Blow By problem. Where to start. Please help !!!

[ford351c]

I have a 1220 with alot of crankcase pressure. It has blown out gasket, thus making an oil leak. I can feel a good bit of pressure coming out of vent tube. I dont want to take this to a dealer. (I have rebuilt many gas engines and transmissions) Im looking for insite as where to start on a diesel. I have a compression gauge for a diesel. Is there a way to determine if its worn rings or a valve not closing before I tear into this? tkx

 

[KennyV]

If you are getting that much blow by it almost has to be either rings or a hole in a piston. If it was a valve problem only, you would not be getting pressure in your crankcase. since you have worked gas engines you should have no problems with diesel. KennyV

 

[v8dave]

I agree with KennyV, it is most likely rings. With the much higher compression ratio of a Diesel, you can get a lot of blow-by with bad rings.

Only guidance I'd offer about working on a diesel over a gas engine is to be exceptionally clean with the fuel injection pump, lines and injectors. The pump and injectors run clearances below a thousandth of an inch (some in the 1/10 of a thousandth range). Because of the close tolerances, if you think the fuel system should be rebuilt, consider taking the pump and injectors to a fuel injection shop for checking/overhaul.

 

[Egon]

Pulling the head may be a place to start as you will have to do it anyway if there is that much blowby.

Egon

 

[JimR]

You could have any of the following problems with your motor, stuck rings, worn rings, hole in a piston which would be a dead giveaway or scored cylinder walls. If I had that much blowby, I would tear it down and take a look inside to see what is going on. A compession test will let you know which cylinder or cylinders are giving you the problem. You can take it from there as to rebuilding it or replacing it, whichever is the cheapest way out for you.

 

[RickB]

Start with a New Holland service manual. 42112020 is the part number for the complete service manual for 1120, 1215, and 1220 tractors. Should be under $70 plus shipping. See your dealer or call 1-800-635-4913 with a credit card in your hand. Don't plan on buying engine parts in the aftermarket; they aren't out there.

 

[gugy]

You don't state if the head gasket is blown (leaking oil).If so start by removing the head.You may be surprized and find that the head gasket is blown between an oil galley/passage which will give you lots of blow-by.If you're lucky all you have to do is replace the head gasket
Good luck

 

[ford351c]

Thanks for all the input. I did a compression test today. This verifys something is bad. Anybody know what values I should get?

Cyl kg/cm^2 PSI

1 8 110
2 24 340
3 12 200

 

[RickB]

The spec for a 1920 is fresh in my head. 425 plus or minus 50 PSI with no more than 50 PSI variation between cylinders. 1220 will be similar, any diesel I know of is over 350PSI. Better order up that manual.

 

[JimR]

</font><font color="blue" class="small">( Thanks for all the input. I did a compression test today. This verifys something is bad. Anybody know what values I should get?

Cyl kg/cm^2 PSI

1 8 110
2 24 340
3 12 200
)</font>

Looks like you need to pull the head to see what is going on. If the head gasket is good the next step would be to pull the motor and do a tear down. #1 looks real bad. You may even have a small hole in the piston on that one.