CAT 3208 failure - how to prevent next time

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Pat T

Pat T

Senior Member
Joined
Sep 6, 2019
Messages
215
Location
United States
Vessel Name
Moondance
Vessel Make
Grand Banks CL 42
Looking seriously at GB42 with CAT 3208 (435HP). Engines are rebuilt and have low hours. Original stb engine went bad due to aftercooler issue - water into the engine -don't have the exact story but I sure don't want to have the same issue. PO decided to replace port engine at the same time. This was BIG BIG $$ and I saw the invoices. So I know you have to keep up with scheduled maintenance and oil analysis but what else do you/can you do to prevent this type of catastrophic failure? Are there any type of gauges one might install?
 
I have not owned those, but would expect them to be exceedingly reliable with diligent maintenance, regular and appropriate use, and some good monitoring via oil analysis and an occasional Cat technician visit.

Seems like you are exercising due diligence based on your other posts. Were you able to attend the engine survey and chat up the Cat technician?

Have you been over to boatdiesel.com yet? It’s a technical forum with a tremendous library of data available for subscribers. You could read the 3208 posts for days.

As others have mentioned, don’t run it “on the pins” continuously or overheat them. DO run them up occasionally to verify WOT RPM, heat them up, clear them out.

You may have found a diamond in the rough with that essentially repowered boat. You may have more concern with fuel tanks and teak decks than those engines at this point (hopefully none of it).
 
3208 435HP E rating

High Performance - For vessels operating at rated load and rated speed up to 8 percent of the time, or one half hour out of 6, (up to 30 percent load factor). Typical applications could include but are not limited to vessels such as pleasure craft, harbor patrol boats, harbor master boats, some fishing or patrol boats. Typical operation ranges from 250 to 1000 hours per year.
 
Some boat makers do not install proper exhaust systems. Exhaust should be designed so that any failure of the water jacket will not drain back into the engine. Boat builders design, or at least choose, and install the exhaust not the engine maker.
 
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I see you are on boatdiesel.
 
I have the 3208 T/A 375hp. According to CAT they recommend running the engines at 80% RPM of WOT. For me that's around 2240.

I run my engines at 2100 on a regular bases. I do Astoria to Neah Bay in 12 hours at these RPMs which is about 190sm.
 
Check out https://www.sbmar.com/

They mostly do Cummins but there are very good articles/advice by Tony Athens on what to look for in marine exhaust (plus other excellent articles not specific to Cummins). Using Tony's knowledge should give you a yardstick to evaluate your installation.

The GB 42 in later years was bastardized into a sort of strange boat that would go much faster than it was designed for, threw a wake like a destroyer and generally would go about 25 knots wot while consuming vast amounts of fuel. It had to have strakes screwed to the hull otherwise you couldn't see out the windows. Not dignified at all like my lovely 32 with 120 hp., hence my curmudgeonly attitude to the later 42s!

The basic naturally aspirated 3208s are lifetime engines but by doubling the horsepower their longevity suffered. Some Cat blocks were not rebuildable but as I'm attached to a Cummins now, I have no idea which.

Check out Tony's stuff.
 
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Aftercoolers need to be pulled ,cleaned, pressure tested every 2-3 years.

Lots of info on Boatdiesel along with a fellow called dave. Note the lower case spelling. dave is a Cat expert who gives a lot of time there. DO a search for his posts. Pose the question about replacement time for the aftercoolers as they do have a definite lifetime.
Note the time is years , not hours as corrosion and fouling don't heed hours meters.

Correct propping is needed on boats with engines like these where there is any likelyhood of planing the boat. THe engines must be able to reach full rpms or they are overloaded and will suffer. You will get all kind of arguement about deliberate overpropping which is fine if you NEVER attempt a high power blast but if you plan on using the boat as a planing boat beware.

You ask about guages to help prevent problems.
--Boost
--EGT measure exhaust temp and will tell you very quickly how hard you are pushing the engines. Especially if too hard.
--one alarm in addition to what you have while you are thinking about this is a loss of raw water alarm.

If you go for the boat then some more questions about these can be answered.
 
I believe that this is the highest HP rating that these engines have. The NA versions will seemingly run forever. As the HP ratings go up life goes down. If they are run at a reasonable level they will last a long time too. But they do need the routine maintenance done. Good luck with the boat if you proceed with the purchase. And of course we will need photos if you do buy it...
 
The POs original problem seems to be from lack of after cooler maintenance not running the engines too hard. But you can wear those engines out if you run them at 90% of wot rpm, 90% of the time.

I don't know anything specific about Cat 3208 aftercoolers, but I can extrapolate from Cummins and Yanmar. Read Tony Athens' articles in the Tony's Tips section of sbmar.com. Basically you should remove, disassemble, clean, reassemble with lots of grease and pressure test your after coolers every 3 years or so. If you do that, you are very unlikely to ever have any after cooler problems.

