Oil Change on Lehman 120

Boat is a 1981 34' Marine Trader with a Lehman Ford 120. I'll be changing my oil this week for the first time and was wondering about the best oil to use. What type and weight of oil do you use? I know the manual says 30 weight for my weather conditions but that was written in 1981. Oil has change over the years. Looks like the PO used Shell 10w40 the last time. Do you use the same oil in the fuel-injector pump, as you do in the engine, or 30 weight? As always thanks for helping out!

Rotella 15W40 (or similar) as do many others. The typical arguments about whether you need a multi or not are just that...an unsettled argument. Using a straight weight is fine..but if you have a temp spread and feel like your Lehman would do better with a multi then you certainly won't be hurting anything even if again the argument is you don't really need a multi.

As you pointed out...Lehman manuals were printed many oil certs ago and really don't apply any more than using any other aftermarket part.

Even the "Lehman" experts have relented to accommodate the new oils and certainly the oil guys see the fallacy in following the tables in a 30 year old manual.

I'm by no means a Lehman guy, but I believe the 120 also needed the injection pump oil changed, is that a different weight?

same as engine oil in Simms injector pump.

I also like Rotella 15-40 for my Lehmans. Don't forget to change the oil in the injector pump too.

Ken

Shell Rotella 15-40 in Perkins 4-236

Remember, your engine virtually sits in the water and does not get as hot/cold as if it were in a truck. Shoot it with an I.R. Thermometer and go from there with your viscosity choice.

Nothing wrong with straight 30 or 40, they've been running on that stuff for, what, 50 years? They will go for 10,000 hours on 30-weight and 10,001 hours on 10-40. Go figure.

Rotella 15W40 for engines and Simms pump. Reason? It's a good buy at Sam's club. Has worked well for the past 850 engine hours (just over 4 years running).

I was told to use non detergent straight weight in the Simms by the old technicians, but I have owned my GB since 1991 so what do I know?

Straight weight for me.
I don't think multi-vis is needed or even desirable in a boat where the engine owners manual says to warm up the engine for 10 minutes. The purpose for MV is as an aid to starting in very cold weather. MV oil is slightly less of a lubricant but most think MV oil is more modern and must be better for that reason and so use it for that reason. The difference in viscosity or lubricity is very small so it matters little or almost none at all which you use. Xbank wrote in a post above "They will go for 10,000 hours on 30-weight and 10,001 hours on 10-40. Go figure." Probably the reverse is more correct. Straight weight oil is not "old" or old fashioned. It's just a different type of oil ... for engines that don't need to start and run under load in very cold temperatures. Like a small town's diesel generator. If you need to run your boat engine when the engine is 15 or 25 degrees you then should use MV oil. Otherwise straight weight oil is a tiny bit better.

Remember that 15-40 oil is actually 15 weight oil. It has viscosity improvers (that don't add or even have lubricity) that changes the oil's viscosity characteristics so it will conform to the 15-40 rating. What that means is that at running temp (probably 170 degrees or so) it is as thick or thin as 40 weight oil would be at that temp. The ability to make 15 weight oil do that has in the past been in question. In the early days of MV oil a 10-30 would perform as advertised when new but in a short time would just revert to 10 weight oil. They say those problems have been taken care of long ago but to what degree I wonder just a bit. And they probably had to add another "additive" to correct the old problem. How they "fixed" the problem I don't know. Most to all additives don't add lubricity and I think FF said lube oil is 15% additives. Some additives are almost necessary and some are not. Viscosity improvers for an inboard boat that dosn't see freezing temperatures is not in need of MV oils IMO. But I'll admit it's probably fly stuff. But one must or should use lube oil that has the rating recommended by the engine manufacturer usually expressed in two letters like "CC".

Since most engine wear occurs during start up and the next few minutes, it's best to get good oil flow using an oil that has lower viscosity the outset...at 50 - 60 degrees 15w is better than 30. Yes the additives can break down but that's why we change it every year.

PuppyR said:

What type and weight of oil do you use? I know the manual says 30 weight for my weather conditions but that was written in 1981. Oil has change over the years. Looks like the PO used Shell 10w40 the last time. Do you use the same oil in the fuel-injector pump, as you do in the engine, or 30 weight?

Click to expand...

