At what point does saving money become a project?

We all want to save money. Sure, it is human nature to spend the least, but get the most. However, there is the old idiom about being “Penny wise, but Pound foolish”, often incorrectly attributed to Benjamin Franklin, that often applies when comparing options.

We once had a suspiciously large parts order from a new, unknown customer. When the parts department received the order, they were perplexed: When did we sell an engine to these guys?

They combed through our accounts history and found nothing. What was going on?

It turns out that the customer had been given a GM engine block on the aftermarket (an old GM truck engine) and was trying to marinize it himself to use it on his boat. There are a number of different reasons why this is not a good idea for the average home mechanic, no matter how experienced or no matter how good his mechanical aptitude:

  • Most workshops lack the facilities for proper marinization.
  • You generally cannot use automotive parts in a marine engine, due to corrosion issues.
  • Marinization is a highly technical process. Without experience, the process can quickly become complicated and expensive.
  • Engines perform differently on the water than on land. The power and torque curves are completely different, and on an electronic engine, significant software knowledge is required.
  • Modern emissions requirements are tricky. In some locations, operating a vessel without certified emissions is illegal. It is very difficult to meet emissions requirements without the proper testing facilities.


Most of all….

Marinediesel, as a manufacturer, has certain economies of scale when purchasing components. Quite simply, when you buy thousands of injectors, you pay much less than when you are buying two. Additionally, though it really isn’t a secret, most manufacturers make most of their profit from spare parts and service, rather than from the sale of the engine. That is why there is usually a big difference in markup on spares, but very little difference in price between similar engines (ie. Volvo Penta D6 vs Marinediesel VGT 400).

In the end, he was a little shocked that refurbishing his old engine would end up costing almost as much as a new engine. We finally convinced him that he would spend so much time and money that he really would save very little in the end, and most likely end up spending more. A project, indeed…

Choosing the Right Engine



As an engine manufacturer, MarineDiesel would love to be able to answer the question, “Which engine should I choose for my project?” with a resounding “MarineDiesel, of course!” every single time. However, that is not the correct answer to give. Different engines have different strengths and weaknesses, and ours are no different. We often get requests to quote where our engines are simply not an appropriate match for a project. Sometimes, people are just price shopping, matching horsepower to horsepower, and sometimes a new project pops up where the shipyard does not have a lot of experience.

When determining the engine to choose, price should be among the last crieria that should be considered. There are far more important questions to ask:

  1. How will the vessel be used? Our engines tend to focus on fast boat applications. They are normally not a good match on tug boats, for instance (Though sometimes, occasionally, they are suitable).
  2. How much space is available for the engine? Smaller spaces require smaller engines.
  3. Is noise a problem? Engines are tested for noise when manufactured. Noise can be controlled through both silencing and insulation, in addition, yet those items also have costs in space and money associated with them.
  4. Is vibration a problem? Some engines, such as our VGT Series, produce much less vibration than inline models, due to their physical characteristics. Additionally, there are aftermarket ways to control vibration, like the use of different mounts or couplings.
  5. How capable is your maintenance team? Some engines are more complex than others. Some require a higher level of skill to maintain.
  6. Price. Price is important, and does play a role. However, consideration also needs to be given to the cost of spares, service, and training.
  7. Life Cycle / Rating. An engine used 2,000 hours per year needs a longer life cycle than an engine used for recreational purposes.
  8. Service network. Some engines may fit all criteria, but there is no service in your country available. Engine maintenance gets expensive very quickly when performed across continents.
  9. Warranty. How good is your engine’s warranty? Some manufacturers have better warranties than others.
  10. Fuel consumption. Fuel costs, on average, exceed 60% of any engine’s operating cost. Cost savings are significant over time.
  11. Performance expectations. You need to have proper calculations made with bona fide data: Not just guesses. Horsepower and torque requirements can vary drastically with small differences in hull design.
  12. Emissions requirements. This can be important. Laws and regulations vary widely between regions / nations.

