I am in pretty deep now!

[Sculldog1]

After examining the exhaust more closely what I have is very close to the MMI tfitting that Joe linked. The difference is that the pipe within the 1 1/4" had a bunch of holes drilled across it that appeared to begin almost at the same level as the riser. It definitely feels like it should have been extended further down before the holes or not at all as the one on the catalog shows. I am going to rebuild and extend the riser to the height of the present injection point (will be very near what Edward C showed) and move the injection point below the manifold level and install antisiphon on the manifold to injection tion hose. Could anyone elaborate on the "open loop" antisiphon set up and weigh in if that is better than the valve set up in the catalog? I ask because I am concerned if the valve might be susceptible to failing in the raw sea water and if the open loop arrangement might be less prone to failure. Thanks to everyone.

[joe_db]

Could anyone elaborate on the "open loop" antisiphon set up and weigh in if that is better than the valve set up in the catalog? I ask because I am concerned if the valve might be susceptible to failing in the raw sea water and if the open loop arrangement might be less prone to failure. Thanks to everyone.

Open loop is better and less prone to failure. You just T off the water injection line and run another hose to a fitting well above the water line for water to exit and/or air to come in. You need a restriction of some kind so too much water does not follow this path instead of cooling the exhaust. This is like the pee hose that outboards have, it might get clogged but it is obvious when it does.

[ndutton]

It may help to understand how an anti-siphon functions. It allows air to enter the cooling system in the event of negative pressure, a suction, thereby interrupting the suction. As you'll remember from the 'Colorado Credit Card' days of siphoning fuel out of a car gas tank, suction is what siphons are all about so interrupting the suction eliminates the siphon.

An anti-siphon valve allows air in under suction but closes when the engine is running and there is positive water pressure in the cooling system. This prevents cooling water from hosing everything down in the immediate area of the anti-siphon loop. The valve is known to have a limited service life and stories of its failure are pretty common. When it fails you either have water spewing in the area or no siphon protection.

The open loop has no valve, just a hose from the top of the anti-siphon loop to allow air in under suction. The other end of the hose is installed so that the water that comes out under positive pressure is routed harmlessly overboard. As I said previously, mine is connected to the galley sink drain plumbing. It is important to note that the entire vent hose must be installed above the heeled waterline.

Here are two poor quality pictures of my open loop system. The first shows the bronze anti-siphon loop with the vent hose attached to the top, the second shows the other end of the vent hose attached to the galley sink drain plumbing.

[Sculldog1]

The quest continues!

So for to possibly be helpful to others I will report.

Having gotten in way over my head on the sailboat engine I found that:

1. My exhaust got a clog that led to water intrusion and the usual sticky valves etc.

2. Removing head to free valves led to exhaust rebuild, manifold clean out, and removal of valves, springs and also a long overdue water jacket clean out. I have the valves in an organized box for to return to exactly where they came from and am soaking keepers, springs and retaining washer/tophatty looking things in vinegar to remove some surface rust. It looks like valve stems are in pretty good fettle with exception of cylinders 3 and 4 where serious pitting is evidenced after I chucked all valves into drill and cleaned carbon off using scouring pad and 120 grit sanding sponge. I will be polishing the good stems by wet sanding in stages to 2000 or 3000 and finally polish with buffer.

I am planning to clean up the seats and lap the good valves before replacing them and ordering new stems for 3 and 4 and lapping them in as well.

For anyone considering work on this scope be advised it is a lot of back breaking effort. It took all day to get the valves out, clean up all the mating surfaces for valve plate, water jacket, manifold and cylinder head as well as muck out the water jacket.

A couple things I learned:

90 degree long nose pliers very handy to help break rusty keepers free and get springs out.
Magnet on a stick very helpful to get black gunky mud/rust/sludge out of water jacket. Basically used wire and rifle brushes to break up WJ gunk and "rake" it into void between cylinders where magnet pulled up teaspoon sized clumps that I transferred to bucket like 300 times till couldn't get no more. Still gonna need a vinegar or acid flush after reassembly.

Anyway got a few parts to get and then reassembly will commence. Just sharing the experience for others to use info for their own decision making process. BTW all this going on while swinging on mooring which I don't recommend but I am beyond the PONR so I soldier on. Thanks to all for insights and support.