Santana 27 exhaust system

[Laszlo]

Hello Everyone,
I am new to this forum after having purchased a Santana 27 (1971) that came with an A-4 engine. The PO went over the engine with me, and we managed to get it running with some encouragement, but it needs some work. In particular, the PO suspected that the water lift muffler is faulty, and that is causing water getting in the oil every once in a while. Replacing the muffler was too much of a project for him, so he had been replacing the oil very frequently instead.

I am in the process of a fuel system upgrade (bought a new fuel pump from MMI, installed new fuel lines, fuel filters, a primer bulb, cleaned carburetor, etc.. ), so I haven't been running the engine much. However, the other day when I was debugging rough idle, I noticed that there was smoke coming up from the back of the engine where the exhaust flange is. I turned the engine off, and hasn't run it since. Inspecting the exhaust system it appears that the water lift has been repaired before with what looks like a not very good weld job. I suspect that the weld has cracked, and now exhaust gases are escaping through it. I will try to attach some pictures, but this is my first post, so bear with me.

My first question is if anybody knows what type of water lift muffler this is, and if this is an acceptable configuration? Reading the MMI manual, and also reading other threads, it doesn't seem usual, and I am wondering if I should completely rebuild the exhaust system, or try repairing this existing water lift muffler.

The other question I had is related to the exhaust line from the muffler to the back of the boat. On my boat it appears that the line is installed so that it has a steady climb all the way to the back of the boat. So the water/exhaust mix has to fight gravity for the length of about 6ft or so. The water is coming out in bursts, as opposed to a steady flow. I suspect that this is not very good for my back-pressure, and I wonder if I need to alter this. There is not a whole lot of room to route the exhaust line in any other way, so perhaps that is the reason why it was done like this in the first place. Any thoughts would be appreciated.

~Laszlo

[Al Schober]

Laszlo,
Looking at your pictures, I'm not sure what you've got there. Water lift units are usually installed low in the boat, then the exhaust/water mix rises to the exhaust - typically coming out in spurts.
Your unit looks like a mixing can or riser, but installed backwards. Exhaust seems to be coming in the side (which should be the outlet), then coming out the bottom (which should be the inlet). Installed like that, residual water in the riser will go back into the engine - not good.
Perhaps someone else will see something I'm missing...

[romantic comedy]

That looks like a a short standpipe to me. I cant see where the exhaust exits the stand pipe, but I assume it is the bottom. Is there another muffler in there somewhere? A stand pipe would not batch water. It would not push water up hill either.

[hanleyclifford]

This looks like an attempt at a homemade standpipe system. It fails because there is insufficient height available to get the water and exhaust high enough such that both can run down hill to transom. These parameters are the heart of the standpipe technology. This boat needs a new exhaust system which will have to be engineered from scratch. First we need a sketch in section showing the engine in relation to the waterline. You have come to the right place - we love projects.

[Laszlo]

Thanks for the replies everyone. To answer questions: the water/exhaust mix comes out in the back at a little higher point where the exhaust flange is. I am posting a picture taken from the top. There is not other muffler, just some exhaust tubing all the way to the transom.
I will take some measurements, and post them. Yes, it seems like a project.
~Laszlo

[hanleyclifford]

This will be an engineering challenge. Unless you are willing to spring for a jacketed system the only real alternative is a water lift. Not much over head space aft of the engine for a riser and not enough room forward of the cockpit deck to get a riser up and down and stay away from the fiberglass. Oddly enough the best choice may be to come out of the forward end of the (new) manifold.

[hanleyclifford]

The good news is that the engine is not real low to the water line, but the room for a hose to transom is limited. This is a tight fit for an Atomic 4.

[Al Schober]

How about running the exhaust out the side? I know this will work with a mixing can - can't see any reason it wouldn't work with a water lift.

[Shelby]

not all interior layouts provide enough heigth for a standpipe to be the best choice. downhill discharge from the standpipe to the through hull is importent. a redesign opens up all options meaning a lift type exhaust too. components for a lift system are easy to find.