We realize that choosing an engine is complicated. Contact your local MarineDiesel dealer for personalized assistance on your project.





When should you repower your boat?


On this blog, we often mention MarineDiesel engines as being suitable for repowering a variety of different vessels and applications. Indeed, perhaps 20% of our new engine orders are destined for repowering or retrofitting projects.

When should you decide that a repower if preferable to simply rebuilding the engine?

This is often not an easy decision to make. Most diesel engines can be rebuilt three or four times without any problems. It is important to note, however, that every time that an engine is rebuilt, no matter how competently, there will always be a degradation in engine performance. This should be a concern when deciding, “Should I rebuild?” or “Should I replace?”

Suppose your engine has never been rebuilt before. It has only been used in fresh water. It is still delivering an appropriate amount of horsepower, but starts sluggishly and you are needing to replace different components more often as they wear out. In this scenario, rebuilding the engine is probably a good bet. It is far less expensive than buying new, and it is just simply starting to near the point of requiring a complete overhaul.

In a different scenario, assume an engine has had extremely heavy use, always in salt water, and under a wide variety of throttle settings. The engine has had some hard wear. Symptoms start going beyond merely sluggish starting and may include smoke, noticeable decreases in power, and high increases in the number of spare parts required to keep it operating. The engine may have been rebuilt one or more times previously. This engine is a good candidate for replacement, and repowering.

Ultimately, the decision usually comes down to cost. Rebuilding an engine, on average, costs approximately 60% of the cost of buying new, assuming the use of OEM parts and keeping in mind the wide variation in labor costs around the world. Additionally, unless being replaced with the exact same engine make and model, new mounts, couplings, shafts, drives, and possibly propellers will also need replacement.

It is also important to note that engine technology has progressed at nearly light speed over the past two decades. In particular, emissions requirements have led to engines that are smaller, more powerful, and far more fuel efficient than even identical brands were twenty years ago.

Indeed, fuel efficiency should never be neglected in making this decision. Gains and operating cost reductions from more fuel efficient operation can easily cover the cost of repowering your vessel, as can the reduced maintenance that owners of new engines will experience.

If you would like a custom quote on your repowering project, contact your local MarineDiesel distributor today, or contact us for a free, no-obligation proposal.




670,000 Liters



670,000 Liters.

That equals:

  1. 3/10 of the volume of a hot air balloon.
  2. 1/4 of the volume of a standard Olympic sized swimming pool.
  3. 1/10 of the volume of the Goodyear Blimp
  4. 60 times the volume of the capacity of a cement mixer truck
  5. The amount of fuel that a MarineDiesel VGT350 engine will consume over its’ total lifespan.

This gives some important room for thought.

At diesel fuel prices of €1.20 / liter in Europe, this equals an expense of  €804,000 in fuel over that engine’s life cycle. When Future Value is taken into account, that cost balloons to over €1,128,000.

Fuel is the biggest operational expense of any engine. More than maintenance. More than spare parts. More than labor.

This is why fuel efficiency is so important when choosing an engine.

This is why many of the articles on this site highlight the engine power and torque curves. The VGT Series produces power curves that are very flat. That means that there is a much bigger RPM range available to reach a required power level. This then means:

The VGT Series of engines has a much lower cruising speed than competing engines. Lower cruising speed means lower fuel consumption.

Lower fuel consumption means bigger bottom line.






Marine Maintenance and Diesel Engines



Maintenance of diesel engines is directly tied to life cycle and reliability. Modern marine engines are proven to perform well over long periods of time, provided that regular routine maintenance is performed.

One factor that is often neglected is the harshness of the marine environment. Salt is corrosive. Humidity causes corrosion. Fuel quality can vary greatly from one place to another. These issues help explain why most marine diesel engines have a much shorter time between overhauls than a similar engine that is installed on a truck or other type of vehicle.

