Yanmar 315 with turbo - exhaust elbow failure

[egauthier@ec.rr.com]

KP Duty - February 9, 2014.pdf

The elbow which attaches to the outlet of the turbo and connects to the mixing elbow failed on our boat. It broke completely off
while we were undway. The engine has 580 hours on it. Is this a unique problem to our boat or is it something to be expected?

Attached is the invoiice for repair. The yanmar parts were the major expense. Are these prices about what anyone should expect?
They seem very high to me.

[whwells]

Paul: There have been recent other posting about the loose or failed exhaust elbow. You should be able to pull it up on a search of the topic. Seems like there posting in the Maintenance Section just couple weeks back. I will take a look again myself. My 35TE series has twin Yanmar's and has not been a problem. However, I have had the exhaust system cleaned and service twice since 2010 purchase just to be on the safe side. The answer it is something to watch at least annually.
There are additional comments under : "yanmar exhaust elbow" search.

whwells "Howard"
2006 35te Sport-fisher/Flybridge Conv./twin yanmars
2004 Osprey Pilothouse 22

[RobS]

Those parts prices are very high, considerably marked up, and 6 hours labor is a bit steep too.

580 hours yes but it is more about marine age for which the clock starts ticking the day she first hits saltwater.

[jleonard]

Why did the piece break? What was the failure mode? Has that been addressed or did they simply fix the symptom and not the cause?
Yanmar elbows are notorius for breaking, aftermarket custom made are better. Note for next time.

[johnmurray]

I have the same boat with the same engine as KP Duty, but in my case with 701 engine hours at last fall's haulout. Are these exhaust elbow failures a salt water problem or should we fresh water boaters be worried as well?

[sharffj]

Price seems steep. In Hawaii now, when get home next week will look up and see what I paid for elbows. Yes if you are in salt water they will fail. I've had the bolt on the ring clamp break on the starboard elbow and the flange lip spring a small pin hole exhaust leak on the port elbow. Both happened in rough seas. The starboard just after crossing the Columbia River Bar, and the port running up the Washington coast with 30knots blowing at our stern. Wonder if the rocking and rolling didn't add to the stress on the elbows
Jeff S

[carolmarie]

John Murray:
Our boating is essentially all fresh water (Lake Champlain) except for an occasional trip to Cape Cod. We had the Carol Marie's exhaust elbow checked last spring (approx. 850 hours) and it was reported to be in excellent condition. Fresh water boating makes a huge, huge difference in overall boat systems O&M, especially the engine.
Carolmarie, 2001TE, 6LP-STE.

[jleonard]

Price seems steep. Wonder if the rocking and rolling didn't add to the stress on the elbows
Jeff S

Only if they are not properly supported. If that kind of fatigue failure is the root cause, then they will fail again, it can be counted on.
It is fairly easy to add a support. I had to support the elbow on my Mainship repower, it was an easy thing to do.

[Halcyon]

I am in the middle of this job. The dry elbow cracked at the clamping point with the wet elbow. Last spring I replaced both dry elbows for $405 ea parts $31 x 4 for clamps and $600 labor. The Wet Elbows were quoted at $680 each. I had SS wet elbows made by National Marine Exhaust for $689 each.
Your parts prices seem high. The picture shows the broken dry elbow on the bottom and the wet elbow above.

IMG_2463.JPG

[Capt Ron]

Mine broke as well while under way. Quite a surprise when you hear open exhaust in the engine room at 3,200 RPM! Take a look at the material left after the machining of the piece. I think there may be 1/16 inch left. A very poor design! I replaced mine myself. It shouldn't take more than an hour. Your labor estimate is extreme unless the tech is counting travel time.

[whwells]

This is starting to look scary. Maybe all of us with the 315's will need to consider the SS replacement. I certainly want to give it more thought as the problem seems to be much wider that one would expect.
whwells "Howard"

[ScubaPete]

Price seems steep. Wonder if the rocking and rolling didn't add to the stress on the elbows
Jeff S

Only if they are not properly supported. If that kind of fatigue failure is the root cause, then they will fail again, it can be counted on.
It is fairly easy to add a support. I had to support the elbow on my Mainship repower, it was an easy thing to do.

I agree that the exhaust elbow and mixed should have an extra support. Just bolted to the turbo or exhaust manifold is not enough.

[elad]

Having to replace three mixing elbows over the last five years I have decided SS is the way to go. Each failure was at the collar for the clamping ring. Truly a very bad design. I'm having both the dry and mixing elbows fabricated as a single piece for $1,100. Also adding extra support, moving the water inlet closer to the wet/dry interface and making smaller but more water jet holes to improve mixing.

[Rybo78]

I wonder if there is any chance that the extreme angle from exhaust elbow to fwd end of muffler is imparting too much stress on the elbow? At least on the 28's. I ask because I'm just now in the process of reinstalling my 315 yanmar and have come to realize that the angle combined with the reinforced exhaust hose is preloading the exhaust elbow. After spending some time thinking of ways to re-engineer the exhaust set up I've tentatively decided on using a mix of Shields Marine silicone 45 degree exhaust elbows along with their 4" single hump exhaust coupling....

I'm anxious to ear if any others have tried similar approach.

R

[jleonard]

One danger from a failure under way is that the engine will suck soot into the air cleaner and into the cylinders. That is not good as soot is abrasive.