I had the exhaust elbow on my Bav 40 replaced. The engine is a well-maintained D2-55 with 4,800 hours. It's 12 years old.
The removed elbow was an original VP - I don't know if it had been replaced before but the inner diameter was only 50% of what it should be. The rest was clogged with a brownish crusty substance and. Rust and salt? It's now replaced with an HDI marine stainless steel part.
For reference, here's a picture of the engine block. It's clearly visible how the exhaust-saltwater mixture is slowly eating away the engine block. It'll be many more hours before I'm in danger of a leak but it's good to know what's happening underneath the sealing, so make sure to check your engines.
https://forum.amicidellavela.it/showthread.php?tid=130304
Read this.
That's dozens of posts in Italian. Images can only be viewed after registration. Mind giving a summary?
Translate only the first post, with images. It is exhaustive.
However no any problem in registering.
Since my Italian was not enough to understand all of it and the translation entertained my quite a bit, here's a YouTube video of a guy doing similar work: https://www.youtube.com/watch?v=49-UiRPoeyM
A lot of work but he did nor repaired the main issue.
You mean the corrosion under the elbow? He had it replaced earlier.
See min 26.12
If you cannot understand Italian see these images that can explain the job I did on my engine. Aluminum plate, 8 mm thickness, must be changed every 2 years to avoid further problems. You can ask to Sermar to buy ss elbow and plates.
I lgot the advice from an expert a few weeks ago that the heat exchanger and the exhaust elbow must be checked and maintained regularly because their failures will cause a real engine death. Every 2 years would be perfect but less often would still be good. Important is that you do it (I didn't check them but next winter it will happen). Exhaust elbow with seawater injection is corroding from its inside (not in 2 years...).
Frank
The exhaust elbow (Cast Iron) on most of the VP eng?nes should be removed add ?nspected at least every two years. Fa?lure to do so can have cat?strop?c consequences. Two videos covering th?s, f?rst one ?s here : https://youtu.be/WXPG6XaWvF8 Hope th?s helps.
Added aluminium plate, 8 mm, between
hather exchange and elbow, save the exchanger from corrosion
In the image a new and used for 2,5 years aluminnium plate that is corroded I the first 6 mm of the thickness