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The boat I used to sail in the Caribbean had a Perkins 4.108, it was in many ways a good engine that helped us out when the winds were unfavorable. If you know anything about diesel engines, you probably know that the Perkins 4.108 is a desirable classic in its field. It’s a timeless engine still used to this day.
The Perkins 4.108 is a diesel engine commonly used in marine equipment and some Jeeps. While this engine’s original design is over 50 years old, it is still prized for its low sound levels. Some people retrofit their Perkins 4.108 with new parts to keep it up to modern operating standards.
Whether you’re knowledgeable about engines or not, I’m here to answer all the questions you may have about the Perkins 4.108!
What Is a Perkins 4.108 Engine?
A Perkins 4.108 (108 cu in or 1.76L) is a 4 stroke diesel engine used mainly in boats. These internal combustion engines ignite fuel using heat made from compressing air in the combustion chamber. It’s old, reliable, and known for being quiet.
This engine was initially introduced at a boat show in 1960s New York. Though the device’s initial design has undoubtedly aged, it was manufactured until the 80s and is still common today.
Its parts are inexpensive to replace, making these engines economical to use in the long term.
What HP Is a Perkins 4.108?
The Perkins 4.108 will output a max of 51hp (horsepower) at 4000 rpm according to Perkin’s official data. Although, the cruising output is suggested to only be 32hp at 3000rpm for longevity purposes.
It’s essential to be aware of the term horsepower to understand what your engine is capable of. HP (horsepower) is calculated by determining how much power is needed to move an object a certain distance for a specific amount of time.
The Perkins 4.108 packs an okay punch for such a small diesel engine. That’s one of the primary reasons it’s still such a prized and favored engine.
How Much Fuel Does a Perkins 4.108 Engine Use?
A Perkins 4.108 engine uses between 0.6 and 0.8 gallons (2.27 to 3.02 liters) of fuel every hour if you run the engine at 2000 revolutions per minute.
RPM (revolutions per minute) refers to the number of complete rotations an engine’s crankshaft makes each minute. This measurement is helpful because it gives you an idea of how fast a machine is running.
So when you run a Perkins 4.108 at 2000 RPM, the average fuel consumption is about 0.6 gallons to 0.8 gallons (2.27-3.02 liters) an hour.
Running one or two engines on a catamaran? Benefits and cons, read my article Catamaran fuel consumption explained.
Are Perkins Engines Still Made?
Perkins engines are still made. However, the production of the Perkins 4.108 came to a stop in the late 1980s. Perkins is still running as a manufacturing company for diesel engines and works through Caterpillar to produce thousands of engines every year.
While Perkins 4.108 engines are no longer actively manufactured, you can still buy used ones or upgrade your current 4.108 with new parts.
According to Caterpillar, Perkins has manufactured over 20 million engines in the company’s lifetime. 4.5 million of those 20 million engines are still being used, which attests to the reliability and broad range of Perkins products. If you can’t find a Perkins 4.108 specifically, the company has plenty of other options to choose from.
Fun fact: there has even been testing trying to run the Perkins engine on compressed natural gas (Source)
How To Identify a Perkins Engine
Perkins has released a wide variety of engines over the years. That means that it can be tricky to identify the exact make of your Perkins engine without finding the serial number first.
Every Perkins engine has a serial number on the engine plate. This serial number will provide you with all the information you need to determine the specifics of your machine.
After you find the serial number on your Perkins 4.108 engine plate, you can break down the numbers to find more information about your engine. You can use this unique number to identify the country of origin, manufacturing year, and build-line.
You can check out this Perkins serial number guide for more information about what your serial number means.
Common Perkins 4.108 Problems
While many mechanics and consumers highly revere a Perkins 4.108 engine, no machine is immune from potential issues.
Here are some of the most common Perkins 4.108 problems:
- Low to significant amounts of oil leakage (I had this issue)
- Changing the fuel filter can be challenging (this one as well…)
- The rear crankshaft seal tends to leak
If you notice your 4.108 engine displaying any of these issues, it’s essential to address them as soon as possible.
Perkin engines are fairly easy to repair by yourself, so if you are interested in being self-reliant, maybe in preparation for a longer sail, then this is a good engine to start with.
However, it’s also important to remember that complete engine replacement is not always necessary.
You can easily replace specific parts of your Perkins 4.108 engine with a broad range of contemporary and vintage replacement parts. eBay is a great place to find replacement parts at reasonable prices.
Pro-tip, remember that this is a diesel engine so if you run out of fuel you will need too bleed the fuel lines from air before you can start it again. This happened to me in the Miami river and it was not a pleasant experience, so learn from my mistake.
Frequently Asked Questions
Where Can You Find a Perkins 4.108 Engine?
You can find a Perkins 4.108 engine on online marketplaces such as eBay, Facebook Marketplace, and Craigslist. While finding a fully functional 4.108 in one working piece might be tricky, you can also search for the individual parts.
While you might have more success searching for this particular engine on online used marketplaces, you can also ask around to search for one. One tip is to seek advice from your local mechanic and see if they know anyone who can sell one to you.
Another tip is to join different Facebook groups to connect with people who can potentially help you out.
Pro tip: when evaluating the condition of the engine, get help from someone that knows this exact engine type, this will reduce the risk of buying one with the above-mentioned problems.
When Was the Perkins 4.108 First Made?
Perkins first made the Perkins 4.108 in the 1960s. This diesel engine was introduced at a boat show in New York, and they are still popular today even though the company no longer produces them.
This particular Perkins engine, unfortunately, stopped being manufactured in the 80s. It was actively made for about 20 years and is still a reliable piece of machinery.
How long will the Perkins 4.108 run before needing a rebuild?
The Perkins 4.108 will run somewhere between 5000 and 15,000 hours therefore it needs a complete rebuild. Maintenance and operational demands decide whether it’s closer to 5000 than 15000.
Conclusion
The Perkins 4.108 is over 50 years old, but it is still used and favored by many for its low noise levels, functional operation, and easily-replaceable parts.
However, the 4.108 is prone to a few problems like oil leakage. Making fuel filter changes can also be challenging, and leaky rear crankshaft seals are typical. Despite these occasional issues, it is a reliable engine built to last for many years. It’s an excellent piece of equipment and a great example of a well-crafted diesel engine.
