Info needed on these custom Lehman mufflers

Hi all,

After a few years of finding all the info I needed by searching this forum in hundreds of situations, I can't seem to find anything this time.

1978 Universal Litton Europa 41 with twin Lehman 120s, new to me a little less than 3 years ago.

I have these unusual (I think) stainless exhaust mufflers/mixers which look custom made. On the prepurchase engine survey, I was told these "umbrella type" mufflers were prone to internal corrosion failure which could allow raw water back into the engine. He recommended replacing with a waterlift style. A mechanic that I followed up with about muffler replacement suggested I wait until they started visibly corroding and/or leaking before replacing.

Both mufflers are now leaking raw water from welded seams at their bottom. They still run cool aside from making a mess. I am looking for info about them to help decide whether they should be rebuilt by a metal shop (?) or replaced with something else.

Photos (apologies for orientation- I can't get iOS photos to orient correctly when uploading): view forward from the aft end of one muffler showing raw water hose into the top of the muffler and wet exhaust hose exiting the side, and side view of same muffler showing the straight pipe exiting the engine welded to the exhaust can.

Not sure if it matters, but other things I found unusual (I think) are that the exhaust hoses seem big (5" OD) and they exit mostly below the waterline, so while I know the appropriate exhaust sound at startup and feel for overheating of the mufflers, I can't actually see the water flow.

Any info about what these are, what I should be thinking about when repairing or replacing, and (if repairing is an option) where I might get that done would be much appreciated. Thank you!!!

Dave Geiger

fiberglass water lift lasts way longer.

When you think about it, hot salt water mixed with diesel exhaust gas is a very corrosive mixture. Add in the wet and dry cycles, welds and who knows what grade stainless they used and I'm amazed any stainless steel exhaust component lasts as long as they do.

Your surveyor suggested replacement with fiberglass water lifts for a reason, sounds like good advice.

I wouldn't screw with it. I would get some quality water lift mufflers and be done with it.

Yep to fiberglass water lifts. Best way to go. Will need some room outboard and aft of engines to mount, that may be a challenge depending on equipment in engine room.

Those mufflers would cause a flunk on my engine survey.

What they all said. Get rid of the ss ones go with fiberglass. Centek maybe a replacement option. Defender stocks them. You'll also probably need new hoses if they are original. Look at it as a safety upgrade plus you'll only have to do it once.

Marine Exhaust Parts | Products | Centek Industries

Thank you all for the advice. It sounds like the best option is to build a new exhaust system using fiberglass water lift mufflers. I think I can find the room, but will need to replace everything from the engine back and that is going to take a lot of time/money, as expected.

I would like to try to repair the existing SS cans to get me through the rest of the season so the whole job can be done properly, assuming that's feasible. These lasted many years already and I imagine that I can get a few months more out of them if they are repaired. Can anyone comment on the existing install and whether it's possible to rework these type of mufflers? Every installation I can find includes a traditional riser and water injection before the actual muffler. Is this another known variant or something crazy that a prior owner invented? Any prior experience appreciated. I do understand the typical water lift setup- I am just trying to learn about what I have, one system at a time.

Thanks for everyone's advice,

Dave

The problem with those type muffler/mixers is I think they hold water after shutdown. If welds perforate (they aready have if leaking externally) the water can drain back into engine creating and even more expensive mess.

You are correct that they lasted many years, but understand that once welds perforate in one area, they could be doing inside as well.

If engine is ever hesitant to start or runs rough on start that may be a sign of water getting in engine. If caught soon, you can dry out engine and avoid damage. Know the warning signs.

Water lift mufflers work great BUT there are two cautions.

Diameter helps reduce the back pressure , so go for a good sized unit.

If the engine is hard to start and needs long cranking (like after running out of fuel) the sea water will still be pumped in to the muffler but there is not enough exhaust pressure to push the water out.

Closing the sea cock till the engine catches is the most common drill.

Water lift planning

Thank you all again for the advice. I pulled off one of the mufflers/mixers and found the inside in very clean condition aside from the area where inner dry exhaust pipe sits in salt water, where it is corroded to the outside of the can- but fortunately not into the dry exhaust pipe, so it looks like no intrusion into the manifold. It looks repairable, but before considering that as a temporary fix, I want to sort out my options to find the best cost vs. benefit.

I am trying to plan a new water lift system as advised. I have looked at several guides that give mixed info about clearances with respect to the waterline and related measurements. Can anyone help with the below questions or direct me to a professional source? I'm in the San Francisco Bay area, pretty far south (Redwood City). I can't move the boat at the moment due to the exhaust situation (and to a broken bolt that I left in the manifold, which is another story, but that one I can deal with!).

1) my exhaust manifold is only located about 4-5" above the waterline. Does this mean I need a custom dry riser ("gooseneck") to get the level higher before raw water injection? Or can I use the standard stock cast iron injection elbow? I know I will need a siphon break in the raw water line.

2) I have about a 16 feet run of 3.5" ID exhaust hose before it exits. This works out to a hose volume of about 8 gallons. I read that the waterlift should be sized to accommodate the whole volume, but is this just for sailboats (where the boat will be pitched/heeled extensively with the engine off)? I'm hoping so because standard water lift capacities seem nowhere near that.

3) my exhaust exits the transom almost completely underwater (why would they do that?). Does this affect my install in terms of needing more insurance against water backflowing and overwhelming the muffler into the engine? Would flappers at the tailpipes suffice? Does anyone have any experience with check valves?

I think the above is starting to explain why the original or previous install used these mufflers- it kept the water injection point and the rest of the system safely elevated, but of course everything relies on the muffler not corroding and that's a big risk.

