Pilot 30-water in turbo

My 2002 Pilot 30 with a Yanmar 4LHA-STP (1215 hrs) has an OEM turbocharger that just failed due to salt water ingestion. The exhaust elbow/mixer and turbo were original to the boat. During disassembly and bead blasting, the cast aluminum elbow/ mixer developed holes between the wet and dry side and the turbo had so much rust that it was toast. Tony, Seaboard Marine, said that I needed a higher riser to prevent the problem, but there's little to no room between the present mixer and engine hatch. The current system lasted 15 years, so I'll probably just replace the turbo and install a new cast stainless riser/mixer. Has anyone else experienced this problem, and how did you solve it. Also, the OEM turbo is very expensive! I won't use the Chinese copy of the turbo due to the horror stories I've heard. What is the least expensive source for a new IHI (Yanmar) turbo, and has anyone used the investment cast mixers on Ebay? Do the water lift mufflers become restrictive over time, maybe causing water back up to the turbo? I need some help!

Lots of good info on marine exhaust system design here.
https://www.sbmar.com/articles/designing-a-marine-exhaust-system/

I have a good friend who purchased exhaust parts from HDI Marine on eBay. He is a super experienced sailor as well as an engineer, and he purchased exhaust riser and other parts for his Volvo turbo charge diesel. He says the quality is as good if not better than the OEM quality.

Here is one of HDI Marine's parts for the Yanmar 6LYA which I have looked at.

https://www.ebay.com/i/332353768524

Let us know what you do and how it turns out.

Here are a few possible solutions if your hatch is too low to add to the existing riser height:

1. Install a flapper on your exhaust outlet. But if you have side exhaust that is not possible.

2. Put a surge tube before the exhaust goes up to the riser. That gives some extra volume to absorb surge that enters from the exhaust outlet.

3. If you have a lift muffer (and I suspect you don't) then you can put an equalization tube from the bottom of the muffler out the hull to limit the height of water build up to the outside water level. The Mainship 34T does this and it works effectively.

Finally your problem could be either or both: not enough riser height or a mixer that doesn't self drain so it sits with sea water in it after shut down and corrodes itself out. The new cast stainless steel riser should solve the second problem.

David

David

I had the same issue with my 4lh Yanmar. (Not in a Mainship) D&W Diesel Will look at the turbo and source it from the OEM that builds them for Yanmar. (Mine was a Borg Warner) Saved me about $300 over the Yanmar price. Very good company to work with. Exhaust flap will help your situation if you have rear exhaust. I also purchased the stainless elbow on eBay. Very well made.

D&W Diesel