Which oil for a Lehman 4D61?

[djblackwood]

The original 30-year old 4D61 manual says SAE30 only, the marina mechanic says 15W40. I'm not particularly inclined to believe one over the other but prolonging the life of my 30 year-old diesel is certainly paramount.

[smacksman]

The engine was built, like mine, before the age of multigrade oils were in common use, I think.
I haven't seen straight grade oil on the shelf for years but I expect vintage car owners may be able to source them.

I use Shell Rotella T SAE 15W-40 in my 4D61 though I haven't owned it long enough to vouch for longevity.
However, I own an old Peugeo 406 diesel car with nearly 150,000 miles on the clock with basically the same 2 litre engine and use Rotella T. It is just about run-in now.

[Chester B]

We have a Ford Lehman 135hp with over 6,000 hours on it. Runs like a top. I use Rotella T 40 which I can get from the NAPA dealer with no problem. We are currently doing the loop and it's fairly warm weather. I am also trying something new suggested but the NAPA guy: at 100 hours I am installing a new oil filter (they are fairly cheap compared to the price of oil) and now at 140 hours the oil is relatively clean. Still plan on doing an entire oil change at 200 hours but the filter refresh seems like a good idea.

[Nepidae]

We have '86 twin 135 Ford Lehman engines with less than 700hr on the engines (bought the boat with less than 500hr on the engines).

According to Bob Smith, the father of the Ford Lehman, 40W Rotella is the only way to go even in todays world of multi-viscosity oils. A couple of years ago I had someone else change my oil and I specified 40W Rotella and he used a 15-40W which of course seemed to work fine. Last oil change, since straight 40W is hard to find I continued with 15-40W, from Walmart.

I am a fan of synthetic oils that I have used in my vehicles almost since Mobil 3 came out and asked Bob. His comment was 40W Rotella oil.

I then asked Steve D'Antonio and included in my question a blend of regular & synthetic and full synthetic (Rotella makes a synthetic and a blend for diesels).

Steve's response was that the engine would support either (the blend had to be done by the manufacturer) but stated that he didn't think either would produce a cost/benefit ratio that would be acceptable. It would certainly allow for a longer duration between oil changes but it in his mind didn't think it would/should produce an exaggerated duration. If you check his posts you will probably find his response.

Our current use has been less than 50hr per year (on the engines, but the boat gets used just about every weekend) but next year we are going to be fully retired and our first big cruise will be to Lake Champlain and up into Canada to Ottawa so we will be putting more hours on the engines and my proclivity would be to change over to a blend (using Rotella).

Based on my car experiences, had to run home, about 20min with a broken radiator hose (patched as good as I could) and while it ran hot, there was no damage to the engine that was ever noticed. I consider that an inexpensive form of insurance.

As to changing the filter in between oil changes, it does seem like a good idea, BUT my filters are on upside down (you need to puncture the top-bottom of the filter to get it off) and my question would be wouldn't any impurities just flow back into the engine with the oil which if you were changing the oil wouldn't matter?

Thanks for any input.

[don123]

According to Bob Smith, the father of the Ford Lehman, 40W Rotella is the only way to go even in todays world of multi-viscosity oils.

Interesting thing to know . . . .

While the 4D61 is indeed a 'Lehman', Ford had nothing to do with this particular engine. Lehman marinized the Ford engines (both 4 and 6 cylinder models) but our 4D61 Lehman Peugeot is a *completely* different animal - It's a marinized Peugeot 504 automobile diesel from the late '70's . . . . and there were plenty of multi-grade oils in use even then

I'd say it's a safe bet that 95% of the Peugeot 504 diesels still on the road are running on multi-viscosity oils and those oils should work equally well for the marinized versions

For my money, either Shell Rotella or Chevron RPM Delo in 15W/40 are of pretty equal stature industry wide and either would be a great choice. I would imagine the engines would live longer running either of those than any brand of straight 40 weight oil. I'll leave the regular vs synthetic debate to others, but if you're not putting at least 100 hours on the engine every year, I think synthetic would be a bit of a waste as I don't believe in letting engine oil set for 2 or 3 years just to get the usual number of hours before a change. For me, it's one change every year *or* every 100 hours, whichever comes first. If you think about it. 100 hours @ 50 mph in a car/truck engine is about 5,000 miles and I'm just not comfortable running oil beyond that measure . . . . unless you're using synthetic. Diesels dirty up their lubricants much faster than engines using other fuels and even if you use synthetics, I don't know how much beyond the usual 100 hours I'd feel safe going

As always, opinions are usually only worth what you paid for them, so this 'free one' may be completely useless for many of you

Don

[Chester B]

RE Changing Filters in the middle of the duty cycle: I'm no expert on this but I think any impurities are trapped in the filter material and would not flow back into the oil. Ours is mounted upside down so I don't seem to lose much oil when I do the change.

[Nepidae]

Don & Chester B,

Don, I agree with your 100hr oil change routine for those who aren’t using their boats on a frequent basis. Can we agree on a point that your Lehman and mine are similar enough to be the same for a comparison? Your block was an auto mine was a tractor. Also, your analogy of a 100hrs @ 50mph could include different engine rpm’s and dirtier environment in use.

We know that people who use diesels in equipment, trucks and the like, probably don’t change their oil every 100hrs. This of course is due to a more continual use. As you stated, diesels dirty up their lubricants, and a diesel which sits at times will have a higher degree of this issue.

I stated that I was thinking of making the change-over next year when we will be ‘going to be fully retired and our first big cruise will be to Lake Champlain and up into Canada to Ottawa so we will be putting more hours on the engines and my proclivity would be to change over to a blend (using Rotella)’ then.

