Blow by

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deere755

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central Illinois near Lake Shelbyville
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Case 2090 Massey Ferguson 4233 John Deere 4700
This is gonna sound bad but explain to me what blow by is and what is acceptable. I noticed on my 4233 Massey that there is a little oil coming out of the tube that hangs down under neath the engine. It is not dripping but if you touch it you will get oil on your fingers. I notice when you pull it hard you will see some smoke coming from the tube. It doesn't use any oil and has been running fine. I just changed the oil after a 104 hours and the oil seemed gritty. I didn't see any metal flakes in it. I am gonna run it 20 hours and drain the oil and change the filter again and see if it seems gritty again. I am gonna be using it to pull some wagons this fall so it won't be on too heavy of a load for a little while. It has me a little concerned but I guess if I have to over haul it I will. Thats the problem with buying used I guess you never know what you are bringing home until you use it awhile. The biggest lemon of a car I ever owned was one My Mom and Dad traded off. They never had any problems with it and I bought it and it was nothing but problems from the 1st day I brought it home.
 
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deere755

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947
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central Illinois near Lake Shelbyville
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Case 2090 Massey Ferguson 4233 John Deere 4700
Another thing I might add is the tractor never smokes out the exhaust except for black smoke when you open it up or give it a real hard pull. It has used no oil in the 1st 104 hours of use. I am using agco 15w40 like my Massey dealer recommended.
 
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gengine

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Blow by is when your cylinders move upward, compressing the fuel/air mixture, some of that compression is leaking (blowing) by into your crankcase. Basically you are losing compression, most likely from worn piston rings. It doesn't sound like you have enough to worry about yet. I've put aorund 500 hours on an old Case that you can see the smoke, and I get a drip of oil about every 5-7 seconds. It's been that way for about 3 years. If you do regular maintenance, you should be fine. I would almost go as far to say that amount you have would be normal for a used tractor.
 
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ultrarunner

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Cat D3, Deere 110 TLB, Kubota BX23 and L3800 and RTV900 with restored 1948 Deere M, 1949 Farmall Cub, 1953 Ford Jubliee and 1957 Ford 740 Row Crop, Craftsman Mower, Deere 350C Dozer 50 assorted vehicles from 1905 to 2006
With antique engines blow-by as describe is either worn rings or worn valve guides... either can pressurize the crankcase forcing vapor out...

Sometimes... rings can get better with use if there is a build up of carbon... worn valve guides will not get better.

The bright side is the engine could still provide years of dependable service before requiring a tear down...
 
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banjodunn

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G'day from what you have described then i would say that it is normal and nothing at all to worry about, even a fresh rebuild will have oil on the breather end. Put her to work and dont worry



Jon
 
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5030

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G'day from what you have described then i would say that it is normal and nothing at all to worry about, even a fresh rebuild will have oil on the breather end. Put her to work and dont worry



Jon

Every engine has some blowby. You don't see it on your car because the PCV Valve routes it back into the intake manifold and it burns in the cylinders.

Some blowby is a direct result of the changing internal mass inside the engine displacing the volume of air inside the crankcase.

Older tractors are emissions exempt. I suspect the newer Tier 3-4 tractors reroute crankcase vapors like a car does....
 
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Snaker

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That breather tube is a crankcase vent to accomodate the changing air volume in the crankcase as the pistons go up and down. You're also seeing condensation and oil vapors coming out. Until you can start counting the drops, no worries.
 
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deere755

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central Illinois near Lake Shelbyville
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Case 2090 Massey Ferguson 4233 John Deere 4700
Thanks for all the replies. What do you all think about the grit I found in the oil? Is this something to be worried about? I ran the old oil thru a paint strainer today found no metal but just sludge looking dirt. Feels like sand when you touch it.
 
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ultrarunner

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Cat D3, Deere 110 TLB, Kubota BX23 and L3800 and RTV900 with restored 1948 Deere M, 1949 Farmall Cub, 1953 Ford Jubliee and 1957 Ford 740 Row Crop, Craftsman Mower, Deere 350C Dozer 50 assorted vehicles from 1905 to 2006
Sounds like carbon deposits...

Might want to change the oil more frequently the next time or two...

Had an old Ford Tractor that I dropped the pan and scraped out a lot of gunk... also did my best to clean the bottom end of the crankcase... the engine started running better and the oil stayed cleaner after the first two changes...
 
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Ken

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The grit in the oil may be the former owner used non detergent oil. When you put in new oil it acted like a soap to wash the engine inside.
My father had a G.P.John Deere that had so much blow by he piped the vent pipe to air cleaner. said at least it stopped his coming in from plowing and being covered with oil.
I also purchased a used Ford pick-up took valve cover off the head to adjust valves and sludge was so thick the valve springs was covered.
Your oil filter should catch the particles from gettin into the engine itself. only if to much in pan could block the oil pump intake filter. causing a lowering of oil pressure. then problems.
Next oil change. if still gritty open the oil filter and check how much has been filtered out of the oil.
ken
 
 
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