Engine ratings also have a bearing in longevity. Engines that are rated for recreational use, for instance, are designed to be used in a recreational application. Use one of these engines in a heavy commercial setting, and problems are certain to ensue. Maintenance costs will certainly multiply exponentially. At MarineDiesel, we see this situation quite frequently. A potential customer will ask us for a quote on a commercial vessel, but they choose a cheaper engine that was rated for recreational use. Will the engine function? Certainly. Will the boat explode? Certainly not. However, the maintenance expense will be much higher, the life cycle will be much shorter, and the vessel performance will be lacking.

Is it still a good deal…?

All engines require periodic maintenance. As a manufacturer, we are in the “Front Lines” regarding maintenance issues. We see patterns as to what issues occur, not only in our engines, but in engines manufactured by competitors. The three most common maintenance issues that we see are often avoidable, and if diligently monitored, can greatly extend the service life of a marine engine (of any brand):

  1. Fuel quality: The number one (by far) problem we see is the use of bad fuel and neglected filter and polishing.
  2. Exhaust temperature: This is probably the number two issue. The biggest leading indicator of required maintenance.
  3. Smoke: Smoke tells you a lot, from a diagnostic perspective. It is nearly always an indication of required maintenance.

Though a bit of a cliche, engineers often state over and over again, “Read the manual”. The maintenance schedules we develop and publish are based on extensive testing results and are updated based on customer feedback, experiences, and warranty returns. In other words, the schedules are not simply made up out of thin air. If we recommend filter changes every 100 hours, there is absolutely a reason.

Bottom line: If maintenance and service schedules are followed, your engine will give you a far longer service life, and cost you far less money over the long term.



Reducing Downtime Costs



One of the benefits of MarineDiesel’s VGT Series of marine engines is the much longer life cycle of our engines over competing brands. Longer life cycle is directly related to the costs of vessel downtime; something that is often very difficult to accurately calculate, particularly with regard to military or government vessels.

How much does it really cost you when your vessel cannot operate?

This is an interesting question, and one where the answer may not be so simple to answer, given the intangible variables that are present. On a commercial vessel, cost of downtime is relatively simple: If the vessel is not operating, or cannot operate, revenue is lost. It is, effectively, a sunk cost. On a military vessel, can inability to complete a mission be strictly placed into solely financial terms? Not really, yet there are real costs associated with not being able to operate.

The one constant is that cost from downtime occur, and it is beneficial to minimize the amount of vessel downtime.

MarineDiesel’s design and quality practices alone help minimize downtime, but there are other things that you can do to keep downtime to an absolute minimum:

  • Always adhere to the maintenance schedule in your manual.
  • Always maintain our recommended onboard spare parts inventory near the vessel location. If the vessel is located in remote regions, contact your MarineDiesel distributor for additional recommended spare parts.
  • Always use OEM spare parts.
  • Pay attention to your engine’s rating and the operating conditions and vessel use. Add additional maintenance intervals if used in harsh conditions or in extreme amounts.
  • Regularly inspect the engines and vessel as a whole, looking for abnormalities or unusual signs of wear.
  • Take advantage of drydock time to repair other systems at the same time.
  • Ensure that vessel crews are either factory trained or trained by MarineDiesel distributors.





Financing Your Engines



Engines usually constitute a major percentage of the costs of any marine or industrial project. Indeed, on some high performance boat designs, the engines and drives can be as much as 30% or more of the total price.

By offering complete propulsion packages, engine, gearbox, and drive, MarineDiesel can often help offset some of these costs while guaranteeing performance levels.

However, formal financing is often a requirement for our customers, particularly on large projects.

Engine purchases are often very difficult to finance, due to the fact that it can be very difficult to separate an engine purchase from the purchase of the vessel. It comes down to risk: The finance company looks at the risk from the “what if the customer doesn’t pay?” perspective. This problem is compounded by the fact that engines depreciate up to 30% of their value on the date of commissioning, whether used beyond that date or not. Therefore, most engine manufacturers that offer financing are only able to make that offer when the engines are tied via lien to the financing of the vessel as a whole. This often causes conflicts with documentation or complications on the financing itself.

