1568 Questions

John M · Aug 12, 2014

Long story short, friend has a 1568 that was willed to him. Tractor hasnt been run since maybe 97 or 98. Last I remember it running was in the early 90s. He had considered selling it to me, but I just dont have the funds. Anyways, he finally got it started yesterday. Everything seems to still work like it should. My question, am I right when I say at idle or no load, it just runs on 4 of the 8 cylinders, and can you tell when its running on all 4, as in it sounds like its skipping, or is there another problem. It does run and sound fine with that big old harrow behind, but at idle it sounds like its skipping.

MikeJM · Aug 12, 2014

You are correct, the orginal pump setups on those engines would run on 4 cylinders at idle and low load conditions. It should sound odd and one manifold should be cooler than the other. It was supposed to save fuel, don't know if it did or didn't, I can count 2 or 3 that I know of in our area, weren't a real popular tractor around us.

Bob M · Aug 12, 2014

Same engine (DV550) was used in some IH trucks of the same era. And yes, they were set up to idle on 4 cylinders - supposedly to save fuel.

A neighbor had one in his grain truck. At idle it made the cab shake like a wet dog. But otherwise it was a decent running truck.

Dieseltech · Aug 12, 2014

Yes, that engine came out to start and idle on four cylinders, and fire on all at about 60% load. It can be made to start and idle on all eight but the pump will need four barrels/plungers, and delivery valves.

Owen Aaland · Aug 12, 2014

The engine runs on four cylinders, two on each side, until the engine load reaches 20%. As the load increases the other four cylinders start to fire until at 80% all cylinders are getting equal amounts of fuel. Above 80% load it runs evenly on all eight. Which four cylinders that are working all the times depends on when the tractor was made. Part way through production they changed which four cylinders ran all the time. Both systems fires the two center cylinders on one side and the end cylinders on the other.

The main reason IH gave for running on only four cylinders at idle and light load was to insure that those cylinders that were working would have enough load on them to keep them warm enough to clear up smoke from a cold cylinder.

Starting with ether assist is standard procedure at temperatures below 70° F. Push the ether assist button after getting the engine to crank over and continue to feed ether after it starts until if no longer pushes out white smoke.

1568 Questions

John M

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MikeJM

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Bob M

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Dieseltech

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Owen Aaland

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