Wet exhaust elbow explosion?

MagicalArmchair

MagicalArmchair

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Hello friends,

I replaced my stock d2 55 exhaust elbow with the stainless steel version from the fine folk at parts4engines during my heat exchanger rebuild adventure (Heat exchanger repair).

I'm going to do a proper write up of this to help others, and doing my reading around the subject I found the below:

FYB Marine. Volvo Penta genuine exhaust elbows and exhaust gaskets

This includes the alarming statement:

"Never fit a stainless copy exhaust elbow onto any Volvo diesel. We have seen too many exhausts, fracture or explode."
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I posed this to Parts4engines technical desk (who I have huge respect for), their response was.

"We have never heard our exhaust outlet to fracture or explode as we have been selling the outlet for years. We sell the replacement outlet in SS for most of our engines.

I can assure this issue we wouldn’t occur and we strongly disagree with the statement from FYB marine"
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I can find no evidence of what FYB marine suggest. Has anyone else experianced Stainless steel exhaust elbows fracturing or exploding??

I have reached out to FYB for comment also.
 
I am sure @vyv_cox, as a metallurgist, will be along to comment on technical matters, but I would also be interested in their response. Sounds like arse covering to me.

I have a surprise in store for them! My exhaust elbow is original and fitted in 1986, but I only average 100 engine hours per year.
 
I cannot imagine any mechanism for an explosion due to mixing metals in an exhaust system. Yanmar supply their engines with a stainless exhaust elbow and many people have substituted copy versions in stainless for a wide variety of engines.

So far as fracture is concerned, fabricated stainless steel elbows fail by fatigue, including Yanmar's own. The cause is differing thicknesses of metal, generating stress on heating and cooling.
 
They have probably seen many exhaust elbows fracture, incuding plenty of original Volvo/Yanmar etc ones. But explode????
 
vyv_cox said:
So far as fracture is concerned, fabricated stainless steel elbows fail by fatigue, including Yanmar's own. The cause is differing thicknesses of metal, generating stress on heating and cooling.
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Thank you all, thanks Vyv. That is interesting. I wonder if this is what FYB are referring to?

Volvo Penta D2-55A and D2-55B Stainless Steel exhaust outlet and connector

So the above casting would potentially, after a period of time, suffer the same kind of fatigue? How common is this and after what period of time could you expect failure?
 
MagicalArmchair said:
Thank you all, thanks Vyv. That is interesting. I wonder if this is what FYB are referring to?

Volvo Penta D2-55A and D2-55B Stainless Steel exhaust outlet and connector

So the above casting would potentially, after a period of time, suffer the same kind of fatigue? How common is this and after what period of time could you expect failure?
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The Volvo elbows are castings. Many others, like my Beta 30 are fabrication Beta 3030 hp @ 3,600 rpm - Marine Propulsion Engines Beta Marine where the exhaust tube is welded to the plate and the injection spigot welded to the tube. Both these welds are potential points of failure. Some Yanmars like the 1GM have concentric inner and outer tubes both welded to a plate that mounts on the exhaust manifold. Again points of failure.

Even then "explosions" is over dramatic. You can see pinholes from corrosion in the welds or fractures/cracking but difficult to see how there are any forces involved that could possibly lead to an explosion.

Will be interesting to see FYB response if any.
 
"Never fit a stainless copy exhaust elbow onto any Volvo diesel. We have seen too many exhausts, fracture or explode."

To me this is just an attempt to justify the high price of an OEM part without real evidence

Its the same as using the word marine in any part description
 
I recently purchased a high rise exhaust elbow from FYB marine for my Mascot 28, (2030 B) I had a few questions and I was put through to an engineer who was very helpful. The elbow was expensive, but the service was excellent.
I couldn't find an alternative cheaper version in stainless for this type of elbow.
 
nevis768 said:
I recently purchased a high rise exhaust elbow from FYB marine for my Mascot 28, (2030 B) I had a few questions and I was put through to an engineer who was very helpful. The elbow was expensive, but the service was excellent.
I couldn't find an alternative cheaper version in stainless for this type of elbow.
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The high rise elbow is rare compared with the standard one plus it would be more difficult to cast so not surprising that there is no alternative to the factory one. It is however possible to fabricate one out of stainless tube but as a one off it would probably be expensive. I have a custom made high rise for my Beta and it was a lot of work to make.
 
MagicalArmchair said:
Hello friends,

I replaced my stock d2 55 exhaust elbow with the stainless steel version from the fine folk at parts4engines during my heat exchanger rebuild adventure (Heat exchanger repair).

I'm going to do a proper write up of this to help others, and doing my reading around the subject I found the below:

FYB Marine. Volvo Penta genuine exhaust elbows and exhaust gaskets

This includes the alarming statement:



I posed this to Parts4engines technical desk (who I have huge respect for), their response was.



I can find no evidence of what FYB marine suggest. Has anyone else experianced Stainless steel exhaust elbows fracturing or exploding??

I have reached out to FYB for comment also.
Click to expand...
Hi There,

I am about to pull my D2-55F out in greece and im considering the stainless steel version from the fine folk at parts4engines,

Can you let me know your thoughts on it, How did you isolate it from the heat exchanger ?

Any corrosion since ?

All the best

Charlie
 
I replaced the cast elbow on my MD2040 with a parts4engines version in 2020, using the supplied gasket, and there was significantly more galvanic corrosion of the heat exchanger flange when I removed it last year. Having had the heat exchanger repaired I've isolated the elbow entirely using a mica gasket, high temperature fibreglass sleeves on the studs and Peek washers. I'm not knocking the elbow but the risk of galvanic corrosion is higher with stainless steel than cast iron and parts4engines have been looking at ways of isolating the elbow themselves, although my DIY solution works well and wasn't expensive as I located an offcut of the mica material. The sleeving is a few quid on Amazon and I ordered the Peek washers from a Chinese supplier on eBay, again for a few quid, although I had to wait three weeks for them to arrive.
 
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Ammonite said:
I replaced the cast elbow on my MD2040 with a parts4engines version in 2020, using the supplied gasket, and there was significantly more galvanic corrosion of the heat exchanger flange when I removed it last year. Having had the heat exchanger repaired I've isolated the elbow entirely using a mica gasket, high temperature fibreglass sleeves on the studs and Peek washers. I'm not knocking the elbow but the risk of galvanic corrosion is higher with stainless steel than cast iron and parts4engines have been looking at ways of isolating the elbow themselves, although my DIY solution works well and wasn't expensive as I located an offcut of the mica material. The sleeving is a few quid on Amazon and I ordered the Peek washers from a Chinese supplier on eBay, again for a few quid, although I had to wait three weeks for them to arrive.
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Why is the elbow not cast in the same alloy as the heat exchanger? Aluminium.alloy elbows seem to be made for other engines, so why not Volvo?
 
vyv_cox said:
Why is the elbow not cast in the same alloy as the heat exchanger? Aluminium.alloy elbows seem to be made for other engines, so why not Volvo?
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No idea, but it would save a lot of grief if this was a practical solution. Or maybe Volvo like selling replacement HE's at £2k a pop.
 
Done mine two years ago as the original was badly corroded. No problems since. I've added a thin Stainless plate between exhaust elbow and engine block as a precaution against different metals expanding at differently. I sealed this all with motorcycle exhaust sealant.
 
Idle Hour said:
Hi There,

I am about to pull my D2-55F out in greece and im considering the stainless steel version from the fine folk at parts4engines,

Can you let me know your thoughts on it, How did you isolate it from the heat exchanger ?

Any corrosion since ?

All the best

Charlie
Click to expand...
 
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