David
 
On my engines I didn’t know the history of the aftercooler maintenance so I bypassed them so now I don’t have to worry about maintaining them. I don’t need or have ever used the extra power.
 
Comodave said:
On my engines I didn’t know the history of the aftercooler maintenance so I bypassed them so now I don’t have to worry about maintaining them. I don’t need or have ever used the extra power.
Click to expand...

Now that is interesting . Do I assume you also bypass the turbos? Tell me more as how you do this. I don't think I will need the 435HP either. I just like the boat and that it is newer (for a GB42 that is). But I don't think they put a lot of smaller powered engines in these newer boats so it is a compromise for me.
 
I wouldn't try to depower the engines. You should have the fueling turned down and bypass the aftercoolers, but I don't see a good reason to do it. And I don't think there was ever a turbo 3208 with no aftercooler.

The high power 3208s will burn the same fuel as a lower powered version when going slow. They'll only burn more fuel when you use the power. As long as the aftercoolers are maintained, I don't see them as a big risk.
 
Mine are a bit different animal than the Cats. I still have the turbos. But on my engines all I had to do to bypass the aftercooler was to unhook the cooling water going in and coming out of the aftercoolers and run a hose around them. It took about 15 minutes per engine and I can go back almost as easily. On mine I didn’t have to adjust the fueling or injector pump at all.
 
Comodave said:
Mine are a bit different animal than the Cats. I still have the turbos. But on my engines all I had to do to bypass the aftercooler was to unhook the cooling water going in and coming out of the aftercoolers and run a hose around them. It took about 15 minutes per engine and I can go back almost as easily. On mine I didn’t have to adjust the fueling or injector pump at all.
Click to expand...
I've been wondering about doing the same thing on my 3208s. Does the cooler make that much difference? That boost air is being pushed in pretty quickly.
I was also pondering an air cooled heat sink type of arrangement with aluminum fins.

Thoughts?
 
Steve1.0 said:
I've been wondering about doing the same thing on my 3208s. Does the cooler make that much difference? That boost air is being pushed in pretty quickly.
I was also pondering an air cooled heat sink type of arrangement with aluminum fins.

Thoughts?
Click to expand...

The maker must have installed aftercoolers just for fun.
 
Bayview, brilliant!
Any other words of wisdom?
 
After coolers do make a difference but usually at higher rpms. At wot when the engine is making full power, the air from the turbo charger can be compressed to 3-500 degrees more than ambient inlet air. If that heat is not removed then the valves will fry and/or the piston will melt due to vary high EGTs, well over the design EGT value.

But if you run the engine at lower rpms and loads, say 600 rpm off of top you should be ok if you reroute the raw water to bypass the after cooler.

Even better would be to look at other Cat 3208s and see if one model doesn't use coolant to cool the after cooler. This type of after cooler is used on turbo charged car engines. You may have to upgrade the raw water cooled heat exchanger because if you do this it will now be putting more btu/hr load on the coolant system. But if there is a Cat 3208 model with coolant cooled after cooler then use its exchanger specs and coolant flow path. Also look at the coolant pump and see if it is bigger on the coolant cooled after cooler engine.

Coolant cooled after coolers have a fraction of the problems as raw water cooled ones.

This will also require you to run at much less than wot rpm as coolant won't cool the air as well as raw water. So maybe 400 rpm off of top will be ok.

And finally you really should recalibrate the injection pump or use a different pump if you are going to change it from raw water after cooling so you can never run at the original wot rpms.

Those figures are all educated guesses.

David
 
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You can cut down on raw water aftercooler maintainence by diligently flushing with fresh water after use.
This doesn’t make them maintenance free, but can extend service interval, and is beneficial to the entire raw water system.
 
DavidM said:
After coolers do make a difference but usually at higher rpms. At wot when the engine is making full power, the air from the turbo charger can be compressed to 3-500 degrees more than ambient inlet air. If that heat is not removed then the valves will fry and/or the piston will melt due to vary high EGTs, well over the design EGT value.

Wow, 3-500 degrees! New respect for the after cooler.



Thanks for that David.


I just reinstalled mine after cleaning the built up crud from the fins. PO never did any maintenance as far as I could tell. I'll post a few pics.
Click to expand...
 
Here is one of my after coolers before and after(cooler) cleaning.:nonono:
 

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This discussion (among others) makes me relieved that our boat has the reliable non-intercooled Detroit 8.2 turbos. Simple, efficient, and sized exactly right for a 40-45 foot semi-planing hull.
 
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Yes, after coolers can be a PITA. If you pay a mechanic or yard to disassemble, clean, reassemble with lots of greaseand pressure test them, it can cost as much as $1,000 per engine. If you DIY it can cost about $30 for three Yanmar o-rings (probably less for Cummins and Cat) and almost a day of your time.

This has to be done every 2-3 years for Cummins (because of the way they are built), maybe as much as 5 years for a Yanmar and 5 years for the Cummins if fresh water cooled.

