yanmar blowby

[jastone502]

ok, I have read lots of posts about blowby. I just got this tractor and have not done anything to it. No compression tests or anything. I am knowleged in engines but a little confused here. I have massive blowby coming out crank vent tube. After a bit oil starts dripping pretty heavy. It seems to have great compression, starts immediately even on cool mornings never have to use compression release.. Has lots of power, smokes black/little blue under load but doesnt skip stutter , runs smooth and strong. what do ya think?

 

[jastone502]

woops forgot to mention , it is a 1401D, 3T72-SB engine with 850 on hour meter and works, it could be 2850 but who knows.

 

[winston1]

Welcome to the forum. :welcome: Not saying you need to do anything but massive blow by is coming by the piston rings. Yanmar 155D Crankcase Vent - YouTube

 

[California]

runs smooth and strong. what do ya think?

Have you changed the oil yet? Possibly that's oil diluted with diesel.

If it were mine I would keep it in service so long as it performs well. Maybe run the heaviest recommended single-weight diesel oil.

If you are going to show it in a parade or something then overhaul it.

 

[normde2001]

hopefully you did not post twice without checking the oil. Change the oil and add a cleaner, (Power Service?). . , possibly stuck rings.

 

[jastone502]

Thanks for advice. No I have not changed the oil yet and it looks pretty crappy. Will do that and post back results.

 

[jastone502]

I agree with keeping it in service , if it doesn’t get better I may have to rearrange exhaust, it is kind of in your face when working.

 

[rScotty]

I agree with keeping it in service , if it doesn’t get better I may have to rearrange exhaust, it is kind of in your face when working.

On some models the exhaust pipe can be mounted to the exhaust manifold in either vertical or horizontal. Don't be afraid to change it. I changed my YM165D from horizontal to vertical and then inserted three feet of 1.25" standard wall EMT galvanized steel tubing between the manifold and exhaust tip. Split the EMT for a few inches with a hacksaw and then clamped it with a U bolt to the manifold stubout - and ran that way for 30 years. Very nice to have the exhaust going up and out well above my head. I angled the top tip to shoot off to the side to avoid the diesel slobber from raining straight down. If you do this, you'll see what I mean....

Yes, I knocked the pipe askew more than once on low branches. But the whole upright pipe assembly is not clamped all that firmly by the one U bolt holding a hack-saw split end of EMT in compression onto the heavy cast-iron exhaust manifold. Just set it up right again, re-tighten the clamp, and continue.
rScotty

 

[rScotty]

ok, I have read lots of posts about blowby. I just got this tractor and have not done anything to it. No compression tests or anything. I am knowleged in engines but a little confused here. I have massive blowby coming out crank vent tube. After a bit oil starts dripping pretty heavy. It seems to have great compression, starts immediately even on cool mornings never have to use compression release.. Has lots of power, smokes black/little blue under load but doesnt skip stutter , runs smooth and strong. what do ya think?

I think you should maybe put put a hose on the vent tube so you can direct that oily puffing into a bucket so you can control the fumes and drips. Then just use it for awhile. You aren't hurting anything, and with it still starting well there is even a chance that it will improve.

The only problem is that this much blowby is also diluting your oil terribly with unburned diesel fuel and that will quickly cause failure of expensive engine parts.

In fact, if it has enough compression to start when cold, that diluted engine oil is just about the only downside to simply using the tractor with that much blowby forever. So I'd change that oil right now - and plan to change it out whenever it starts feeling thin.. Protect what you've got.
I'd guess to change every 25 hrs of use at the most....which is a whole lot more tractor running time than you might think it is. The average homeowner tractor only gets about 100 hrs a year of use. You could easily change the oil 3 or 4 times a year versus a rebuild.

In fact, with that fume & drip catching bucket plus those frequent oil changes you could be fine for decades. Maybe the blowby will even get better; there's a couple of ways that could happen. And maybe the horse will learn to sing....
rScotty

 

[careyo63]

My Ym2000 was purchased ASIS. never refurbished. All I asked the seller to do was just make sure everything was working until I could return in a couple days with a Trailer. Honestly wasn't planning on buying it and kicking tires so to speak. . It was all Org. and the reason I bought it. When I got it home and after some use found out I had the Oil bomb problem also. The muffler had been replaced sometime before but it wasn't brand new looking. After checking and looking at my options I just cleaned the Exhaust out. Removed and Closed the exhaust pipe and poured some Reg. Gas in it and shook it up. After pouring it out I was amazed how much crap came out. I repeated new it was cleaning up so just blew it with out with the air compressor and put it back on. Been 10yrs. and every so often I may find a oil smear on my arm or somewhere noticeable. I do have a cap/flap and have put quite a few hundred Hrs. on it since. I'm so **** about it now that when I'm warming it up I'll wipe the Carbon off it.............