Cat 3406 td

Anyone out there have specs on this engine, specifically fuel consumption rates? I did a forum search and keep coming up with CAT 3206. Looks similar but obviously not the same. The genesis of the question pertains to an interesting fishing charter boat I found on yacht world. Just curious as to why two of these engines are on a boat that is in the overall scope of things not huge. Best I can think is they want speed to get out to the deep sea fishing areas. Anyhow chec out the link below. Thoughts?


https://www.yachtworld.com/boats/2007/open-sea-fishing-dive-tour-charter-3112426/

Photos shows what looks like a 3406. Does not look like the 800hp version as that has a unique charge air cooler not seen. Probably more in the 400-500hp range. A very good engine in general.

Ok......are the first set of pics (grey color) generators then later the yellow the CAT engines?

The first pics (blue and grey engines) are gennies. Blue one looks inoperable (split pipe, no hose on water pump). Can't really tell what brand engines drive the gennies. Yellow engines are the Cat propulsion engines.

3406 was before the world went nuts with electronic controls and sensors. So it's a reliable, long running engine compared to newer models. Many were used in trucks, marine and larger generators. Around here, Oregon, logging trucks are routinely going a million miles or more between rebuilds.

Those engines are there for speed and at WOT together probably burn 50 gph or more. A engine kit runs about $1500+ depending on hp. The injector pump costs about $600 to rebuild. Parts are everywhere.

3406 Marine engine didn't reach 800hp till it went all electronic. (3406E). The one's in the pics look like an A model. They are easy to tell the difference between them and the b,c because the injection pump is really long. The b,c pump's we're right up close to the front housing. All the 3406's are damn good engine's. Ski is right on point with the hp being in the 400 range. If the data tag is still there. It lists the HP and fuel spec's. With a sn I could probably pull up the spec but it wouldn't tell you if someone has bumped it up some.

Due to the success of the 3406, last I heard it is still being manufactured for certain markets.

sunchaser said:

Due to the success of the 3406, last I heard it is still being manufactured for certain markets.

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It's still being mfg for none us markets and the military. The same basic electronic engine is still being used here but is called the c15 and the larger c18.

Awesome responses.....thanks! I figured that the two earlier pics were generators. So the consensus is these engines are A models correct? Im particularly interested in the fuel consumption and will now look it up. Question......for a boat this size are those standard? I ask because Ive seen similar boats with smaller and in the case of tugs and other fishing vessels Ive seen one engine. Dont know if a singapore trip is in the cards but Ive thought of one day running a deep sea charter so this boat caught my eye.

i tried to pull up the test spec for a 91u a model but its too old. i looked up a 410hp 3406c. the numbers should be close.

Good stuff! Thank you!

I have twin 3406 Turbo Cats on my 1991 Cheoy Lee 66’ LRC. They are rated at 335 hp each (and they are turbocharged) and are NOT electronically controlled (thank goodness for the reliability of mechanical diesels)!
They have 5000 hrs on the motors and the FloScan meter shows 5 gals per hour/ per engine at around 1500 RPM. This gives me over 9 knots (for comparison purposes).
That’s about 1 MPG. If I slow down to 8.5 knots, the fuel economy jumps up substantially.

@Taras so theoretically despite the twin engines running at a speed of 7 to 8 knots would enable a boat such as this to have quite a bit of range depending on fuel capacity of course. I keep getting beat over the head about two engine garbage fuel efficiency and it is good to here from someone with personal experience with these specific engines.

I have a single Cat 3406b rated at 540hp @ 2100rpm (E rating)
It is the original engine (1980) and has done 20,000 hrs (rebuilt at 18,000)
We cruise at hull speed (9.2 kn) which is 1300 rpm and burn 18L per hour or 4.7 US gals per hour. At 8 kn which is 1100 rpm we burn 11L per hour or 2.8 US gals /hr.

The boat is 53 ft and weighs 36,000 lbs

The 3406 series marine engines are jacket-water after-cooled so very low maintenance, and have a reputation as one of the best engines Caterpillar ever produced.

Does running the engine at the low RPMs have any adverse effects?

calicojack767 said:

Does running the engine at the low RPMs have any adverse effects?

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The only thing that happens is it will start to glaze the cylinder walls and will use more oil than normal. It's not something that is going to happen in just a couple hours. The fix is just run it hard for little while. Once the exhaust clears up your good to drop back to where you normally run. You will have to play around with the hrs at low vs high load. Also the 3406's have always been good when it comes to oil consumption. The 3306's where pretty bad about burning oil at light load's. Cat did come out with a improved piston design to help but that engine just likes to be worked harder than most.

Never noticed any adverse effects.
I have heard that these were the engine of choice for North Sea oil rig tenders because they were happy at low revs or idle for long periods. I run up to 1600 rpm (11.5 kn) occasionally - maybe every second trip. Have never needed to add oil between changes. Level moves from full to about half-full in 150 hrs running.

CalicoJack,
Not to start another tread on single vs. twin engine set up..... but your point on single engine vs twin engine efficiency has benefits and costs.
Yes, a single is probably a bit more efficient, but you get a lot of piece of mind with twin engines as you have a back up if one fails. Slowing down will have a huge impact on fuel economy. Additionally, you can run 1 engine only if your transmission will allow free spooling.

Taras said:

CalicoJack,
Not to start another tread on single vs. twin engine set up..... but your point on single engine vs twin engine efficiency has benefits and costs.
Yes, a single is probably a bit more efficient, but you get a lot of piece of mind with twin engines as you have a back up if one fails. Slowing down will have a huge impact on fuel economy. Additionally, you can run 1 engine only if your transmission will allow free spooling.

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We’ve had one failure in 15 years. The starter solenoid failed. Since we were at anchor and close to our marina, it wasn’t a huge problem.
Got a tow home. The anchor windlass is hydraulic, so we had to haul the anchor manually. Fortunately we were in shallow water.