Oil weight for older diesels?

I recently (perhaps foolishly) purchased a boat with twin Lehman 275 turbos...
They smoke a little.
I am in the Chesapeake bay so temperature is a factor with no block heaters.
So ok. A bit of wear... Thicker oil maybe right?
My initial thoughts were to just replace the cheap rotella 15/40 with straight 40 weight for a little less viscosity and possibly less smoke
Is there any sage advice out there before I attempt such madness?

'Smoking a bit' might not mean burning oil excessively, it might be the injectors are dirty etc. My advice is watch oil consumption, but don't overfill. If you fill above the middle of the normal level some will often blow by until it settles down. However, putting some Diesel Power or equivalent in the fuel at the right ratio has always cured smoking for me so far.
Just don't rush to conclusions, as a thicker oil is unlikely to cure true oil consumption.

Maybe talk to Brian Smith of American Diesel, the "successors" to Lehman. Bob Smith was VP of Lehman.
How many hours on the engines? Have they been run underloaded and the bores are glazed? I`d say a single weight oil probably gives less wear protection. Can`t comment on US brands, are there better multigrades than Rotella, or are they all much the same, with different hype?
Checking available additives as Pete says is a good idea. An additive sold by a respected oil supplier fixed glazed bores in my Onan genset.

Thanks for the input.
2000 hrs only. And those hours on the icw, so low rpms pretty much all the time.
I had a fellow pull the injectors and send them away for service. Put them back in. And it's better but not great.
Do you mind if I ask what was the additive you used?
Somebody suggested intercoolers, so next time I'm home ill be addressing those as well.

Smoke comes in many colors .

If you are showing white from initial start up , even till after the coolant is over 140F it is probable that the compression is low.

If it smokes white with 180F coolant temp oil viscosity will not help .

Either the rings are stuck or the cylinder is burnished smooth.

Oil is cheap, so you might want to stay as is .

The outboard guys have a treatment for stuck rings , I have never tried it on a diesel, but rings are rings and a carbon deposit is a carbon deposit.

Did you do a compression check when the injectors were out?

Straight weight is recommended for these engines but plenty of people run the 15W40 with no ill effects.

I would stick with 15W40 in the colder climes and if ever in really hot areas for an oil change period...switch up to the 40 weight.

As others have posted...smoke must be read carefully to use it as a diagnostic tool. Unless running these Lehmans hard (which most people don't)...seein smoke doesn't seem uncommon. Mine smokes at startup and even sometimes when I've let it cool down but not off.

Submarine deckhand said:

Thanks for the input.
2000 hrs only. And those hours on the icw, so low rpms pretty much all the time.
I had a fellow pull the injectors and send them away for service. Put them back in. And it's better but not great.
Do you mind if I ask what was the additive you used?
Somebody suggested intercoolers, so next time I'm home ill be addressing those as well.

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In my post, I was referring to a diesel additive. A good one of these does seem to clean injectors and improve completeness of combustion, and usually discourages the growth of, well, lets say 'crap', in the diesel, which in turn, can also add to smoke. I know nus-sing about oil additives to deglaze bores, but BruceK seems to, so what do you recommend Bruce, or were you also referring to a fuel additive..?

Our boat has been run all it's 32 years with a straight weight 30 diesel oil along with a litre of Rislone Diesel oil treatment at each oil change (every fall). The engine does not smoke at all at cruise speeds and uses no oil. Not sure if that is due to the oil and additive or not, just sayin'. We also use SeaFoam in the fuel to help keep injectors clean.

Engine Treatment Concentrate (p/n 34102) | Products | Rislone - Premium Automotive Chemicals

"Cheap Rotella"....I am of the opinion that is some of the best stuff out there!?

Submarine deckhand said:

Thanks for the input.
2000 hrs only. And those hours on the icw, so low rpms pretty much all the time.
I had a fellow pull the injectors and send them away for service. Put them back in. And it's better but not great.
Do you mind if I ask what was the additive you used?
Somebody suggested intercoolers, so next time I'm home ill be addressing those as well.

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You may want to communicate with Daddyo, he has some smokey Lehmans he's been dealing with.

You cannot go wrong by a 100 per cent book servicing of all systems. This includes the above mentioned inter coolers but don't stop there. You've got the air intake system, CCV, belts, hoses, turbo etc.

