knottyBuoyz III The TW28 Project

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Cracker Larry
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Re: knottyBuoyz III The TW28 Project

Post by Cracker Larry » Fri Nov 06, 2009 9:23 pm

LMAO :!: :!:

KB, if the engine is not in the boat, heck there aint even a boat yet, why the antifreeze? Why not just drain it, lube it up and store it dry?

PS: Your buddy would have been on his own :wink: The excessive alcohol must have been in the dunkers and not the dunkee :lol:
Not even gonna ask where ya cut the new hole 8O


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Re: knottyBuoyz III The TW28 Project

Post by TW28RJ » Mon Nov 09, 2009 2:23 pm

Hey Rick,

you had mentioned modifying your tw28 to 31 feet. Is that still the plan? If so I'm sure that you drawn something up and would love to see it..

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Knottybuoyz
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Re: knottyBuoyz III The TW28 Project

Post by Knottybuoyz » Mon Nov 09, 2009 5:34 pm

TW28RJ wrote:you had mentioned modifying your tw28 to 31 feet. Is that still the plan? If so I'm sure that you drawn something up and would love to see it..
Likely. Haven't discussed specifics with Jacques yet. It's his design if I'm going to mess with it I want his blessing on a few issues.

I have a question for you diesel guru's. I have a Yanmar 4JH-TE. Exhaust outlet from mixing elbow is 3" Dia. The muffler and exhaust hose that came with the engine has inlet/outlet size of 1-5/8". Somewhere along the line there must have been a reducer of some sort but that wasn't included. I have the service manual for the engine but there's no mention of minimum exhaust size requirements. I don't know much about diesel engines, well actually at this point I know nothing about them, but if they breath better, larger exhaust, they should run better no? Can I go down to 2" all the way back (approx 12' run through water lock, muffler & gooseneck)? That should be better for the engine or should I keep it 3" all the way back?
Yours Aye! Rick
"It's not the boat "you built" until you've sworn at it, bled on it, sweated over it, cried beside it and then threatened to haul the POS outside and burn it!"

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Re: knottyBuoyz III The TW28 Project

Post by Cracker Larry » Mon Nov 09, 2009 5:47 pm

I think you'd better talk to a Yanmar tech about that. Is that a wet exhaust or dry? Most exhausts I've seen have no reduction and it would be bad for the engine to restrict the exhaust and cause a back pressure. But there are some engines that are designed to run with a specific amount of back pressure, and if so you don't want to run it without. You'll want a solid answer to that question.
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Re: knottyBuoyz III The TW28 Project

Post by Knottybuoyz » Mon Nov 09, 2009 6:14 pm

It's a wet exhaust system Larry. I'll see if I can locate a Yanmar dealer nearby. When I pulled the old exhaust hose off the muffler the inner liner of the hose was crumpled up reducing the size of the hose to about 1/2". I'm wondering if that's why they pulled it? :doh:
Yours Aye! Rick
"It's not the boat "you built" until you've sworn at it, bled on it, sweated over it, cried beside it and then threatened to haul the POS outside and burn it!"

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Re: knottyBuoyz III The TW28 Project

Post by Cracker Larry » Mon Nov 09, 2009 6:17 pm

I figured it was wet. I would not reduce it from the manifold exit size unless Yanmar specifically needs back pressure. Not something you want to guess at. I'd be surprised if it would run with 1/2 exhaust 8O
Completed GF12 X 2, GF16, OD18, FS18, GF5, GF18, CL6
"Ships are the nearest things to dreams that hands have ever made." -Robert N. Rose

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Re: knottyBuoyz III The TW28 Project

Post by Knottybuoyz » Mon Nov 09, 2009 6:29 pm

I checked the manual I have and there's no mention of backpressure requirements. I'll try to pick the brains of some of the engineers at work tomorrow. That is if I can find one with a brain! :wink:
Yours Aye! Rick
"It's not the boat "you built" until you've sworn at it, bled on it, sweated over it, cried beside it and then threatened to haul the POS outside and burn it!"

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Re: knottyBuoyz III The TW28 Project

Post by topwater » Tue Nov 10, 2009 8:44 am

Been around diesels most of my life but they were the big ones " off roadheavey equipment, trucks etc"
never seen an exhaust under 3" most have been larger, 5" to 8". Being a small marine engine and water cooled
it mite be different but it sounds small to me.
Novi 23 finally launched !

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Re: knottyBuoyz III The TW28 Project

Post by Knottybuoyz » Tue Nov 10, 2009 9:24 am

I've asked around. Surrounded by marine engineers here at work. Boatdiesel.com etc. consensus is 3" is minimum so that's what it'll be all the way back. Just means having to buy a new muffler. New hoses were required anyways. Thnx for the input. Bit of a steep learning curve with diesels.
Yours Aye! Rick
"It's not the boat "you built" until you've sworn at it, bled on it, sweated over it, cried beside it and then threatened to haul the POS outside and burn it!"

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Re: knottyBuoyz III The TW28 Project

Post by Daddy » Tue Nov 10, 2009 9:41 am

When you went to pick up the motor did you get into any of the marine salvage stores in the area? I remember there was a pretty good one in Mystic.
Daddy

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