How do I Replace the Exhaust Pipe?
Exhaust Pipe Replacement
(for Hump Hose Information,
see 3/4 down page)
Original Message:
Subject: Exhaust Pipe Replacement
Several weeks ago there was a thread regarding the replacement
of the exhaust pipe. I was looking into doing the same for our boat.
I contacted Catalina direct and got the part number, price etc. from
them. To my surprise they told me that their part did not include a
flange fitting to mount to the engine manifold and that I would have
to purchase the part from "Trans Pacific". At Trans
Pacific they had no idea how the Catalina Direct part was to attach
to their part, i.e threaded fitting or ??.
This has all been somewhat of a surprise to me, since my
recollection of the discussion here on the list was that the new
"one-piece" stainless steel pipe was the way to go. It
seems as though that this is in fact not a one piece part. Since it
isn't, I'm not so anxious to replace the exhaust pipe. I've checked
the pipe and it appears to be sound and well fitted. The only
problem that I have is that the end fitting at the raw water inlet,
has developed a pinhole leak. I repaired it with epoxy in an
overnight stop late last season, but don't want to rely on it for a
full season. The part is about 6" long, has a threaded end that
screws into the black iron pipe, has a 3/4" "Y" that
the raw water hose clamps onto and a smooth end that the 1 5/8"
hose clamps onto to take the wet exhaust to the muffler.
Does anyone know where I can obtain this end fitting? Or was it
custom made by the last Owner ?
Frank, Kik N Bak
Subject: Re: Exhaust Pipe Replacement
Frank: There have been a number of exhaust Iron & Stainless
riser articles in the past issues of Mainsheet . The (Universal
part) flange at the engine that adapts to the exhaust riser
(Catalina part) is not an item I'd trust to epoxy - Mainsheet Nov.
98. It would also help, if in the future you identify your C34
by year and hull# -- as all C34's are not identical.
Ron, APACHE, #788
Subject: Re: Exhaust Pipe Replacement
From: holder@unixg.ubc.ca (Barbara and Charles Holder)
The part you're describing is similar to one I had made when the
original exhaust on my boat failed due to corrosion at the weld
between the 5/8 inch water injection pipe and the 1 1/4 inch nominal
size pipe (actually 1 5/8 inch OD).
Rather than buy from Catalina, which can be a Border Customs
nightmare for those of us in Canada, I had a local fabricator, who
could weld stainless steel, make up the whole thing out of screw
coupled, stainless steel, schedule 40 pipe. The only welding
required was to connect the water injection pipe to the last pipe
section.
Next time, if there is another, I'll use schedule 80 pipe for the
last section where the water injection pipe is welded in. Schedule
80 pipe has a thicker wall but the same outside diameter. I'm fairly
sure that the original Catalina exhaust was schedule 80 for the end
section. There are two reasons for using the schedule 80 pipe: the
hot gas and water form a fairly corrosive mix that attacks the weld
heat altered steel and the screw threads remove quite a bit of the
pipe wall reducing its strength perhaps too much.
By the way, I reused the coupling to the engine. It can be removed
from the exhaust pipe but might require a lot of heat, a very large
pipe wrench and a large mechanic's vice. The heat, and I'm taking
about to dull red, makes the coupling expand loosening (a relative
term) the joint. A couple of strong friends would be a useful
addition for this part of the job.
Regards
Charles Holder, Discover, #617, 1988
Subject: Re: Exhaust Pipe Replacement
From: ronphylhill@erols.com (James R. Hill)
Dave, The first step in replacing your exhaust riser is to drain the
coolant through the starboard side petcock near the front of the
engine. Squirt some liquid wrench on the three nuts that hold the
riser and flange to the back of the engine and let it sit over
night. I believe these nuts are 7/16" and are best removed with
a box end wrench rather than a socket, especially the one
underneath. After you remove these nuts, you have to undo the raw
water hose from the riser and the two clamps from the inlet exhaust
hose to the muffler. With some gyrations the flange/exhaust riser
will come out thru the engine compartment.
