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Author Topic: Replace Exhaust Riser?  (Read 1278 times)

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Sailing Sirona

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Re: Replace Exhaust Riser?
« Reply #15 on: May 12, 2022, 08:31:16 PM »

>>>>>>>>>>>>>>>>

1) Any place other than Catalina or CD to buy the riser, or any point even spending much time looking? (I was talking to a Marine supply store near me on Vancouver Island, so asked, and they seemed to think there wasn't much option other than ordering from the US, from Catalina or CD)

2) Anyone had any luck with using automotive exhaust weld and/or tape as a temporary fix (i.e. until i can get a full replacement riser, flange, gasket, hump hose and do the full job)? --- kinda dreading the whole process.

1)  Making up your own.  The Old Projects & FAQs (https://www.c34.org/faq-pages/faq.html) have some ideas:

https://www.c34.org/faq-pages/faq-exhaust-pipe.html

2)  The nipple is where they usually go bad.  Yes, muffler tape will tide you over.  From the 101 Topics:
Westerbeke Nipple Source  https://www.westerbeke.com/Product/NIPPLE/299693

thanks for all of the input - has taken a while to get parts, and to have a local welder build a new riser for me, but finally got it today (needless to say, once I had the old one out and unwrapped it was clear that it was done).

Speaking of wrapping - the old riser had 2 layers of fibreglass wrap, and under those a layer of fibreglass "fleece"... it was a lot.  I've got a 2" X 50' roll of exhaust wrap, which I'm thinking should give me 2 layers (with overlapping).  Any input on if that is likely to be enough heat protection? overkill?  Thanks.
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Steve Richards
"Sirona"
1992 C34 1.5 (#1194), M35
Cowichan Bay, BC

Ron Hill

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Re: Replace Exhaust Riser?
« Reply #16 on: May 13, 2022, 12:28:07 PM »

Steve : Just remember to replace the stiff wire reinforced hose from the anti syphon valve to the riser nipple with a nylon reinforced hose.

It looks like that stiff hose and the riser itself transmitted all of the engine vibrations right to the nipple area cracking it!!  The stiff wire reinforced hose from the riser to the muffler inlet didn't help!!

A few thoughts
« Last Edit: May 13, 2022, 12:32:42 PM by Ron Hill »
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Sailing Sirona

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Re: Replace Exhaust Riser?
« Reply #17 on: May 15, 2022, 09:09:16 AM »

Thanks Ron, and all.

I did change to a silicone hump hose and the hose from the vented loop to the injection nipple.  Installation of the riser took some time yesterday, but I got it done...

However - after reinstalling the heat exchanger (and replacing the 7/8 hoses) and refilling the coolant, the engine is overheating.  I have read multiple posts about how to burp the system, and followed the advice there... I filled through the 3/8" hose from the thermostat reservoir until I had coolant flowing from the nipple there.  After running a short time, the engine was up over 180.  I tried other fixes... I ran the engine with the cap off, and opened the petcock on top of the thermostat housing; I throttled up to between 2500 and 3000 RPM a few times (as was getting some bubbling at the petcock). 

I also re-did the fill from the hose to the water heater loop, just in case I hadn't gotten it reconnected quickly enough and had introduced some air there when I filled it.  (I don't have a fluid pump right now as I lent mine out, but I'm pretty confident the water heater loop is fluid-filled... was a good stream coming from the nipple, and we got the 3/8 hose on there quickly).

Was still up to about 200 degrees when I stopped trying yesterday. 

I'm going back today to keep trying to find the issue (perhaps try again a couple of times to open the system and run the engine at elevated RPMP) - but any ideas of why else I might still have an air lock (or other potential issue), or other steps to try?

thanks.
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Steve Richards
"Sirona"
1992 C34 1.5 (#1194), M35
Cowichan Bay, BC

waughoo

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Re: Replace Exhaust Riser?
« Reply #18 on: May 15, 2022, 09:51:52 AM »

I had a pretty good air bubble in the hose from the heat exchanger where it runs under the exhaust manifold and then to the lower part of the coolant pump.  A solid wiggle there helped me get all the air out.
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Alex - Seattle, WA
91 mk1.5 #1120
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Noah

