Fred Matzer
New Member
My E34T needs exhaust work, so I've been reading up on design recommendations. Most designers require a 4 inch drop from the engine exhaust outlet to the point where cooling water is injected, and a further 8 to 12 inch drop from the injection point to the inlet of a plastic muffler. That's a lot of room, and it's not easy to find in a typical sailboat installation!
One solution is to use a section of dry exhaust pipe to gain the necessary elevation. Run black iron pipe (or stainless if you have deep enough pockets!) up from the engine manifold outlet until you have adequate height above the muffler. Add a short horizontal section and then run down 4 inches to a wye or tee fitting, where the cooling water will be injected. From there you can use reinforced rubber exhaust hose down to the muffler inlet. What you have done is to move the engine exhaust outlet to a usable height. All of the dry piping will get extremely hot in use, and will have to be heavily and securely lagged (same as with the standpipe) to prevent a fire hazard. New fiberglass lagging in various widths is available from www.hamiltonmarine.com .
The Sept.-Oct. 98 issue of Good Old Boat magazine has an excellent article on wet exhaust systems. The author includes all the critical dimensions for an installation that will keep the engine happy and keep following seas out of the boat. There's a discussion and drawing of an improved version of the standpipe exhaust, if you decide there's not enough room to use the muffler.
Hope your project goes well!
One solution is to use a section of dry exhaust pipe to gain the necessary elevation. Run black iron pipe (or stainless if you have deep enough pockets!) up from the engine manifold outlet until you have adequate height above the muffler. Add a short horizontal section and then run down 4 inches to a wye or tee fitting, where the cooling water will be injected. From there you can use reinforced rubber exhaust hose down to the muffler inlet. What you have done is to move the engine exhaust outlet to a usable height. All of the dry piping will get extremely hot in use, and will have to be heavily and securely lagged (same as with the standpipe) to prevent a fire hazard. New fiberglass lagging in various widths is available from www.hamiltonmarine.com .
The Sept.-Oct. 98 issue of Good Old Boat magazine has an excellent article on wet exhaust systems. The author includes all the critical dimensions for an installation that will keep the engine happy and keep following seas out of the boat. There's a discussion and drawing of an improved version of the standpipe exhaust, if you decide there's not enough room to use the muffler.
Hope your project goes well!
Jim Baldwin
Member II
Get gravity on your side
Check again for downstream location for waterlock. Be creative and cut fiberglass if you have to but you really need gravity on your side. Try some Vetus flex exhaust hose, (because it really is more flexible than the other brand).
I don't think I would install any vertical or horizontal metal pipe extensions, or anything like that.
If you just can't find a suitable location for your plastic waterlock then return it to the store and stick with your original factory riser. Take the old one to the marine muffler shop and have them make you a new one.
If you were to install the trap at the same level as the exhaust port, then as it fills with water, it would simply run back into the engine block. (Trapping the water and then feeding it back into the exhaust is not what you want happening here.)
Check again for downstream location for waterlock. Be creative and cut fiberglass if you have to but you really need gravity on your side. Try some Vetus flex exhaust hose, (because it really is more flexible than the other brand).
I don't think I would install any vertical or horizontal metal pipe extensions, or anything like that.
If you just can't find a suitable location for your plastic waterlock then return it to the store and stick with your original factory riser. Take the old one to the marine muffler shop and have them make you a new one.
If you were to install the trap at the same level as the exhaust port, then as it fills with water, it would simply run back into the engine block. (Trapping the water and then feeding it back into the exhaust is not what you want happening here.)
Re: Re:E29 exhaust
Thanks Fred and Jim for your responses.
Jim, I surveyed the entire bottom in the engine area and there's no possible way I can lower the Vetus.
With fingers crossed I'm installing a hot pipe riser 24 inches up from the exh. outlet , with an elbow, a nipple and a reducing elbow. I will have the water enter at this second elbow, then the exhaust goes down 18 inches to the vetus. My tailpipe exits 6 inches above the vetus, so if water really seeks its own level, I should expect reasonable drainage before any backflow to the system. Ain't boats fun?
Thanks Again
Dave - Ericson E29 #253, Long Island Sound
Thanks Fred and Jim for your responses.
Jim, I surveyed the entire bottom in the engine area and there's no possible way I can lower the Vetus.
With fingers crossed I'm installing a hot pipe riser 24 inches up from the exh. outlet , with an elbow, a nipple and a reducing elbow. I will have the water enter at this second elbow, then the exhaust goes down 18 inches to the vetus. My tailpipe exits 6 inches above the vetus, so if water really seeks its own level, I should expect reasonable drainage before any backflow to the system. Ain't boats fun?
Thanks Again
Dave - Ericson E29 #253, Long Island Sound