Preventing Turbo Hot Side Rust Lockup

[Turtle Blues]

50 years ago, before some of the current high tech additive companies stole their thunder about metal absorption, MMO had a whole subculture of injection system enthusiasts. I fondly remember the sweet smell and white cloud drifting over the marina when overused for winterizing, not sure other slip holders felt the same.

It is still a great low tech solution to a problem like this. The specific engineering to get the correct amount where you want it the key.

[Manateeman]

Sorry. Got a bit thin skinned. We talked to Yanmar about going up then down then injecting. DeAngelo does this all the time with real big HP in mega yachts.
We got a very firm no from Yanmar. No explanation.
Your solution is correct but for some reason Yanmar nixed it.
I’m still waiting on China. They needed more photos which we sent today.
We pulled apart the old turbo and it could be rebuilt with just a new hot wheel.
I’m concerned the manatee crew will try to fit it into another project. I saw a sketch titled exhaust powered super horn.
Mark

[kapnd]

Originally Posted by Sailmonkey

.... I’d bet dollars to donuts that a mixer with a riser prior to the injection point would cure this problem. Something with a 1’+ dry rise followed by a dry inverted “U” followed by the injection point facing down.
...

A fresh water flush in the last few minutes of engine operation would help.
Sailmonkey has nailed the solution, the problem is in the design.

[Manateeman]

We’ve considered fresh water flush...and with a water maker, maybe it will help.
As to design. Again, Yanmar says it’s absolutely NO.
DeAngelo Exhaust is just about the best exhaust builders you can find and they are not sure how BEST to solve this problem.
Off the cuff “ he nailed it” well I wish it were that simple because we could build it.
A lot of times when I read a simple two line answer I got to laugh because...well...isn’t it funny how all these experienced and licensed engineers are rolling along in the wrong direction?
We KNOW the basics of exhaust design and that ought to be obvious from prior posts. Just saying it’s a simple cure doesn’t make it a solution. The Chinese turbo builders asked for a number of specific photos. I’m not sure why. We shall see.
Mark

[rslifkin]

I'd press Yanmar for more info on why you can't do a longer dry section with enough rise and then inject on the downhill. I can't think of any good reason why it wouldn't work.

[Ericson38]

We just went through this with a 4JH2-DTE in a 1991 Taswell 49, engine otherwise perfect, 3023 hours.

Replaced the Turbo (ISI out of Fontana, Ca).

https://turboturbos.com/collections/yanmar


Now after reading this I understand why the mufflers for the gen and the engine have 1 inch bronze seacock drains into the bilge. The valves are on the ends of the mufflers that are on the low side. I thought they were only for winterizing (water draining) but they can also be opened to drained after every use.

The fall distance from the Mixing T to the muffler intake side is 20 inches or so, then through the muffler (about 2 cu feet), then up about 40 inches to the underside of the center cockpit coaming area (underside), then down along the hull, then out under the swim step. Generator takes the same route.

I plan on taking off the mixing T at every oil change from now on.

[Manateeman]

The Yanmar NO. Well we were surprised by that as well and so we’re the guys at DeAngelos shop. After the first turbo didn’t sound great we took off the rusted injection elbow and replaced it with a stainless. But before we did that, we asked Yanmar. We were told, just replace it with stainless in the same design. That was when we thought Cera-Kote would fix the issue...which it didn’t.
It’s a big walk around engine room and we were not concerned with heat so we thought let’s go up a foot, make a u turn down then we have almost three feet to the top of the water lift and we can stick the injection section nice and far away from the turbo. All I can think is that they don’t want to admit the original elbow injector was wrong or it’s something about the fluid dynamics / pressures /or the turbo itself. We have very low back pressure as the water / gas separator works well and the engine isn’t pushing water all the always to the stern. We also increased the diameter of everything including the out pipe of the water lift.
I don’t want to argue with Yanmar, but if the Chinese don’t have an answer we will do it the way DeAngelo does it all the time. Up, loop, down.
Another guess. Do turbos need some back pressure ? We know the water lift provides some but we thought the less back pressure...the better.
The guys in China produce turbos for major diesel names here so we just wait.
Mark

[chowdan]

Originally Posted by Manateeman

The Yanmar NO. Well we were surprised by that as well and so we’re the guys at DeAngelos shop. After the first turbo didn’t sound great we took off the rusted injection elbow and replaced it with a stainless. But before we did that, we asked Yanmar. We were told, just replace it with stainless in the same design. That was when we thought Cera-Kote would fix the issue...which it didn’t.

It’s a big walk around engine room and we were not concerned with heat so we thought let’s go up a foot, make a u turn down then we have almost three feet to the top of the water lift and we can stick the injection section nice and far away from the turbo. All I can think is that they don’t want to admit the original elbow injector was wrong or it’s something about the fluid dynamics / pressures /or the turbo itself. We have very low back pressure as the water / gas separator works well and the engine isn’t pushing water all the always to the stern. We also increased the diameter of everything including the out pipe of the water lift.

I don’t want to argue with Yanmar, but if the Chinese don’t have an answer we will do it the way DeAngelo does it all the time. Up, loop, down.

Another guess. Do turbos need some back pressure ? We know the water lift provides some but we thought the less back pressure...the better.

The guys in China produce turbos for major diesel names here so we just wait.

Mark

Have you reached out to SB Mar in Cali? I worked with them and they helped build my exhaust. They worked with me as they mocked it up based on my PVC mock. In one of the photos the injection port seemed too straight so I had them angle it to match the exhaust.

I don't have much space like it sounds like you do, but i would guess if you moved the injection port farther from the turbo, the better you are going to be at getting the moisture to the turbo.

I also got a 'no' with no answer from Yanmar as to why I can't do this. I suspect it was due to increase backpressure if I ran same diameter as standard exhaust elbow. I went up to 1.5" tubing and also have a low backpressure last I checked.

I highly recommend talking with SB mar and DeAngelo and specifically talk about how moisture will move if you move the injection port not only vertically higher as you talk, but horizontally away from the engine itself.


As I was about to post this I was thinking, I wonder if you could get a vacuum gauge or something on the exhaust side to see how much pressure is being pulled towards the turbo. I am skeptical of the water being hot enough to cause vapor problems considering the polished section of my elbow is cool enough to touch without any issues(easily hold my hand on it for 10+ minutes)

[Sailmonkey]

I’m going to go out on a limb and guess that yanmar cannot say yes because they sell engines as a package with a mixing elbow. Their elbow is proven to be correct for most installations to not stress/fracture the turbo housing, flood the engine, etc…. I’d bet more persistent digging would reveal something like this.

And less back pressure is what the turbo wants.