To reassemble the first step is to put the flange in a vise. Screw
the exhaust riser into the flange until you get the angles aligned
properly (use the old exhaust riser and flange as your pattern).
Then back off the riser counting the number of turns until it is all
the way off. With the flange still in the vise, treat the riser
threads with some muffler patch and screw back in the flange the
same number of turns. Remember don't over tighten because you don't
want to have to back off (you may break your seal). You want to end
up tightening it to get the proper angle. Ensure that all of the
gasket material is off of the exhaust/reservoir casting on the back
of the engine. It's a real bear to get in there and make sure the
surface is clean, but quadruple check this or you will not get a
good seal and lose your coolant (when you refill) and have to start
over with a new gasket. Make a dry run without the gasket just
fitting the flange/riser assembly in place. As I mentioned in the
Nov 98 Mainsheet Tech Notes, try the "dollar bill test."
It's more important for a 25XP with the larger diameter heat
exchanger than the M25, because the factory may have wrapped too
much insulation in that area where the riser goes over the heat
exchanger. I couldn't get the flange to completely seat until I cut
out some of that insulation. If you can pass a dollar bill between
the riser and the heat exchanger, you are in good shape. If you
can't, whittle away some insulation. Also measure the length of hose
that you'll need between the riser and the inlet to the Aqualift
muffler (with a new riser it may not be the same distance as it was
with your old riser). After you are sure the flange/riser is going
to seat and that surface is absolutely clean, place the gasket on
the three studs. I even used some of the muffler patch around both
sides of the gasket to make sure I had a good seal. This is a
perfect time to install the single hump hose which I wrote up in
that same Mainsheet article and again in the Aug 99 issue( the
81/2" hose from the factory is $33.75). Up to this point,
disassembly and reassembly has been a one person job. Now you need a
second pair of hands. As one person aligns the flange with the three
studs on the back of the engine, the other person aligns and inserts
the single hump hose into the flange and muffler inlet. Tighten down
the three nuts to secure the flange, double clamp the single hump
hose on the flange and muffler ends. When I attached the new raw
water hose from the anti-syphon, I made it a little bit longer than
the original factory installation so it could flex a little and put
less strain on that welded nipple that goes into the riser. Reclamp
that hose and you are ready to refill the reservoir with coolant
(50/50 Prestone). To ensure that you don't have an air bubble in
your internal cooling system that goes through the water heater,
remove the inlet hose to the thermostat housing. Insert one of those
Par Junior Pumps and with the pump exit pointed into the reservoir,
keep pumping until you have coolant being pumped back into the
reservoir. Remove pump and insert hose into the thermostat reservoir
and tighten the hose clamp( you shouldn't have to "bleed"
that system as all of the air has been purged) . Recheck that the
reservoir is full & replace the cap, start the engine and check
for any leaks. You should be in good shape. Hope this helps.
Ron, APACHE, #788
Subject: Re: Exhaust Pipe Replacement
From: RPDIII@aol.com
Dave: The letter written to you about draining the expansion tank is
good advice and a good way to drain the tank. I have replaced my
exhaust system twice and I only have this to offer. Using the drain
plug does drain the tank however when you remove the gasket for the
flange the remaining fluid will drain out the rear of the tank. If
you use the drain plug the fluid (may) end up soaking into the
engine compartment sound proofing. If you drain it from the rear it
will fall onto the fiberglass and end up in the bilge. I also
suggest taking this opportunity to wash the tank out to remove
whatever particles have settled in the bottom of the tank over the
last 11 years. Just a thought because you will have to replace the
gasket no matter which way you go. You will also notice the gasket
has a stamp on it indicating which side goes against the tank, (very
important).
Good Luck;
Rich Dwyer, Rebellious, #328
Subject: Re: Exhaust Pipe Replacement
From: davis_707@yahoo.com (dave davis)
Ron, I did the draining today and caught maybe 95% of the coolant. I
used a small plastic bendable cup and used my finger to stop the
flow every time the cup filled up. I also spayed the the bolts with
liquid wrench.
