New Engine for S&S Swan 36
I replaced the Volvo engine in my s&s 36 with a 19 hp yanmar. It has been a bad experience. The current problem involves salt water in the crank case. We suspect that it leaked in through a crack in the exhaust pipe. Has anyone had experience replacing the exhaust pipe in the 36? Are there other replacement engines that have been suitable as replacements? Thanks for your help.

Jim Lawlor
Swan 36 Swansong

Jim,
I want to comfort you about water in the oil sump (or crankcase). To date it happened to me already twice and, fortunately, without immediate consequences - I cannot say in the long run but my Perkins is already 34 years old and in quite good health.
In both my cases the fault was in a plugged anti-siphon break circuit. The first time the offenders were spiteful but otherwise innocent bugs but the second time the offender was an ignorant shipyard worker who believed that the small vent hole on the side of the boat needed caulking lest the boat risked sinking (?).
All this just to say: before losing faith in your new engine, check the anti-siphon break circuit.
Beside this, as soon as you realize the problem (the oil level increases and the oil pressure gauge moves erratically) stop the engine, drain very well the oil sump undoing all possible drain plugs, change the oil filter and fill with fresh oil. The sooner the better.

Daniel, 411/004

Jim
Was Daniele's answer helpful? It is likely that the S36 exhaust system is rather different compared to the S411. Could you describe the main components and their location?
Best regards
Lars

Thanks to both of you. At this point the engine has been removed and will be broken down next week. We will know the extent of the damage soon

The exhaust system is thought to be the source of the problem. The exhaust pipe runs aft under the floor supports to a point under the forward end of the cockpit then it turns to the starboard side and turns upward to a muffler or heat exchanger. It then runs aft where the exhaust is discharged. The exhaust pipe is enclosed in an outer jacket running from a point just behind the engine and runs to the muffler. Sea water flows through the outer jacket.

I have been persuaded that the exhaust pipe is cracked and allowed water to leak into the pipe from the outer jacket. It does not appear that the pipe can be repaired in place. Removal and replacement is a major project. I am looking for a modern solution and looked recently at the Vetus components which are more flexible and might be able to be installed without making major structural changes in the hull.

I will appreciate your thoughts.

Jim
Your description confims that this is the original water jacketed exhaust system. There are earlier posts on this forum about leaks in such systems, and the reason is usually pinhole corrosion in the stainless steel inner tube. Unfortunately stainless is not immune to such corrosion, but in your case it took some 40 years before a leak developed.
Putting in pen type zinc anodes into the jacket would postpone the problems, but this has to be done in time, before they occur.

You could well change to a wet exhaust with water lock and anti-siphon loop. I can give a number of detailed recommendations for this, but would prefer to mail them to you personally
Best regards
Lars

Dear Lars

Thank you for your advice. I note that you have been the principal source for information for several others. Thank you for your generous sharing of your knowledge. I have sent my mailing address

Jim