exhaust cape dory 22

[Hymodyne]

Hello,

An exhaust system came with my A4:


the issue is that if I install the manifold with the flange as pictured, the vertical loop won't fit in the space where the engine will be located; the area forward of the cockpit floor. There is space, however, behind the rearmost port access panel, which would locate all of the exhaust parts pictured basically under and behind the cockpit seating area, port side.

I planned to install a straight aluminized metal flange and pipe to the manifold on the engine, and run that pipe back to the rear port-side space mentioned above to then connect with the mounted exhaust parts pictured.

There is a barb on the exhaust canister pictured for cooling water. Since there will most likely be a 3-4 ft run of straight pipe prior to that pipe meeting up with the system pictured, at what point in the new pipe after the manifold flange should I locate a barb for cooling water on the long pipe, and does doing that mean I can block off the barb on the expansion chamber?

James

[Mo]

If the engine is in the boat take some pics of the rear aspect of the engine, cockpit floor or whatever is around there. You want to try and put a riser just after the exhaust manifold...it can be as high as you have room for. The problem with a long straight run further back sternward means there will be water on the engine side of the loop...this will make it back into the engine and that is exactly what you DO NOT want to happen.

Keep in mind that your exhaust construction will be largely determined by boat construction, available room etc. Can it be done? You betcha...just keep in mind that you need it to come high in places to keep water out of the engine.

Attaching a pic just for you to get the idea.

[ndutton]

James,

Do you intend to keep the (for lack of a better word) muffler? If yes, we really need to know how it's configured internally to answer your question. If no, you can inject the water anywhere after the high point in the hot section. A foot lower than the top is really good.

[Hymodyne]

I do plan to keep the muffler. I can't really tell anything about it beyond it being made of cast iron and it having a hose barb near the front. rubber hose is attached to the rear opening of the muffler. The engine is out of the boat and the boat is on the hard. If I were to install a vertical loop section, early after the exhaust manifold, could I make that out of muffler pipe, or does it have to be made from cast iron pipe? I could cut a portion of the loop pictured off the existing system, thread the lower portions and use that loop.

James

[ndutton]

If the hot section is threaded the ABYC and the USCG requires schedule 80 pipe. If bent and/or welded the requirement does not apply (I think).

I have no way of knowing what you have there but typically water injected into a "muffler" is only done in standpipe systems and standpipes are mounted vertically to function properly. The exhaust inlet and outlet as well as the relative water injection point on yours is not typical though. It looks like a standpipe on its side but seems to function like a waterlift. Then again, it doesn't look like any waterlift I've ever seen. A real puzzlement.

In the design of your installation it's best to keep the exhaust system at least up to the waterlift (if that's what it is) as close to the boat's centerline as possible. This minimizes the effect of heeling.

[romantic comedy]

My guess is that it was someones idea of a muffler.

You can make the exhaust out of iron pipe. (cast iron is not used this way)
We use black iron, because galvanized emits toxic fumes when hot. They are the same pipe though.

The basic idea is to have the exhaust gasses go as high as possible, to avoid sea water back flow. Then the cooling water is injected on the down hill side toward the exit. Usually a water lift muffler is installed. Also standpipes can be used.

[Hymodyne]

a better picture of the muffler:



james

[hanleyclifford]

Your system is unsatisfactory because it places way too much weight on the manifold flange. The hot section is too long and the water is injected way too far downstream. Your "muffler" is way too heavy and does not look like a marine unit. I suggest you start fresh with black iron pipe after the engine is in the boat.

[Hymodyne]

Would this size waterlift muffler work?

http://www.ebay.com/itm/Vernalift-sailboat-muffler-exhaust-/140923801992?pt=Boat_Parts_Accessories_Gear&hash=item20cfb69188&vxp=mtr

[hanleyclifford]

Would this size waterlift muffler work?

http://www.ebay.com/itm/Vernalift-sa...b69188&vxp=mtr

Yes, but your hot section would have to be 2" or stepped up to 2" before the inlet. Your long exhaust run to transom would be 1 1/2" ID hose.

[hanleyclifford]

Here is a sample 2" hot section: