MTU SERIES 60 DIESEL ENGINE

They're good motors, they run smooth, efficient, and quiet for their size......they are not torquey like equivalent cats but not nearly as noisy either, so weight changes speed a little (full fuel/light on fuel). They had some aftercooler issues in that era but should long be solved by now.......They used them tons in semi's and they've got very good longevity.

The S60 is a 14 liter engine, producing up to 825hp at 2300rpms. The nearest equivalent of the time was a 14 liter 3406 CAT, which came in at 800 hp at 2300 rpm. Both are inline 6 cylinder engines.

Since Torque (foot - pounds) is calculated as (5252 x hp)/rpm, you can only change hp or rpm so not sure what you mean by not as "torquey"? An apples to apples comparison would have to include the same gear ratio for each vessel, otherwise you are introducing another variable.

My family used to run over-the-road trucks. Our 6-71's were overhauled at 250k miles. When we switched to 60 series overhaul intervals went to 1 million miles. I have no experience with the marinized version, but the truck engine was awesome.

i ran 3 identical boats with the exceptions of the power plant, all at the same time and all were 2007's (as well as 45' cabo's with S60 and cats and mans). I ran 3 55' Neptunus cabriolets. 1 had 825hp series 60, 1 had C 15 cats 800 or 825hp, and 1 with 1000hp C18s and ran them all 1000s of NM's. They all had the same gear ratio. For a matter of purpose I won't talk about the c 18 boat. The series 60 boat full of fuel/water and food would only cruise at 23.6 knots at 80% load, then once you burned off 1/2 fuel 80% load would run the boat 25.6-26 knots..... the C15 boat would cruise at 25.6 knots at 80% load full of fuel, 26.5 knots 1/2 full of fuel. The C18 boat loaded......80% load was 2 knots faster than the same HP series 60 boat. The series 60 didn't have the torque to carry the weight. The series 60 boat also took noticably longer to get on plane......boats were sisterships with identical equipment. In larger waves rpms would dip and rise as much as 75 RPMs at the same throttle setting with the series 60, whereas the most the rpm's varied were 20 rpms with the CATS. The series 60's acted the same in the 45' cabo's versus the 800hp cats (cabo used 3196's or later C15/18s).....

Man's are the same way......they don't have the brute torque of the CATs.....in the 62' Sunseeker predator.......full fuel/water, etc..... 80% load is 1960 rpms and 24.6 knots......as soon as you burn off 160 gallons of fuel (2 hours) rpms at 80% load increase 100 rpms and speed is about 27 knots.....and at 1/2 tank 80% load is 2100rpms and 29 knots........we're talking about 350 gallons of diesel in weight on the same trip on the same day with the same sea state. And, no the boat is not overpropped, with full fuel and water it makes 2360 rpms and rated for 2300rpms or above with full weight.

Different motors make different torque ratings at different RPM points, pull up the propellor charts for both a series 60 and say 3406 Cat both 800 HP and you'll see the CAT's make more torque and they make more torque early on in the rpm range.......

The CAT 3406 has a torque advantage in the 1600 - 1800 rpm mid-range while the S60 has the torque advantage above and below that 200 rpm mid-range.



But how was the Neptunus 55 Cabrio with S60 propped? The only boat test I could find showed a max rpm of 2250, which is about 100 rpm off for a test boat. What rpm where you running at 80%load?

I don't remember how either boat was propped. I do remember both barely made it over factory rated full RPM's at full weight. Both made 10-15 rpms over factory rated. Series 60's are 2300 rpm motors.....C15's and C18's are 2350 rpms . Had issues with both engines. The series 60 had a leaking aftercooler on the port engine at 2 years old and 200 hours....they changed both aftercoolers under warranty.......Port V drive also had a leaking lip seal taken care of under warranty. The C15 boat had a head gasket leaking coolant on the port engine and they had to yank the head. The 55' Cabriolet is a very good riding and running boat though.

I remember when the Series 60 was first being offered to the general market. They gave a case study using a JB Hunt I think it was from Alabama semi, It was stripped at 1,000,000 miles and found to be in good shape. There was one thing that did get my attention though and that was the mention of the crankshaft of that engine having been replaced as routine maintenance at some much lower mileage.

That said, I know a few guys who are still in the truck repair business who sing the praises of these and a couple of others.

Yes, the series 60s are very well regarded in tractor trailers. However they're also at the 600hp rating or below in tractor trailers. They're a good motor longevity wise in yachts.

All manufacturers on-highway ratings are exceeded by their off-highway marine applications across the board.

If you want to see these engines in a dyno pull. Check them out on u tube.
The 1000hp C 18 Cat had brute torque, the 1000hp man not so much. Impressive watching these brutes under load, with numbers.
I think the big difference between marine and on-highway ratings is that it is a lot easier to keep the coolant temperature where it needs to be with seawater as the cooling medium.

Saw a couple of nice RPH's with those engines. How available are parts and service for the Series 60?

In your area, talk with FDDA: http://www.fdda.com/

I know the USCG has them in all 174 of their RBM patrol vessels: https://www.uscg.mil/hq/cg9/RBM/

Parts support usually goes out for at least 30 years on government programs.

Thanks , good info.