Clear rust out of exhaust elbow/water injector

r-rossow · Aug 29, 2011

My exhaust elbow is filling up with rust and stopping sea water from getting into the exhaust and cooling the hot gases. The lower part of the exhaust elbow is all blocked with rust. As a new exhaust elbow runs at about 1 grand, I am looking for a way to clear out the rust.

A friend suggested*removing the exhaust elbow from the engine and lower the injector part of the exhaust elbow in a plastic bucket*filled with muriatic acid.

*

*

Edelweiss · Aug 29, 2011

*My Perkins 6.354 NA's exhaust system have been out of production for many years.* Youre lucky you can still purchase NOS exhaust elbows. I have to have them fabricated by MESA Marine in Mobile, Alabama.**
Depends on the style of elbow, but with cast iron try this.*
Be really careful digging them out, you don't want to overdo it.* If you haven't cleaned them before, it's best to take them off.* If you have freeze plugs take them out.* I took mine to an engine overhaul shop and they dropped them in their boil out tank overnight.* Then it wasn't too much trouble to clean them out with a couple of really small wire brushes and an old coat hanger. Bend the coat hanger in half, use the loop end and run it deep up into the passages from the bottom end.* Just be careful, remember that those accretion you are digging out are part seawater minerals and part exhaust system metal.* So your elbows are getting thinner don't take out more metal than necessary.
After that, every couple of years, I drop the rubber exhaust elbows and run the doubled over coat hanger through the water passages from the bottom end.
Larry B

-- Edited by Edelweiss on Monday 29th of August 2011 09:13:36 AM

Larry M · Aug 29, 2011

We had a Perkins engine where the exhaust elbow wore out at the water injection point. Water would sit in the number 4 cylinder at shut down. It corroded the exhaust valve stem so badly that the valve head dropped into the cylinder. This was 16 months after it had been removed, cleaned and inspected.* At the time, the engine was occasionally a little hard to start but ran fine.*

Since then we have always looked at exhaust elbows as a replacement maintenance item. I keep the valve head around as a reminder.

Fotoman · Aug 29, 2011

You don't mention the make/model of your engine (I am asking because I am surprised at the cost. I replaced mine on a Lehman 120 recently and it was $150).
At best this will be a temporary fix to buy you some time. As Larry mentionned, the metal is getting thinner. And if there's enough rust to cause a blockage, it means you are loosing a lot of metal.

Edelweiss · Aug 29, 2011

Larry M wrote:
We had a Perkins engine where the exhaust elbow wore out at the water injection point. Water would sit in the number 4 cylinder at shut down. It corroded the exhaust valve stem so badly that the valve head dropped into the cylinder. This was 16 months after it had been removed, cleaned and inspected.* At the time, the engine was occasionally a little hard to start but ran fine.*

Since then we have always looked at exhaust elbows as a replacement maintenance item. I keep the valve head around as a reminder.

Yikes that's bad!! *Just another reason for me to do scheduled mantenance.

Which engines NA or turbo? *The 6.354 NA uses a different head and the BARR cast re-pop, exhaust manifold and elbow, fits turbo only. *They haven't been available for many years for the NA. *Mesa (Marine Exhaust Systems of Alabama) are abuout $2000 each for the Stainless manifold, but they are done right, with the correct stainless and will probably last my lifetime. *(below) The far left picture is the BARR cast for turbo's, they look similar but the valve ports are opposite angles. *The last pics are the stainless MESA manifolds a perfect fit!! *

Larry B

-- Edited by Edelweiss on Monday 29th of August 2011 12:10:38 PM

Doc · Aug 29, 2011

I paid a grand for a new one for my 330 Cummins...installed. My mechanic happened to have one laying around. I saw several on ebay in the same price range. Mine was starting to weep at a weld on the bottom.

r-rossow · Aug 30, 2011

The engines are Volvo Penta TAMD63L's. Checked ebay, and found this at 1 grand.

I live just 150 nautical miles from Volvo Penta's main office in Gothenburg, Sweden. Parts for these engines are no cheaper over here.*

I have tapped the elbow carefully with a hammer. By listening to the sound it does not seem to be thin anywhere.

They main problem seems to be even smaller rust flakes block the small water injection orifices

r-rossow · Oct 5, 2011

Removed the exhaust elbow the other day. Turned out most spitzers were blocked by rust. Filled a bucket with muriatic acid (30% solution) and let the exhaust elbow sit in it for 5 - 6 hours.

Result: A clean shower head!

1: How it looked pre treatment
2: Muriatic acid
3: Soaking
4: Nice and shiny after 5 - 6 hours
5: Melted upper part of Vetus silencer*

*

RickB · Oct 5, 2011

Something to keep in mind is that most of what looks like flaked off metal is just salt and minerals precipitated out of the seawater. Cast iron has excellent corrosion resistance properties and the corrosion products tend to adhere very strongly to the surface and forms a protective layer.

