How to clean stainless steel elbow

[GavDog]

I've got twin d1-30 stainless steel elbows. How can I best clean them given they are stainless and clogged? Thanks!

[SOLAR SUPPORT]

There are two important problems of VP elbows, which are produced by casting technique from iron casting material. The first is that they oxidize in a very short time. Oxidation makes the flow of the exhaust gas and seawater mixture discharged through the elbow unstable, and as a result of advanced oxidation, the sea coolant splashes back towards the engine exhaust manifold.

When used in this way for a few years, the manifold made of aluminum is exposed to corrosion by the effect of seawater splashing back and can be punctured. In this case, the fresh coolant flows into the engine and the engine is damaged greatly. The second problem with the elbow is that they are short in length, and this short design is one reason why the sea coolant splashes back.

I have been using the 50 mm longer elbow, which was manufactured by welding method from 3 mm thickness 316L Stainless Steel in my own boat, for four years without any problems. Upon the request of fellow sailors, we manufactured the same elbows for approximately 20 boats and replaced them with cast iron ones. There has been no problem for a long time. Engine performance is always at maximum level. Clogging, oxidation is left behind.

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[GavDog]

Thanks for your reply. I don't have the original VP elbow though. These are stainless replacements but they need a clean. Do you have any advice on how to clean stainless ones? E.g is muriatic acid/hydroclauric acid suitable or?

Also, where the elbow connects is also caked with black soot. By this I mean the lower inside lip of the exhaust manifold, ( just inside where the elbow bolts on). What is the best way to clean this? Thanks!

[Manateeman]

Volvo ? We are guessing VP . More information always helps our readers to help you. Here’s our questions. How many hours. What boat. Any engine issues. Do you always warm up. Do you run them hard all the time. Are the props correct for the engines. When did you change to stainless. Who made them. Why’d I’d you change to stainless. Why did you take them off...what made you suspect them. What has been the service history. Do you have hard carbon buildup or soot.
We can’t guess and expect you’ll send us a pizza gift card.
The manatee crew.

[Jammer]

A long soak in any aggressive alkaline detergent, possibly with heat. TSP if locally available. There are commercial decarbonizing compounds available e.g. Piston Kleen that are essentially detergent. Ammonia cleaning compounds may work OK. Wear goggles and gloves.

[SOLAR SUPPORT]

You can use approximately 0.5 liter of diesel to clean carbon deposits. Gloves and protective eye glass should be used.

[ItDepends]

Another option is a soak in warm 20% sodium hydroxide (lye or caustic soda)). Or just use spray-on oven cleaner (same stuff). Will not hurt stainless or iron at all (keep it far away from aluminum however!) and works really well on oily soot.

Eye protection and gloves REQUIRED when working with caustic soda.

[Brioche]

I second the oven cleaner approach. Buy liquid oven cleaner from restaurant supply house (it comes with a pum spray head, but pours out). Heat up the metal moderately and pour on a little oven cleaner -- it should sizzle just a bit. It will dissolve surface coat of black stuff. Repeat until clean. Don't inhale.

[wingssail]

You should ask the 6 Million Dollar Man. I think he had a stainless steel elbow.

[GavDog]

Originally Posted by Manateeman

Volvo ? We are guessing VP . More information always helps our readers to help you. Here’s our questions. How many hours. What boat. Any engine issues. Do you always warm up. Do you run them hard all the time. Are the props correct for the engines. When did you change to stainless. Who made them. Why’d I’d you change to stainless. Why did you take them off...what made you suspect them. What has been the service history. Do you have hard carbon buildup or soot.
We can’t guess and expect you’ll send us a pizza gift card.
The manatee crew.

