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Loose exhaust riser

yalcin

Junior Member
I have started working on the aft end of our Universal 5432, taking off the muffler and the heat exchanger. The plan was to replace the leaking muffler, check the hoses for build up, clean the heat exchanger. Then I realized the exhaust riser rotates easily, as seen in the video.


I'd like to remove the heat shield and take a look but I don't know how hard it is to put it back. We need to commission the engine next week so I do not want to start a project too hard. I guess what I am scared of is to break a seal somewhere and have to wait for parts for weeks.

We haven't spotted a leak from there so far but maybe we were not paying enough attention. I don't think there is significant coloring around the junction that is loose. Looking for some advice here.
 

Christian Williams

E381 - Los Angeles
Senior Moderator
Blogs Author
Great to have the video.

Personally, I wouldn't hesitate to unwrap the heat shield material (I've never tried it, however). A hose clamp could always reattach the end if needed.

I'd want to look at that loose connection and tighten or seal it.
 

yalcin

Junior Member
It looks pretty beaten up at that junction. I don't think it's possible to tighten without taking the elbow off. I cannot rotate the piece around.

IMG_20201124_132552.jpg

However, it looks like it is necessary to address this though. Now the hesitation is to remove the exhaust flange.
 

clayton

Member III
I had to replace the water injection elbow 5 years back, the original Onan cracked. Could not find another Onan, wound up going with a Westerbeke and then a Centek reducer to match the exhaust hose. Replaced the exhaust flange mounting gasket as well. Hopefully you can get it apart and find its not cracked and put it back together with hi temp pipe dope and get it in the correct orientation.
 

Kenneth K

1985 32-3, Puget Sound
Blogs Author
The exhaust flange should be easy to remove, it should just be three bolts. Be sure you drain all the coolant from the manifold first, or it’ll all drain out of the flange when you pull it. Once the flange and riser are off, you’ll have to rotate that loose section 360° to get it both tight and into the proper orientation. If you can’t do that, you’ll likely have to rebuild the whole riser. From the looks of it, it’s mostly off-the-shelf 316 stainless pipe and fittings. (except for that elbow which looks like it has a custom welded water injection fitting added to it). Of course, If you damage the flange in the process, you’ll have to order a new one from Westerbeke.com. And even if you don’t, you‘ll have to order a new flange gasket for reassembly (unless you want to cut one yourself out of gasket paper).

In an “emergency,” I wouldn’t hesitate to run the engine like that. But it’s likely you’ll get exhaust fumes. Which could be a safety issue if it leaks badly. You‘d have to figure out how to keep the engine room and the cockpit well ventilated.
 
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yalcin

Junior Member
We will attempt to remove the flange tomorrow. I have just come to the realization that the pipe has to turn 360, otherwise it won't work. If that's the reason that the connection is loose and the orientation doesn't allow tightening it more, would it be reasonable to jam as much pipe sealer as possible in there? I was thinking teflon tape but I don't know if it is even safe to use in this high temp place.

I have already ordered the gasket and I really hope the flange comes in one piece.

The heat shield looks like a thick fiberglass cloth. I am not sure what it is but it was easy to get it back on.
 

Kenneth K

1985 32-3, Puget Sound
Blogs Author
Sealing leaks from the outside almost never works long term, but it might help for a couple of hours. I wouldn’t use Teflon tape, I don’t think it’ll stand the heat. I‘d probably try high-temp-RTV sealant. Auto parts stores sell it for cars, and hardware stores sell it for fireplaces and heaters.

If you only work on that loose joint, it has to swing 360°, but if you can get the adjacent joint to move as well, each joint could move 180°, and get you to the same result. It can take a lot of force to move those joints. Just make sure that the force you apply is acting on the pipes and the fittings—not on the flange.

Some photos from my riser replacement (M25 engine):
20170125_223148.jpg
That small shiny dot at the lowest point in the manifold (just forward of the flange) is a brass drain plug.

20170429_001637.jpg
I went with a Yanmar elbow on top of 316 stainless pipe with nickel-based anti-seizing compound on all the joints.
 
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jtsai

Member III
I recommend not taking short cut on this repair. My former boat had a Westerbeke 13 and my crew complained about headache during trip from Annapolis to North Carolina. It was not until the injector elbow blew apart on the Albrermarle Sound and spewed exhaust in the engine compartment we realized his headache was attributed to CO in the cabin. Elbow was replaced and CO detector was immediately installed. The pipe connects to the exhaust manifold also blew up within two years. If all the components are original, remove and inspect the entire assembly.
 

yalcin

Junior Member
Exhaust elbow flange was not hard to remove at all. I did not even need to use a penetrating oil.

The elbow looks good to me except for some carbon build-up. I think I can tighten the loose connection without much trouble but for now I will wait for the gasket and thread sealer. Every little thing is an online order which takes time to arrive. Meanwhile, all there is to do is cleaning.


IMG_20201125_102551.jpg


IMG_20201125_104732.jpg
 

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nquigley

Sustaining Member
Exhaust elbow flange was not hard to remove at all. I did not even need to use a penetrating oil.

The elbow looks good to me except for some carbon build-up. I think I can tighten the loose connection without much trouble but for now I will wait for the gasket and thread sealer. Every little thing is an online order which takes time to arrive. Meanwhile, all there is to do is cleaning.

View attachment 36170
It looks like you don't have to swing one of the risers around the other to get them re-connected. It seems that you'd barely insert the double-threaded connector to both riser segments (in the orientation they need to be in the engine room), and then use a pipe wrench to turn the connector, simultaneously screwing it into both of the other segments. Right? (you'll want to clean up those threads as much as possible to minimize friction as you tighten the connector.) Good luck!
 

