What’s better Inox or aluminum exhaust elbow Volvo D2-50

[CaptainRivet]

Hi all,

To avoid the well-known problem problem with the original Volvo iron cast exhaust elbow on my two 2019 Volvo D2-50 engines i wanna exchange them already now.
Besides the rust build up inside the iron cast elbow you will also find galvanic corrosion on the flange of the 3500Euro heat exchanger caused by the iron cast elbow.

From my research I found 2 solutions to tackle this problem:

A: aftermarket stainless steel exhaust elbow. It’s still stainless to cast Aluminium so still a bit of galvanic corrosion but much less and inox won‘t rust, so no clog up.
The d2-55 will fit too I was told eg. https://www.parts4engines.com/volvo-...connector-kit/
Cost 500Euro

B: the Perkins prima 50 elbow will fit 2019 d2-50 and is made out of cast aluminum, the same Material as the Heat exchanger body. So no galvanic corrosion between the 2 and Aluminium won’t rust, so it won‘t clog up.
https://www.parts4engines.com/perkin...-outlet-elbow/
Costs 180Euro

To me it seems the much cheaper solution with the prima 50 Alu cast exhaust elbow is also the better solution, as no galvanic corrosion at all.
But why most choose the inox solution?

Does it make sense to polish the inside walls of the elbow so the Carbon cannot stick to it?
That’s a common practice to greatly reduce carbon buildup on Audi‘s V8 engines in R8 and RS4 and should work here too.

[Manateeman]

Stainless. Gasket. Cera -Kote .
The manatees

[Bill O]

CR,
Will agree w/MM that the cast stainless exhaust elbow is the way to go.

Not sure where you are located, but when I was looking for a replacement elbow recently that HDIMarine in the States made many of the SS elbows sold on parts4engines.

I believe this is the same part you listed for the D2-55 at HDI. Since there may be subtle differences in the bolt pattern, make certain that part will fit your D2-50 engine.

[CaptainRivet]

Originally Posted by Manateeman

Stainless. Gasket. Cera -Kote .
The manatees

Thank you both. Located in the Canaries Islands at the moment and will be close te Europe mainland next year.

But why not the cast alu version? Same material then the heat exchanger so no contact corrosion and now rust. Problem is the iron cast...i see no advantages of the ss one over the alu cast here.
Stainless on 2 Engines is triple cost over alu cast.

[Manateeman]

Please take a look at Ceracote. Aluminum is great stuff...our boat is aluminum.
If we had the time, we would Ceracote every piece of aluminum on our engine.
We had the HOT side of our turbo...the INNER side done professionally with Ceracote. If that’s not a torture test, I give up.
If you want a good fun video, see the Ceracote torture test.
But seriously, a cast stainless elbow is going to outlast the diesel. So where will you see failure. The aluminum because aluminum self heals IF it’s exposed to oxygen. If you Ceracote it, you have probably the best protection possible for a reasonable price. Good stuff..the military uses it to coat guns. The manatee crew thinks it’s the best stuff invented since Tef-Gel, take out pizza and aluminum beer bottles which they recycle into boats. Burp.
Happy trails to you.
Captain Mark

[CaptainRivet]

Originally Posted by Manateeman

Please take a look at Ceracote. Aluminum is great stuff...our boat is aluminum.
If we had the time, we would Ceracote every piece of aluminum on our engine.
We had the HOT side of our turbo...the INNER side done professionally with Ceracote. If that’s not a torture test, I give up.
If you want a good fun video, see the Ceracote torture test.
But seriously, a cast stainless elbow is going to outlast the diesel. So where will you see failure. The aluminum because aluminum self heals IF it’s exposed to oxygen. If you Ceracote it, you have probably the best protection possible for a reasonable price. Good stuff..the military uses it to coat guns. The manatee crew thinks it’s the best stuff invented since Tef-Gel, take out pizza and aluminum beer bottles which they recycle into boats. Burp.
Happy trails to you.
Captain Mark

HI Mark,
thanks for your answer. Yes I know ceracote well, had some enginge parts of my race cars coated with that. Well in Canaries you won't find that ceracote stuff.
Just wondering that the problem with the D1 and D2 exhaust elbows are around for 15 years+ now and nobody used the alu one. 40% of costs then SS, same material and no problem expected.

Yes SS bow may outlast the engine but still destroys the flange to the 3500EURO heat exchanger too through galvanic corrosion, not that bad then iron but still...parts4engine supplies a different seal already as the manufacturer of the SS bow as they are aware of this problem. The expensive fix is not the elbow, its the heat exhanger.



the effort to get a cast alu bow Ceracoted and send to Canaries wil cost the same then another new alu cast one as replacement plus min. 2 month time. If the iron lasts 8 years then alu should do 15 years minimum without any treatment and without damaging the heat exchanger.


Why no one found a perfect fix for this 15 year old problem with thousands of D1 and D2....

[moseriw]

on the flange of the 3500Euro heat exchanger caused by the iron cast elbow.

Wow - hell this is half the price of a refurbished Ford Lehman 2712E engine with all parts including all heat exchangers and even the alternator and starter motor.

Thank you my god that you gave me an engine that has 6000 hrs within the last 40 years without any major problems.

[johnn33]

https://www.cerakote.com/contact-us
John

[Martkimwat]

Just had a look to see if it is available in UK, which it is and it appears you can get a kit to do it yourself, including a spray gun for £164.99 Ex VAT. Just need an air compressor. An exhaust elbow cannot be that difficult to spray. Here's the link to the UK site.https://www.cerakote.co.uk

[Cheechako]

I'd try the aluminum, because you want the elbow to be sacrificial if anything. With stainless your Volvo part will be sacrificial. I kinda doubt stainless is any less corrosive than cast iron though also.