Dave
Subject: Re: Exhaust Pipe Replacement
Hello Ron. Our exhaust riser on our 1988 C34 (#542) finally
cracked just below the raw water injection nipple. I reread all the
info in the tech notes and mail list, and called Catalina to order a
new riser. They said I'd have to send in the old one and they would
fabricate a new one using the old one as a pattern. Greg in parts
said turnaround would be around a week and a half. Was this your
experience? I was fantasizing that they would send a new one right
out. Any reason to send it to Catalina if I can have one fabricated
locally?
Steve, C34 "Sunshine" #542
Subject: Re: Exhaust Pipe Replacement
From: ronphylhill@erols.com (James R. Hill)
Steve : Although I ordered a new ss riser I took the old one to a
welding shop and they put a ss weld over the hair line crack - so I
now have a spare. I'd take yours off and take it to ss welding shop
and see what they say. I'm sure that if the crack isn't to bad they
can repair it for $10- $15. With the money you saved call Greg and
order a single hump hose (same length of your old hose). Also
install a new hose from the anti syphon to that nipple. Make sure
that the new hose has some flexure in it so it places the least
amount of vibration stress on the repaired nipple. Make SURE you
have all the old gasket off the engine or you'll screw up the new
gasket on reinstallation. It's hard to get to so you'll need a
mirror.
When I ordered my new riser Catalina only wanted certain
measurements to make up my new one. They could have had an unhappy
customer because the new riser didn't fit and now require they send
the old one back. If you send your old one to them as a pattern I'd
ask for the old one back, repair it and have a spare.
You could have one made locally, but I'll guess that Catalina will
have the best price. A few thoughts.
Ron, APACHE, #788
Subject: Re: Exhaust Pipe Replacement
From: holder@telus.net (Charles & Ba Holder)
My suggestion would be to fabricate from schedule 80 stainless steel
screwed pipe and bends. That way you only have to weld the injection
pipe into the last short piece of pipe. I found the same piece
rotted out frequently, probably due to heat alteration of the metal
when welding and the presence of heat and salt water. Using screwed
fittings enables one to replace one part and means a lot less
expensive SS welding. Lots of pipefitters can cut and thread pipe.
Two cautions: you'll need to use a thread sealer - I used regular
exhaust paste spread on the pipe threads; welding in the injection
pipe will distort the pipe section to out of round - have the
welding done first, then the pipe cut and threaded.
Schedule 80 is thicker than normal steel pipe and provides more
metal after cutting the screw threads. As to which stainless steel
grade, I'd suggest regular marine grade 18/8.
Charles and Barbara Holder, holder@telus.net
Subject: Re: Exhaust Pipe Replacement
From: davis_707@yahoo.com (dave davis)
Hi Mike and George, When I bought my Exhaust Manifold from the
factory, they wrapped it with lots and lots of insulation. I'm not
sure , but I think the main function is to protect YOU from getting
burned. The pipe would run cooler if it had a place to radiate the
heat. But I left all the wrapping in place. The results were such
that it would not pass the "dollar bill test" that Ron use
to talk about. That is, there must be a space between the manifold
and the heat exchanger so the they would not rub each other and
cause more problems. To solve that problem, the yard man took off
the HX and bent the support flange about 1/2-1 inch so that there
would be a good clearance. Hope this helps
Dave
Subject: Re: Exhaust Pipe Replacement
From: ronphylhill@erols.com (James R. Hill)
Mike : As far as all the wrappings - they are there to keep all the
HEAT inside the riser and not let it get into the interior of the
cabin. TRIPLE check that the mounting flange on the engine to insure
it is absolutely clean of old gasket material. Then check this
again!! If the welding shop was capable of doing a good job of
stainless welding, you should be good for another 5-10 years - if
the rest of the flange piping is OK. Make sure that you have a slack
bend in the raw water line that empties the heat exchanger water
into the nipple in the riser.