Christian Williams

E381 - Los Angeles
Senior Moderator
Blogs Author
I realized I was not quite sure what to do when pipe fittings can't be tightened hard at each end for proper alignment .

Apparently the answer is pipe "sealant," as opposed to anti-seize. It is designed with more body, and to fill gaps. In the case of connections without a temperature factor, Teflon tape does the same thing.

Passing on a link to a discussion of exhaust elbow issues in which Maine Sail participates:

 

yalcin

Junior Member
use a pipe wrench to turn the connector, simultaneously screwing it into both of the other segments. Right?
Here, both sides have right handed threads so this does not work.
Passing on a link to a discussion of exhaust elbow issues in which Maine Sail participates:
I was already waiting for the thread sealant Maine Sail recommend in the above link. Real-Tuff is not in stock in Home Depot around here so I ordered it online from a different site. Thank you Christian for the reference.
I also replaced the nipple piece with a new 316 one. Svendsen's marine shop in Alameda has full selection of these pieces on the shelf, I was impressed. Unfortunately the exact match was sold out and the replacement I got is half inch longer. Not noticeable to me.IMG_20201128_162441.jpgIMG_20201128_162856.jpg
I was able to align it right and it's tighter than finger tight. I can still move it if I have a good grip on it though. I am not sure if I am totally satisfied with what we have here, but it is definitely an improvement from what it used to be.
Now the wait continues for the exhaust flange gasket, new muffler, new coolant temperature gauge etc.
 

Kenneth K

1985 32-3, Puget Sound
Blogs Author
Sorry for not mentioning this early earlier, but those 316 stainless pipe sections come in two varieties—-schedule 40 (thin walled) and schedule 80 (thick walled). You probably want the schedule 80 for this job due to weight of the attached hose, the vibrating engine, etc. Or, at least make sure that the new piece you have is as thick-walled as the one you’re replacing. If the plumbing store doesn’t have Schedule 80 on the shelf, they can order it.
 

yalcin

Junior Member
I made sure that the wall thickness matches the old piece. I haven't verified that it is the thick one though, partly because I am not sure if I want to know or not. I am definitely not replacing the whole elbow even if it's made of schedule 40 pipes so maybe it's better not to know.
I cleaned it up as best as I can though and that's the limit of my love for the exhaust system. No 2 inch elbow upgrade this time, maybe one day.
 

Kenneth K

1985 32-3, Puget Sound
Blogs Author
Hey, if you replaced like for like, it should be good for another 30 years.....
 
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jtsai

Member III
If it can be loosen by hand then it is not tight enough for the installation. The exhaust pipe should have tapered threads and can be tighten with pipe wench beyond hand tight position. I suggest give it a try to eliminate all possibility of exhaust leak.
 

yalcin

Junior Member
We wrapped up this project and here is the update.

I was able to get one more full turn on the loose junction, 3/4 of it was without any tools except for a vice to hold the pipe in place. The last quarter turn required a long pipe for more leverage but it turned without cracking or anything. I don't think it's going to leak or anything.

Muffler is replaced with a slightly bigger one with 2" inlet and outlet. I have ordered CENTEK-1601805 from marinepartssource.com but the dimensions did not fit the description they had online. It is bigger than the description but a piece of starboard made a satisfactory installation.

In order to fit the 2" hose to the elbow (for the elbow to muffler connection) which has a 1.5" outlet, I cut a small piece of the old hose to go over the elbow outlet. The old hose has an outer diameter of 2 inches so it makes an acceptable sleeve.

The long exhaust hose from the muffler to the thruhull was 1 5/8 hose. I was planning to use it as is and in order to connect it to the 2" outlet of the muffler I bought a fiberglass reducer. It was all nice and good until I started shortening this long hose for installing the reducer. As I cut the hose, it started dripping water, the more I cut the more water came out of the hose. Until then I did not check inside of this hose because it looked perfectly fine from outside. This is what I saw:
IMG_20201203_162120.jpg
There was a huge restriction in the exhaust. I was so happy to find it because one of the potential reasons for the white smoke problem we have in the exhaust was high exhaust back pressure. We talked about it here: https://ericsonyachts.org/ie/threads/white-smoke-in-e38-universal-diesel-engine.17203/
And it is right here. I happily bought 9 feet of new 2 inch exhaust hose and installed it the next day. Here is another picture when the hose was outside:
IMG_20201205_090626.jpg
With this, the project wrapped up:
- Exhaust elbow cleaned
- Heat exchanger lightly cleaned with vinegar (it looked pretty good to me)
- Muffler replaced, all new hoses from the elbow to the thru-hull
- Replaced the broken coolant temperature gauge which is installed at the manifold outlet
- Replaced the thermostat and the temperature sender at the thermostat housing, now we have two temp gauges. We are a bit paranoid around losing the raw water underway which happened twice already. Now we have two overheat alarms.

Started the engine yesterday and after warming up and making sure the coolant levels are good, the good old white smoke was back. Such a disappointment.
I am still happy with all this work done especially after seeing the failure of the hose. White smoke still comes out but I guess it comes out more easily.

Also, there is no exhaust smell in the cockpit locker after running the engine as opposed to what we had before.
 

Loren Beach

O34 - Portland, OR
Senior Moderator
Blogs Author
Glad you replaced that old hose. I had rusty water starting to weep thru the outer cover layer on our original '88 hose when I replaced all of it as part of re-powering our boat two years ago. FWIW newer diesels often require a larger ID exhaust hose -- I suspect it maximizes their rated HP a little bit. Diesels pump a LOT of air thru their cylinders.

This is the second time I have seen an "aneurism" in an old exhaust hose on a sailboat diesel. Lotsa layers bonded together in those heavy duty hoses, and they do have a design life... !
 
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