Bavaria Yacht Info
Member Forums => Bavaria Yacht Help! => Topic started by: MagicalArmchair on December 14 2020, 17:55
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I have taken the elbow off the engine to inspect it and the intake is about 50% rusted up. The exhaust airway itself is pretty clear. Do I chip out that rusted intake, repaint, and reattach?
Or do I replace with one of these suckers? https://www.parts4engines.com/volvo-penta-d2-55a-and-d2-55b-stainless-steel-exhaust-outlet-and-connector/
(https://i.imgur.com/cMGdMTDl.png)
(https://i.imgur.com/kXuA5rul.png)
(https://i.imgur.com/P46mCW5l.png)
(https://i.imgur.com/0JHpJmGl.png)
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You know the answer- for peace of mind spend the money!
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Two years ago i removed and checked the same exhaust elbow as part of my preventative maintenance program on my 2001 Bavaria 42 with the VP 50hp engine (Perkins Prima 50) due to numerous reports re the clogging of the elbow and found it to be significantly clogged up with carbon deposits. There was really no option other than to replace the part. I ordered the part from Parts4Engines and had it delivered to Australia within 10 working days. My opinion is, spend the money, replace the elbow and the connector for trouble free motoring. Note:- I purchased the elbow and connector for a Perkins Prima 50 and fitted exactly. The price for the Perkins Prima 50 parts were significantly cheaper. Also available from Parts4Engines.
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I too spent the money and bought the stainless steel one.
Only had it a year and have yet to inspect the innards to see how it was getting on, but the old one was horrible inside and it had caused us numerous problems, so figured it was worth getting something a bit better.
Mark
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Give the two hose ends a few taps with a hammer and see if the metal is still good. On our MD-22 the exhaust injector (the small bolted on part) does crumble to bits after 2-3 years and needs replacing. Never had to replace the actual exhaust elbow itself yet, just cleaned up and re-painted. I switched to the stainless injector this time, will see how long that lasts.
Different engine though, it looks like on yours the deposits go further down the exhaust which may effect where the metal rots.
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Our original Volvo Exhaust Elbow looked like yours, so I 'tested' it along the lines suggested by Yngmar. The end that fits into the exhaust hose shattered rather easily as the metal was mostly rust..
So, if in any doubt just buy a new one for the peace of mind.....Bill
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Thank you all, I've bitten the bullet and purchased a SS one (Christmas cancelled then :D). Any tips for fitting it? I'm guessing the Hylomar it comes with is to smear the gaskets with pre fitting?
Anything worth looking at whilst its off?
Does the below sound about right?:
- Clean up mating surface on the engine.
- Put the gasket on engine smeared with the Hylomar.
- Fit Elbow to Engine. Do up nuts in diagonal pattern. Copper slip on these? (I've had aggro with this on my old boat :D http://www.albinballad.co.uk/how-tos/remove-a-sheared-off-exhaust-elbow-bolt/)
- Fit gasket (with Hylomar) and intake to the elbow, Copper slip on those bolts too?
- Refit the intake hose and the Exhaust hose. Test.
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Whilst the exhaust elbow is off suggest you carefully check the mating surface of the heat exchanger and make sure the metal is sound. On mine the severe restriction of the elbow caused back pressure and water erosion on the heat exchanger such that it perforated allowing water into the engine (rebuild necessary). See photo attached of perforation. I don't know the time it took to erode the heat exchanger (probably many years) as boat was new to me, but keeping the exhaust elbow clear of severe obstruction is key.
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Whilst the exhaust elbow is off suggest you carefully check the mating surface of the heat exchanger and make sure the metal is sound. On mine the severe restriction of the elbow caused back pressure and water erosion on the heat exchanger such that it perforated allowing water into the engine (rebuild necessary). See photo attached of perforation. I don't know the time it took to erode the heat exchanger (probably many years) as boat was new to me, but keeping the exhaust elbow clear of severe obstruction is key.
Ouch..!! Goes to show that an external inspection is not enough. We should all take note...
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Whilst the exhaust elbow is off suggest you carefully check the mating surface of the heat exchanger and make sure the metal is sound. On mine the severe restriction of the elbow caused back pressure and water erosion on the heat exchanger such that it perforated allowing water into the engine (rebuild necessary). See photo attached of perforation. I don't know the time it took to erode the heat exchanger (probably many years) as boat was new to me, but keeping the exhaust elbow clear of severe obstruction is key.
