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Old 03-21-2011, 02:27 PM
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Hot Section Rebuild

As part of my engine replacement project, I decided to junk the boat's existing, inadequate hot section and design and built a new one with a proper riser out of stainless steel pipe. The results came out pretty good:

http://www.moyermarine.com/forums/album.php?albumid=73
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Old 03-21-2011, 04:20 PM
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Thumbs up

Ed - very nice!

Although not replacing mine, I had to pull it off to get the painting done..now I am switching over to studs in the manifold .
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Old 03-21-2011, 05:43 PM
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Ed,
You must consider yourself fortunate to have the room for such a nice hot riser. Well done!

Al
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Old 03-21-2011, 11:33 PM
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Thank you Ed for posting your photos as I'm about to rebuild my hot section as well. Unfortunately I don't have the room you seem to have so I'm stuck with severely rusted parts and trying to wrench them with a 6 inch wrench isn't making it. So for me it's PB Blaster time! And when the rain stops I'll be back in the hole again.

Crash
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Old 03-22-2011, 07:06 AM
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Possible dumb question time :

How is it that your exhaust leaves the manifold on the front , or flywheel end of the engine?
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Old 03-22-2011, 08:00 AM
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Quoth our benefactor:

"Original factory manifolds were produced in two different types: Those with exhaust openings only in the reversing gear end and those with openings on both ends. The double-ended manifolds accommodated engines with "V-drives" and other boats which had exhaust systems that exited the vessel other than through the transom."

To be found about 1/4 of the way down the page here.
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Old 03-22-2011, 08:40 AM
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Quote:
Originally Posted by Crash View Post
Thank you Ed for posting your photos as I'm about to rebuild my hot section as well. Unfortunately I don't have the room you seem to have so I'm stuck with severely rusted parts and trying to wrench them with a 6 inch wrench isn't making it. So for me it's PB Blaster time! And when the rain stops I'll be back in the hole again.

Crash
The camera always seems to make it look roomier than it really is. The side view is taken by holding a camera at arms length through a small opening while crouched in a sail locker!

In my case, I had to remove the hose clamps from the waterlift muffler and the exhaust flange bolts (which, thankfully, were already stainless) and remove the whole hot section as a unit.

Quote:
Originally Posted by ILikeRust View Post
... The double-ended manifolds accommodated engines with "V-drives"..."
Bill, you are correct. I have a v-drive. The engine sits "backwards" from most installations, with the flywheel end towards the stern. The v-drive reverses the direction and rotation of the shaft, alowing the engine to be located further aft, right on top of the shaft log and under the cockpit floor. There's a picture of the engine without the v-drive installed in my Engine Install album: http://www.moyermarine.com/forums/al...&pictureid=524
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Last edited by edwardc; 03-22-2011 at 08:54 AM.
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Old 03-22-2011, 02:02 PM
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Ah , backwards , and along with that comes an alternative oil fill installation. It all makes sense to me now. Thanks.
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Old 03-23-2011, 03:11 PM
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Nice hot riser Ed. I wish i hard the room you have lol... I have room to get one arm and my head in through the starboard quarterberth, even less on the port side.

Nick
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Old 03-23-2011, 03:44 PM
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Good job mister Mister plummer.Your V-drive exit had me wondering.
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Old 04-19-2011, 07:08 PM
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Just came back from the boat where I installed a rebuilt hot section. This is not the final "in-place" section as I'll go back to install thread sealant before tighten every thing. I had to fuss a little with all the fittings to get them lined up correctly but it turned to looking like the pictures I attached to this post. I started the engine up (first time in a month) and she kicked over the first time...darn near sounded like a race car! After an acid flush and the hot section rebuild it seems there's more cooling water discharging out the stern so I'm actually real happy.

Conceptually I think it works??? Comments??

Thanks,
Crash

Sorry for the huge picture files..not sure how to scale em down..
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Old 04-19-2011, 08:14 PM
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Smile Nice Job.

Nice job Edward. Hope it all goes well for you....the engine rebuild as well.
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Old 04-19-2011, 09:49 PM
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Crash, if it was me, I would get the injection mixer as low as possible. From what I've read around here, you want a minimum of 6" of hose between the mixer & the muffler. I even have a plastic Vetus muffler and I have about 4" and have never had a heat/melting problem. The idea is to give more space in a hard starting condition for the water (being injected while the starter is spinning) to not fill up the hot section and dump into #4 cylinder. So, maybe add a piece of black pipe between the mixer & 90 degree elbow and cut the hose at 6" and see how it looks.

I also notice you have a bend in the hose which may make my theory above difficult...why not make another 90 degree with hard pipe and then have the mixer between that and then a few inches of hose between the mixer and the metal muffler.???

My $0.02
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http://www.moyermarine.com/forums/signaturepics/sigpic3231_6.gif

Last edited by sastanley; 04-19-2011 at 09:51 PM.
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Old 04-19-2011, 10:43 PM
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Thank you Shawn! I actually had the mixer piece closer to the muffler but working with that wire reinforced exhaust hose is a #*@%#! And all the while I'm in a fetal position I just said #$@* it and left it this way just to see what y'all thought. I'll be back down to the boat tomorrow and try it out your suggestion and see how it'll work. I'll be armed with heat gun this time.

The bend in the hose is actually a nice transition into the muffler all because the hose is a 'pain' to work with. With the thought of getting the mixer closer to the muffler I'll see how everything works and keep you all posted.

