Excessive Blow-by on Kama 554

[Dave_Lilly]

Not on this engine Dave. It's a 90 degree cast iron appendage that's bolted on to the side of the valve cover. It's not a true breather in the in-out sense, it serves more of an exhaust function (and doubles as an aggravating oil fill location). There's nothing inside but a floppy rubber disc that covers half a dozen holes. When pressure inside the valve cover is higher than outside, the flap is lifted to relieve the pressure. Otherwise gravity holds it in place to minimize intruding outside air and moisture.

I disassemble mine for inspection at every oil change, the only thing I've ever wiped out was a little emulsion. That said, it bears inspecting for excess emulsion. If there's a water leak, what looks like blow-by could actually be condensation (like the initial white smoke out of a cold muffler)

//greg//

3RRL complained about oil being blown our of his breather cap. Pressure inside the valve cover is equal to pressure inside the crankcase. If his tractor is blowing oil out of this breather cap without white smoke out of his exhaust, which was not mentioned in his post, I still feel that he should check for worn valve guides or bad compression rings. A water leak into the cylinders would result in white smoke out of the exhaust, not oil being blown out of the breather cap.

 

[greg_g]

Don't get your nickers in a twist Dave, remember that Rob has a completely different engine than do you. And anyway, I suggested the possibility of bad valve guide seals in my initial reply. Subsequent mention of condensation and emulsion was posted to hint that puffs of oily condensation might also be mistaken for oil fumes.

My response to you was was an attempt to explain how the "breather" works on Rob's FeiDong 495 engine. I've got the 3 cylinder version of the same engine in my KM454, so I think it's fair to assume I've got the same breather/fill cap. You said clean/replace breather, I merely attempted to explain why that particular suggestion was not applicable to Rob's (or my) engine. Note also I specified that Rob's breather/fill cap is 90 degree side-mounted on the valve cover. I assumed you'd understand that meant it takes considerably less oil accumulation under the valve cover for oil to get into his breather/fill cap than would on a top mounted breather.

And I made absolutely no allusion to water in the cylinders, so let's not go down that street right now - ok?. I merely stated that moisture accumulated under the valve cover will puff out the breather/fill cap in the form of (white) condensation, similar to the way white smoke (condensation) puffs briefly out of a cold muffler. And that moisture from any source will also cling to the inside of the valve cover - and inside the breather - in the form of emulsion. I wipe that crap outa mine every time I add/change oil

So miscommunication aside, we both actually are recommending that Rob consider the issue might be related to valve guides. As an after-thought, plugged oil return port(s) could cause the oil level under the cover to rise as well. In either case, I'd take the valve cover off for a looksee

//greg//

 

[Egon]

I'd do an oil change and see what may fall out! And also check the filter for some metallic/rubber/plastic material!

 

[3RRL]

Here is a photo of the oil fill/breather on my Kama 554.



The cap is off on the very left. You can see the breather holes in it. Then there is a metal sleeve with the bottom open (cross hatch) and a steel wool like element that goes inside it.

I am with you guys that the root of the problem is worn valve guides. I think that is a good bet.
There are no water leaks whatsoever and there is no white smoke to indicate that. There is never a radiator water level change, nor does it ever run hot. (Except when I'm brush hogging when the air filter and radiator fins get plugged up.)

Only oily smoke that blows out of those holes in the cap above. You can see in that photo how the right rear of the valve cover gets oily. It's not very much in this photo, buts gets worse by the end of a long day. There is no noticeable loss of power either...but then again I am not positive about that. I haven't done a compression check to see if it could be worn rings though. Might not be enough to worry about after all.
Thanks for all your replies!

 

[greg_g]

My breather is almost the same, you've got steel wool - I've got a fine mesh basket (like in the fuel filler neck). But mine also disassembles farther. The knurled cap comes off the part with the vent holes. Inside is the rubber flapper I described.

//greg//

 

[3RRL]

My breather is almost the same, you've got steel wool - I've got a fine mesh basket (like in the fuel filler neck). But mine also disassembles farther. The knurled cap comes off the part with the vent holes. Inside is the rubber flapper I described.