Thanks for any advice or direction.

Dave

Look up Seaboard Marine in Oxnard, Ca. Phone them. Yes they are away away but they really know exhausts and have done long distance relationship re&re often.
Look up their website
www.sbmar.com
And spend some time reading about exhausts. They have made a lot of info available that will help you understand

tdcody said:

1) my exhaust manifold is only located about 4-5" above the waterline. Does this mean I need a custom dry riser ("gooseneck") to get the level higher before raw water injection? Or can I use the standard stock cast iron injection elbow? I know I will need a siphon break in the raw water line.

I believe best practice will dictate a new dry riser and mixer to get you higher above the waterline. 18" is a height often quoted

2) I have about a 16 feet run of 3.5" ID exhaust hose before it exits. This works out to a hose volume of about 8 gallons. I read that the waterlift should be sized to accommodate the whole volume, but is this just for sailboats (where the boat will be pitched/heeled extensively with the engine off)? I'm hoping so because standard water lift capacities seem nowhere near that.

There are ways to reduce the chances of backflooding, as you mentioned a flapper, a larger lift muffler, or if you have the height in the engine room a separator. A Separator will split the water and gas and drain the water separate from the gas, any water travelling back up the exhaust will detour at the separator to the drain.

For example one concern is if you are docked with your transom into a chop. The water might eventually fill your lift and then up to the riser. The conditions for this to happen with a 16' run would be unusual, but not impossible. This could not happen with the engine running.

3) my exhaust exits the transom almost completely underwater (why would they do that?). Does this affect my install in terms of needing more insurance against water backflowing and overwhelming the muffler into the engine? Would flappers at the tailpipes suffice? Does anyone have any experience with check valves?

"almost completely underwater" At idle speeds there is minimum exhaust gas and therefore minimum need for the full 3.5" exhaust and as a result backpressure is very probably within spec. Underway the full 3.5" becomes
exposed as it is needed. Your arrangement is actually pretty common. A flapper is a type of check valve, I'm not a fan of in-line units
because you can't see whats going on and excessive backpressure from a damaged one can create real engine problems.

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$0.02

Keysdisease said:

$0.02

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C lectric- thanks for the tip. Seaboard Marine has a lot of good info andcose enough to work with them if needed.

Keysdisease- thank you for the detailed answers- worth quite a bit more than $.02!

I'm having a local marine metal shop (Svendsens) take a look at my existing mufflers to see what would be involved in repair or replacement so I can start a comparison between that and a custom riser and waterlift setup. I learned that these units are called standpipe mufflers, and apparently were common before the water lifts became standard.

Thanks again,

Dave

I have a '79 41' Litton Europa, had the exact setup. Mine never did leak but I scraped it because it was in the way and UGLY. Installed a new water lift. BTW, I would enjoy swapping pics and ideas about our Littons.

Howdy Dixie Life

Dixie Life-
Thanks for posting about your Litton- I'd definitely like to compare notes. Its been an adventure trying to sort out some of the systems on mine. I assume your engines are mounted about the same as mine, with the heat exchangers about at the waterline. Can you tell me about your water lift install? Where did you put them? Did you have custom risers made for the engines or just use the stock mixing elbows? Do you think the stainless mufflers were original? Please feel free to send me a PM!

Dave

Dixie Life said:

I have a '79 41' Litton Europa, had the exact setup. Meine never did leak but I scraped it because it was in the way and UGLY. Installed a new water lift. BTW, I would enjoy swapping pics and ideas about our Littons.

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We have a very similar "standpipe exhaust" our raw goes in the side. Age unknown.
1977 GB36CL #527 2715E just started leaking.
Label has Van Vetter Inc Seattle. Have not been able to find a replacement

I was concerned about weight hanging off exhaust elbow, corrosion, and zero ability to repair in typical boatyards. I replaced with Centek water lifts. I reused most of existing exhaust hose from ER to transom. Combination of fiberglass elbows and reducers and some new hose coming off elbow now. I recall using the 18" number previously mentioned.

Zero problems, Can be easily repaired/replaced with stock hose and parts, and no worries about backflow. I mounted them on marine plywood covered with diamond plate. Only change I would make is ensuring proper grade of stainless hold down screws. Mine rusted.

A lot of design ideas online about where things should be located in relation to waterline.

cgood said:

We have a very similar "standpipe exhaust" our raw goes in the side. Age unknown.
1977 GB36CL #527 2715E just started leaking.
Label has Van Vetter Inc Seattle. Have not been able to find a replacement

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Have you tried Brian at American Diesel?

Brian at American diesel is going to tell you to get rid of them. Then you ask him to ship you the exhaust elbow kit so you can set up regular fiberglass lifters. My GB 36 had regular exhausts with lifters, my new 42 has what you have. I already have all the parts to convert as I don't want to suck seawater into my exhaust manifold. Pro tip, don't use bolts to fasten the elbow to the manifold. Put in studs, with some grease jic, and use nuts, with some grease. You don't want to have to remove four lower snapped bolts like I did the first time I swapped elbows. Make sure and use grease and not noseize as it can contain metal and will cause dissimilar metals issues.

Not going to get in the discussion, but I would like to make a point. You say your mufflers make a mess, but you may try to "get by" till later. Well, just understand you are probably poisoning yourself , because there's exhaust gas entering the boat too.

I am a Welding Engineer and work with 316 all day. There is no perfect grade of stainless that can survive elevated temperatures that are cycled along with exhaust gases and salt water. If you have a leak now, you are betting your engines life on a better solution. There is a reason designers moved to fiberglass.