Hole in my exhaust can.

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Rperlot
Posts: 53
Joined: Jun 1st, '05, 23:03
Location: CD28Megan Ann #352,Bainbridge Island, WA

Hole in my exhaust can.

Post by Rperlot »

I have a CD28 with a MD7B.

My exhaust can is rusted through and dripping hot seawater into my bilge. Does anyone know if there is a supply somewhere for this part? It appears to be a custom fit job by Cape Dory.

Has anyone rebuild their system using industry standard parts? It doesn't seem to be rocket science, but I'm no engineer. I'm going to need consultation, even with boat science.

Any suggestions are appreciated.

RPerlot
CD28 #352
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Parfait's Provider
Posts: 764
Joined: Feb 6th, '05, 13:06
Location: CD/36 #84, Parfait, Raleigh, NC
berthed Whortonsville, NC

Muffler? Mixing Elbow?

Post by Parfait's Provider »

Not sure what part you need, but Vetus is a good start. It may not be rocket science, but you do want to be certain that everything possible has been done to keep water out of the engine: vacuum breaker, loop in the exhaust hose, flapper valve at the transom, correct placement of mixing elbow relative to load water line, etc., etc, and so forth.
Keep on sailing,

Ken Coit, ND7N
CD/36 #84
Parfait
Raleigh, NC
Bob Maguire
Posts: 31
Joined: Feb 8th, '05, 17:13
Location: 30' Cape Dory "Temerity"
Anacortes, WA

Muffler

Post by Bob Maguire »

Richard,
Have an MD7A and am having a similar problem but not so severe. Just small pin holes where the exhaust pipe meets the muffler and raw water hose. For now, easily fixed with liquid metal. Most of these muffler types on the MD7's are large pieces of rust by now but can be replaced with something like the Vernalift muffler. I'm trying to hold mine together until I repower in September. Although the hot seawater is a nuisance, you should be concerned about the exhaust gasses in the cabin. I've installed a CO detector.
Bob
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Mitch F
Posts: 110
Joined: Feb 9th, '05, 09:56
Location: Pilgrim
CD30K, Mere Point, Maine

Post by Mitch F »

Our exhaust can was "perforated" with pinholes too. We searched for a replacement but since these parts were custom made for/by CD we could not find an exact replacement. In the end I had a buddy reweld the seam where the pipe meets the can. It has been two seasons and the exhaust has not leaked a drop (or vapor). If you had a professional welder do the job it would probably cost less than $20. I think it cost me a case of Milwakee's Best, which is significantly less than $20.
Rollergirl
Posts: 87
Joined: May 21st, '05, 14:27
Location: Flying Scott, Sunfish

Quite an excellent article

Post by Rollergirl »

http://www.boatus.com/goodoldboat/Marine_exhaust.htm

Powlas & Gerr are both great highly knowledgable technical writers, and the illustrations are first class. If you have to start to reconstruct with new parts that require more modifications then you planned, at least you will know what you are doing.

Good luck

Bill

PS: Go subscribe to Good Old Boat
Rperlot
Posts: 53
Joined: Jun 1st, '05, 23:03
Location: CD28Megan Ann #352,Bainbridge Island, WA

Just a drip.

Post by Rperlot »

I went out today and kept an eye on the unit. There is just a drip from the bottom of the can, right by the drain plug. The drip is staining my bilge, but the stain makes the problem look a lot worse than it is.

I've found some articles from earlier postings years ago where a couple of folks have used aftermarket fiberglass parts to rebuild theirs. Apparently the pipe off the manifold has standard piping threads and you can use standard black iron threaded pipe. The postings are supposed to have pictures attached. The links to the pictures are broken. So if anyone has done this work and can provide pictures, that would be great.

I think I'll get through the season then dismount the can and take a closer look at it. Maybe a new weld will do, that's a good idea. I'm concerned about the location of the leak though. Where it is it seems to me there might be a much bigger problem than just a small part of a seam. Itis in the can itself rather than where the pipe meets the can. I might need to throw in the towel and do a full replacement.

So my thought was to study the article provided. It looks to be a very detailed, good read for another, non-friday night when I have less wine swimming around in my head. Then I'm thinking of buying a fiberglass, aftermarket can like one of those suggested. It seems that the mounting will be the hardest part of the reman, as it is a custom design by CD. But if I cut the can along the bottom seam, at the base, I can use the bottom of the existing can as a mounting platform for the new fiberglass one.

That's my best laid plan for now.

Thanks for the ideas and the article.
Kent Martin
Posts: 19
Joined: Mar 30th, '06, 16:55
Location: S/V Munin
1979 CD30
Clear Lake, Texas

Post by Kent Martin »

All,

I just had this problem on my new CD30. The old muffler had rusted out, apparently due to an oversized line running to the muffler. My shipyard could not find any commercial replacement (including Spartan) to fit the space, so I am now waiting for a machine shop to fab up a new one. It should be delivered in the next couple of days; I will report to the board once it gets here.

Kent
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