As per initial post, they are both volvo penta d1-30. It seems to be hard carbon buildup as I cannot seem to scrape it easily and it is quite smooth. Ideally trying to avoid needing to remove whole heat exchanger and just clean with some product and then scrape/wipe out. Thanks

[Manateeman]

We asked a lot of questions with good reason. Soot...really not an issue but hard baked on carbon kinda means your diesel is not running perfectly.
It’s like hearing one of the manatee crew coughing and producing...well let’s say green stuff. Is it their diet of pizza and beer or are they sick and need an X-ray of their lungs. I’ll take them to a doctor because I can’t do anything at sea.
Same with your diesel.
We can’t say...go ahead and clean it out and bolt it back together...because we don’t know the CAUSE. It may be a simple case of running rich (lots of reasons) or a case which requires looking at numerous diesel components...valves, injectors...we didn’t ask all these questions for no reason.
Giving my manatee crew vitamins won’t prevent liver failure.
Mark

[GavDog]

Originally Posted by Manateeman

We asked a lot of questions with good reason. Soot...really not an issue but hard baked on carbon kinda means your diesel is not running perfectly.
It’s like hearing one of the manatee crew coughing and producing...well let’s say green stuff. Is it their diet of pizza and beer or are they sick and need an X-ray of their lungs. I’ll take them to a doctor because I can’t do anything at sea.
Same with your diesel.
We can’t say...go ahead and clean it out and bolt it back together...because we don’t know the CAUSE. It may be a simple case of running rich (lots of reasons) or a case which requires looking at numerous diesel components...valves, injectors...we didn’t ask all these questions for no reason.
Giving my manatee crew vitamins won’t prevent liver failure.
Mark

Ah OK. Sorry I thought it was just normal. The starboard engine had a pinprick hole in the injection pump that led to it racing for a few minutes. Had that repaired. Currently it sends out black liquid (soot perhaps?) at above 2200rpm.

Port engine currently won't go above 2000rpm in drive under load. Achieves normal revs in neutral and reverse so its not getting power. Definitely not fuel issue as plugged in tote tank past the filters to confirm that. Multiple mechanics have looked at it but can't figure it out.

Thanks

[SOLAR SUPPORT]

Originally Posted by GavDog

Port engine currently won't go above 2000rpm in drive under load. Achieves normal revs in neutral and reverse so its not getting power. Definitely not fuel issue as plugged in tote tank past the filters to confirm that. Multiple mechanics have looked at it but can't figure it out.

Thanks

Residues of carbon - salt - calcium mixture that adhere to the inner wall of the exhaust gas passage channel of the elbows narrow this passage. The exhaust gas flow trapped in the narrowing exhaust passage negatively affects the volumetric efficiency of the engine. After the residues formed in this area are cleaned, the volumetric efficiency of the engine will increase and the number of revolutions will increase.

[GavDog]

Originally Posted by SOLAR SUPPORT

Residues of carbon - salt - calcium mixture that adhere to the inner wall of the exhaust gas passage channel of the elbows narrow this passage. The exhaust gas flow trapped in the narrowing exhaust passage negatively affects the volumetric efficiency of the engine. After the residues formed in this area are cleaned, the volumetric efficiency of the engine will increase and the number of revolutions will increase.

Thanks for that. In the heat exchanger where the elbow connects can I safely use some foaming oven cleaner to clean in there? When I feel inside with my fingers it feels like there small circular gaps that may be a bit clogged but not sure what they are or whether I am OK to try cleaning them. Will whatevet I clean inside the exchanger just flush out when I start up the engine again once all reinstalled? Thanks!

[SOLAR SUPPORT]

Originally Posted by GavDog

Thanks for that. In the heat exchanger where the elbow connects can I safely use some foaming oven cleaner to clean in there? When I feel inside with my fingers it feels like there small circular gaps that may be a bit clogged but not sure what they are or whether I am OK to try cleaning them. Will whatevet I clean inside the exchanger just flush out when I start up the engine again once all reinstalled? Thanks!

You must remove the heat exchanger copper tube bundle from the chamber it is in. If you leave it in vinegar for 12-16 hours, the calcium in the pipes will dissolve.