YSE 8 oil "leak" question

[Sandy D.]

Howdy folks,
After returning to the harbor from this years first sail I discovered about a quart of motor oil in the engine pan. After adding more oil and firing the engine back up I discovered the oil coming from the tube on the port side of the motor. This tube usually has a soft foam cap on it, however now the cap blows off and oil is coming out of the tube ( I assume this is a dipstick tube )

So, I removed the breather plate and cleaned up the reed valve inside and reassembled. Unfortunately the problem continues.

The breather hose is clear and unobstructed, and if removed I can feel puffs of air coming from it. The little foam cap on the dipstick however still pops off immediately and I can feel puffs of air coming from the tube and small amounts of oil escaping. ( approximately half a quart in a matter of an hour of operation )

I'm a bit lost. Seems like I need a tighter fitting foam cap but I'm not sure the fix is that simple.

I haven't done anything any different this year than in the past, the crankcase is not over filled.

Any ideas-suggestions?

Thanks a ton,
-Sandy Davis

[okawbow]

I have a YSE8 on my Bristol 24. I used to have oil come out of the breather tube sometimes when I sailed heeled over. I fixed the problem by slipping a clear vinyl hose over the tube, and securing the end above the top of the engine. Haven't lost any since.

It sounds like you might be getting a little blow by from your piston rings. You might try changing your oil, and using straight grade 30wt Rottella or equivilent. Then, run your motor for several hours at near hull speed to "blow the cobs out" and maybe seat the rings a little. Be sure it doesn't overheat.

I motored about 600 miles in 10 days once, and the motor ran much better at the end, than it did at first.

[SurryMark]

I had the same problem: one of the first times out with the engine on, smoke billowed from the cabin, with Tula 200 yards from a lee shore in 100' of water. Glad I read the book on heaving to. The smoke was from oil all over the engine, and the engine was almost empty. After sailing back to the mooring, I found that the plug had blown off. I believe the hole is there for pump to empty the sump, but my engine doesn't have one. Same as Okabow, I clamped a vinyl tube to the little pipe, ran it above the engine, and clamped in a rubber stopper. It's been ok since.

[Oswego John]

I fixed the problem by slipping a clear vinyl hose over the tube.

It sounds like you might be getting a little blow by from your piston rings. You might try changing your oil, and using straight grade 30wt Rottella or equivilent. Then, run your motor for several hours at near hull speed to "blow the cobs out" and maybe seat the rings a little. Be sure it doesn't overheat.

I don't know if you fixed the problem or circumvented it.

I'm thinking along the same lines as okawbow. It sounds like blowby to me. I would suggest having your motor checked by a diesel mechanic with special emphasis on a compression check, rings, valve guides and clear oil return tubes from the upper gallery.

My guess is that the puffing you feel at the top of the tube is compression bypass being blown past the combustion chamber and down into the oil pan sump. Each power stroke of the piston leaks some compression.

With the tube capped, some compression leakage builds up in the pan until enough accumulates to blow off the tube cover.

There is one way I used to zero in on worn rings. Take a few compression checks with the engine warm and average them out. If I had access, I would put a few tablespoons of heavy motor oil into each cylinder and retake the compression. Oftentimes, the heavy oil would seal the rings and raise the compression.

Whatever the case, I wish you luck and hope that the solution is an easy one.

O J

[Joe Mac Phee]

Sandy,

All of the comments so far are relevant and apply to all diesel engines. In addition, the YSE has unique features.

I have a YSB on my 1977 Cape Dory ketch. There are multiple tubes venting this engine.

As you know, these single cylinder engines are laid over on their side with the cylinder axis horizontal. This arrangement provides challenges, especially for the lubricating oil in the crankcase. My recollection is that the crankcase vent tube on the YSE series went back to the air intake. This arrangement sometimes created runaway conditions with the engine running on its lubricationg oil. I read that some users removed this arrangement and just ran the vent line over the top of the engine.

There is also a vent for the clutch housing running over the top of the clutch.

The tube with the cap that is connected to the bottom of the crankcase is used for access to change the oil.

Were you running the engine while sailing (and heeled way over)? My engine does not tolerate heeling very well especially on the tack that puts the vents on the low side (starboard tack on my reversed engine).It will send oil out the tube with the cap simply by gravity. I rebuilt my engine a few years ago, it has good compression and no blowby and it will still leak oil when heeled

If you take the vented cover off the side of the crankcase, there is only one way to ressemble it. If parts get rearranged, the vent assembly will send liquid through the vent instead of just vapor.

The parts book shows the assembly in good detail. I have the book for the YSB. The YSE may be different.

I think it is difficult to wear out these little beasts. Dig furthur to identify which vent is leaking oil and procede from there.

Good luck,

Joe Mac Phee

[Sandy D.]

Hey guys.........thanks for the help!
It makes perfect sense that blow-by would increase crankcase pressure that would need to escape someplace and I don't think the vent tube was handling the extra pressure resulting in it going out the dip stick and taking some oil with it. I've added a hose to the dipstick. While this doesn't fix the problem it does keep the oil in the motor instead of the pan/bilge.

I've used a product called "Lucas"for years in my old pick up with great results, the bottle says it works for diesels also. I'm going to add some lucas and use straight 30 weight in the crankcase to see if this helps.

I've had to crank the starter longer the last couple years before she fires, I assume low combustion would be the culprit here also?

I've been wanting to learn more about the workings of a diesel engine, looks like the time has arrived!!

Thanks again for taking the time to respond, it was greatly appreciated.

-Sandy

[Ray Garcia]

In case you do not have a parts book; here is a link to one online.
http://gertsen-olufsen.dk/Files/Billede ... og_YSE.pdf

/Ray