These are not new engines, likely 25 plus years and if all they do is smoke a little (what color per FF) you're in pretty good shape. Marine engines sitting a lot - as do most - age without turning over with cylinders rusting and rings setting. All this can lead to less than perfect exhaust.

You may want to consider Wolverine heaters affixed to the bottom of the oil pan, 250 watt size. These can relieve smoke too as you've already guessed. Easier to install than block heaters.

I agree here totally and completely with Walt, LaBomba and Baker on this one.

Multi-vis oils are a little less desirable that straight weight oils in inboard boats ... especially in southern climates. If a boat engine will crank plenty fast enough for starting w straight weight oil multi-vis oils are not needed and putting something that is not oil in oil makes it (all other things being the same) a lower performing oil. Put in 40W now and as we get into the winter see if your engine cranks normally. If so (I'm sure there will be nobody or almost nobody experiencing cranking problems) multi-vis oil is a waste of money and dosn't lubricate as well. A small waste of money and a small loss in performance but why do it for no gain?

It would probably be better to find out what Ford recommended for their 380 cu in engine than Mr Smith. If you were to seek that information for your car you probably wouldn't get the best information from the trailer hitch manufacturer on your car. That is a bit extreme but the point is probably clear. Bob Smith may have been an engineer but it's just as likely he was a diesel mechanic gone entrepreneur. Ford probably had many engineers w various specialties working on that engine.

There is Boat Diesel .com but that is also basically a bunch of opinions (very very good opinions) but for our purposes the best available information short of the best and the best is the engine manufacturer or a lubricating engineer.

I just looked at the "Sabre Lehman" manual and it recommends for both turbo and NA engines;
For temps -32 to 32 deg f ........... straight 10W oil.
For temps 10 to 60 deg f ............ straight 20W oil.
For temps 32 to 90 deg f ............ straight 30W oil
Above 90 deg f .......................... 40W oil
No mention was made for multi-vis oils.

SubDeck:

You have not given us the age of the engines, but by telling us you have Lehman 275s, you have already told us that your engines smoke a bit at startup, and that you can still see a little smoke on the water at idle after they warm up.

This has little to do with the oil you are using. The injection pressure, the style of the injector nozzles, wear on the cylinders and rings, etc all contribute to the smoke. The biggest contributor is injection pressure. In the 90s, injection pressure rose from a few hundred psi to over a thousand, then to over 10000 psi and now some are over 30000 psi. Each increase in injection pressure is accompanied by better spray patterns, with more modern nozzle design. All of those advances reduce smoke by improving total combustion, to the point that new diesels simply don't smoke.

Don't worry about your Lehmans, as they are performing as designed.

Thank you all for your advice.

Ill change all filters, clean intercoolers, oil change to exact amount, change out old fuel, have a martini and try not to be so uptight...

looks like mine on start....it then it drops to maybe 1/4-1/5 that when I slow down enough from cruise to se it before air currents dissipate it.

not saying mine's right...just what I'm living with on a 4 year/800 hr rebuild...

ps...I run a lot at 1600 so I am running on the cool side....

Submarine deckhand said:

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That looks like mine at start up (Lehman 80 1500 hrs). In fact, it looks like every old Lehman I have seen at start up. I am not saying you don't have a problem, just be careful that you're not 'chasing problem$'.

I've been using Shell Rotella 30 weight in my Lehman 225HP (same 363 cubic inch block as the 275HP) since the early 90's. She has about 1500 hours use. The engine does smoke when not warmed up which I've been told is a common problem with Lehmans. I've tried different additives to no avail. I've used Soltron, Startron, Biobor and Racor additives and she still smokes.Once underway and up to operating temperature, I do not see much smoke.

The oil additive I used is " "Heavy-Duty Diesel engine Treatment". Sold in Australia by Nulon Products( www.nulon.com.au), a supplier of lube oil products (maybe a BP re-packager, or affiliate). No idea what`s in it, I bought it after an internet search about glazed bores (not me, the Onan genset). Instructions say use it double strength to cure glazing, it worked, the blue smoke stopped. I still use it, normal strength, in the genset which sometimes inevitably runs underloaded, I don`t use it in the main engines (Lehmans 120s) where I use Nulon 15-40 High Protection Diesel Formula.
The brands may not help outside OZ, but I supply them anyway.

Looks like my boat on start up, too. Once they're warmed up, they look fine. If you're not getting soot stains on your transom, maybe you're just chasing rainbows here.