//greg//

Yes, I didn't take the cap apart for that photo.
What I referred to as "steel wool" is not really steel wool, it is probably the same as your mesh material.
I was thinking of taking the knurled cap off and adding a hose that went directly to the intake manifold so those vapors would get sucked in and burned up. Most of them should condense on the mesh and drip back into the valve cover.

 

[SPYDERLK]

I am with you guys that the root of the problem is worn valve guides. I think that is a good bet.
There are no water leaks whatsoever and there is no white smoke to indicate that. There is never a radiator water level change, nor does it ever run hot. (Except when I'm brush hogging when the air filter and radiator fins get plugged up.)

Only oily smoke that blows out of those holes in the cap above. You can see in that photo how the right rear of the valve cover gets oily. It's not very much in this photo, buts gets worse by the end of a long day. There is no noticeable loss of power either...but then again I am not positive about that. I haven't done a compression check to see if it could be worn rings though. Might not be enough to worry about after all.
Thanks for all your replies!

Rob, normally the high velocity flow past the valve stem in a port causes a suction on the valve guide, sucking oil past the seal or guide if it is worn. It isnt likely that worn guides are causing the crankcase to be pressurized. More likely cracked rings or a cracked piston that causes the rings to be stuck in the grooves and not seal well. Did the blowby show up suddenly? Can you check compression? 500hrs just isnt enuf for critical wear to develop. I think it is a failure, maybe not bad enuf to warrant repair if you can let the crankcase breathe and it doesnt worsen. Definitely try changing the oil.
Good luck.
larry

 

[bluechip]

If we have decided the blowby is excessive (considerint this is a non PVC type engine so some blowby is normal). then it will be a ring problem more likely than valve guides. the only flow available to pressurize the crankase would be around the exhaust valve stem, and then, with the valve open, most of the pressure will be lost out the exhaust pipe. There is a tremendous amount of pressure in the combustion chamber and some will go past the rings. As was said, if this happended all of a sudden, a ring or rings may be damaged.Rob, have you by any chance ever used strting fluid (either) on your engine? Has it been running well prior, no excess smoking? sometimes a bad injector will "wash" the oil our of a cylinder and could casue premature ring failure (either definately can crack a ring or damage a piston).

Still, if the blowby is not excessive, I would try some fresh oil and go from there. a compression test could reveal all....

 

[3RRL]

Thanks Larry and Chip.
I will change the oil and filter since it's near 100 hours on it now. I'm hoping that will reduce it if you think fresh oil is a reasonable cure. BTW, I change the oil and filter every 100 hours. Is that frequent enough or should I do it every 50 hours? I use 15w50 Mobil1 synthetic since it gets over 110F+ out here during the Summer.

As far as the smoke, it is not that bad. And it didn't happen suddenly. I've started to notice it more than before, but it always blew a little smoke from that breather. It's not like it's "billowing" out or anything like that, but it's gotten to be more than I remember before. that was the original reason I asked about it. I don't think (?) it's a ring problem either, although I'm not certain. So I'll check that next time up via a compression test. If it is the rings, I'll call Chip and order a complete repair set for it.
Chip, what should the normal compression be on my Kama 554?

What I've learned, and Chip just mentioned it again, is that it's pretty normal for what is happening to my Kama 554. Brad made a post about his Kama 554 and said his "vigorously" expels from the breather also. Except he did not work the tractor all day, rather he had it running to check what his did. So that makes me feel a lot better too. When mine first starts up it also does the same with very little or no smoke at all. Only after several hours working. Perhaps that is the indicator that I really need to change my oil. With fresh oil, maybe it won't do that? (as much)

I'll be sure to change the oil and report back.
Just wanted to thank everybody again for all the replies and help.

 

[JerryG]

Rob,
I had an engine one time that wouldn't run on 50w oil without smoking. I could use any kind of ??-40 and all was fine. You might try a lighter oil just to see if that is the problem. I can't really see it being that but it might be.