Once again I am in need of advice from this excellent group (I’m not going to double post to other forums). I am in the process of repowering my old Morgan Out Island 415. The plan is to replace the Perkins 4-154 (which I can’t get new parts for anymore) with a Cummins 4B3.3. The specs on the 4B3.3 calls for a minimum exhaust line diameter of 2.5”. My old exhaust line is a kludge 2” and 2.5” exhaust line. Furthermore, the old waterlift muffler utilizes 2” in and out ports. (In retrospect, the use of 2” line on a 62 BHP engine is probably what caused the excessive build-up of soot on my transom.) The engine room is directly under the center cockpit. It is going to be a bear to run new exhaust line from the engine room to the transom. I’ll be doing the work myself in very hot and humid conditions. I’m not as flexible as I once was (back fusion).
There is a lazy part of me that wants to use all 2.5” exhaust line (probably trident wire reinforced wet exhaust line). However, to my surprise, I cannot find a manufacture of a waterlift muffler that has 2.5” in and out ports. Unless such a beast exists, I will have to utilize 2.5” to 3” fiberglass reducers. Such a reducer is mandated between the mixing elbow and the bottom of the waterlift muffler. I hate the thought of inserting an inflexible reducer between the engine and the muffler because of the short distance between the two. The old installation resulted in little fore-and-aft dampening between engine and exhaust, resulting in vibration. A hump hose would reduce vibration; however, the use of a hump hose would necessitate the insertion of yet more rigid pipe to clamp the hump hose to. I probably won’t use a hump hose unless someone comes up with a compelling reason to do so.
It would make sense to go with all 3” hose from the top of the waterlift to the transom. However, from the experience of installing my genset that required a run of 2” hose from the engine room to the transom, I know how tough it will be to work with 3” hose. I guess the smart thing would be to use a 3” to 2.5” reducer at the top of the muffler and stick with 2.5” line. Does this logic sound good? Would using 2.5” hose result in a substantial savings in effort? The money savings seems minor to me.
Additionally, what is a good source for 3” to 2.5” reducers? What should I use for clamps? T-bolt clamps are a pain because there is no room to get a socket over the nut, forcing the use of an open-ended wrench to tighten the suckers. It takes a very long time to tork a T-Clamp using a wrench, especially when contorted in a tight confine. Would the use of SS ABYC (sp?) engraved hose clamps be strong enough? Also, I guess it wouldn’t make sense to use both fiberglass exhaust tube in conjunction with hose because the money savings would be offset by the need for extra clamps. And finally, is the use of non-reinforced wet-exhaust hose a viable option? If so, would it be more flexible? Tell me what y’all think?
There is a lazy part of me that wants to use all 2.5” exhaust line (probably trident wire reinforced wet exhaust line). However, to my surprise, I cannot find a manufacture of a waterlift muffler that has 2.5” in and out ports. Unless such a beast exists, I will have to utilize 2.5” to 3” fiberglass reducers. Such a reducer is mandated between the mixing elbow and the bottom of the waterlift muffler. I hate the thought of inserting an inflexible reducer between the engine and the muffler because of the short distance between the two. The old installation resulted in little fore-and-aft dampening between engine and exhaust, resulting in vibration. A hump hose would reduce vibration; however, the use of a hump hose would necessitate the insertion of yet more rigid pipe to clamp the hump hose to. I probably won’t use a hump hose unless someone comes up with a compelling reason to do so.
It would make sense to go with all 3” hose from the top of the waterlift to the transom. However, from the experience of installing my genset that required a run of 2” hose from the engine room to the transom, I know how tough it will be to work with 3” hose. I guess the smart thing would be to use a 3” to 2.5” reducer at the top of the muffler and stick with 2.5” line. Does this logic sound good? Would using 2.5” hose result in a substantial savings in effort? The money savings seems minor to me.
Additionally, what is a good source for 3” to 2.5” reducers? What should I use for clamps? T-bolt clamps are a pain because there is no room to get a socket over the nut, forcing the use of an open-ended wrench to tighten the suckers. It takes a very long time to tork a T-Clamp using a wrench, especially when contorted in a tight confine. Would the use of SS ABYC (sp?) engraved hose clamps be strong enough? Also, I guess it wouldn’t make sense to use both fiberglass exhaust tube in conjunction with hose because the money savings would be offset by the need for extra clamps. And finally, is the use of non-reinforced wet-exhaust hose a viable option? If so, would it be more flexible? Tell me what y’all think?