My old Volvo MD-2B had cast iron. I replaced it with a SS elbow and it failed far faster than the original.

[Compass790]

Originally Posted by Cheechako

I'd try the aluminum, because you want the elbow to be sacrificial if anything. With stainless your Volvo part will be sacrificial. I kinda doubt stainless is any less corrosive than cast iron though also.

My old Volvo MD-2B had cast iron. I replaced it with a SS elbow and it failed far faster than the original.

interesting, I'm curious about your experience, it raises some questions.

Was the ss elbow cast or fabricated out of pipe or tube?
If welded was it purge welded?
Do you know what grade of ss it was made of?
Did it fail at a weld or was it was a case of general decay
Apologies for thread drift but its related

[Cheechako]

Originally Posted by Compass790

interesting, I'm curious about your experience, it raises some questions.

Was the ss elbow cast or fabricated out of pipe or tube?
If welded was it purge welded?
Do you know what grade of ss it was made of?
Did it fail at a weld or was it was a case of general decay
Apologies for thread drift but its related

Good thoughts.
It was TIG welded at the aircraft supply company I managed. Of course... it was purged. However, the best thing would have been to anneal it afterwards so the weld areas were not sensitive to corrosion. I didn't anneal it though. It was long ago and I cant remember for sure but was likely type 321 as we had a lot of that around at the time. (321= Ti alloyed and a good application for welded exhaust structures.)
Cast iron is known to hold up well, I would be more concerned about which part is going to be sacrificial... unless the Volvo exhaust manifold ( is it cast as the head on your engine? or separate? ) is cheap!

[s/v Jedi]

Originally Posted by Martkimwat

Just had a look to see if it is available in UK, which it is and it appears you can get a kit to do it yourself, including a spray gun for £164.99 Ex VAT. Just need an air compressor. An exhaust elbow cannot be that difficult to spray. Here's the link to the UK site.https://www.cerakote.co.uk

Well it also needs to bake in an oven… that may not be suited for baking food afterwards…

Originally Posted by Cheechako

Good thoughts.
It was TIG welded at the aircraft supply company I managed. Of course... it was purged. However, the best thing would have been to anneal it afterwards so the weld areas were not sensitive to corrosion. I didn't anneal it though. It was long ago and I cant remember for sure but was likely type 321 as we had a lot of that around at the time. (321= Ti alloyed and a good application for welded exhaust structures.)
Cast iron is known to hold up well, I would be more concerned about which part is going to be sacrificial... unless the Volvo exhaust manifold ( is it cast as the head on your engine? or separate? ) is cheap!

I understand that the HDI marine elbows are one piece investment cast stainless steel. Mine seems to gonna last forever…

[Compass790]

Originally Posted by Cheechako

Good thoughts.
It was TIG welded at the aircraft supply company I managed. Of course... it was purged. However, the best thing would have been to anneal it afterwards so the weld areas were not sensitive to corrosion. I didn't anneal it though. It was long ago and I cant remember for sure but was likely type 321 as we had a lot of that around at the time. (321= Ti alloyed and a good application for welded exhaust structures.)
Cast iron is known to hold up well, I would be more concerned about which part is going to be sacrificial... unless the Volvo exhaust manifold ( is it cast as the head on your engine? or separate? ) is cheap!

Thanks for reply,
Ummm, purged doesnt happen "of course" IME. I have come across more than one marine exhausts made out of tube that wasnt purged.
I notice you did not say wether it was tube or pipe. IME sched 10 pipe is a much longer lasting material naturally being thicker walled.
I personally would only use ss tube on a dry exhaust.
Could certainly understand a tube ( 1.5mm thk ) exhaust wouldnt last as long as cast-iron.
Yes agree you would want to avoid sacrificing any volvo part unless you are in the NFL team owner income category.
No experience with ali on exhausts but doesnt seem to be a common material for exhausts, guess that's why OP is asking.
I'd be tempted to try the ali but I like to experiment.

[CaptainRivet]

Originally Posted by s/v Jedi

Well it also needs to bake in an oven… that may not be suited for baking food afterwards…



I understand that the HDI marine elbows are one piece investment cast stainless steel. Mine seems to gonna last forever…

Problem on the d2-50 is
A) the cast iron elbow rusts inside and cloggs up the inlet which causes different flow pattern that creats cavital corrosion around the flange to the alu cast heat exchanger
B) this then causes that the seal partly breaks and the iron and alu cast gets in contact so you get contact corrosion and the flange of the alu cast heat exchanger corrodes away. This then causes a leak where salt water drips on starter causing to rust quickly and break down.
C) additionally then heat exchanger starts to corrode and salt water gets into the sweet water cooling cycle. Game over....

Parts4engine sells the HDI stainless cast elbow with different seals then HDI delivers as their customers experienced the same contact corrosion (see B) as with the original part.
Got told that fixes this issue but they don't have long term experience with it as they sell this different seal since 2 years.

Too me it looks like that the alu cast really solves the problem as there are no contact corrosion and much cheaper then SS version .
Just wondering why not more D2 owners choose the alu cast part...
My experience tells me if a solution sounds that good but nobody in the marine world done it that there is a major flaw that I didn't discover till now..
And I agree then I want the elbow to break before the heat exchanger.