Cruisers Forum
 


Join CruisersForum Today

Reply
 
Thread Tools Rate Thread Display Modes
Old 26-11-2010, 20:24   #16
Mooderator
 
capngeo's Avatar

Cruisers Forum Supporter

Join Date: Jul 2010
Location: Key West & Sarasota
Boat: Cal 28 "Happy Days"
Posts: 4,211
Images: 12
Send a message via Yahoo to capngeo Send a message via Skype™ to capngeo
Quote:
Originally Posted by ShipShape View Post
crashkahuna, as a surveyor I am obligated to tell you that the reinforced PVC water hose on your wet exhaust is a danger to you and your boat. If the vessel is afloat and the seacock is not closed, IMMEDIATELY CLOSE YOUR ENGINE'S RAW WATER INTAKE SEACOCK, AND REPLACE THE PVC HOSE WITH APPROVED MARINE WET EXHAUST HOSE BEFORE STARTING YOUR ENGINE AGAIN. I also see other reinforced PVC water hoses in the picture, if they are part of the engine system then also renew those with approved hoses at the same time.

Surveyor hat off.

Replacing my engine's exhaust elbow is so close to the top of THE LIST that I'm already looking into it. Given that this part is doomed to corrode, and that a failure has the potential to sink a boat and kill people with CO poisoning, I do not understand why replacements are not readily available. Nigel Calder usually has good advice and in his Marine Diesel Engines book he says that, "The elbow is frequently custom-made and hard to replace, so you should inspect it annually and carry a spare on board." Given that it looks like I'll have to fabricate my own exhaust elbow I intend to make two. If it is really fun I'll make three.

The main reason I have not considered stainless is the issue of drilling and tapping a hole for the water injection nipple - George how did you handle that part of it? What grade stainless did you choose?
Just threading the nipple in is a recipe for disaster! The water injection nipple either needs to only go into a water jacket OR continue downstream past (below) the level of the inlet. Failure to do this will either allow water or spray to possibly follow the manifold back to the engine, corrosion or hydrolocking being the result.

To answer your question... I weld it in

To the OP (or anyone else on the forum): If you need help with a mixing elbow and can't find a local shop to fab it... let me know. Attached are pix of one I just finished for a genny
Attached Thumbnails
Click image for larger version

Name:	081907 005.jpg
Views:	138
Size:	409.3 KB
ID:	21496   Click image for larger version

Name:	081907 016.jpg
Views:	127
Size:	417.0 KB
ID:	21497  

Click image for larger version

Name:	081907 006.jpg
Views:	108
Size:	410.3 KB
ID:	21498   Click image for larger version

Name:	081907 007.jpg
Views:	115
Size:	406.4 KB
ID:	21499  

__________________

__________________
Any fool with a big enough checkbook can BUY a boat; it takes a SPECIAL type of fool to build his own! -Capngeo
capngeo is offline   Reply With Quote
Old 26-11-2010, 21:35   #17
Eternal Member
 
Chief Engineer's Avatar

Join Date: Aug 2006
Location: North of Baltimore
Boat: Ericson 27 & 18' Herrmann Catboat
Posts: 3,798
Nice work!!!!
__________________

__________________
Chief Engineer is offline   Reply With Quote
Old 27-11-2010, 08:38   #18
Registered User
 
crashkahuna's Avatar

Join Date: Nov 2010
Location: So. Calif
Boat: Catalina 28
Posts: 124
Images: 20
Good eye. I bought this boat recently and surveyor also noticed that incorrect hoses were used. Replacements are in the works.
__________________
crashkahuna is offline   Reply With Quote
Old 27-11-2010, 08:49   #19
Registered User
 
marc2012's Avatar

Join Date: Apr 2008
Location: abbeville la
Boat: seawind II Patience
Posts: 542
There was a thread either here or sailnet re.risers.The opinion was ss was not as good as black or galv in salt water.Don't know but worth ckng.marc
__________________
marc2012 is offline   Reply With Quote
Old 27-11-2010, 09:06   #20
Registered User
 
crashkahuna's Avatar

Join Date: Nov 2010
Location: So. Calif
Boat: Catalina 28
Posts: 124
Images: 20
Yeah looks real nice. Can you explain more about the inlet nipple going into a water jacket? (ie what is a water jacket in this application-trying to visualize.)

Does going downstream past level of inlet mean the water exits the nipple below the level where the nipple first enters the riser? Does it matter if inlet nipple enters vertical or horizontal? Thanks.
__________________
crashkahuna is offline   Reply With Quote
Old 02-12-2010, 23:40   #21
Registered User
 
nknowland's Avatar

Join Date: Mar 2010
Location: Currently in Brunswick, GA
Boat: Bayfield 40
Posts: 159
I am also replacing my exhaust elbow (cast aluminum from Westerbeke) and plan to replace the riser as well. I have the replacement from Westerbeke but at $300+ can I just as well use a black pipe elbow with a T fitting that could be fabricated by a plumber or marine shop?