Ee gads, was it the airways that were restricted? As opposed to mine where it was the intake that was getting blocked? I took a VERY bad photo into the engine once I had the elbow off, I'll take a better one when I get down next. The bit in red looks like the exhaust has been weeping a little from the bottom of the elbow, which means exhaust gases would have been seeping out too. One of the reasons I bumped the job up the list was because that cabin smelled a bit too 'enginey'. I did wave my Carbon Monoxide alarm around the area with the engine running, and it didn't go off, so it may well be a red herring. Still, I'm glad I made the effort. Thanks for alerting me to that.
Remaining questions:
- Copper grease on the nuts?
- Smear Hylomar on the gaskets pre fitting?
(https://i.imgur.com/2ZHryEyl.png)
(https://i.imgur.com/tcXezJAl.png)
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Yes to copper grease on the bolts. Also, have a peek in the hose ends - that's a mating surface too and if not smooth (e.g. wire reinforcement broken through), it will leak and corrode the new elbow needlessly.
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Just for curiosity reasons: How many hours did the engine run until the elbow looks this way?
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Thanks Yngmar. I'll check the hoses and put some silicone grease on those as well to try and help that seal.
As for the hours - that's yet another job I need to do! The LCD display on the taco is (predictably) cooked, so I need to replace that (watch out for a thread on that soon, eep). Once I know Florian68 I will report back.
The new exhaust elbow is due to arrive today, so hopefully I'll be able to put that all back together at the weekend.
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I changed the LCD display on my boat in October, I found this video quite good and it is really just a 15 Minute job.....
https://www.youtube.com/watch?v=I4GjY2NxXto
Got my one from Ebay/China and worked just fine
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Thanks Florian - look forward to that one. I might take the panel off next time I'm down so I can fix it in the bat cave.
I've unboxed the new elbow, and it looks very well made indeed.
(https://i.imgur.com/8iV1hYvl.png?1)
It comes with a metal gasket for the engine, and then a normal gasket. Which way around doe the metal guy go? I guess the nodules sticking out are designed to dig into the gasket?
(https://i.imgur.com/TjRHSPYl.png?1)
I'm guessing the metal one goes next to the engine, nodules out, then the gasket?
(https://i.imgur.com/qYcvyQgl.png)
Or, nodules towards engine? Which makes less sense...
(https://i.imgur.com/gEWmQTJl.png)
And I presume you smear all gaskets with this jazz?
(https://i.imgur.com/ce3es7El.png?1)
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I spoke to the awesome chaps at https://www.parts4engines.com/ and they answered those questions wonderfully:
- Only use ONE of the gaskets, you don't need both. The one they supply is composite (the grey one), the metal one is supplied by the manufacturer; Parts4Engines supply their own one to limit galvanic corrosion (given some photos I've seen, that's not a bad plan), so I'll use that.
- The Hylomar is supplied for the water pipes and not the gaskets. The gaskets are dry fit.
Anything else I need to consider on fitting?
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hi, regarding the tacho, there is lots of info on here or on the web, i did mine in September, got the LCD from AK speedo, £20. on their web page look for 'vdo lcd pixel repair' in the top black header. easy job, tested and works but not been back to fit to boat due to restrictions :(
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I took the stainless elbow down and, heeding the advice here, studied the surface of the heat exchanger carefully, congratulating myself that it looked pretty damn good...
(https://i.imgur.com/2FOHyZ4l.jpg)
...until I realised that was the old gasket... on taking that off I was greeted with this horror:
(https://i.imgur.com/2Sv5vCtl.jpg)
I had thought it was blowing from the bottom of the elbow, the above backs this up - galvanic corrosion had eaten through the bottom of the exchanger, and around the mated surfaces!
(https://i.imgur.com/2Sv5vCtl.jpg)
Once cleaned up, we have the below:
(https://i.imgur.com/iwUJvScl.jpg)
The good news it, it hasn't eaten through to the engine. How on earth do I fix this? Take the heat exchanger off and take it to an engineering shop to fill that in?
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I had exactly the same problem on my D2-55. The heat exchanger is made of an alloy and very difficult to repair. My only solution was to buy a new heat exchanger or find a second hand unit. Luckily I was able to track a secondhand unit down and get it refurbished, this still cost me a substantial amount but considerably less than a new one.
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The good news it, it hasn't eaten through to the engine. How on earth do I fix this? Take the heat exchanger off and take it to an engineering shop to fill that in?
Before taking it off and replacing the whole thing, I wonder if it would make sense to clean the area completely with a dremel or similar to bright metal and use JB Weld or similar epoxy to fill the whole corroded area up to the original sealing flange. You could probably use release paper and a blind flange to make the epoxy flush. It would for sure be a quick fix but not sure if it would be a permanent one...