On the recommendation of our engine manual, our diesel shop, and good friends in the marine diesel and generator manufacturing industry, we use 30 wt oil in our FL120s. We use Chevron Delo 400 oil. We use the same oil in the injection pumps that we use in the engines.

We change the engine oil and oil filters every 100-150 hours (the book says 200 hours but I've yet to have a mechanic-- marine, aviation, or automotive--- tell me that fresh oil is bad for an engine). We change the injection pump oil every 50 hours.

Marin I agree.

I now have one of my cars w 30wt oil. Only downside is that I need to take a bit more time warming it up. Easy to do where we live.

mike66 wrote "Since most engine wear occurs during start up and the next few minutes, it's best to get good oil flow using an oil that has lower viscosity the outset...at 50 - 60 degrees 15w is better than 30. Yes the additives can break down but that's why we change it every year."

I don't believe that but ... I'm open. I'm here to be convinced. I've read it many times though. Seems to me we'd have pre-lubricators our cars if it were true. One could crank their engine over 10 seconds or so before injecting fuel or starting ignition. I've never heard of that recommended and most people run their engines fairly fast and hard way before they are warmed up. If it was as you say it would seem to me much more caution would be commonplace.

I think pre lubrication is a good idea, especially with single weight oils in cooler climates. I believe some diesel trucks have them. I think the reason that they're not in common use is the evolution of multi viscosity oils which helps reduce that start up wear. Some synthetics go with a 0w or 5w to get better low temperature flow. This probably is all more theoretical than practical; most engines probably die of other causes than choice of oil weight.

Mike,
I worked in a mine powerhouse that heated the lube oil and coolant to operating temps all the while circulating both fluids through the engine as though it was running. Took 24hrs to pre-lube and pre-heat prior to starting. Started by compressed air and the moment of starting was confirmed by me when the compressed air was turned off and the flywheel didn't slow down.

Engine was a 16 X 20 X 8 Enterprise w turbo.

PuppyR said:

Boat is a 1981 34' Marine Trader with a Lehman Ford 120. I'll be changing my oil this week for the first time and was wondering about the best oil to use. What type and weight of oil do you use? I know the manual says 30 weight for my weather conditions but that was written in 1981. Oil has change over the years. Looks like the PO used Shell 10w40 the last time. Do you use the same oil in the fuel-injector pump, as you do in the engine, or 30 weight? As always thanks for helping out!

Click to expand...

The real answer might just be use whatever diesel rated oil you want of almost any weight rating. Injector pump aside, change it every 100 or 1000 hours. In the long run. with those engines, I seriously doubt you'd ever notice any difference in longevity or have any mechanical issues do to what oil you use.

The major difference in oils is the additive package.

This is the 20% of the oil that gets upgraded as the gov changes exhaust requirements for big trucks.

The old Std CD is still fine for engines that are not fed their exhaust (EGR) .

I prefer 30 wt , not multigrade as the oil is more stable , and there is no flour like chemicals to thicken the oil as it warms.

Esp on displacement boats that operate on a small percentage of the engines HP,
remember coolant temp is NOT oil temp. And it takes oil temp to thicken the oil.

I cant believe some still subscribe to the long warm up theory.


I use modern oils in everything because of their better anti wear additives but you could probably use any cheap detergent oil and never notice the difference. in an old engine.

It don't remember ever reading of an oil related failure on any boat web site.

Excellent post FF,

Except the oil never thickens .. as it warms up .. ever. 15W40 oil is 15W oil .. but it has the VI additive or additives that have a thickening effect on the oil as it warms but the effect of thinning from heat as the oil heats is far more dominant. And when it gets to operating temp it's much thinner than at startup temp. But it has the viscosity characteristics (thickness) of 40W oil at 170 degrees (or whatever they rate it at) so the MV oil gets much thinner as it heats up like straight weight oil .. just not quite so much so.

When 30W oil is at startup temp it's a little bit thicker than 15W40. And when 15W40 gets to operating temp (if the load is high enough) it is a little bit thicker than 30W. It's just a little bit higher in viscosity stability.

Speaking of stability What is it about 30W oil that is more stable FF?

