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Discussion Starter · #1 · (Edited)
well the motor is back in the boat and bolted down. if you want to see all the pictures got to Diesel Conversion pictures by PaperboyRacing - Photobucket

My question is on the exhaust. the exhaust in our case with a v-drive to towrds the bow of the boat and with the stairs I wrapped the exhaust around between the motor and wall. I know I still need to wrap the pipe with the header wrap to insulate the pipe, wondering how many layer do I need? to keep the outside cool. as you can see the flex section on the exhaust has a slight bend in it to make up for the angle diffrence, is that a problem? also I need to add some support to the 1.5 pipe, does the support need to go from the motor to the pipe and not the wall since the motor may move some?

 

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holy hardware store exhaust

yes it needs to go to the motor, not the wall. the bend should not be a problem.

just a question thou, i dont see a water injection elbow, does it do it in the head?

and if money was not an issue i would take that exhaust measurements to a good sheet metal shop and get one welded up out of stainless dom tubing.

last question, how is the oiling on the motor working with the motor on its side? :cool:

edit i think i just saw an issue with the exhaust, i maybe wrong thou. does it matter that the exhaust tilts back to the motor, ie when you shut down how much water in the pipe can run back to the motor? it might be just the sideways view and the angle the shot is taken from but it looks like it runs down hill back to the motor
 

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Discussion Starter · #3 ·
Ok I rotated the picture, does not look as confusing. the water is not injected into the system until right before it exits the stern. so 90% of the system is a dry system. and there is a good 2-3' high loop so water should never flow back towards the motor. I agree its a hardware store exhast and does not look pretty, but if it works it works and thats what were going for.

Scott
 

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its a dry system, the you really want to put some header wrap on it. you also might want to put a sheet of aluminum spaced of the wall by a 1/4 some spacers to help too. just a piece about 6 by 12 with some cheap metal spacers would do a lot by that elbow.

as for looks, you should see the custom built by me exhaust of my car, yes it was built on purpose, but i did an ugly job. i used electrical emt in 3 inch size. but i copied a race exhaust sense the maker of the exhaust would not build me one but told me how to. btw my car is a 75 porsche 914
 

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Discussion Starter · #5 ·
yeah I will do the header wrap, but wondering how many layers I need to do to keep the temp of the pipe down. the metal heat shield is a good idea as well but there might not be alot of room.
 

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I used that fiberglass wrap that looks like 2" webbing and did 3 layers...down and back and down again.
Then tied in place with two pieces of SS wire wrapped in alternate directions then twisted around each other then wrapped again then on and on, this helps to keep it tight.
Where rubber gloves this stuff is FG and itches the same.
I am considering a final wrap of something else to keep the fibers from sluffing off....which they do at a rapid pace.
 

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Discussion Starter · #8 ·
very nice setup!, after more thought where as what I have will work, I am going to take and bring it home with me next weekend and see if I can get a shop to bend up a piece of pipe for me and weld the 90 on one end and the union on the other end, would look alot cleaner and be lighter and not need a support.
 

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R. Furborough
The factory in England where the engine is made did the marinization.

Columbia 34
Even if you have that pipe made in a lighter material you will still need a brace or bracket to support it...the vibration WILL fatigue it at the flange where it bolts to the engine.

Valiente
Thanks for the complement.
That loop is the highest point in my system...it drops down into the water lock/lift then goes under the sole and has another loop (the S shaped one in the pictures) about 8 inches lower than the dry stack, then slopes down/back out to the skin fitting.
I did it like that so no matter what happens the water will always drain back out...even if I crank the engine excessively, I cant flood it…..I think!
I also tried to isolate all the exhaust system from the boat with rubber mounts…I’ve heard this can help with the noise.
 

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Thanks again.
Agreed...seems conventional designs really jeopardize the most valuable piece of safety equipment on the boat.
I was very disappointed at what I found the industry sees as adequate.
 

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well the motor is back in the boat and bolted down. if you want to see all the pictures got to Diesel Conversion pictures by PaperboyRacing - Photobucket

My question is on the exhaust. the exhaust in our case with a v-drive to towrds the bow of the boat and with the stairs I wrapped the exhaust around between the motor and wall. I know I still need to wrap the pipe with the header wrap to insulate the pipe, wondering how many layer do I need? to keep the outside cool. as you can see the flex section on the exhaust has a slight bend in it to make up for the angle diffrence, is that a problem? also I need to add some support to the 1.5 pipe, does the support need to go from the motor to the pipe and not the wall since the motor may move some?

What is your Back Pressure after the mix elbow at WOT? What size is that engine? I agree, it looks like the water would run back into the exhaust. If you say it does not, that is fine, but is that also included in a rolling sea where you are going x-degrees vertical?

Brian
 

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I guess I'm wrong since it hasn't been mentioned, but I thought ALL marine exhausts had to be "wet" exhausts to pass CG approval.
 

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Wayne—

Lots of work boats I've seen use a dry stack, just like a diesel truck.
 

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I guess I'm wrong since it hasn't been mentioned, but I thought ALL marine exhausts had to be "wet" exhausts to pass CG approval.
It's an open question, however, where the "wet" part enters the equation. Most marine exhausts are wet for reasons of noise, not safety, although obviously an f/g boat will burn easier than a steel one.

In the example above provided by Kaluvic, the mixing elbow is below the waterline, but also ahead of the "turn" of the exhaust, which to my mind has many advantages over the more typical "mix in water just past the manifold and down a bit", because the waterlift and the anti-siphon valve in the typical "loop" can be points of clog or failure or backsiphoning due to sea conditions or overcranking.

I've had such failures, and now before we go tootling around the world, I want to solve them in a permanent way.
 

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Discussion Starter · #20 ·
the exhaust is pretty much 90% dry water does not get injected back into the exhaust tell just above the muffler. and the picture is a bit decieving the exhaust does slope away from the motor but not a lot. the loop in the exhaust is a good 3' above the waterline. see diagram.

 
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