Thursday, October 24, 2013

Exhaust System Project - Mock UP

I had to replace all exhaust system components from the old engines 1 ½ inch system because the new engine uses a 2 inch system. This is the mock up of the new exhaust system. A sailboat with an inboard engine is usually water cooled. Instead of a radiator like your car (water to air heat exchanger) boats use a water to water heat exchanger. Sea water is pumped from outside the boat and used it to cool the engine coolant. The sea water is then disposed of through the exhaust system. The water cools the exhaust and is used to muffle the sound in a water lift muffler or wet muffler. The water lift muffler instructions give a generic layout (see below) with key dimensions required to function optimally.


From Centek muffler installation instructions
 
Here is what the 1st mocked up exhaust looked like inside Something Else.



1st Mock  up.  Exhaust elbow silver piece on the left, muffler black object on right of picture.


One concern after putting it together is the water fall dimension from the exhaust manifold and the top of the muffler. The requirement is 12 inches minimum. It is hard to measure because there is a bulkhead between the engine and the muffler and everything is on a slope. I have about 11 inches. So I need to raise the engine exhaust elbow a little since I can’t lower the muffler. I’ll raise it by installing a longer pipe. This mean the exhaust elbow will go above the engine compartment and into a storage area above the engine compartment. I made a cutout to accommodate the exhaust elbow and have installed a loaf pan to close out the area… No Mom, the loaf pan is not a good one, I bought it at a thrift shop.



Final Mock up.  Exhaust Elbow is silver object on the left and muffler is black object on right of picture.


Loaf Pan close out for exhaust elbow.


The water lift portion of the mock up looks good. I have not decided all the details of the installation from here to the transom of the boat but I have a plan.



Muffler and water lift portion of mocked up exhaust system.


TBD... How to plumb a slope from A down to B.  I think I have a plan.
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3 comments:

  1. Thru Prairie Grass: Govert, South DakotaOctober 25, 2013 at 2:02 PM

    I studied the generic layout really hard. I understand hangers serve a function in an untold number and variety of repairs, but I don't understand the use of a hanger here (at 4). Or the boot, for that matter directly under the hanger. Is that a right boot or a left boot? And what do you do with the other boot for Pete's sake? Now as to the loaf pan, great idea!

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    1. Greg Vanderboom ~ Something ElseOctober 25, 2013 at 7:31 PM

      Yep, it’s complicated! I’ve looked at the same or similar exhaust system pictures for a year now and I hope I have it figured out. I never saw the hanger or boot until you mentioned it. Who is Pete? The boot shaped thing is suppose to be the outline of a generic engine. The hanger is the water break do-hickey. The sea water that was used to cool the engine is dumped into the exhaust here. The hook part lets air into the system so it can’t siphon water and fill up the engine… or worst case sink the boat. Oh boy, I hope I have it figured out.

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  2. UnknownOctober 26, 2013 at 11:17 AM

    I agree...it looks complicated. But, it also looks like you've again made some clever adjustments to make this repair project work out.

    From the schematic drawing it looks like the engine sits mostly under water, I assume to help facilitate the water-cooled nature of the system. Doesn't that greatly shorten the life-span of an engine? Also, that means there's water inside the boat, inside the outer hull. Is the engine in a separate compartment of some sort that keeps that water from going elsewhere into the boat? Seems like a screwy design that intentionally lets water into the boat, when you'd think the whole point is to keep the water outside the boat!

    Thanks for including the pictures of what you're doing. Without them it'd be really hard to visualize or understand what you're doing.

    Good luck with the rest of this project. Hope it all works out. But, oh yeah, you "have a plan"...which I assume has it all working out okay in the end!!

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