Thanks!
Crash
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Old 04-20-2011, 02:15 AM
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Different opinion:
I think your water injection point into the hot section is fine where it is. If, and only if, the integrity of your entire exhaust system is intact/adequate.
What i mean is, whether in a hard starting situation, normal starting situation or even when hand cranking, the relationship of water being pumped through the system to the amount of exhaust/air (engine as an air pump, which it is) being pumped through the engine, remains the same at all RPM's.
So, If you have a good manifold gasket, the manifold is torqued properly, the exhaust flange and gasket are air tight and all connections up to and beyond the water injection point are tight, I can't see how water can back up into cylinder #4.

I've seen many threads that suggest closing the thruhull until the engine is started, to prevent water back up, and I don't see why.
Am I missing something here?

I had to get that off my chest...been bugging me for a while now.
What am I missing?
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Old 04-20-2011, 06:16 AM
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My view, and I could be corrected, is that if the engine cranks and cranks without firing and the seawater throughull is open, then the water pump keeps dumping water into the waterlock muffler, filling it up because when the engine is not running there is no exhaust gas to push it out the stern. Eventually the water backs up into the hot stack and then into the manifold, and trickles backwards into a cylinder through an open valve, displacing air inside the engine which I guess bubbles up through the hot stack as water comes down. Am I right?
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Old 04-20-2011, 10:37 AM
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Much more exhaust gas comes out of the engine when running than air does when it is just an air pump and not firing. Some systems will not clear the water with just air.

On another note - in another thread Tom from Indigo had a stainless exhaust corrode to pieces pretty quickly. I was about to order stainless when I read that. Then I decided bronze would be good and it seems there is no such thing as bronze nipples - only brass

So is it back to black iron
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Old 04-20-2011, 07:16 PM
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Second attempt

Missed the rain this afternoon but I completed setting up the second attempt at installing the hot section but this time it's somewhat a combination of all the comments I received from the first install.

All I did this time was to extend the mixer 6" down with black iron and screwed on a 45 degree elbow. This actually put the mixer in a better angle to the water lift (thanks Shawn). The wire reinforced exhaust hose was still a #*&%@ but at least I had a heat gun to help out.

I fired up the engine (kick over the first time again with moderate choke, ) and was working like a charm. Water and exhaust discharge was much better than with the original set up and still sounding like a race engine. Going to finish the project with heat wrap soon.

Sorry folks I'm really stoked right now! Oh sorry for the over sized photo...
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Old 04-20-2011, 09:08 PM
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Crash...looks good to me!

That blue striped exhaust hose should handle the heat no problem...just check it (without burning yourself) to make sure it is not distorted after some run time...I found that on all soft connections (i.e., you needed a heat gun to bend it) that they leak as it warms up...expect to re-tighten the hose clamps around the system.

Every inch in the hot stack I think gives you a little more wiggle room & keeps water away from the cylinders...Also, expect to need full choke to start her...it is not uncommon...if you are old enough like me that you've driven a car with manual choke, they never needed it full on, but these updraft carbs usually need full choke to start..
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http://www.moyermarine.com/forums/signaturepics/sigpic3231_6.gif
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Old 04-20-2011, 10:16 PM
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Thumbs up

Shawn, yup that blue striped hose is the wire reinforced exhaust hose, brand spanking new. With this version I was able to cut off another 12" of hose and even though in the picture the hose looks curved (to the left) it's actually curved slightly down ward to the water lift.

Yes, checking for distortion (and kinks)in the hoses is a practice I've already had since my first boat. Thanks for the reminder, as it's always a good thing. As I removed the old exhaust hose and inspected it for the possibility of reusing I noticed the interior of the hose was severely "bubbled" to the point it restricted (in my guess) more than half it's capacity. I plan to replace the rest of the hose from the water lift to the stern soon.

Thanks to everyone here on the forum I got a new hot section and a wifey that's a little excited the boats back in order!
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Old 04-21-2011, 01:01 AM
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Yet another consideration

This is a terrific thread! I thought I read somewhere that there should be 2 feet of metal pipe post the point of mixing gases and cooling water, before the muffler--to allow for some space/time for the gases to cool a bit before hitting the fiberglass waterlift, or any hose. I think the waterlift manufacturer recommends that.
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Old 04-21-2011, 04:16 AM
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I was a little uneasy about that hose too. Will it tolerate the heat? A section of hose connecting hot stack to waterlift muffler reduces engine vibration problems at that joint, but I imagine the gas is pretty hot at the water injection point and for several inches past that point.
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Old 04-21-2011, 06:51 AM
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My boat came with an anti-sphone loop between the manifold and injection point. It's mounted high above the engine compartment and makes me feel good.

I had water backing up while heeling that went away after replacing the worn out hot section in the same configuration here. It's gone through the first summer season and never a worry.

Tim
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Old 04-21-2011, 02:42 PM
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Hose OK downstream of 2 feet of pipe post mixing.

RIGSPELT,
After the 2 feet, hose is OK to connect into the waterlift--to address the vibration issue.
Mary
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Old 04-21-2011, 04:11 PM
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The sum of all the hot section parts including the mixer equals to 25 1/4" total. The new exhaust hose is actually 8" shorter than the original hose and after letting the engine warm up the hose was only warm to the touch at most. I'll know more once I get her out of the marina under full load. The hose is rated for this application so I'm more then confident it'll handle the heat. I'm watching to see if I need to install an anti-siphon in the water loop since the original didn't come with one and now she's performing better than when I purchased her. With better water flow I feel better knowing the hose will be a lot cooler now as I can see the discharge at the stern is 3x's better.
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