Heat Exchangers

[Dockhead]

A data point, for people trying to decide on preventative maintenance.

At 2000 hours, I thought I should check the multitudinous heat exchangers in my engine for calcification, clogging, etc.

I hired a pro to take the engine apart -- intercooler, transmission oil cooler, heat exchanger.

As it turns out -- everything completely clean; I could have saved the money.

FWIW to others thinking about this.

[skipmac]

Pulled all the coolers on my 30 year old, 2000 hour Westerbeke, and they did have some crud and blockage so was glad I did it. Nothing that was so bad it would have killed the engine but definitely enough to restrict flow a bit.

Also installed all new hoses while I was at it.

[Tayana42]

At around 2000 hours the heat exchanger in my 25 year old Yanmar 4JHE was almost completely clogged. Tried having it bathed in acid but had to replace it.


S/V B'Shert

[accomplice]

At 1900hrs, my 7 year old Yanmar 4LHA was squeaky clean inside too.

I had gotten some strange oil test results showing fuel contamination (which is bad), but it turns out to most likely have been an off-brand of oil used by a PO.

[Arthur Garfield]

@ Dockhead,You mention an "intercooler".Are you running turbo-charged engine(s) ?

Good for you all came up clean!
For those that can- I suggest closed loop with anti-scale solution to clear scale
at leisure.


All the Best

[Tiki2]

Hi. I have been looking at setting up a closed loop system to flush as suggested. Is there any particular anti-scale solution that is most effective? Has anyone done this and could give some thoughts?

[Dockhead]

Originally Posted by Arthur Garfield

@ Dockhead,You mention an "intercooler".Are you running turbo-charged engine(s) ?

Good for you all came up clean!
For those that can- I suggest closed loop with anti-scale solution to clear scale
at leisure.


All the Best

Indeed. Turbocharged and intercooled.

That's why it's able to make 100 horsepower out of only 2000cc displacement, same specific power output as my first BMW (a 2002).

I used to thing that this is just wrong in a marine engine -- should be as simple and heavy as possible, naturally aspirated, etc., I thought.

But I have come around to liking this engine. Quarter ton of weight saved (compared to the 82 horsepower Perkins which would have been the alternative) helps sailing performance (almost makes up for my generator). It's incomparably smoother and quieter than the Perkins.

It has much less volume, so it's easier to get to things on it -- there's more room around it.

The turbo does make it more efficient -- lower specific fuel consumption. And I think the engine is loaded better at lower power settings, than a bigger naturally aspirated engine, which is good for sailboats.


What I don't like about it is the poor quality of finishing -- rusting through the paintwork. Poor quality electrical connections. Expensive parts.

[ranger58sb]

Originally Posted by Tiki2

Hi. I have been looking at setting up a closed loop system to flush as suggested. Is there any particular anti-scale solution that is most effective? Has anyone done this and could give some thoughts?

I'm "mid-project" in that I've just finished flushing (descaling) our starboard engine. Haven't evaluated results yet; we'll do that when we run the boat this weekend.

The three most common commercial products (that I know of) are Rydlyme, Barnacle Buster, and Triton Green something-or-other. I used Rydlyme.

Pumped the stuff in through a flush valve between that seacock and the sea strainer, then through the fuel cooler, aftercooler, gear cooler, and heat exchanger. Capture for recirculation was from the discharge hose that leads from heat exchanger to exhaust elbow.

The water pump">raw water pump impeller has to be out of the way; I was due for replacement, anyway, so that was no hardship. The stuff is said to be OK for engine zincs when diluted to working strength; I didn't see any serious impact on existing zincs, but I was due for checking/replacing those, too.

I can't tell whether raw water flow has improved or not; might have. I'll get an operating temperature read-out -- for comparison to previous, and comparison to the as-yet-un-flushed port engine -- before deciding whether it was worth the effort. Or worth the effort doing it the way I did.

It's probably worth emphasizing that an on-engine raw water flush like that absolutely does not replace periodic aftercooler removal/cleaning. The raw water flush doesn't touch the air side, which needs equal attention.

For Dockhead: I'd presume your intercooler needs periodic maintenance similar to the way our aftercooler does. Our engine manufacturer (and onsite mechanic, too) says it's absolutely critical. OTOH, ours are likely used much differently than yours.

-Chris

[a64pilot]

I believe most all are aftercoolers, aftercooler of course cools the charge after the turbo or blower compresses it and therefore heats it.
I think the only time you ever see an intercooler is when there are multiple compressors, like a DD maybe that could have both a turbo and a blower, the intercooler is the between the compressors.
The names are used interchangeably though.

[Dockhead]

Originally Posted by ranger42c

. . . For Dockhead: I'd presume your intercooler needs periodic maintenance similar to the way our aftercooler does. Our engine manufacturer (and onsite mechanic, too) says it's absolutely critical. OTOH, ours are likely used much differently than yours.
-Chris

When I write "intercooler" I mean what is known in the marine world as "aftercooler". I was using car terminology, but it's the same thing -- it cools the intake air compressed by the turbocharger in order to increase charge density -- in order to increase the mass of air aspirated into the engine.

