Exhaust Riser Question

[bigd14]

Hey everyone-

I've started to address the exhaust system on my raw-water cooled Atomic 4 in my 1972 Ericson 27. It looks like its been poorly cobbled together, with a very loose attachment to the manifold (at least it came off easily!) and no support or anchors anywhere. The exhaust exits the manifold and almost immediately enters an aluminum exhaust riser, where the cooling water is injected. It then leads aft to an old plastic water lift muffler, and then up a long length of hose to the top of the port lazarette locker and out the stern. See the attached photos.

I've been wondering if the aluminum exhaust riser/elbow (Barr Mfg model 20-0101/20-0094) has been installed backwards- it appears that the cooling water enters on the wrong side of the riser and higher than the manifold! In all the exhaust diagrams I have seen, cooling water is supposed to be injected on the downstream end below the level of the exhaust manifold, but then I have never seen this type of exhaust riser used either. Is using this type of riser even a valid installation method for a gas engine? Has anyone seen a similar setup?

If anyone has any advice on this current system or what I should do for a new system, or photos and/or descriptions of their currently functioning systems I would really appreciate it!

Thanks,


Doug

[rigspelt]

I'm not an expert. Interesting system, great photos.
1. I wonder if the riser is correctly installed, and the cooling water only mixes with the exhaust gasses inside that riser on the far (down) side after going over the top? Perhaps there is a jacket system on the near (up) side that starts cooling the gasses before mixing with the water on the far side, before entering the pipe to the waterlift muffler?
2. I don't understand the blocked off port on the bottom of that riser. Maybe it is an optional port?

Is there a manufacturer's name or part number stamped on the riser? Googling them could help.

I did not find a riser quite like that when I searched for available options among currently available models, but it would solve my exhaust problems nicely if they are still available. I shall follow this with interest.

[luvmyi36]

Doug,
not sure about your question, but it looks like you are lacking an anti siphon device. On mine, it is in the rubber hose exiting the manifold before it mixes.. Adding one could save you future aggrivation. Just food for thought.

[rigspelt]

Found it: looks like it is a Barr Marine Diesel mixing elbow: http://www.manifoldwarehouse.com/mes/mgr?brch=mani&id=18. Took about an hour. So I went to http://www.barrmarine.net/. They list two numbers for the Atomic 4: UV-1-259624, UV47-261050 but googling those numbers show they refer to the manifold and gasket, not riser. I found no other reference to that model except at manifoldwarehouse.

Here's the results of my search prior to making that hit:

Google image search:
Same riser shown here: http://www.yachtsurvey.com/exhaust_risers.htm. Notice the hose is fitted the same as yours (on the rising side).
This one makes me think it could be Westerbeke riser, since they made the Atomic 4: http://www.gulf32aeolus.blogspot.com/

So I went looking for Westerbeke or Universal exhaust riser/mixing elbows. Go here http://shop.torresen.com and search for their "universal exhaust riser" to see a similar model, though not the same.
Also http://www.go2marine.com/product.do?no=115172F

I found this information "The exhaust riser is a very common part used on many Yanmar engines up to 30 hp. Yanmar p/n 104214-13521 ($99.91). The inlet is left hand threads, so you will need an adaptor, Yanmar p/n 104214-13580 ($27.10). The riser may look strange because the water injection nipple is on the engine side. This is because there is a passage inside that dumps water out of the outlet side. This is a big advantage because the water cools the entire riser." at this page hhttp://www.ericsonyachts.org/infoexchange/showthread.php?p=43352 which suggests how your mixing elbow/riser might be plumbed, perhaps.

The other thing I realized doing this search was that cobbling together galvanized pipe exhaust riser/mixing elbows on small sailboat engines must have come about as a cheaper solution than buying expensive elbows, and to get custom fits in some installations.

[bigd14]

Wow, Rigspelt, great info! I found the manufacturer to be Barr by Googling the numbers stamped on the side, but you've gone above and beyond- thank you! So it looks like the water intake may be in the correct position after all and this is not uncommon in diesel installations.

Jim, I'll have to look into the anti siphon issue- you're right, I have seen that in most of the diagrams too.

Now I just have to get brave and try to remove the fittings from this piece and see if its re-usable.

Thanks again.

Doug

[adab1402]

soak those fittings in atomic blaster for ease of deconstruction and use anti-sieze paste when reassembling . fair winds adab1402