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Michael Halsall

Gas Start diesel general questions

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Hi guys,

reading through the posts here and on the Construction Equipment board I realise that REDPOWER is the only place to go on the Internet to ask about GAS START diesel engines.

I know my way around petrol (gasoline) engines, but not diesels.

I am learning as much as I can about IH diesel engines, especially the rather unique Gas Start diesel engines.

Question time-

If the air temperature was high enough could you start the engine in the"diesel setting" without having to use the "gasoline setting" ?

How did you know when the engine was ready to switch to diesel fuel ? Engine idle speed? Temperature gauge reading?

I have heard that correct shut-down procedure was vital for engine life.

I assume that means "idling down" the engine before turn it off.

Finally when the engine was in the diesel mode did the magneto and spark-plugs keep firing?

Is are there any businesses, anywhere in the world, that specialize in repairing this type of engine?

Regards from Michael Halsall Australia

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Question time-

If the air temperature was high enough could you start the engine in the"diesel setting" without having to use the "gasoline setting" ?

-Yes and some have, starter technology wasn't the best yet and if made a regular practice of it could cost you some grief. The extra compression was hard on starters.

How did you know when the engine was ready to switch to diesel fuel ? Engine idle speed? Temperature gauge reading?

-Don't know what the textbook answer would be but I usually go by sound or sense, I switch over way before a temp guage would ever move, I guess idle speed would be closer or smoothness.

I have heard that correct shut-down procedure was vital for engine life.

I assume that means "idling down" the engine before turn it off.

-I believe that to possibly be the most single significant factor, proper cooldown period after some work is essential, some switch back to gas others just kill it on diesel, reasons for both.

Finally when the engine was in the diesel mode did the magneto and spark-plugs keep firing?

-No the air switch in the gas manifold is part of the mag wiring circuit so it only functions during the gas cycle position. No air-no spark.

Is are there any businesses, anywhere in the world, that specialize in repairing this type of engine?

-There are still a few but I doubt it would be anyones main bread and butter.

http://www.jobbersinc.com/ih.htm

Regards from Michael Halsall Australia

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Hi guys,

reading through the posts here and on the Construction Equipment board I realise that REDPOWER is the only place to go on the Internet to ask about GAS START diesel engines.

I know my way around petrol (gasoline) engines, but not diesels.

I am learning as much as I can about IH diesel engines, especially the rather unique Gas Start diesel engines.

Question time-

If the air temperature was high enough could you start the engine in the"diesel setting" without having to use the "gasoline setting" ?

How did you know when the engine was ready to switch to diesel fuel ? Engine idle speed? Temperature gauge reading?

I have heard that correct shut-down procedure was vital for engine life.

I assume that means "idling down" the engine before turn it off.

Finally when the engine was in the diesel mode did the magneto and spark-plugs keep firing?

Is are there any businesses, anywhere in the world, that specialize in repairing this type of engine?

Regards from Michael Halsall Australia

yes you could start them on diesel after there warm.

i think the best way to shut them off was in the diesel mode,as this meant the gas valves where against there seats and could not warp from the heat.

there is a rotary switch in the intake manifold that controls the spark.when you move the lever to engage the diesel operation the switch rotates and shuts the spark off.

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I always heard you switched them back to gas to cool them down and then switched back to diesel to close the valves after it was shut down. I guess I'm going to find out since I just acquired one!! :blink:

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R99, once you start flippin the lever on a regular basis, it hits you that just flipping it back to diesel with the throttle down is the smooth way to go. No mistakes that way. Killing it on gas means you have to remember to switch after the motor has stopped, and for some reason my brain wants to skip that step. Danged stupid brain...

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No personal experience on this but have talked with neighbor who farmed with Super MD for years. Most interesting thing to me is Extra valve. Said spark plug was in small chamber in head, much like diesel pre chamber, with a valve that closed to separate from the cylinder when on diesel. These were built when Cat had starting engines and air motor starters were used on many larger gas and diesel engines because electric starters and batteries were not powerful enough.

