Blow by

notjustair · Oct 21, 2016

What is considered acceptable blowby on a 360 diesel?

Growing up I remember all of our IH tractors smoking from the draft tube. That was when they were new with few hours. My 886 has 3600 hours on it. I usually add some oil at 50 hours and change it every 100. It smokes a little and slobbers some oil out the draft tube into the loader frame which I don't recall ours doing but our loaders didn't have an under belly cross beam so I don't know that I would have seen it. It's a loader tractor but ran the moco for hay this year which worked it really hard. Today I ran it all day pulling the buggy with 12000 pounds of fertilizer through the soft fields so she worked pretty good today, too. I don't think it's slobbering due to lack of work!

I'm perfectly happy with the way the engine performs. I was just curious.

fastfarmall · Oct 21, 2016

If u don't have to add oil the first 50 hours, i really doubt if it's wore out,if you took it apart, i am sure you could see the crosshatch marks in the sleeves yet.If it has a little blow bye, sounds normal, i agree it looks bad. Too bad you cant reburn that blow bye.

Dieseltech · Oct 22, 2016

Having been around all diesel engine makes in over forty years of pump repair I've noticed the most blowby fumes from the AC 301 engine. I have an AC 7000 on the front mount snowblower that looks like it could use a muffler on the fumes it puts out. It is getting a bit tired though, but still puts out rated power.

David G · Oct 22, 2016

Blow by is pretty normal on a Diesel, the compression is really high, which makes it worse.

I would not worry if you can go 50 hours without adding oil

pete 23 · Oct 22, 2016

There are service limit specs for blowby. You measure it with a water mamometer that every IH dealer was supplied with. They will fool you as one that looks quite normal may have a whole lot of crankcase pressure and another that looks bad may fall in specs. I used to test and compare quite a few engines. Fact is, when I went to John Deere dealer, I made my own tester, later bought one on liquidation sale of IH dealer. When I used it a few times at Deere, they though enough of it that they purchased one after I retired. It is just another tool in diagnosing engine condition. Easy test also.

Jim Becker · Oct 22, 2016

What range are the normal pressure readings? What range of abnormal pressures have you seen? How do you run the engine to take the reading? idle? fast idle? under a dyno load?

pete 23 · Oct 22, 2016

I don't remember the exact specs, have to find them in the book but about 4.5 inch's of water is high limit I think. You test at high idle , warmed up, no load and you have to have the proper orfice size for engine being tested. Again, that is in book, not my head. You cannot completely plug breather when testing. You use a tube with orfice in it and hook manometer parallel to that.

Jim Becker · Oct 22, 2016

Thanks. The general range and procedure is all I was looking for.

tomstractorsandtoys · Oct 23, 2016

Knew of a farmer who did that. His 656 diesel was so worn out that he tied a gallon jug on the blowby tube and at the end of the day poured the oil back into the engine.Tractor ran for years that way. It was his big tractor and did all tillage and even ran a forage harvester. He never changed oil just added. Tom

Blow by

notjustair

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fastfarmall

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Dieseltech

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David G

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pete 23

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Jim Becker

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pete 23

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Jim Becker

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tomstractorsandtoys

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