A labor of love, right?

David
 
A few years ago a transient Duffy trawler pulled into the adjacent slip with an engine fuel leak (375 Cats). Turned out it was a fuel pump, which is apparently in the "V" and under the intercooler. The owner called the closest CAT dealer who sent out two guys. They spent two long days with their nose to the grindstone. Pulled and cleaned the coolers, which were filthy. Replaced both fuel pumps. They did a very nice job...north of $4000.
 
rslifkin said:
I wouldn't try to depower the engines. You should have the fueling turned down and bypass the aftercoolers, but I don't see a good reason to do it. And I don't think there was ever a turbo 3208 with no aftercooler.

The high power 3208s will burn the same fuel as a lower powered version when going slow. They'll only burn more fuel when you use the power. As long as the aftercoolers are maintained, I don't see them as a big risk.
Click to expand...

I have a pair of 3208T’s, no aftercooler, 302hp. They’re kind of a bastard engine for my 40,000 lb tub, but they start when I look at the ignition, and run like a watch at 1250.
 
CAT raw water aftercooler maintenance requirement is service every 2 years (requires disassembly and seal replacement), replace every 6, regardless of hours.

3208s over 400 HP were acknowledged to be more "fragile" than the sub 400 HP 3208s. If run under modest loads, they are less prone to failure.

Oil analysis, as you noted, is valuable, assuming the sampling technique is correct, and you have someone who can properly interpret the results. https://vimeo.com/sdmcinc

Raw water after coolers on any brand engine need careful attention and maintenance, as failures are always costly, as this PO found out. Failures are almost 100% preventable.
 
Back to basics for a minute, please -- after all this is the Trawler Forum, for boats that don't scream over the water.


Those are very powerful engines for a GB42 -- a boat that displaces around 35,000 pounds and originally was usually delivered with a pair of Lehmans rated at 120HP each. If you actually crank them up to WOT, you'll burn more than forty gallons an hour (a good rough estimate is twenty diesel horsepower per gallon). Even at trawler speeds, they will burn more than smaller, lighter, engines rated at maybe 200 HP each. Fintry (photo to the left) uses about 160HP to do 8.5 knots and with full tanks she displaces around ten times the GB42.
 
Our new to us 1991 OA 42 sedan is powered by twin 3208T's..... 320 hp Turbo non-aftercooled. My mechanical suveyor told us 2600 rpm is very common WOT (spec is 2800). Most everybody I know with these boats run them at 8 to 11 kts, 1300-1700 rpm where they might get 1.5 to 2 mpg. But from what I gather, these are happiest at 70% WOT, or 2000-ish propped correctly, where they guzzle fuel and probably make .75 mpg. Babying these engines if underpropped is especially hard on them regardless of speed. Many on boatdiesel have correlated this with head gasket problems. Sure enough, my babied boat had a head problem that evaded a surveyor. Was detected once I got her home. I'm not sure it's possible to know with any great certainty whether you are going to end up with bulletproof 3208s or sooted up ones that aren't so much.
 
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I've had and worked on these engines. A few remarks on several comments above:
- 3208 are non-sleeved. They actually were called throw away engines. However when maintained they last very long.
- Highest rating is 450hp. Anything above the 375s I would think twice about.
- In the 425/435 series they had a design fault. There wasn't a drain in the aftercooler. As the AC is on top, the condensation dripped on the middle cilinders and corroded at least the valves. There was a CAT program to solve this afterwards but not all have done this. Be aware.
- The fuel pump had the tendency to leak fuel along the regulator shaft seal and fill the V on the engine block. Replacing this $3 part is a real PITA on the AC models as you have to remove everything...in what is typically a cramped installation.
- Be very sure the engines reach their rated WOT. Don't be fooled by brokers that say 100 oor 200 lower is also OK. IT IS NOT!
- Some models have an exhaust limiter valve to reduce startup smoke. If present research it is operating correctly as it can really damage the engine if it's not operating correctly for a longer time. Personally I would remove this and live with the (white) startup smoke.

Lots of luck!
 
Circumnavigator said:
Back to basics for a minute, please -- after all this is the Trawler Forum, for boats that don't scream over the water.


Those are very powerful engines for a GB42 -- a boat that displaces around 35,000 pounds and originally was usually delivered with a pair of Lehmans rated at 120HP each. If you actually crank them up to WOT, you'll burn more than forty gallons an hour (a good rough estimate is twenty diesel horsepower per gallon). Even at trawler speeds, they will burn more than smaller, lighter, engines rated at maybe 200 HP each. Fintry (photo to the left) uses about 160HP to do 8.5 knots and with full tanks she displaces around ten times the GB42.
Click to expand...

Agee whole heartedly. These engines defeat the whole trawler concept adding complexity and expense to what should be a simple economical boat. The Cats are great engines when in the intended application.
 
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