The tip from your mechanic is correct on worrying about a scored or
pitted surface on either the engine / riser flanges. What I used for
a "liquid gasket" material was muffler patch paste. It's
the only material I know of that could stand up to the exhaust heat.
Mine is sealed and w/o leaks, 3 yrs later.
Ron, APACHE, #788
Subject: Re: Exhaust Pipe Replacement
From: davis_707@yahoo.com (dave davis)
George: The exhaust flange for the Universal 25 XP is Part #
298599-R14. It cost me $51.90 in Oct.99. From SEA POWER Oakland CA.
510-533-9290 Ask for Colin, the parts man. Make sure they install a
rubber hose that has a hump to take up the vertical vibration
stress. Good Luck,
Dave
Subject: Re: Exhaust Pipe Replacement
From: davis_707@yahoo.com (dave davis)
George, I worked with Ron on this problem and at the time we
gathered information about engine hours vs. failure for the
stainless and for the iron exhaust manifolds. If you would like, I
have the CY drawing of the replacement Stainless which I could send
you by S-mail. Some skippers went out and replaced the manifold with
sections they rigged from galvanized iron but I have not heard back
how long they lasted. To get a replacement we need to know your hull
# and the length of the rubber hose that connects it to the Exhaust
riser. You may also need the flange that connects the the exhaust
manifold depending how hard it is to remove. I replaced mine. I can
tell you where to purchase a new flange. Or your rigger might have
all this information.
Good luck, I hope this doesn't ruin your summer plans.
Dave Davis
Subject: Re: Exhaust Pipe Replacement
GeorgeM2nd@aol.com wrote:
For information only - my exhaust riser manifold failed at the first
90 deg. turn from the engine mounting flange. This failure (and
action) was addressed by Ron Hill in the 1997 tech notes index. I do
not have the newer stainless manifold. Total engine hours - 748
George, OK-3, 1987 #339
Subject: Re: Exhaust Pipe Replacement
From: ronphylhill@erols.com (James R. Hill)
George : If you have a little time & are a Boat US member you
can order that same flange for $43 through their engine parts --
Mainsheet Tech notes a couple of years ago. A thought.
Ron, APACHE, #788
Exhaust hump hose
Subj: Re: Exhaust hump hose
From: dnkkay@prodigy.net
I have an exhaust leak from my exhaust manifold to the Aqua-lift
muffler. I pump water into my bilge when the engine is running
(Universal Model 25). It's a short piece of hose (about 5 inches)
that seems to be leaking. I don't think I can replace the hose
without removing the exhaust manifold/pipe. The nuts and studs that
hold this manifold seem so rusted that I'm afraid to tackle them.
Has anyone tackled this job before? I'm wrapping it in a vulcanizing
tape, then wrapping inner tube around it (and using hose clamps to
hold it down) for a temporary fix.
Thanks
Ken Kay, Watercolors, Long Beach, CA
Subj: Re: Exhaust hump hose
Gary Wilson wrote:
Hi, I want to install a hump hose between the manifold and muffler,
but cannot find a source for the part (1-5/8" dia). I can't put
my finger on Ron Hill's article to double check, but I have had no
luck at the local marine diesel dealers, hose suppliers or West
Marine. They checked in the manufacturer's catalog (Gates) and it is
not listed. I checked with the Catalina factory and David Graas said
the hump hose they stock will not fit the C34 application. Does
anyone know of a source?
Thanks, Gary Wilson, Childsong #138
Subj: Re: Exhaust hump hose
From: ronphylhill@erols.com (James R. Hill)
Story on the Single Hump Hose: Last June Gerry Douglas told me about
this when I talked to him when I was ordering a new stainless steel
exhaust riser. After installation of the new riser and the new
single hump hose on my 1988 hull #788 C34, I wrote Gerry Douglas on
27 July - that it was a great modification but it could only be
changed out with a new exhaust riser. "The new hump hose is
only 5-1/2 inches tall and the old hose I removed from the old SS
riser is 8-1/2 inches. The new hump hose would have to be 8-1/2
inches tall to make it fit with an old riser system." (My old
riser was stainless steel with a crack in the exhaust water nipple
that joins into the exhaust riser just above the muffler.)
