Engine Room Discussions

[tkwan]

I am lover of boats, but I never owned one myself.

Looking for used 16-20 meter yacht.  What is the life expectancy of a marine motor with proper care and maintenance?  If the engine has 446 hours, should I be worried?

[Fishsteyn]

G/day

446 hrs for a inboard diesel engine is very low and iof they are the rtrue hours then engine has barely even run itslef in.

These engines under good maintenace will reach 10,000hrs before require any kind of substantial repair work to be required.

What is more important to consider if the running hrs are so low is the year of manufacture of the engines? & who the manufacturer is?

Are the running hours on the clock since overhaul or since new? sometimes after engines have been overhauled they will be fitted with new hour meters.

Then one should ask for service records or Chief engineers log?

If the engine is in a Pleasure craft then usually the engines would have been serviced by the manufacturers appointed dealer for the specific territory, ask for a dealer reference!

& finally before buying the boat & investing alot of money spend a small amount of money & get the authorised engine dealers to carry out a engine performance test & evaluation first.

I hope this helps

Cheers

[tkwan]

Thanks for your reply.  I'm sorry but I forgot one "0" -- it's actually 4460 hours!

The engine is two Caterpillar 3412.  Does anyone have experience with these engines?  I plan on talking more with my local dealer, but I wanted to know if there were any persons with personal experience since Caterpillar does not make these engines any further?

[Malqui]

Hello, the 3412 is a very good engine(performance), but everything depends on the maintenance .Now according of the hours, i recommend that the dealer apply the sea trial and evaluate the best recommendations.We also need to know what as the history of the engine( all repairs, maintenance,etc)

good luck

[Dutchie]

Tkwan,

Apart from the usual compression tests, etc., suggest taking a lube oil sample for analysis in a recognized lubrication engineers laboratory.

Ensure the lube oil is old and not been replaced recently.  Smell it.  It should be of slight acidic odour. 

With the 4000 odd hours on the Hobbs Meter, the oil should be pretty black unless an additional bi-pass oil filters or an 'Alfa-laval' type system has been incorporated.

[CatDoctor]

Depend on horse power rating, maintenance, etc.

I would not rely on a compression test.  Caterpillar DOES NOT have specifications for a compression test.  They rely on what is called a blowby test.  To due a compression test, would require you to remove the injection nozzles, which involves removing the injection lines, valve covers, air filter assemblies, and quite possibly the compressor housing of the turbo.

The blow-by test requires simple hook up to the breathers and a sea trial.  The tooling takes readings of crankcase pressure.  The volume of air that comes out is proportioanl to the horsepower rating measured in cubic feet per hour.

Have an oil sample done.  If the sample comes up fairly low with particulate, then the oil was probably changed, and it should be rechecked within 25 to 50 hours.

All in all, your best bet would be to have an engine survey done.  It should be wholely separate of the boat survey, and should be done by a CAT dealership with trained marine technicians.

[Tommy]

Hi tkwan,

Below is my personal comments:

For application like yacht, the designed operational hour is usually max. 500+ hours/year when sales do the engine selection. And usually the engine can produce higher power than continous rating, of course, shorter TBO (time between overhual) is expected.

According to your input, 4460 hours means the engines have been running quite within design scope (200+hours year) and i think usually now is the time when the engine should go for an overhaul.

So, my suggestion is before you make the deal, talk to the seller and local CAT dealer/distributor to get a overhual package (shaftline components might also needs to do some replacements), just to ensure you will have a safer journey ahead. 

Hope my words helps.