So, what is the solution?

MarineDiesel works with EKN, the Swedish government’s export finance department ( EKN Website ), to offer financing plans to our customers. The financing program requires approval, and is not available in every region or on every project, but we have financed numerous projects through them in the past, and the process is relatively straightforward.

Additionally, MarineDiesel works with other lenders in different regions, and we can occasionally make arrangements for specific projects. Simply inquire with us or your local distributor at the time of quotation and we will try and arrange a financing proposal for your project.




Best of 2014 – Life Cycle Cost calculator



We wish all MarineDiesel customers a happy holiday season. Our factory will close from December 22 through January 5. For the balance of the year, we will be re-running our most popular articles from 2014, based on the number of visitors. We will start new daily articles in the New Year. We hope that you continue to find them interesting.

At MarineDiesel, we often come across potential customer who are confused about which engine to purchase. Yes, there are brand loyalties at play in any power decision, yet, more often than not, cost and price usually plays the biggest part in purchasing decisions, often eclipsing performance or technical requirements.

However, when choosing between two engines, much more goes into the cost calculation than simply purchase price.

Yes, very inexpensive engines are available in the market, usually, but not always, produced in China. Though these engines may be cheaper to purchase outright, their real cost becomes evident when maintenance, service life, and fuel consumption are taken into account.

When choosing an engine, you need to look at the following factors:

Purchase price

Engine rating

Life Cycle

Time between overhauls

Time between service

Fuel consumption

Cost of engine downtime

Cost of spares

Cost of service / labor

All of these factors add to the real cost of an engine, and in comparing one engine to another.

Therefore, in order to make your purchasing decision easier (Whether you choose us, or not), we have made the calculator below available for download for your use, free of charge.

Simply fill in the blanks indicated by yellow, and your real cost is indicated at the bottom. The spreadsheet is pre-loaded with the data from our VGT Series.

We hope you find it useful and helpful in making engine comparisons.

Life Cycle Cost Calculator



Engine Comparisons: VGT500



This week, we will be highlighting several of our engine models and be comparing them with others that are in the market. Our engines stand on their own merits. All data on other engines is available online. Comparisons are based on closest models / ratings for each manufacturer.

We start with our flagship product: The MarineDiesel VGT 500. Using the Duramax 6.6L as a base, we have created the lightest, smallest, and most powerful marine engine in the market today. Ideally suited for small, very fast craft, the VGT 500 delivers the high performance standards that simply leave other engines lacking.

Figures are based on commercial rating, when possible (Some manufacturers only have one rating, others have multiple ratings.)

Some specifications:

Engine Comparison MarineDiesel Volvo Cummins Yanmar Iveco / FPT
Engine Model VGT500 D6 435 QSB 5.9 6LY3-ETP N67 560
Retail Price (Manufacturer’s Suggested Retail Price, online. Prices may vary significantly. Add’l discounts may be avail) € 41,552 € 57,976 € 44,144 € 41,905 €40,929* (UK Only, Sale Price)
BHP 500 435 472 480 500
kW 373 320 352 353 368
RPM 3600 3500 3400 3300 3000
Cyl 8 6 6 6 6
Displacement (l) 6.6 5.5 5.9 5.8 6.7
Bore / Stroke (mm) 103/98 103/110 102/120 106/110 104/132
Maximum Torque Nm 1130 1040 1278 1280 1500
Time Between Overhaul (hours) 2500 1000 2000 1000 1500
Time Between Maintenance (hours) 100 50 75 50 100
Dry Weight 510 699 612 640 650
Fuel Cons at Top Speed g/kWh 230 208 232 228 215.5
Power / Weight kW/kg 0.73 0.46 0.58 0.55 0.57
Euros per kW € 111.40 € 181.18 € 125.41 € 118.71 € 111.22
Overhaul Cost (60% of New) € 24,931.20 € 34,785.60 € 26,486.40 € 25,143.00 € 24,557.40
Cost at 10,000 hours (Purchase, Overhauls, and Maintenance) € 141,279 € 405,836 € 176,579 € 293,339 € 204,647
Fuel Cost at 10,000 hours, Fuel EUR 0.80 / Litre (Calculated at 435 hp) € 710,476 € 633,905 €733,728 € 696,830 €656,761
Total Cost of Ownership 10,000 hours € 851,755 € 1,039,741 € 910,310 € 990,169 € 861,408

