Yanmar exhaust elbows

So it is getting time to replace the exhaust elbows on my new to me yanmar 4LHA-STP 240 hp motors. My mechanic said that off the top of his head the part would run about $200 each. Does this seem in line to you guys?

I'm thinking about doing it myself, anybody done it?

TIA.

Also, I'm not positive they need to be replaced. My motors are 2005's but only have 290 hours on them. I know their age could have allowed corrosion build up, but still... If I pull them can they be visually inspected with any confidence?

How many hours

That is not a lot of hours! I just replaced the exhaust elbow on my 1984 Perkins 6-354 na. This engine has almost 3400 hours and the elbow was original to the motor.

Some insurers want them pulled and inspected every 5 years. $200 sounds ok, I think my Lehman ones from USA were about $160-180. The hard part is getting the flexible exhaust tubing off and back on, tough wire reinforced stuff.

Exhaust elbows can be changed out fro Mfg style to more common screw on (NPT) .

There are at least a dozen sources to choose from.

It might be a PIA the first time but after that the ability to do without OEM parts should save big.

Exhaust elbows like other marine engine parts are governed by marine age and not clock hours, especially so in salt water. It is common to change out every five to ten years. The complications off not doing so are unpleasant, particularly for a Yanmar with turbo.

I don't know that engine specifically, but if it is built like the Yanmar 6LY, the exhaust elbow is cast stainless steel and will last a long time.

It is fairly easy to remove and inspect. It is held together with v-clamp fittings and all it takes is loosening the clamping band. Use a heat gun on the exhaust hose and work a scew driver blade underneath the end to loosen.

Also when you reassemble you can reuse the gasket, just put a dab of red, high temperature Permatex on the gasket surface.

But they aren't cheap. I think the one for my boat is $1000.

David

Yanmar 3GM 30E, very low hours (my get home engine) exhaust elbow and the connecting nipple corroded out after 10 years. Warning if you have a nipple connection, do not remove the exhaust elbow unless you have a replacement nipple or time to order and have one delivered. Likely won't be a problem but you should be prepared for the nipple falling apart as you take off the elbow.

Marty

Doug, I have Yanmar 4LH-DTE's which appear to have similar exhaust elbows. They are cast iron held onto the turbo by four studs. There is no reason why you cannot do the job yourself. Getting the hoses to let go can be something of a struggle. I squirt WD40 into the joint while wriggling an old blunted table knife to separate hose from metal. Examine the exhaust side of the turbos carefully for any evidence of sea water corrosion. Spin them by hand, they should turn freely with no sign of binding. Don't forget to order new gaskets. Good luck.

While waiting for my new elbows ordered from USA I made good my old ones which began leaking with that underwater setting epoxy putty which comes in 2 sticks you fork together to mix. Worked a treat, obviously you can only patch/reinforce, grinding back would make pinholes big holes.

Just found out the elbows are $600 each. Ouch.

4LHA should use a cast stainless mixer. These should last a very long time. If there is a dry connecting elbow between turbo and mixer, those are usually just cast Fe and do not last long.

Post a photo of your turbo/exhaust. Rigging the exhaust is up to the boatbuilder and they often do crazy things.

Thanks ski. I'll shoot a pic next time I'm at the boat and post it

OK Here are some pics, sorry they are somewhat obscured. Let me know what y'all think.

as many have said the elbow/discharge part lasts quite a while, one weak part is that piece in the middle between the turbo and elbow, that fatigues and cracks. Given your low hours, you have time, when you get closer to 1000 hours change out the center piece with new one and metal ring gaskets and inspect elbow.

You can loosen those v-clamp joints in a few minutes. All it takes is a 12 mm wrench. Then you can inspect the dry elbow and the water injection elbow. Even though you can see rust spots on the outside, these were left by the cast iron dies when they were cast. They are cast stainless steel and will last a long time.

When you have them off, take a good look at the exhaust turbo outlet. The inside of the housing should be smooth with a light soot coating.

Any roughness indicates corrosion from sea water backing up.

David

Hard to tell from the photos, but mixer looks like it has little down angle at outlet. Typical Mainship. Maybe mixer can be rotated a little downward at vband clamp.

Thanks everybody, I'm more hopeful now that $1,500 won't be flying out of my wallet...at least not on this project. I'll pull them and try to post some pics.

Doug

Cracked open the elbows yesterday, really easy to do with the V=Clamps. They look really good to me, plenty of soot, but no scale or rust that I could see. I scraped around inside them with a flat head screwdriver, they seemed fine to me.

