Just curious how folks here would rank Diesel Engine Manufacturers
Aug. 04, 2025
Just curious how folks here would rank Diesel Engine Manufacturers
You really can't rank them by manufacturer. Each has made some gems, each has made some turds. Also varies with years. Cat made the awesome , but also made the at 350, which did not hold up very well. Now Cat is making some of their marine engines, but outsourcing some models from Euro suppliers and painting them yellow. Not really Cat engines.
I generally like Cummins, but they made some turds too. One thing I like about that company is that all they make is engines. So they have some focus!!
The Japanese really own the small engine market (under say 50-100hp), like Kubota, Shibarua, Mitsubishi, Isuzu, Yanmar, etc. Most of these little engines are gems.
Cummins sorta owns the 200-700hp market. Some products better than others.
Cat still makes great engines in the 800-hp range (C18, C32). I don't know their Euro engines very well, just not exposed to them much. I don't like when product ownership is split between companies.
Volvo makes some nice engines, as does Yanmar, but tend to be very expensive to buy parts and once engines get old, parts can be tough to get.
There is no one "best" engine mfr. You need to figure out what power you need, what the duty cycle will look like and start from there. There will be several mfr's that make a decent machine that meets the specs. I will only address current vintage engines as that's where my experience is and rather than a ranking, I'll address strengths as I see them.
MAN-I don't think you can beat them for the 800- hp range. The combination of size to performance and dependability. A+
CAT-I think in the US they're a bit overrated. Many long time boaters just think they are the only engine to have. I think they have as many issues as anyone plus they're noisy. I'd choose MAN over them. Now, I would give them a C except their warranty service is excellent (Unless you're waiting on Pantropic) so B.
Cummins-I'd almost give them a top rating just based on how they treated Dhays. Dependable, solid engines. A.
Yanmar-In the smaller diesels, we've found them dependable and trouble free on the whole. B+
MTU-MTU has all the upper horsepower business from hp up plus a part of the smaller engines. Because many of their engines are pushed to the limits and in ranges others don't offer, I do think they get a bit more negative response than deserved. A hp pressed to it's limit is likely to have more issues than a 600 hp. Their warranty service is strong so I'll give them a B.
Deere/Lugger and all the variations. I personally prefer the Lugger versions slightly having used them extensively in Northern Lights generators. There is no more dependable engine, in my opinion. A+
Volvo-Rating just the engine here and trying not to cloud it by IPS. Solid. Really gaining share with European and Asian builders. Their history of parts availability and service in the US hasn't been what it is in Europe but is improving rapidly. However, until it makes a bit more progress, I must do the opposite of what I did on CAT and reduce them from a B to a C+.
Mercury-Why? Now that Searay no longer builds larger boats will they die? With so many excellent engines, theirs are not. D
In smaller engines, there are many others out there who build fine engines but their service networks and general usage just isn't enough for me to evaluate. VW, Kubota, Suzuki are just some that quickly come to mind.
Also, it must be said that one can experience trouble with the best engine and one can have a lifelong wonderful experience with the worst. On the whole, all the engines are good, just some better than others, especially in their prime ranges. All good points. While new to marine spent my life in trucking and machinery. Each manufacture has its gem and also its turd. Old days with mechanical engines reliability was good and simple to keep running. Now with such high pressure injection electronically controlled with muti-fireing one needs a laptop to even get started.My Favorites have been cat , cummins big cam 400s ,international dt466, and the deer engines have all been good. We needed to move a deer dozer last week that has been sitting for 20 years. They dropped two battery's in it and it fired right up old fuel and all. Only problem was fuel running from rusted fuel lines so some duct tape and got it on a trailer. Right now were having a lot of trouble with cummins 15 liters dropping valves on number 6. 30k repair. They have just upgraded the head but its a good example of a manufacture having something wrong and then after some time they figure it out then come up with a fix. I have about a dozen ISX600s with one failure. My advise is to ask on the forum about a specific engine and what series.