I don't really have a good idea about what maintenance is "absolutely critical" and what is not. I don't much trust the Yanmar manual, which says to replace impellers every ten years or some such nonsense. On the other hand, it says you have to wash the turbocharger every two weeks or something, which is also nonsense.

I have seen photos of severely clogged aftercoolers on just my engine -- on the air side, as you said. One of the reasons why it seemed to me a good idea to do this at 2000 hours.


It would be so great if a really experienced and deeply knowledgeable Yanmar mechanic would write a book on the care and feeding of these engines, written from an absolutely practical point of view, with practical tips. Something like that old hippy mechanic book on Volkswagens -- what was it called? Yes, "How to Keep Your Volkswagen Alive for the Compleat Idiot", by John Muir (surely the inspiration for all those "idiot's guides" we have nowadays). "How to Keep Your Yanmar Alive". I would pay dearly for such a thing.

I do not feel comfortable, even after all these years, that I really know my main engine all that well. Part of that is because it has been so reliable, but still.

[Dockhead]

Originally Posted by a64pilot

I believe most all are aftercoolers, aftercooler of course cools the charge after the turbo or blower compresses it and therefore heats it.
I think the only time you ever see an intercooler is when there are multiple compressors, like a DD maybe that could have both a turbo and a blower, the intercooler is the between the compressors.
The names are used interchangeably though.

It's the same thing, just different naming convention. I apologize for inappropriate use of the land term.

Cools the air after the turbo and before the intake manifold.

INTERcooler -- BETWEEN turbo and manifold

AFTERcooler -- AFTER turbo


It was exotic technology not so long ago. I remember the upgrade on the 3.3 liter 930 Turbo included an intercooler mounted in the whale tail (also much bigger brakes), resulting in 300 horsepower vs 240 or something for the 3 liter.

I actually owned a 3.0 liter 930, one of the first Ruf conversions, without the awful cosmetic alterations, but with souped up engine with "dampfrad" (external boost regulator). That was a cool car, but even with the Ruf mods, not as fast as the later 3.3 with intercooler. That was about a million years ago.


Turbos and diesels go together like cookies and cream. That's because you don't have any detonation problem (diesel combustion IS detonation) and so you don't need a wastegate. More boost is all good in a diesel engine, up to the limits of the strength of the engine.

[ranger58sb]

Originally Posted by Dockhead

When I write "intercooler" I mean what is known in the marine world as "aftercooler".

I don't really have a good idea about what maintenance is "absolutely critical" and what is not. I don't much trust the Yanmar manual, which says to replace impellers every ten years or some such nonsense. On the other hand, it says you have to wash the turbocharger every two weeks or something, which is also nonsense.

I have seen photos of severely clogged aftercoolers on just my engine -- on the air side, as you said. One of the reasons why it seemed to me a good idea to do this at 2000 hours.

I do not feel comfortable, even after all these years, that I really know my main engine all that well. Part of that is because it has been so reliable, but still.

Fair enough, I wasn't all that worried about the terminology...

An Idiot's Guide would be good for me, too

FWIW, our manual says every 300 hours or 1 year for the aftercooler. One year isn't practical, for us, but 300 hours is.

And I think every 100 hours or 1 year for the raw water pump impellers... but every two years is working.

But that's with our kind of design usage (on plane), whereas we probably run closer to the way you do (8 kts) quite often, maybe more often than on plane, and we troll for a month at 2.0 kts. That said, I don't know that I'd postulate slow speeds are any easier on aftercoolers than our design speeds would be; might even be harder on 'em.

Mack Boring in NJ (I think) offers some kind of Yanmar (and other brand) classes. They might have some of that material in softcopy format...

-Chris

[Dockhead]

Originally Posted by ranger42c

Fair enough, I wasn't all that worried about the terminology...

An Idiot's Guide would be good for me, too

FWIW, our manual says every 300 hours or 1 year for the aftercooler. One year isn't practical, for us, but 300 hours is.

And I think every 100 hours or 1 year for the raw water pump impellers... but every two years is working.

But that's with our kind of design usage (on plane), whereas we probably run closer to the way you do (8 kts) quite often, maybe more often than on plane, and we troll for a month at 2.0 kts. That said, I don't know that I'd postulate slow speeds are any easier on aftercoolers than our design speeds would be; might even be harder on 'em.

Mack Boring in NJ (I think) offers some kind of Yanmar (and other brand) classes. They might have some of that material in softcopy format...

-Chris

Your trolling at 2 knots is probably similar to my motorsailing, using a variable pitch prop, sometimes 1700 RPM or so.

The constant, frequent cleaning of the aftercooler is like the frequent washing of the turbo -- cannot possibly be right. Mine was clean both air and water side, after 2000 hours. Likewise, I have washed the turbo once as instructed, but it was also very clean.

[Kenomac]

Mine's still a baby at 1000 hours. Identical to your Yanmar turbo.

[ranger58sb]

Originally Posted by Dockhead

Your trolling at 2 knots is probably similar to my motorsailing, using a variable pitch prop, sometimes 1700 RPM or so.

Sorta, only at that speed we're usually idling on one engine at about 600 RPMs... and using trolling valves to slow down 'cause even our idle speed is about 4.5 kts.



-Chris