For a period, I was seeing high oil consumption and worried about it. Then I dropped my cruise power to 2000 RPM from 2300 (2800RPM WOT) and have enjoyed quieter ride, practically no oil burn and 0.5 knot reduction in cruise speed. Life is good and I'm relaxing and enjoying the boat. Hope you're doing the same soon!

Marvel Mystery Oil. Let the fun begin.

If people didn't buy snake oil...there would be no snake oil salesmen, a lower economy and no one to make fun of...or the snake oil salesmen either.

Baker said:

"Cheap Rotella"....I am of the opinion that is some of the best stuff out there!?

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Ditto!!

psneeld said:

If people didn't buy snake oil...there would be no snake oil salesmen, a lower economy and no one to make fun of...or the snake oil salesmen either.

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It's a time honored tradition :lol:

Set the valves and retorque the heads, you've already done the injectors. They all put a little diesel in the water and they all smoke until full temperature. I ran straight 30 (Delo) and it ran fine. A common issue is these engines were installed in boats at an angle and their dipsticks were not re calibrated, resulting in owners putting in too much oil. Next oil change, measure the oil carefully as per the manual and recheck your sticks, they may need re calibrating. Too much oil has to go somewhere and usually it's out the exhaust, if it doesn't come out a seal. You will find that Lehmans use oil down to a certain level then stop. This level seems to be different for each, but mine, if I recall correctly, was about 9 litres. YMMV.
It sounds like your engines are happy. I was told to run WOT for a few minutes every few hours (forget the interval, Bob Smith will tell you). This gets the engine entirely warm, tests the cooling system and prevents glazing. Makes a hell of a racket but never hurt my engine. In fact, when I bought it, the engine surveyor ran it WOT.

Xsbank,
No need to run WOT except when you need to see if all is well. To keep the rings free and such I'm sure an 80% load (probably 2 or 300 rpm down from WOT) should do the trick for boats propped to rated rpm. My opinion.

More opinion. You wrote "if you over fill the oil needs to go somewhere" may not in many circumstances and w many engines be the case. I think it depends a lot on engine design and the amount of over fill. Many engines may be fine a quart or so over and some may not.

That's probably so but this discussion has morphed into Lehmans and the presentation I attended by Bob Smith at GB Rendezvous, he said WOT. Which is what I said.

Of course, you will do what you want with your own engine as WOT seems to scare some people. My Lehman was rated at 120 hp at 2800 rpm. Which also happens to be WOT. If WOT was unhealthy, the manufacturer would have rated the engine at, say 100 hp at 2400 rpm, which would be WOT and well within the engines ability. WOT should not scare you, unless you never do maintenance, for WOT is when the heat exchangers etc. fail.

The oil. If you own a Lehman you will see the mysterious oil consumption after an oil change, then it won't move again for ages. They do that.

manyboats said:

... I think it depends a lot on engine design and the amount of over fill. Many engines may be fine a quart or so over and some may not.

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Your right on the engine design Eric but I know on our Ford Lehman SP135, when oil was put to the factory dip stick mark, which is where it was when we bought her, it took 18.5 quarts of oil. The engine specs via the shop manual and American Diesel say 14.5 quarts unless you have the a high inclination sump which takes 21 qts.

On oil weights, when we were in Alaska and the PNW we ran Delo 400, 30 weight. When we got to warmer climates we switched to 40 weight.

That's the infamous miss-marked dipstick problem with some Lehmans installed by certain manufacturers. You're lucky if that excess doesn't do damage but it is usually just wasted.

Fortunately, Lehmans and Keith Richard will be the only things still alive after the apocalypse.

Larry and Xbank,
Yes I run Delo 30W too. I have been known to mix 30W and 40W together. 35W ? .. For summer.

I think if you put quite a bit of excess oil in the pressure will blow the crankcase seals. No first hand experience on that one though.

Re the oil capacity it looks like ther'e were things Lehman overlooked when they converted the truck and tractor engine to marine use. Not very smart of them to overlook the shaft angle element of the marine conversion. All 4 stroke engines are oil cooled to some extent but the Lehman/Ford must be more so than most. How does that compare w other 120 hp marine engines?

Bank,
Just saw your other post. I'm quite sure Lehman's are rated at 2500 rpm. You may have an odd ball but you should probably check. You may be too much under propped.