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Re: Replace Exhaust Riser?
« Reply #19 on: May 15, 2022, 10:57:17 AM »

I am NOT a mechanic. But once upon a time, when changing coolant, I ran my engine at higher RPM, a bit past “temperature comfort level (200+?)” with the coolant cap loose/open, and the air ran itself out of the system after a few minutes. You might consider this, depending how brave you are.
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1990 hull #1014, San Diego, CA,  Fin Keel,
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KWKloeber

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Re: Replace Exhaust Riser?
« Reply #20 on: May 15, 2022, 01:17:01 PM »

Make sure the Tstat is opening.  Is the hose hot to the exh manifold?

Good return from the Hx?  Hot water in the 7/8” hose to the coolant pump?

Are you getting good seawater flow?  Hot water in the hose to the injection wye?

The coolant pump can get an air lock but it sounds as if you have coolant circulating.

You can eliminate one variable by disconnecting the WH hoses and inserting a short bypass hose, then reattach once you know the beast is cooling properly.

We have a particular issue w/ the plumbing on the C30 mk-I due to the WH location and burp similar to how Noah describes.  Leaving the pressure cap off we run up the rpm for a while; idle down. Repeat this pumping/surging several times to bubble air out of the pressure cap while topping off there.
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Twenty years from now you'll be more disappointed by the things you didn't do, than by the ones you did.
So throw off the bowlines.  Sail away from the safe harbor.  Catch the tradewinds in your sails.
Explore.  Dream.  Discover.   -Mark Twain

Sailing Sirona

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Re: Replace Exhaust Riser?
« Reply #21 on: May 15, 2022, 04:54:21 PM »

Thanks - ran through some of these to further isolate the issue... including removing both WH hoses and creating a short bypass loop - definitely had good flow from the pump.

In any case - third time was the charm... I managed to borrow a 12V fluid pump, and put a lot of coolant through the WH loop (there was air coming through for quite a while for some reason), then reconnected and that got it.  I ran the engine, including under load, at the dock for over 1/2 hour, and never did quite get to 160 degrees.

I was finally able to check how the exhaust riser replacement was working, which was the whole point, and was very discouraged to see a pretty good coolant leak onto the area of the aft port engine mount.  Thankfully, though, it doesn't look like it's from the exhaust flange, but from the fresh water return hose connection on the Hx... ran out of time today, but will go back to tighten and confirm that tomorrow (and also investigate why, after running the engine for as long as I did today, I didn't have hot water... ).

thanks again for the suggestions
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Steve Richards
"Sirona"
1992 C34 1.5 (#1194), M35
Cowichan Bay, BC

KWKloeber

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Re: Replace Exhaust Riser?
« Reply #22 on: May 16, 2022, 04:33:54 AM »

Steve,

Did you check the Hx end cap for a leak?

“Our” problem is that our WH sits high in the cockpit sail locker so air accumulates there and is difficult to move out of the high loop.  From what I understand about your hoses they run down to the sole then up to the WH?  So that could create the same sort of air trap.  Air fights like heck from “going down.

How long was the WH hooked up w/ engine running after purging that loop?
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Twenty years from now you'll be more disappointed by the things you didn't do, than by the ones you did.
So throw off the bowlines.  Sail away from the safe harbor.  Catch the tradewinds in your sails.
Explore.  Dream.  Discover.   -Mark Twain

Noah

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Re: Replace Exhaust Riser?
« Reply #23 on: May 16, 2022, 08:39:53 AM »

Ken-the OEM C34 water heaters are under the galley sink at the same height or lower than the engine. The hose run under the sole and then rise up slightly (8-10 inches?) to the heater.
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1990 hull #1014, San Diego, CA,  Fin Keel,
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KWKloeber

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Re: Replace Exhaust Riser?
« Reply #24 on: May 16, 2022, 09:16:15 AM »

Thx Noah.  Our “up” is probably not much more than that.  The hoses enter at the bottom of the locker, basically just above hull level (slopes up from the engine of course.)  So I’d think they are comparable.  Your engine connections are higher than ours ( stuffed underneath a seat height) Tthe mk-II WH was moved onboard and lowered.  I’d think any “up” pocket could potentially be problematic.