[Laszlo]

Hi Everyone,
Thank you for the thoughts and tips. I managed to get the "standpipe" off. It was rusty, and stuff rattles inside, so it will have to go. At this point I am committed to an exhaust system redesign. I will try to get the exhaust flange off the old standpipe, and invent some kind of hot section routing. I have two possibilities in mind.
One is to go straight up with the exhaust hot section, do an inverse U bend, have the cooling-water come in, and from that point forward let gravity take the exhaust-CW mix out through the transom. I am attaching a cartoon with what I have in mind. I think I might be able to pull it off with the space limitations. I wonder how noisy it would be though, without a muffler? This would be the cheapest way to do it. Also, since CW exits gravity-fed, I wouldn't swamp the engine with water when accidentally over-cranking. Disadvantage is that it needs some elaborate pipe-routing, and the hot section would run close to fiberglass and ply-wood.
The other way is to put a water lift muffler in the bilge. I would have to invent a mount or pedestal for it (so that it sits horizontal), and the muffler is expensive. Other than that this second option seems more attractive actually.
Any thoughts?
I am also attaching a few pictures I took of the working space.
~Laszlo

[hanleyclifford]

With that kind of engine manifold height above the water line it's easy to see why the choice was for a standpipe. They just didn't get the right one. Since the standpipe is much preferred over the water lift and you have the room I would do everything possible to keep the standpipe concept. The unit will have to modified for less height (moving the discharge up). I also think the system will be cleaner if run off the front of the manifold where much less bending and angling will be required. MMI sells a manifold with front discharge.

[Laszlo]

Interesting thoughts about the standpipe. I couldn't find much information on how to install a standpipe in the MMI service manual, it only talks about water lifts. I will have to do some more research on that, as I haven't really considered that option yet.
I cannot really come out in the front of the manifold. It is not shown in the pictures, but there is a plywood plate that covers up much of the "engine room" (or at least on the top and on the sides, it still has a hole in the middle). The stairs attach to that plate. If if came out in the front of the manifold, the plate wouldn't fit into its place any more.
Back to standpipes: The MMI Tartan style muffler seems a bit too long. I need to take some more measurements, but it seems that (leaving room for CW entry) the bottom of the unit would come down just a few inches above the waterline. Given that the standpipe cannot push, this would not be ideal. Google search on standpipes doesn't give a whole lot of shopping hits (and searching West Marine website for keyword "standpipe" returns a washing machine). Could anyone recommend a vendor of standpipes?

[ndutton]

I think you just realized what new member Shelby said three days ago. Waterlift components are readily available, standpipes not so much.

BTW, I'm surprised no one has said it yet, welcome Shelby.

[hanleyclifford]

Interesting thoughts about the standpipe. I couldn't find much information on how to install a standpipe in the MMI service manual, it only talks about water lifts. I will have to do some more research on that, as I haven't really considered that option yet.
I cannot really come out in the front of the manifold. It is not shown in the pictures, but there is a plywood plate that covers up much of the "engine room" (or at least on the top and on the sides, it still has a hole in the middle). The stairs attach to that plate. If if came out in the front of the manifold, the plate wouldn't fit into its place any more.
Back to standpipes: The MMI Tartan style muffler seems a bit too long. I need to take some more measurements, but it seems that (leaving room for CW entry) the bottom of the unit would come down just a few inches above the waterline. Given that the standpipe cannot push, this would not be ideal. Google search on standpipes doesn't give a whole lot of shopping hits (and searching West Marine website for keyword "standpipe" returns a washing machine). Could anyone recommend a vendor of standpipes?

The standpipe does not need to "push". Even a few inches and any downward pitch at all allows the hose to drain with minimum effort. The water lift compels the engine to drive water up hill many feet and that is the stuff back pressure is made of. Even a short stand pipe is better than a water lift. Those of us with engines well below the waterline have no real choice but to go water lift. You have options.

[ndutton]

Good, better, best . . . whatever

Lazlo,

If budget and parts availability dictate (as they often do), there's nothing wrong with a well designed and properly installed waterlift exhaust system. Using a single boat model to support the statement, there are more than 7500 Catalina 30's produced with waterlift systems and they've performed well for three decades, I'd guess at least a third of them originally with Atomic 4's. Extrapolate that over all the other sailboat manufacturers and the number of successful waterlift installations is staggering.

I'm not suggesting you have to use a waterlift, not suggesting you have to use a standpipe either. In fact, your original straight pipe plan is exactly what over 5000 Catalina 27's had, also successful for decades and MMI offers a Catalina 27 inspired exhaust system in their catalog.

One last comment: if considering a waterlift, it's my opinion that the Vetus blow molded LP40 is the lightest constructed waterlift around and grossly overpriced for what it is. I'd go with either a Centek filament wound fiberglass unit (less cost than a Vetus and IMO vastly superior quality) or MMI's stainless offering.

Apologies to members with blow molded Vetus waterlifts.

edit: BTW, engine level below the waterline has nothing to do with a standpipe system's viability. What matters is a clear shot from the engine up to preferably the deck level and the ability to provide a downhill discharge hose without traps from the standpipe to the exhaust thru-hull.