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Before taking it off and replacing the whole thing, I wonder if it would make sense to clean the area completely with a dremel or similar to bright metal and use JB Weld or similar epoxy to fill the whole corroded area up to the original sealing flange. You could probably use release paper and a blind flange to make the epoxy flush. It would for sure be a quick fix but not sure if it would be a permanent one...
This is what we did. It seems to be holding together OK. I can't remember how many engine hours we have done since the fix, but it has been there a couple of years now.
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The good news it, it hasn't eaten through to the engine. How on earth do I fix this? Take the heat exchanger off and take it to an engineering shop to fill that in?
Before taking it off and replacing the whole thing, I wonder if it would make sense to clean the area completely with a dremel or similar to bright metal and use JB Weld or similar epoxy to fill the whole corroded area up to the original sealing flange. You could probably use release paper and a blind flange to make the epoxy flush. It would for sure be a quick fix but not sure if it would be a permanent one...
I could do that with the heat exchanger in situ, without needing to remove the studs etc - that's a cracking idea... so long as it doesn't crack... I wonder what kind of temperature the repair would subject to in that area? This stuff says it will survive up to 230 Degrees Celsius.
https://www.jb-weld.co.uk/highheatep
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I did a similar but smaller repair on my md22 using car silencer repair paste Gungum from memory . Very sticky and high temperature no problem. I did it a couple of years ago. Geoff
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It looks like there is enough metal left to take the heat exchanger off, remove the studs and have it machined down flat.
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Hello Laysula, I think it's gone a little too far at the bottom here:
(https://i.imgur.com/a5qClPql.png)
Geoff, thanks for the update. Have you had the elbow off again to inspect the repair since your did it?
- Get hold of some of this jollop (HighHeatEP | JB-Weld), good to 230 degrees C.
- Grid the areas back with a dremel to bright metal.
- Build the eaten away areas back up.
- Use a blind flange with release film on it to make the mating surface nice and flat and squish the goo in. Bolt that guy down, allow to set.
- Remove blind flange.
- Tidy up and grind down any overage.
- Keep a weather eye on it, remove next season and check thoroughly.
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Not had it off since the repair, but having used this stuff on car exhausts many years ago it withstands pretty much any thing and sticks like s%$t in blankets. Geoff
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It sounds a damn sight cheaper than the adventure @Seagoon had here too: http://bavariayacht.org/forum/index.php?topic=1352.0
I'll travel along this route and see how it goes!
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This stuff I have purchased is rated to around 240 degrees C... the exhaust at that point reaches a staggering 570 degrees C, making it technically underrated.
(https://i.imgur.com/qXRjudrl.jpg)
Back to the lapping option then I think...
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This stuff I have purchased is rated to around 240 degrees C... the exhaust at that point reaches a staggering 570 degrees C, making it technically underrated.
While technically at 3000 rpm it seems that exhaust gas can reach 570 °C, please note that this is the gas temperature and not solid temperature. With water injection point being quite close to this area and with the thick-walled parts that conduct heat quite well, my gut feeling is that it should be fine - but do not blame me if it does not hold... :)
If you consider the lapping option, make sure there's not internal cooling channels in the area as it looks to me you would need to remove a lot of material, maybe around 10 mm or so.
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Ouch, that's an unfortunate find. :(
Agree with Markus, it seems unlikely that the exhaust elbow gets to such high temperatures - the heat exchanger manifold itself is also water cooled and aluminium conducts heat quite well (epoxy with metal shavings much less so though).
Holts Firegum is rated for 1000°C, but it's just a heat setting paste with no structural strength, so it may or may not be suitable to fill a gap that large. If the gap however could be reduced somewhat by machining down the flange, it might do the job. You'll have to clean up the corrosion to sound metal anyways.
Either way you'll probably have to get those bolts out, which could be a bit of a challenge itself. So while you think about how to proceed, spray some of this on (works on stuck cushion zippers as well): https://wd40.co.uk/product/fast-release-penetrant-spray/
Good luck :)
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Thanks all, and thanks Yngmar - It's a boat - something is always broken somewheres! I am bloody glad I checked though, crikey. If anyone hasn't had theirs off, get it off - it took me ten minutes to drop the elbow off, and may have saved the engine.
So, new plan, whist epoxy would probably hold, given the rated max of 240 degrees C and a potential for greater temperatures, I've decided to resist the urge to epoxy it and take the rapid route and will drop it off this afternoon.
A local engineering firm with pressure test both the fresh water and raw water sides of the unit, and then, as they specialise in ally welding, try and weld up and polish up that flange. If it doesn't hold pressure... the quote for a new one in £2,500 :D... Christmas cancelled my friends!!