In our wheelhouse we don’t have the tips to fill/hand pump that loop but would be a good thing to add.
« Last Edit: May 16, 2022, 01:16:01 PM by KWKloeber »
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Twenty years from now you'll be more disappointed by the things you didn't do, than by the ones you did.
So throw off the bowlines.  Sail away from the safe harbor.  Catch the tradewinds in your sails.
Explore.  Dream.  Discover.   -Mark Twain

Ron Hill

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Re: Replace Exhaust Riser?
« Reply #25 on: May 16, 2022, 02:46:39 PM »

Steve : To "burp" (get all the air out of the Water Heater line) I disconnect the WH return line (from the thermostat) and connected in a small hand "PAR pump".  Then pumped fluid (into the open reservoir on the engine) until all the air is out of the line and just fluid is coming out!!  Then reconnect the W heater hose line back to the thermostat.  Easy as that!!  :thumb:

A few thoughts

« Last Edit: May 16, 2022, 02:48:27 PM by Ron Hill »
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Sailing Sirona

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Re: Replace Exhaust Riser?
« Reply #26 on: May 16, 2022, 03:51:35 PM »

thanks guys,

I had lent my hand pump out (of course, just when needed it), but a borrowed 12V fluid pump did the trick - I was surprised by how much air it pushed through, and I must not have been getting it all just by pouring into the raised 3/8" hose from the Tstat reservoir.

Also confirmed my suspicion that the coolant leak I had was from that hard-to-reach 7/8" return hose on the back of the Hx (ironically, when I took the Hx off, I had disconnected that hose at the elbow at the front of the engine, and left it on the Hx to make it easier... but then decided to replace it with new).  Just glad it wasn't leaking at the flange.

Ran at the dock for about 45 minutes today and engine temp only got to just under 160, no leaks, and no real hot spots on the new riser -- looking alright.  I'm hoping to get out to give it a proper run tomorrow out of the marina to confirm everything is good before a planned 4-nighter this weekend  :D

photo is of the new riser just before I adjusted the wrap one last time and installed.
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Steve Richards
"Sirona"
1992 C34 1.5 (#1194), M35
Cowichan Bay, BC

KWKloeber

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Re: Replace Exhaust Riser?
« Reply #27 on: May 16, 2022, 04:10:31 PM »

Steve

That’s purdy!!

That begs the question, are you getting hot water now?

Consider using ABA or AWAB hose clamps for any future work!

Bravo 👏 🙌 🎉 👍 👌
« Last Edit: May 16, 2022, 04:11:42 PM by KWKloeber »
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Twenty years from now you'll be more disappointed by the things you didn't do, than by the ones you did.
So throw off the bowlines.  Sail away from the safe harbor.  Catch the tradewinds in your sails.
Explore.  Dream.  Discover.   -Mark Twain

waughoo

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Re: Replace Exhaust Riser?
« Reply #28 on: May 16, 2022, 04:36:16 PM »

NOICE!!!  I am going to second Ken's suggestion on the better hose clamps.  I have seen a lot of hoses PRESSING through the serrations of the clamps that I decided to quit using them unless I had to due to inavailability.  That said, I wouldn't go in there and change them.  I still have some in my boat from before I decided to switch.  They will be just fine till I need to mess with those hoses again. 

Also wanted to know the answer about the hot water question.
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Alex - Seattle, WA
91 mk1.5 #1120
Std rig w/wing keel
Universal M35
Belafonte

KWKloeber

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Re: Replace Exhaust Riser?
« Reply #29 on: May 16, 2022, 04:52:42 PM »

>> T I wouldn’t go in there and change them.<<<

Actually (I didn’t want to throw out an arrow but) I would where subject to a wide temp swing (eg, Hx and exh.)
Even tho the hump hose may be more forgiving.

(Or use T bolts on the exhaust.)

I’ve seen broken M25 Hx mounting clamps due to the expansion (that’s why Seakamp supplies T-bolts for its M25XP Hx brackets.)
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Twenty years from now you'll be more disappointed by the things you didn't do, than by the ones you did.
So throw off the bowlines.  Sail away from the safe harbor.  Catch the tradewinds in your sails.
Explore.  Dream.  Discover.   -Mark Twain
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