Here are pics of the inside of the elbows, tough to see I realize, but it is hard to take a pic of the inside of an elbow!

Only thing I didn't do was pull the little elbow where the water line attaches. Should I?

[/ATTACH]

Somehow inserted the same pic twice, sorry about that. The one in the above post is the dry elbow, this is the wet elbow.

Doug:

Elbows look fine. But what does the exhaust turbo look like?

David

Hey David,

I'll pull that clamp next time I am down at the boat. You were right, the v-clamps were super easy. Do you think I should pull the water inlet on the mixer and look in there as well?

It is obscene to me that the dry elbow is $730 from yanmar. It is just an elbow, not at all complex. When replacement time rolls around is it possible to replace that dry elbow with something else? I've seen synthetic elbows for under $200, they have the added advantage of no rust, but they obviously wouldn't fit the v clamps and the bracket. Is it possible to engineer a system that doesn't use that dry elbow?

Thanks,
Doug

Doug:

Every part on a Yanmar is obscenely expensive. In their defense it is a low volume, specialty casting that requires machining the clamping surfaces, but $730???

But I don't think you will ever replace that dry elbow. It runs hot, so there is never any moisture droplets to condense and corrode it. And it is stainless steel. So it should last a couple of engine lifetimes.

The water inlet to the mixer is very unlikely to be plugged, but why not take a look. I am assuming that on yours it is a separate piece like a pipe elbow threaded in to the mixer. So it might be tough to break it free. If so, don't bother. The one on my Yanmar 6LY was all one casting integral with the mixer.

BTW get some red Permatex (high temp sealant) and put a dab on each side of the gaskets at the v-clamp joint when you reassemble.

David

djmarchand said:

Doug:

But I don't think you will ever replace that dry elbow. It runs hot, so there is never any moisture droplets to condense and corrode it. And it is stainless steel. So it should last a couple of engine lifetimes.

David

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I've actually seen them cracked at our boat yard, nothing to do with corrosion, but fatigue (vibration and heat cycles).

Marlinmike said:

I've actually seen them cracked at our boat yard, nothing to do with corrosion, but fatigue (vibration and heat cycles).

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Chloride Stress Corrosion Cracking is (SCC) the likely mechanism of the previous and maybe the next failure. Unless a duplex or high Mo SS was used.

The mixing elbow here in the UK costs a staggering £1,000 !!!

Mine on my 4hla has cracked near the rectangular boss on the side of the casting. I managed to repair it temporarily with epoxy metal but it is leaking again so I picked up a second hand one in very good repair for £200.

When I came to fit it I found that the 4" internal diameter flexible hose between that and the lower exhaust section was perished so now have to find one of those!

It might be of help to know that several companies on both sides of the pond sell one to fit the Mercruiser set ups that also fit the yanmar. Mercruiser reference is #32-443488T

Hope to have mine sorted later this week, meanwhile we await the remnants of your hurricane Bertha!

After market exhaust elbow?

djmarchand said:

I don't know that engine specifically, but if it is built like the Yanmar 6LY, the exhaust elbow is cast stainless steel and will last a long time.

It is fairly easy to remove and inspect. It is held together with v-clamp fittings and all it takes is loosening the clamping band. Use a heat gun on the exhaust hose and work a scew driver blade underneath the end to loosen.

Also when you reassemble you can reuse the gasket, just put a dab of red, high temperature Permatex on the gasket surface.

But they aren't cheap. I think the one for my boat is $1000.

David

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Would you have any hesitation about getting an after-market exhaust elbow?
Like this: Stainless Steel Exhaust Mixing Elbow for Yanmar 6LY 119574 13501 119574 13500 | eBay

I have seen those mixers on eBay and they are indistinguishable from a real Yanmar part. The casting and machining look first class.


So, if you get the same thing as in the picture, I would buy one. EBay protects you from fraud and I suspect that you could get your money back if they didn't look like the picture.


David

I just bought 2 for my Yanmar 4JH3's last month. They are very well made, should outlast the originals by a lot. The seller was great to deal with, solving a small issue immediately. I am a completely satisfied customer.

Rafe

BruceK said:

Some insurers want them pulled and inspected every 5 years. $200 sounds ok, I think my Lehman ones from USA were about $160-180. The hard part is getting the flexible exhaust tubing off and back on, tough wire reinforced stuff.

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Heat it with a heat gun and twist, it will come off a lot easier. pushing a butter knife in and around the hose will break the seal on an old one.

Same with putting one on, heat it and twist. slober some dish soap all around the inside of the hose that will grip to the elbow and it will slide on really easy.