Turbo maintenance advice needed.

[Tom Mann]

Hello all,
I’ve got QSM11’s, 660 hp. 1276 hours. I’m doing my routine inspection of the engines and found that both air cleaners were a little dirty. Not bad since the last cleaning and re-oiling was done 260 hours ago (18 months). I normally check the air cleaners and turbos for wear every 100 or so hours. During my inspection I noticed a small amount of soot on the end of the blades of the turbos. I’ve cleaned, oiled and inspected the air cleaners and ready to re-install. I need to know the best product to wipe off and clean the “soot” off the turbo blades. The last time I cleaned the turbo blades I used some brake clean on a cloth an just wiped the off. Should I be concerned and use something for turbo blades or is using brake clean sufficient?

There is no soot anywear on the engines, not at the heads or manifolds. The engines are clean, run great and have no issues. I do all of my own maintenance and repairs. After coolers, head set adjusted, thermostats, hoses, etc. etc were serviced/replaced at 1180 hours.

Thanks,
Tom Mann
Bow Tie

Topic

[Bill Desmarais]

Tom,

I’ll leave your final questions for Tony.

Being a long time 6BTA 370 owner, I have ZERO experience with the particulars of
the QSMs.

Bill D

[Tom Mann]

Soot

I mentioned that the soot was oily, actually it was very think and don’t think it was oily. More of a thick paste.

Don’t know if that makes a difference but I wanted to clarify that and here is the other pic of the port side.

Tom Mann
Bow Tie

[Tom Mann]

Thank you!

Hello Tony & Bill,

Thank you for the information, my typical cruising speed is 23-24 MPH @ 1860 RPM’s burning 19 port engine and 20 starboard engine. That was before I cleaned the air cleaners. I will check fuel burn in a couple of days when I run to Sanibel Island for a 1.5 hr trip. I anticipate a little better on fuel. The engine will do 2360 RPM’s without breaking a sweat.
I took a couple of pics of the turbos as they were when I wrote the first post.

So, Tony what I think you are saying is: By not pushing and over loading my engines I can expect around 2500 (plus or minus) hours out of my turbos, correct? I constantly watch: temps, fuel burn, RPM, oil temp and pressure.

The black oily soot on the turbo came off easily with some soapy water, I’m still not comfortable using water but, I’ll take your word on it. Hell, 30 years of experience is good enough for me! Plus it works wonders on my wrinkled hands!

Thanks again guys!
Tom Mann
Bow Tie

Thanks

[Tony Athens]

From 30+ years of experience, there are a few ways to gauge modern turbo life..

1) A typical Cummins QSM11 operating in a mid-sized short haul truck can easily make 400,000 +++ miles–Hours would be in the range of 6000-15,000 hours .. That “truck” would basically have the same turbo as yours..

2) In your case, it will come down to how your engines loads at CRUISE RPM.. If you cruise in the 18~22 GPH range 25-30% of your operating time, then I’d say you’d be lucky to get 2500 hours between replacements.. If you cruise around or less than 10 GPH, you may see 10,000-20,000 hours..

Why the big discrepancy? Because the couch engineers at Cummins decided to wrap a “dry” truck turbo and truck manifold so save $$ ( but was done under the pretense of “being more efficient) and under your heat shield/wrap, things start glowing red hot in the 12-15 GPH range and the turbo’s life shorten dramatically from there up in load.. In a TRUCK, the turbo has 1000’s of cubic feet of air passing over it per minute pulling of the most of the heat .. Yes, a truck turbo can glow after a big/long up hill climb, but that is measured in minutes, not hours.. Plus when a truck this size, with your same basic engine, is “cruising down the freeway” at 65 MPH, engine load is typically well under 8 GPH ..

Now let’s look at your basic same engine with a coolant cooled turbo & manifold? I watch over plenty of them that operate at 8-15 GPH for 2000+ hours per year.. Turbo life—20,000 to 40,000 hours?? From my experience with coolant cooler turbo’s in marine application, in many cases the original turbo can outlive the rest of the engine..

What should you do? Not worry about your turbo, but worry about overloading your engine at CRUISE RPM’s by being 100% sure your cruise RPM loads do not get above the fuel curve graphs for you particular version of the QSM11 you have….

Tony

[Tom Mann]

Soapy water?

Thanks Bill,
I read that article on th “other” forum, I’ve also been a subscriber on that forum for a few years.

Another thought, how often should turbos come off for a complete bench service and cleaning. Or am I better off to buy new turbos and install myself? Cost wise and performance wise?
As I started in my post, right now the engines have 1276 hours and the turbos are fine. What is the life span of a turbo if the engines are maintained properly, kept clean and inspected on a regular basis? I would want to replace them rather than get stuck somewhere at the mercy of a “backyard mechanic”.

I’ll be at the boat today and can send you a few pics of the turbos if you would like to see the general condition of the turbo blades before I clean them.

Thanks again,
Tom Mann
Bow Tie

[Bill Desmarais]

Tom,

A few years back Tony Athens had posted up a turbo washing procedure on another forum.
As I recall it was a 50/50 mix of water and Dawn dish detergent sprayed into the turbo at cruise speeds.
Yes, spraying water into the intake.

I’m sure he’ll chime in .

[Author]

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