In Nov 98, I received my first inquiry on where to get a single hump
hose for the Catalina exhaust system that I had mentioned in the Nov
Mainsheet. Again I wrote Gerry Douglas and reminded him of our
previous correspondence in July that the single hump hose I received
from Catalina parts was 5-1/2" long and with the new riser it
fit well. However, IF I had wanted the single hump hose for my old
stainless riser the length had to be 8-1/2" long. I also told
Gerry that I had forwarded a copy of our correspondence to Marvin in
Catalina parts so the parts department wouldn't sell a hose that
might be 3" too short to a customer. In the meantime I
contacted Rich Becker, General Manager of Trident Rubber and found
out that a 1-5/8" inside diameter silicone single hump hose is
a non-standard diameter size for Trident and made only for Catalina.
They keep none in stock.
At this time they only make this hose in a 5-1/2" length per
Catalina's request. Trident would gladly make an 8-1/2" length
if any individual wants to buy 50 or more of them! Later in Nov I
relayed this new Trident information to Gerry Douglas and
recommended that they might buy the longer hose which Gerry said
they would do on their next purchase.
The key to the puzzle is to measure the distance between the
Aqualift muffler and the base of the exhaust riser and determine its
length. Then contact Marvin at Catalina Parts (1-818-884-7700) and
see if they have a single hump hose of the length that you want. If
the hose length is too long, you can always cut it off. Hope this
helps.
Ron Hill C34 Mainsheet Tech. Editor
Subj: Re: Exhaust hump hose
From: holder@unixg.ubc.ca (Barbara and Charles Holder)
Your note about Catalina Parts is intriguing. I just bought two hump
hoses from them, one to use and one as a spare. They fitted
perfectly. They are actually made by Trident and are an
off-catalogue item. That means the normal parts suppliers will deny
their existence but if you force them to contact Trident they'll
find they do exist. The size I obtained is 1 5/8 inch diameter to
fit a 1 1/4 nominal pipe size exhaust and it is about 6 inches long.
My boat is a 1988 Cat 34 fitted with a Universal 25XP engine.
Regards, Charles Holder
Subj: Re: Exhaust hump hose
From: FRANKKUL@prodigy.net (Frank Kulscar)
Well, it seems that my spring projects are coming to a close.
Exhaust pipe replacement: Couldn't buy into Catalina Direct's
stainless steel $141 super tube. My opinion is that its a flawed
system since there still remains a black iron (or galvanized) pipe
from the manifold flange and the elbow to the s.s. tube. I made ours
from all galvanized for about $25 from a local plumbing store.
Sealed each joint, tested it and it works fine.
Good luck on finishing spring projects!
Frank, Kik N Bak
Subj: Re: Exhaust hump hose
From: ronphylhill@erols.com (James R. Hill)
Tom : The only place to get the 1-5/8" single hump hose is from
the Catalina factory. Trident Co. only makes that diameter hose for
Catalina. I think it's about $30. Let Marvin or Greg in parts know
the length you need . When you get ready to put it on it let me know
and I'll give you a few installation tips.
Ron, APACHE, #788
Important: The opinions expressed here are
those of the individual contributors to this page, and not those of
the Catalina 34 National Association or Catalina Yachts, Inc.
Additionally, this material has not been reviewed by Catalina
Yachts, Inc. for technical accuracy. This page's maintainer cannot
guarantee the accuracy of this information or the desirability of
suggested modifications or upgrades. Please obtain assistance from a
competent marine mechanic or boatyard prior to making any
significant modifications to your vessel. |