He does not remember for sure but thinks the Magneto always turned but spark was off when on Diesel. Same for shutting off; pretty sure could shut off diesel to kill or switch to gas start position. My guess is that moving to gas with engine just off load would get pre-ignition. Letting cool down and changing to gas would shut off with gas in manifold and cylinders so more ready to start if going to be shut off only a few minutes.

Anyone know some of this for sure please let us know.

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The statements are all basically correct except for one mention. There is no shut off switch in gas. It either runs the carb bowl dry or you flip to diesel with the throttle down (off). The early books said to turn off the gas and let it run out but I don't really care for this. It isn't necessary. Technically you can't switch to gas with throttle open, but the mechanical linkage that blocks this isn't very good.

Note: They will sometimes run rough during change to diesel due to high compression with some residual gas present. They will often not like to switch to gas because the carb float needle is shut off while in diesel and the carb has evaporated dry over time. It takes several seconds for the bowl to fill again when switched back to gas mode.

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What is the purpose of a gas start Diesle engine?

Does it have anything to do with cold starts?

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What is the purpose of a gas start Diesle engine?

Does it have anything to do with cold starts?

I read somewhere the main reason is it allows you to hand crank it to start.

Phil

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What is the purpose of a gas start Diesle engine?

Does it have anything to do with cold starts?

I read somewhere the main reason is it allows you to hand crank it to start.

Phil

That along with it was IH answer to the pony motor and air start. The pony was a little gas engine that would spin fast and crank over the larger engine to start it. Later the 6 volt and early starters could crank them over while they could not start the high compression of a diesel like they do now.

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The statements are all basically correct except for one mention. There is no shut off switch in gas. It either runs the carb bowl dry or you flip to diesel with the throttle down (off). The early books said to turn off the gas and let it run out but I don't really care for this. It isn't necessary. Technically you can't switch to gas with throttle open, but the mechanical linkage that blocks this isn't very good.

Note: They will sometimes run rough during change to diesel due to high compression with some residual gas present. They will often not like to switch to gas because the carb float needle is shut off while in diesel and the carb has evaporated dry over time. It takes several seconds for the bowl to fill again when switched back to gas mode.

There is a kill switch for gas on the 91 series.

Jim P

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The statements are all basically correct except for one mention. There is no shut off switch in gas. It either runs the carb bowl dry or you flip to diesel with the throttle down (off). The early books said to turn off the gas and let it run out but I don't really care for this. It isn't necessary. Technically you can't switch to gas with throttle open, but the mechanical linkage that blocks this isn't very good.

Note: They will sometimes run rough during change to diesel due to high compression with some residual gas present. They will often not like to switch to gas because the carb float needle is shut off while in diesel and the carb has evaporated dry over time. It takes several seconds for the bowl to fill again when switched back to gas mode.

There is a kill switch for gas on the 91 series.

Jim P

Well it's about friggin time they got around to it. :lol:

Hmm. I gotta check my 18A documentation stuff. It's the newest machine I have but the wiring has been changed around so I don't know what was original. Maybe it had a switch for the ignition too? I would still prefer flipping back to diesel.

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:lol::lol::lol::lol::)

The statements are all basically correct except for one mention. There is no shut off switch in gas. It either runs the carb bowl dry or you flip to diesel with the throttle down (off). The early books said to turn off the gas and let it run out but I don't really care for this. It isn't necessary. Technically you can't switch to gas with throttle open, but the mechanical linkage that blocks this isn't very good.

Note: They will sometimes run rough during change to diesel due to high compression with some residual gas present. They will often not like to switch to gas because the carb float needle is shut off while in diesel and the carb has evaporated dry over time. It takes several seconds for the bowl to fill again when switched back to gas mode.

There is a kill switch for gas on the 91 series.

Jim P

Well it's about friggin time they got around to it. :lol:

Hmm. I gotta check my 18A documentation stuff. It's the newest machine I have but the wiring has been changed around so I don't know what was original. Maybe it had a switch for the ignition too? I would still prefer flipping back to diesel.

:lol:

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