So, engine weights are listed in the table above. What about engine size?

(L) X (W) X (H), in mm

MarineDiesel VGT 500: 779 X 825 X 973 (Note: MarineDiesel engines always allow for remote location of some components, such as the grid cooler, filters, or starter motor. Dimensions, particularly height, can often be reduced considerably or shifted around to a great extent.)

Volvo Penta D6 435: 1,456 X 753 X 897

Cummins QSB 5.9: 1,255 X 836 X 858

Yanmar 6LY3 – ETP: 1,458 X 801 X 793

FPT N67 560: 1,063 X 843 X 766



When comparing power, and especially torque, curves, you need to keep in mind how the vessel will be used. All engine manufacturers rate their engines differently, many times with several different ratings under a single model. Others, like MarineDiesel, can change the ECU and engine programming to suit a vessel’s mission. The curves below are the most common ratings, but when reviewing, attention must be given that these curves can be different or altered due to rating.

MarineDiesel VGT 500:

Volvo Penta D6 435:

d6 pwr torque

Cummins QSB 5.9 472:

qsb power torque

Yanmar 6LY3-ETP:

yanmar 6ly3etp curves

FPT N67 560:

n67 560 curves











Cost / Benefit Analysis: LPG Engine to Power Generator



The following article is a cost / benefit analysis we prepared recently for a MarineDiesel customer showing a financial case for using LPG instead of diesel to power a medium  sized generator. The customer name has been removed, and costs are converted to Euros at local rates (prices will vary, based on your region, but this is a good, general comparison). The engine p

roposed is based on the 5.7L GM Vortec engine block.

Initial benefits of the MarineDiesel product line include:

  1. The ability to use LPG instead of gasoline or diesel for power.
  2. Customer payback time in a matter of months through fuel cost savings.
  3. Multiple markets for the engines, ranging in use from small generators to irrigation, mining, marine, pumps, or small vehicle power.
  4. Factory conversion to LPG, as opposed to cheap converter kits commonly found in the market. A primary benefit of this procedure is seamless integration of the LPG kit into the engine’s ECU. Aftermarket conversion kits often do not integrate fully, voiding the warranty or rendering engine fault warnings incorrect. For this reason, aftermarket conversion kits, such as are currently being sold cannot be recommended for proper installation and life cycle. Furthermore, MarineDiesel engines have been designed specifically with alternate fuels taken into account. Though there are some immediate cost savings associated with aftermarket conversions, they simply are not an accurate substitution for a proper OEM design.
  5. Full MarineDiesel warranty terms apply.
  6. Government financing may be available. 


Life Cycle

General Motors has been manufacturing the Vortec block configured to LPG for nearly thirty years.

Thousands of units have been sold and the engine has proved to be extremely reliable.

The MTBO is at 10,000 hours of use, however, it is highly dependent on climate and continuous RPM.


Cost to Operate

The 5.7L LPG consumes fuel based on engine load.