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Question - we replaced our clogged up elbow with a stainless steel one about 6 months ago. We have not checked it since as I see no reason to after such a short period, but, has anyone any experience with galvanic corrosion using the stainless steel elbow after a period of time? I understand that due to the two different alloys, this can be an issue, although we have checked another engine which had the original elbow (non stainless steel) and there was corrosion as well on the heat exchanger.
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Hello Markram, it really depends. When I got the stainless steel new elbow from Parts4Engines it came with TWO gaskets - it was supplied to Parts4Engines with a STAINLESS gasket, Parts4Engines supplied a composite gasket. I spoke to their technical department and they said due to galvanic corrosion, they supply the latter and we should bin off the stainless gasket that came with the new elbow.
If your gasket was METAL - check and replace, if it was a cardboard looking composite thing, you should be protected.
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Thanks magicalarmchair - will definitely check that. What is interesting is that even with the original elbow there was galvanic corrosion on the heat exchanger - you would think that the manufacturer would use similar alloys to avoid this. But then again he would sell less spare parts I guess...
Thanks again
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I am not sure that stainless is the complete answer.
The problem is carbon deposition.
I had the problem a few year ago and hammered, ground and burnt the carbon back to bare metal which was pitted but sound.
I epoxy coated the elbow by immersion with a thick epoxy paint and refaced the sealing surfaces without breaking through the epoxy coating.
The idea was to create a very smooth epoxy finish in the hope that the carbon will not stick to it.
A week ago I took the elbow off and found it covered in carbon. I will attempt to clean it to see if the effort was worth while.
Will advise.
Regards
Aquapore
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Years ago I used JB weld on an alloy part of my Yanmar engine. The repair was excellent and the damaged gearbox housing lasted right through until I replaced the engine. Later someone wanted a working Yanmar gearbox so it was sold and is functioning fine! JB weld I found really good.
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I came across the Volvo-Pentra Neutra Salt flushing concentrate https://www.volvopentashop.com/epc/en-US/Details/AccessoriesCatalog/5627?path=1532%2F1961%2F5626%2F5627 which is supposed to dissolve salt and prevent rust and corrosion mainly in saltwater cooled powerboat engines. Wouldn‘t it be a good idea to flush our cooling system with this concentrate at least if the boat is not used for longer periods?
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Hi Just looking at the Exhaust Elbow how many hrs are on your engine? Also how hard do you run it? The reason for me asking is i have a D1 30F with 650hr, and it would appear this has not been remove yet.
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The normal cruising RPM for a D1 30 is 2200+ and you should be able to get around 3100RPM at maximum with a clean bottom. It is good practice to periodically run at maximum for a short period, say 10-15 minutes as this helps burn off the carbon and oily deposits in the elbow. This is particularly important if you do a lot of low load hours or just run the engine for short periods at a time. The life of the elbow is as much usage pattern related as total hours. My last boat was used as a charter boat for most of its life and still had the original elbow at 13 years and over 3000 hours.
Your 650 hours is less than 100 hours a year and typical of "weekend" leisure usage where the proportion of low load, short run time is high so suggest it is well worth removing the elbow to check it. I also have a D1 30 in my new boat with 350 hours in 5 years. I try to remember each time I come back from a trip to motor the last couple of miles up the harbour and 10 minutes of 3000RPM.
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https://forum.amicidellavela.it/showthread.php?tid=130304
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Hi Just looking at the Exhaust Elbow how many hrs are on your engine? Also how hard do you run it? The reason for me asking is i have a D1 30F with 650hr, and it would appear this has not been remove yet.
I have a D1-30f too, on a 2009 boat with 600-hours, and prompted by the forum I removed the exhaust elbow today for inspection. Elbow clearly needs replacing, which is fine - will upgrade to stainless.
Unfortunately significant corrosion at back end of heat exchanger, as show in photos. Assuming this will need replacing too, although I know how much they cost so still coming to terms with this news ...!
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That doesn't look too bad to me. Just clean up the mating face and put the new elbow on.
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The main thing is that there are no gaps around the flange where exhaust gases could escape so I reckon your prudent check and replacement of that exhaust elbow would be enough. Make sure that you use a composite gasket between the aluminium heat exchanger and the stainless new elbow to limit the possibility of galvanic corrosion continuing should water once again make its way back up to that point.
How will you proceed? Well done for taking the initiative and checking!!
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Thanks both - having offered the gasket up dry, there is still a reasonable amount of surface so relieved to just replace the elbow. Which I will do this weekend, before adding ‘check exhaust elbow’ to my routine maintenance list!
Also have a new Darglow Featherstream prop to fit, so looking forward to a motor as well as a sail - it’s been a long lockdown winter!