When steel rusts, the corrosion products expand about 3 times so a flake of rust is not the same as the metal lost. Cast iron can pit and can produce what looks like a lot of rust but keep in mind the surface area that provides the very small amount of rust that colors the salt and minerals you see clogging the spray ring. If you can remove chunks with a piece of bent coat hanger wire you are not removing anything that has any structural value.

JAT · Oct 5, 2011

Edelweiss wrote:
*

Yikes that's bad!! *Just another reason for me to do scheduled mantenance.

Which engines NA or turbo? *The 6.354 NA uses a different head and the BARR cast re-pop, exhaust manifold and elbow, fits turbo only. *They haven't been available for many years for the NA. *Mesa (Marine Exhaust Systems of Alabama) are abuout $2000 each for the Stainless manifold, but they are done right, with the correct stainless and will probably last my lifetime. *(below) The far left picture is the BARR cast for turbo's, they look similar but the valve ports are opposite angles. *The last pics are the stainless MESA manifolds a perfect fit!! *

Larry B

-- Edited by Edelweiss on Monday 29th of August 2011 12:10:38 PM

*

I had to replaced my wet manifolds and elbows last year.... Mark @ MESA got us fixed up....but it wasn't a day at K-Mart.... *My port manifold clogged up completely just after we entered Lake Okeechobee, and we ended up limping across the lake to Indiantown Marina on one engine.... I elected to replace the manifolds and elbows on both engines....after pulling both...they were pretty much gone...acid bathing wouldn't have helped.... *Here's a picture of what we installed on our 6.354 NA's...

Here's what was replaced....

Spent a week or so turning North America upside down looking for factory originals, to no avail....was tempted to buy one of the other retrofit kits...can't remember the name at the moment....but opted for MESA's parts....direct bolt ons, perfect fit, and haven't had a bit of trouble since!!

-- Edited by JAT on Wednesday 5th of October 2011 06:38:51 PM

Edelweiss · Oct 5, 2011

JAT wrote:
*I had to replaced my wet manifolds and elbows last year.... Mark @ MESA got us fixed up....but it wasn't a day at K-Mart.... *My port manifold clogged up completely just after we entered Lake Okeechobee, and we ended up limping across the lake to Indiantown Marina on one engine.... I elected to replace the manifolds and elbows on both engines....after pulling both...they were pretty much gone...acid bathing wouldn't have helped.... *Here's a picture of what we installed on our 6.354 NA's...

*

---------------------------------------------

Yup!! *Those are beauties alright (just like mine. *Mark at Mesa is a good guy and while their prices are right up there, their workmanship is outstanding. *Those manifolds will last you a lifetime.

Larry B

*

Edelweiss · Oct 5, 2011

superdiver wrote:
I have the perkins 6.34...na as well... ill keep that Mark guy in mind when it comes time to replace mine. about how many hours did you have on the engines before you had to replace the exhaust parts?

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Mine were originals and had about 1500 hours on them. *But the boat is a 1976, so they have been bathed in salt water for 34 years. *Each set is custom built and it took about four months from request date, to receive the last manifold I ordered.

-- Edited by Edelweiss on Wednesday 5th of October 2011 09:38:02 PM

JAT · Oct 6, 2011

Edelweiss wrote:JAT wrote:
*I had to replaced my wet manifolds and elbows last year.... Mark @ MESA got us fixed up....but it wasn't a day at K-Mart.... *My port manifold clogged up completely just after we entered Lake Okeechobee, and we ended up limping across the lake to Indiantown Marina on one engine.... I elected to replace the manifolds and elbows on both engines....after pulling both...they were pretty much gone...acid bathing wouldn't have helped.... *Here's a picture of what we installed on our 6.354 NA's...

*

---------------------------------------------

Yup!! *Those are beauties alright (just like mine. *Mark at Mesa is a good guy and while their prices are right up there, their workmanship is outstanding. *Those manifolds will last you a lifetime.

Larry B

*

*

I agree that Mark is a good guy, and very helpful!! *

I am counting on them lasting long after I am gone!!

JAT · Oct 6, 2011

superdiver wrote:
I have the perkins 6.34...na as well... ill keep that Mark guy in mind when it comes time to replace mine. about how many hours did you have on the engines before you had to replace the exhaust parts?

*

I don't know how many hours were on the manifolds or elbows.... But I do know my engines have about 6500 hours on them.... The engines are the originals and the boat was built in 1979.

I know they were on the engines more than 10 years, and the boat was definitely used during that period.

-- Edited by JAT on Thursday 6th of October 2011 09:14:45 PM

Clear rust out of exhaust elbow/water injector

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