100% Load:         9.3 m3 / hour

75% Load:            7.1 m3 / hour

50% Load:            5.4 m3 / hour

25% Load:            3.8 m3 / hour



100% Load:         27 L / hour

75% Load:            20 L / hour

50% Load:            12 L / hour

25% Load:            8 L  / hour


Current prices of fuel (local converted to Euros):

LPG:   0.30 / litre

Diesel: 0.79 / litre

Average annual use of 4,400 hours per year, assuming 75% load at 1,800 RPM.

LPG consumption 3.85 Liters / m3

27.335 Liters LPG / Hour

LPG annual cost of fuel consumption: 33,075

Diesel annual fuel consumption: 65,978

Cost of ownership, year one


Cost of Engine:                                                  5,000

Operating Cost:                                                                65,978

Service and spares (oil filters, etc):          2,900

Total Cost Year One:                73,878


Cost of Engine:                                                  7,250

Operating Cost:                                                                33,075

Service and Spares:                                         2,500

Total Cost Year One:                42,825


Payback Time: 3 months


Amount of Power Produced

This is a difficult question to answer, since it will vary greatly based on the alternator chosen. In order to keep everything consistent, the same Kohler alternator 4P10X, will be used. This same alternator is used by numerous other manufacturers to produce the same amount of electricity, using LPG, Diesel, or CNG.

This alternator will produce 52 kW of power at 110 / 220 50 hz, using the 5.7L engine.

To put this amount in context, 52 kW is roughly enough to power 20 medium to large window unit air conditioners, or a medium-sized restaurant.

Therefore, given the usage described above, using LPG,

One Hour: 4.37

One Day: 91.88

One Month: 2756

One Year: 33,075

Cost per kWH: 0.147


A diesel genset produced by Baifa, using a Deutz engine made in China, producing 48kW using the same alternator would cost to run continuously:

One Hour: 10.35

One Day: 124.15

One Month: 3,725

One Year: 44,696

Cost per kWH: 0.216


A similar diesel genset, produced by John Deere using a four cylinder, John Deere diesel engine and using, again, the same alternator,

One Hour: 26.93

One Day: 323

One Month: 9,690

One Year: 116,276

Cost per kWH: 0.518


Tank Capacities

For small home / commercial use, portable LPG tanks come in the following sizes: 4 kg, 7 kg, 15 kg, and 48 kg.

The standard size for tanks installed in vehicles (permanently mounted, even on trailers, for safety reasons) is 58L (30.39 kg).

For commercial or industrial use, particularly when the engines will be used to power continuously, rather than as standby, typically large, above ground or underground tanks are used. The most common sizes of above ground tank are 1T (1,908 L) and 4.3 T (8,204 L).

Which tank that should be used and how long the generator will provide power on a single tank are really highly dependent on how the genset will be used. The smaller LPG “cooking gas” cylinders will occasionally “freeze” due to the atmospheric pressure difference if too much is drawn from the tank. Therefore, the smaller 4kg and 7kg tanks should not be used with the 5.7L. Remember additionally, 100% of the tank volume will never be able to be removed, again due to pressure. Therefore, a factor of 15% is reduced for simple numbers on LPG.


5.7 L Vortec with 4P10X, 12 hours per day continuous RPM use (1,800 RPM)

Tank Size Diesel Equivalent Cubic Meters LPG Reduce 15% below Full on LPG (Usable Amount in tank) Time between Fill-ups LPG Time between Fill-ups Diesel
15kg (Cylinder) 28.6L 8.085 7.03 m3 59 minutes 1 hour, 20 minutes
48 kg (Cylinder) 91.6 L 25.872 22.5 m3 3 hours, 10 minutes 4 hours, 40 minutes
30.39 kg (Taxi standard) 58 L 16.38 14.24 m3 2 hours 2 hours, 50 minutes
73.36 kg (Trailer max) 140 L 43.5 37.83 m3 5 hours, 30 minutes 7 hours
1,000 kg (above ground) 1,908 L 539 468.7 m3 5.5 days 8 days
4,300 kg (above ground) 8,204 L 2,317.7 2,015.4 m3 23.5 days 34 days