are direct injection.

I guess it depends on what is considered new or small- for direct injection

Ford used it from 1965 forward on most of their 3 cylinder and up tractor diesels
with Simms and CAV direct injection systems. Stanadyne also was used by some from 1950's on.

 

[777777]

It may well be that LD1 is hitting the nail on the head. Spoke to the guy again and the hour meter is non functional so true hours unknown.

I was concerned that it may be a worn out engine because of the glow plug use.

Thanks

 

[Texasmark]

I need to study this further, because clearly I don't understand. I thought a diesel engine compressed the air til it was red hot at which time fuel was injected into the top of the cylinder. That sounds like direct injection.

True and in the winter you can burn up your starter while waiting for the internal air temp to get hot enough to light off the fuel....or you can use some assistance. Opinion: Most hard to start older tractors are lacking in compression which is necessary to compress the incoming air to the temperature required to explode the diesel mist....or that and clogged injectors that are slobbering rather than misting the fuel.

 

[Texasmark]

My 1995 Kubota had indirect injection with a glow plug.

Direct injection did not really get going for small engines till the injection systems got better. Most new engines, common rail, are direct injection.

Having both, a 65 with direct and 24 with indirect, I read that indirect, (like the swirl chamber indirect on my 24) is cheaper to manufacture and requires less precision and maintenance than direct.

Just because you have the preheat light illuminated doesn't mean you have to wait out the timer. On my 24 on summer days, I just roll it over to start and it lights right up without waiting out the glow plugs. It does belch a little smoke for a couple of seconds if it's cooler and I don't wait out the timer.

 

[DieselBound]

LD1 posted great info.

I'd state that the tractor's issue could very well be a bad injection pump. Hard warm/hot starts are typical symptoms of injection pumps needing a rebuild (or replaced).

I've got glow plugs in everything diesel I own. All works just as it should. There are manually operated GP systems (only lit when specifically switched by the operator) and GP systems with electronic operation. For the later there is usually some sort of relay that may (newer stuff does it) continue to run a circuit timer and hold the GPs on for a while AFTER your GP light is turned off; this is done to keep the engine running more smoothly until the cylinder temps heat up sufficiently.

Oh! My VW TDIs (ALH engines - rotary injection pumps) -Direct Injection- DO have GPs. Compression ratio on these is 19.5:1.

If an engine is warm GPs are NOT necessary: I believe that my VWs don't operate unless 40 degrees Fahrenheit or less.

GPs aren't even needed to start a cold engine. BLOCK HEATER! (my old IDI truck when I got it wouldn't start for crap- bad GPs and GP relay; I plugged in the block heater and it would fire right off, which verified my suspicion that the GPs were crapped out [and, yes, one can verify GPs via simple resistance testing]).

Back to the OP's question... IF it were starting hard cold AND hot then it might be air incursion from several different places. IF it's only starting hard when warm then I'd suspect the injection pump.

 

[KYErik]

Cranking speed is a factor . Drag from a hydraulic pump usually can not be helped unless there is some manner of "destroker".
Any machine with a manual transmission will crank faster if the clutch is pushed to the floor.
Not unusual to see a tractor while being cranked wasting power raising a leaked down three point hitch.
Sometimes it's just a matter of enough voltage and current to a starter that is in good condition . Often somebody will cheap out on one battery instead of two. Cheapo Walmart light weight battery cables . Connections to chassis are often suspect , best solution is to run a new HD ground cable to a starter bolt . Generic starters are not that expensive, sometimes a size or two larger is a simple bolt on.
Start off by measuring the voltage between the starter's main stud and the starters cast body. I'll bet you a beer it's way under 10-1/2 volts.

This is an excellent point. Awhile back, I installed a rebuilt starter on my old worn diesel backhoe (60's vintage). The cranking speed is so much faster that it now starts well down to 30 degrees F without ether. Before the rebuilt starter, starting it below 40 degrees was a gamble even with ether. The cranking speeds sounds about twice as fast as it used to.