Taking a cruising calendar of May to October there are 184 days and allowing for all that cruising is, which includes non-cruising, I figured we’d be moving about 46 days and usually for about 5hrs/day which equates to about 230 hrs. Understand we’ve never done this trip before so there is a certain amount of conjecture here.

Rotella at Walmart in the 15W-40 regular oil sells for $12.74/gal. I have 2 engines which each take about 5gal of oil, so an oil change is 10gal of oil. Therefore an oil change is $127.40.

Rotella T-5 is the blended version of oil, part regular and part synthetic. Shell on their web site states, “Shell Rotella® T5 is designed to provide fuel-economy savings, extended-drain capability, enhanced engine cleanliness, and excellent wear protection”. Extended-drain capabilities is a point as is fuel-economy savings and wear protection. Walmart sells T-5 for $16.47/gal and therefore $164.70 per oil change.

Thinking I’d get a 2 to 1 change in my new use of the boat, the engines working more, I’d be looking at doing oil changes every 200 hrs. 2 oil changes of standard oil will cost $254.80. T-5 oil change will only be once in 200hrs and cost $164.70 for a savings of $90.00 per oil change. Keep in mind that I will be doing oil checks every time we start the engines and can keep an eye on things. I also need to mention that we will be continuing on the Loop the following season. Taking that the basic Loop is 6000mi, or 30 oil changes, the savings in oil changes would amount to $2,700.00, not a small amount. This also doesn’t take into consideration any fuel savings.

But, let’s look at it this way. The difference in costs ($164.70-$127.40) between the 2 oil changes is $37.30. Shell says that there is an enhanced engine cleanliness and wear protection in T-5. If I had to drop back to an oil change every 150hrs, which I don’t think would be pushing the envelope a whole lot, I’d be spending $18.65 more (or saving only $71.35) per oil change, for cleanliness and wear protection, as well as fuel economy savings, which I could live with.

In closing I’d also say, As always, opinions are usually only worth what you paid for them, so this 'free one' may be completely useless for many of you.

Chester B, in respect to the upside down filter, I was thinking what you stated when I wrote but wanted to get some additional input. The amount of oil loss would be only what was still clinging to the element in the filter when it was removed and most impurities would still be attached to the filter.

I do think that if the filter were in the ‘normal’ position the benefit of changing a mid-oil change filter would be greatly enhanced though.

Thanks for your input.

[don123]

Can we agree on a point that your Lehman and mine are similar enough to be the same for a comparison? Your block was an auto mine was a tractor.

Actually, I was thinking quite the opposite which is why I mentioned that the 4D61 is not a 'Ford'

If a Ford expert says you should only use Rotella straight 40 weight oil in a 1950's British tractor engine, how does that apply at all to a 1970's French car engine? If ever there was an example of apples and oranges, that must be it

Personally, I believe the advent of modern multi-viscosity lubricants was a major breakthrough and their advanced technology trumps everything we had in the 50's and 60's when single weight oils were all there was - No matter what any 'expert' may say, I believe using a modern oil in an antique engine is all plusses and no minuses. The API oil ratings have changed many times over the years and modern oils are specifically formulated for engines using the blends of diesel fuel available today. I would not hesitate to use any modern API rated 15W/40 oil in any diesel I owned. If you were to insist on using an antique straight weight oil, it would probably be a good idea to use the antique diesel formulation which was sold back then to go with it. Because those fuels haven't been made for many years probably explains why the old oil formulations aren't around anymore either. If you look up the API ratings for the old single weight oils, it will have 'Obsolete' next to the rating. Today, all lubricants are specifically formulated for the fuels the engines are using

As an example, the API CG-4 oil rating introduced in 1995 specifically for fuels with less than 0.5% sulfur is today also rated as 'Obsolete'. Time and lubricant technology marches on!

Don

[Panhdjoe]

Ditto on the Peugeot being a completly different engine than the Ford, however Bob or Brian Smith is who I would seek advice from. On another note during some training I had by a lubrication engineer I learned that pre mid 90s engines that have always run regular oil may leak oil if changed over to syn. due to chemicals attacking tho old seals. I am sticking with Regular 40w shell in my Ford Lehman. They need the heavy oil on cold start due to the high compression pressures. Also my ford had 15w40 shell in it when we bought it. When I changed to straight 40wt shell in knocked out 90% of the blue smoke on cold start. At ambient temp above about 70 degrees with fresh fuel and 40wt I get no smoke at all.

[don123]

I am sticking with Regular 40w shell in my Ford Lehman. They need the heavy oil on cold start due to the high compression pressures. Also my ford had 15w40 shell in it when we bought it. When I changed to straight 40wt shell in knocked out 90% of the blue smoke on cold start. At ambient temp above about 70 degrees with fresh fuel and 40wt I get no smoke at all.

Your engine, your choice of course, but I wouldn't let a little blue smoke at start-up be the deciding factor

What's so great about multi-viscosity oils is that they are thinner when they are cold which allows them to quickly get to the places they need to be and then they reach the viscosity you want when they warm up. Your 40 weight oil is probably actually more like 80 or 90 weight when it's cold and then it thins out to be an actual 40 weight when it warms up. Starting a cold engine, all of the lubricant has drained away from all of the places it really needs to be and it takes more time to get that thick oil through all the engine passages - The bottom oil ring on the piston is bone dry, so until it gets wet, things are grinding metal to metal. Maybe 90% of the total wear in an average engine occurs during cold starts. This is exactly why multi-vis oils were invented. The blue smoke you see means the thin oil is getting all of the rings (even the top one) lubricated as soon as possible, greatly cutting down on that initial cold start wear. So long as it goes away as the engine warms, I would maintain that a little blue smoke during a cold start is actually a good thing

Don