Exhaust transition 2" to 1 3/4" HELP?

[Capt Ben]

Sailing hive, I’m seeking ideas for the best way to make the engine to water lift muffler connection provide the best flow with the least obstruction.
I’d like to be able to bulk up the water lift ss fitting from 1 3/4” to 2”. At least I think that’s the best solution. It seems though that I’m creating a slight dam for buildup of carbon at this transition point.
Does anyone know of a flared fitting that would not impede any flow?
BTW, this is a refit to accommodate a new engine installation.
Any suggestions?
see attached drawing…...

[Uncle Bob]

Originally Posted by Capt Ben

Sailing hive, I’m seeking ideas for the best way to make the engine to water lift muffler connection provide the best flow with the least obstruction.
I’d like to be able to bulk up the water lift ss fitting from 1 3/4” to 2”. At least I think that’s the best solution. It seems though that I’m creating a slight dam for buildup of carbon at this transition point.
Does anyone know of a flared fitting that would not impede any flow?
BTW, this is a refit to accommodate a new engine installation.
Any suggestions?
see attached drawing…...

How about a piece of correct size hose for the muffler a couple of inches or so long that will allow the larger hose to fit over it and all clamp down tight with a pair of really good quality ss hose clamps.

[Capt Ben]

Originally Posted by Uncle Bob

How about a piece of correct size hose for the muffler a couple of inches or so long that will allow the larger hose to fit over it and all clamp down tight with a pair of really good quality ss hose clamps.

Thanks Uncle Bob.

I think this would work but the slip hose would need to only be 1/8” thick wall. Would a silicone tape or a build up of high heat PC7 to a smooth cured new size and then new hose and good ss clamps work? I think it should be serviceable and not permanently affixed.

[timeout2]

New 2" Centek waterlift muffler is $150 or so.

[Uncle Bob]

Originally Posted by Capt Ben

Thanks Uncle Bob.

I think this would work but the slip hose would need to only be 1/8” thick wall. Would a silicone tape or a build up of high heat PC7 to a smooth cured new size and then new hose and good ss clamps work? I think it should be serviceable and not permanently affixed.

I reckon that any good quality rubber hose, it doesn't need to be heavily reinforced, would do, effectively you'r making the exhaust hose just a little thicker under the clamps. Possibly some of the silicone hose as used on turbo installs in the auto industry? I agree, it should be serviceable.

[Rapanui]

You can buy on eBay and elsewhere silicone hose flared reducers

[Capt Ben]

Originally Posted by Rapanui

You can buy on eBay and elsewhere silicone hose flared reducers

Thank you for the idea. I’ve found what you are suggesting but I’d need to place a joiner to utilize which is one more fitting and place for blockage.
https://www.pegasusautoracing.com/pr...sp?RecID=11163

[Capt Ben]

Originally Posted by timeout2

New 2" Centek waterlift muffler is $150 or so.

I’d rather not replace a perfectly good muffler. Thanks though.

[Sailmonkey]

The exhaust people (centek) make this.

2" X 1.75" Coupling - Centek Marine

I would suggest changing the water lift to 2" though. Especially if the original is old and made of stainless.

[Capt Ben]

Originally Posted by Capt Ben

Thanks Uncle Bob.

I think this would work but the slip hose would need to only be 1/8” thick wall. Would a silicone tape or a build up of high heat PC7 to a smooth cured new size and then new hose and good ss clamps work? I think it should be serviceable and not permanently affixed.

Would something like this be a bad idea? https://cdn.shopify.com/s/files/1/04...g?v=1418307668

[Capt Ben]

Originally Posted by Sailmonkey

The exhaust people (centek) make this.

2" X 1.75" Coupling - Centek Marine

I would suggest changing the water lift to 2" though. Especially if the original is old and made of stainless.

Thank you for the suggestion and link. Yes, the end fittings of the muffler are SS but it’s in great shape. With the Centek reducer, I guess I’d use a short length of the 1 3/4” and fittings reducer at the muffler and use about a 30” length of 2” from the engine. An other option would be to place a short length of 2” hose at the engine exhaust and then use the Centek reducer and a 30” length of 1 3/4” hose to the muffler. Where is the best place to reduce the flow? At the engine is a downward fitting. The muffler fitting is nearly horizontal.

[Sailmonkey]

I would reduce it where it’s least subject to vibration and movement. IE at the water lift. Although if you use corrugated 1.75” hose a short section of 2” right at the engine should be quite simple to work with.

[Terra Nova]

Originally Posted by Capt Ben

I’d rather not replace a perfectly good muffler...

Perfectly good except for being the wrong size.

[Cheechako]

I'd buy the right fiberglass muffler. SS is not a great choice in that environment anyway and may be corroding from the inside out. But, other solutions:
-Have a ring of sheet metal welded on the muffler to make it 2"
-Put a barb/barb hose reducer in the hose between the muffler and the engine. maybe there are bronze reducers available that size
-Use the fiberglass reducer shown above.
BTW, those are easy to make. layup fiberglass around a proper size piece of round stock coated with wax. When it's set up, use a hole saw with appropriate ID in the saw to clean up the OD of each end. or just grind it smooth and round.
I made my own mufflers for some 12V gen sets I made.

[artisanmach]

https://www.pegasusautoracing.com/images/L/SR51-45K.JPG