Yanmar 260 hp 6LPt

[DKing]

I have a pair of 2001 Yanmar 260 hp (the 12 valve 4.2 engines based on Toyota Land Cruiser units) They are very smokey at low revs and breathe hard at high speed.
These are professionally fited to a Birchwood TS37 aft cabin Motor Cruiser.
Delighted with the performance and economy. But boy do they contaminate the turbos and intercoolers with oil mist from the rocker covers.
I have fitted a retro kit from Yanmar to 'cure' the smoke with no positive result and have fitted additional seperators to cure the oil contamination to the turbochargers which have 'done the job'.
Anyone else had similar issues?

 

[oceanfroggie]

I think we have the same engines (Yanmar 6LP DTE), and we love them. Quieter and smoother than 4 cyl Volvos and very economic. Occaisionally they smoke a little at start up if not used for a long while, but once warmed up they don't smoke even at idle. We operate them at 1600rpm inland (7.5kt) and 3000 (15.5kt) on coastal runs (max is 4000rpm), or 3600 (20kt) rarely when in a hurry. The 310/315hp models as far as I know allegedly had a significant problem smoking at low rpm, perhaps over cooling the oil at low rpm! The 260hp and 350hp don't seem to have this problem.

I know one dealer who refuses to supply boats with the 310/315, but happy with the 260 or 350. Marine engineers tell me that as converted 4x4 engines they can be over stressed if operated close to max RPM all the time, and are much happier if run at 75-80% of max. Hence some folk fit slightly larger engines and run them at lower RPM. Very happy with ours thus far which are 2000 versions with 420hrs on the clock (previous owner hardly used them, we're doing 120hr PA).

 

[omega2]

My mate has a 420 hp 6 something or other not sure what it's called, but he not long back had breathing problems, i.e. it would not rev above 1600 rpm and produced clouds of black smoke, we had all sorts of experts to look at it and many pronouncements such as Turbo, Pump, timing, broken valves, you name it we got it. Being sure it was being starved of air, and the fact that it was breathing it's own muck from the rocker cover, we eventually removed the charge air cooler and removed the core, guess what it was solid with carbon and oil. Having cleaned it out and rerouted the breather pipe all is well, hope this helps

 

[DKing]

Thanks for the info.
We only run at 1000 rpm on the non tidal Thames = 5 kt
and cruise at 3400 rpm tidal = 18 kt top speed at 3900 is 26kt. Like you we find them smooth and more economical than the volvos. My only beef is what I have had to do to get rid of the turbo and intercooler contamination by the oil fumes from the breathers! Anyway, they are set up for this season and running perfectly with 800 hrs on the clock, compared to 225 when we bought her 3 yrs ago! Happy Boating! Dick King

 

[DKing]

Thanks for the info.
Dick

 

[lazza803]

I have a pair of 2001 Yanmar 260 hp (the 12 valve 4.2 engines based on Toyota Land Cruiser units) They are very smokey at low revs and breathe hard at high speed.
These are professionally fited to a Birchwood TS37 aft cabin Motor Cruiser.
Delighted with the performance and economy. But boy do they contaminate the turbos and intercoolers with oil mist from the rocker covers.
I have fitted a retro kit from Yanmar to 'cure' the smoke with no positive result and have fitted additional seperators to cure the oil contamination to the turbochargers which have 'done the job'.
Anyone else had similar issues?

Can any one tell me what boost is normal on the 6 LP DTE

 

[Latestarter1]

Can any one tell me what boost is normal on the 6 LP DTE

Stayed away from this thread cos some of the comments were raising my blood pressure, however simple question deserves a kind of simple reply.

Boost curve of any engine is characteristic of propeller demand, however CORRECTLY PROPPED you should see 29/30 psi on a 12 valve 260 and 32/34 psi on a 24 valve 315 AT RATED SPEED.

Can we get a few facts straight:

Toyota based Yanmar LP is a great engine IF properly applied and due to Mickey Mouse instruments majority are not. Tachometer is wildly optimistic and 315 rating is actually 300 hp and installers clueless as to what they are dealing with. If your engine is breathing it is being overloaded, propeller is wringing the engines neck.
You need to see 4,000 rpm @ WOT with a properly calibrated tacho,

Pontoon talk about LP's not being capable of continuous operation is plain ill informed stupidity, they are a 1hr pleasure rating at WOT pretty much the same as all contributors pleasure rated engines here. Over the years when I go to SeaWork and look at these engines being sold into commercial applications where they get the guts ragged out of them and they have the life of a disposable cigarette lighter, see the same with Volvo D3's and a few others.

White smoke, yes they do, because Yanmar and Toyota think that they can get away with automotive thermostat as well as the seawater cooled oil cooler is a tad too effective and under piston oil cooling dragging down combustion temperatures.

 

[lazza803]

Stayed away from this thread cos some of the comments were raising my blood pressure, however simple question deserves a kind of simple reply.

Boost curve of any engine is characteristic of propeller demand, however CORRECTLY PROPPED you should see 29/30 psi on a 12 valve 260 and 32/34 psi on a 24 valve 315 AT RATED SPEED.

Can we get a few facts straight:

Toyota based Yanmar LP is a great engine IF properly applied and due to Mickey Mouse instruments majority are not. Tachometer is wildly optimistic and 315 rating is actually 300 hp and installers clueless as to what they are dealing with. If your engine is breathing it is being overloaded, propeller is wringing the engines neck.
You need to see 4,000 rpm @ WOT with a properly calibrated tacho,

Pontoon talk about LP's not being capable of continuous operation is plain ill informed stupidity, they are a 1hr pleasure rating at WOT pretty much the same as all contributors pleasure rated engines here. Over the years when I go to SeaWork and look at these engines being sold into commercial applications where they get the guts ragged out of them and they have the life of a disposable cigarette lighter, see the same with Volvo D3's and a few others.

White smoke, yes they do, because Yanmar and Toyota think that they can get away with automotive thermostat as well as the seawater cooled oil cooler is a tad too effective and under piston oil cooling dragging down combustion temperatures.

 

[lazza803]

Cheers for that. All makes sense so far. Took this boat as a part trade on my sailing cat. Its a 25 ft Wellcraft Sportsman. Boost was not working from day 1. Sender unit cannister has totally rotted out. Its running a Bravo 3 leg with duo 24P props and gear ratio 1.81 : 1 . Quite a lively performer once on the plane and turbo sound comes on. Tacho runs out at 3800 and most of our cruising is at 2700 - 3000 in fresh water. Engine hours are 750. Priced a elec. sender unit in NZ $ 280. Decided to go for plumbed in model and needed to confirm what top end range should be. Will try some GPS runs verses RPM next time out and post them. Thanks for your time.