And baywiew 15W40 oil is only more modern in that it was developed and introduced to market much later than straight weight oil. There are applications where MV is a better product (road vehicles) and there are applications where 30W is a better product (most stationary engines) for example. In industry I doubt you'll find stationary engine manufacturers recommending anything but straight weight oil. There's no need for continuously run engines to have MV oil. Really large engines (or any other size) that don't need MV shouldn't use it. But if you have a fireboat (they have a few in Alaska) MV oil would be an appropriate lube oil to use as they wouldn't be warmed up normally.
And a long warm-up for any engine in a trawler would be undesirable irregardless of what viscosity oil was used.

the oil argument will never end because there are no controlled experiments in boats, however I subscribe to the modern additives targeted on wear reduction for modern tight engines using modern fuel. I don't see how wear reduction additives can be a bad thing.
I wont go as far as synthetic oil however. As I said in older engines IMO virtually any detergent oil would likely never show any difference.

Capthead wrote via his link;
"SAE 30 or 40 would probably become so stiff at sub-zero temperatures the engine might not crank fast enough to start."

That's the bottom line. That's the reason for MV so if your engine cranks fine at the lowest temp you'll encounter you don't need MV oil. And our trawler engines snug in their engine compartments don't get that cold.

I have already posted a thread on my oil. I use synthetic and it's a multi of course. I run cooler and I have much less smoke and oil sheen at start up.

I have had people tell me I don't know what I'm talking about in reference to less sheen and smoke. I also think they didn't believe the temp gauges show a 5 degree drop in temp. I'm fantasizing that.

The oil debate is in a close tie to the anchor debate. Neck and neck. No clear winner yet.

Capthead,
When you say you use MV "of course" do you mean you wouldn't use straight weight synthetic if it was available? It isn't because there is no such thing. Synthetic meets the MV rating requirements w/o any viscosity improvers because it's stable enough. And that's another benefit of syn oil. Your syn oil is better in the same way Dino oil is as it dosn't have any viscosity improvers. Syn oils that have wide viscosity ratings like 5W40 probably do though.

I'm not convinced syn has lower friction due to anything beyond a lower viscosity and I remain convinced it's not cost effective. But I'll never say it's not better.

Is my anchor better than your oil??

Anchor ...... Wazatt?

American Diesel is adamant about using single grade 30 or 40. They are the experts on these engines and I am not about to disagree with them.

For the OP, The Trawler Beach House has an excellent series of tutorials regarding the care and feeding of the Lehman 120. Really helped me the first time I changed my oil.

Arch

I try not to exceed 2000 RPM in my gasoline-powered Ford vehicle and 1400 RPM with my boat's JD4045 diesel before reaching operating temperature. Perhaps this explains my sister's statement that I drive like a "grandmother."

I have a diesel truck and the GB with twin Ford Lehman natural Aspiration engines. I've constantly viewed the truck as a test platform for the boat. As such I went through about ten years of testing additives and then I switched to oils.

The boat's hour meters had failed and been replaced a few times so your guess is as good as mine on engine hours. Keeping in mind my boat came from Boston to Los Angeles via the ditch it has hours. Lots of hours.

Everyone in 1994 told me "you can't put synthetic in an old engine"
DON'T PUT SYNTHETIC HIGH DETERGENT OIL IN AN OLD ENGINE!!!

I said, watch me.

I changed one engine to synthetic the other was Rotella fossil. Started them both. Major difference in smoke and sheen and thats immediately. after a trip to Catalina and back I changed the Rotella to Delvac1 and I haven't regretted the change ever since.

It's much more expensive and my next change might be a different brand of synthetic if I can't find Delvac1 reasonable.

One last note.

I replaced the engine in my Jimmy at 616,000 miles. I had a complete engine build, balanced, ceramic coated pistons, longer duration cam, etc plus a newer year block. I drove that on fossil for 16,000 miles and switched to Delvac1 synthetic. I was never real happy with it and I was burning oil more than I expected for a new engine.

Finally after many years and about 60,000 miles I changed to fossil oil. The first 3000 miles I went through three quarts. Changed it to fossil again. This is that change now and my engine has finally seated in. I'm not burning oil and I went up 1.2 MPG as well. I'm going to go one more fossil change then I'll switch back to Delvac 1.

BTW, I'm using Delvac 15W 40 I think. I have to check.