It sounds like black pipe is better than galvanized. I am concerned about the gassing of the zinc with galvanized pipe. My existing riser is covered with a woven material and don't want to risk removing on the chance that it could be asbestos. I plan to wrap the new riser with fiberglass manifold wrap Fiberglass Tape Manifold Exhaust Wrap .

There was a recommendation to use bronze nipples but is that for direct exhaust elbow to manifold arrangement vs. manifold to riser pipe then exhaust elbow? What about sealing the threads with a high temp furnace cement vs. teflon past or tape?

I may also replace the hose to the waterlift muffler and the muffler while I am at it.

Any other suggestions?
__________________
nknowland is offline   Reply With Quote
Old 03-12-2010, 03:19   #22
Mooderator
 
capngeo's Avatar

Cruisers Forum Supporter

Join Date: Jul 2010
Location: Key West & Sarasota
Boat: Cal 28 "Happy Days"
Posts: 4,211
Images: 12
Send a message via Yahoo to capngeo Send a message via Skype™ to capngeo
Quote:
Originally Posted by crashkahuna View Post
Yeah looks real nice. Can you explain more about the inlet nipple going into a water jacket? (ie what is a water jacket in this application-trying to visualize.)

Does going downstream past level of inlet mean the water exits the nipple below the level where the nipple first enters the riser? Does it matter if inlet nipple enters vertical or horizontal? Thanks.
This is one of those picture is worth a thousand word situations!

If you use a simple "T" to inject cooling water, there is nothing to stop water from entering the exhaust port of the head (or turbo) when the engine is shut down or overcranked (as when purging air).

A proper mixing elbow is essentially a pipe within a pipe; the water is injected into the space between the pipes. The inner pipe which carries the exhaust gasses is shorter than the outer pipe which is connected to the exhaust hose. The exhaust becomes "wet" only where the inner pipe ends. This point is ALWAYS well down "hill" from the engine manifold.

I'm on my phone, but if it still doesn't make sense, I'll draw a diagram when I'm next on a computer.
__________________
Any fool with a big enough checkbook can BUY a boat; it takes a SPECIAL type of fool to build his own! -Capngeo
capngeo is offline   Reply With Quote
Old 13-12-2010, 07:29   #23
Registered User

Join Date: Dec 2008
Location: ontario canada
Boat: grampian 26
Posts: 1,743
Quote:
Originally Posted by Chief Engineer View Post
You can make the entire thing out of black iron pipe....for the water injection you will need a TEE that is 1 1/4 x 1 1/4 x 3/4 or 1/2......any plumbing supply store will have that.

No need to buy an overpriced water injection elbow.

PM me if you want more info
I knew I had seen a elbow in black iron similar to a water injection elbow but couldn't remember where till I looked up at the ceiling at my grandsons hockey arena and there it was on the sprinkler system.
__________________
perchance is offline   Reply With Quote
Old 13-12-2010, 08:18   #24
Moderator Emeritus
 
GordMay's Avatar

Join Date: Mar 2003
Location: Thunder Bay, Ontario - 48-29N x 89-20W
Boat: (Cruiser Living On Dirt)
Posts: 31,596
Images: 240
Quote:
Originally Posted by perchance View Post
I knew I had seen a elbow in black iron similar to a water injection elbow but couldn't remember where till I looked up at the ceiling at my grandsons hockey arena and there it was on the sprinkler system.
Google < Ductile Iron Threaded Fittings >
__________________

__________________
Gord May
"If you didn't have the time or money to do it right in the first place, when will you get the time/$ to fix it?"



GordMay is offline   Reply With Quote
Reply

Tags
exhaust

Thread Tools
Display Modes Rate This Thread
Rate This Thread:

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Riser for Helm on a Catalina 30 Dennisketch Construction, Maintenance & Refit 0 14-10-2010 22:41
Yanmar 2GM20 F Exhaust Riser bolt Torque specs ronsunni Engines and Propulsion Systems 1 08-10-2009 12:48
High riser exhaust James S Construction, Maintenance & Refit 2 30-10-2008 01:47
Universal 5411 Exhaust Flange Search Chief Engineer Engines and Propulsion Systems 1 21-10-2007 20:02



Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -7. The time now is 10:39.


Google+
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.
Social Knowledge Networks
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.

ShowCase vBulletin Plugins by Drive Thru Online, Inc.