We went the other way
Our boat was clearly looking at a 6lxb when being converted (brochures and comparison numbers on file) but an NTA855m , same as previous engine was chosen and for that I am glad.
Reasons are
1) 6lxb would have been running hard in ours where as the 855 is at a fast idle
2) Parts and service for Gardner are difficult in most parts of the world, certainly not Cummins easy.
But, if I had no intention of venturing far yep, a Gardner is a pretty thing.
One thing I was 100% adamant about was no electronics and I would have preferred non turbo and.....the 855 would have the grunt in ours imho to be non turbo .
Well, maybe in the US, but not everywhere. And for anyone that goes back to the 60's, 70's or even 80's they will know Mercury outboards by their other name: "black anchors". Earned, deserved.
But times change. These days you can find some Mercury around, and for race engines they may well be preferred. However, for both commercial and recreational users Yamaha have owned the market since the mid 80's in these parts. Then daylight, and a bunch of others with Mercury not near the front of that pack either. Reputations can take a very long time to rebuild.
As for diesels, 'nothing runs like a Deere'. In the case below, it was still running even after the train dis-assembled it a bit. Not relevant here - boats aren't going to encounter trains in normal use!
Caterpillar = Crap-a-pillar or Clatter Tractor.
Cummins = Come-a-part.
Detroit Diesel = Dirty Diesel. (I don't prefer Screaming Jimmy or Screaming green leaker but that's just me).
MTU = EMpT You Pockets = Reflective of the operating costs...
For some additional flavor on Lugger branded marinization, the Tier III threshold stopped their pursuit of marine propulsion for a few reasons:
1-Komatsu entered an agreement with Cummins to provide their electronic engine/fuel system controls as a "black box solution" that made it expensive for Komatsu to do any aftermarket tuning on their industrial certified engines to allow for higher power marine ratings as had been done in the past. In the end, the cost to continue with the product dramatically outweighed the profit of the business (10%GM/10% of company sales revenue).
2-John Deere decided not to offer NL/Lugger their T-3 Industrial engine to allow Lugger marinization, instead offering the JD marinized engine which again restricted the opportunity for adding value.
Sad end as they were well regarded in the boutique marinization market.
Personally, I like EMD's the best today...but that's only because I know the strengths and weaknesses rather well. -HP but a little heavier than your high speed engines.
Interesting as that domination has seriously eroded. First, the I/O market has diminished greatly. So their percentage there is of a much smaller market. Then, on top of that, Volvo has acquired a significant percentage of that market. Part of that has been builder revolt although that has calmed some. At one time many builders switched to Volvo as a defense to Sea Ray and Bayliner and all their Mercruisers and what the builders felt were unfair advantages given to their in house brands. Mercruiser did more openly solicit others and now most other brands are about 50/50 Mercruiser/Volvo. Again, a problem for Mercruiser is the decline or Sea Ray and Bayliner stern drives. Another party that influenced the bowrider market significantly was Yamaha jets. Those took a huge chunk from Mercruiser.
As to outboards, Yamaha dominates that market outside the Brunswick brands which are sold only with Mercury. Of course, Yamaha now has it's boat brands too. It will be interesting to see what becomes of the share Evinrude held. Will it go to Yamaha and Mercury or does this open a path for Honda and Suzuki and others? With the rise in outboard market share, I'd see this as a good opportunity for others. Tohatsu also could take advantage. Then at the upper end, Volvo has shut down Seven, but their market share was miniscule to start with.
Lugger also used Komatsu engines, not just JDs. They simply got out of the propulsion business when Tier 3 requirements made it too expensive to qualify their engines. I do not believe it was a JD issue (though I'm sure there was some friction there too).
Peter
I generally like Cummins, but they made some turds too. One thing I like about that company is that all they make is engines. So they have some focus!!
The Japanese really own the small engine market (under say 50-100hp), like Kubota, Shibarua, Mitsubishi, Isuzu, Yanmar, etc. Most of these little engines are gems.
Cummins sorta owns the 200-700hp market. Some products better than others.
Cat still makes great engines in the 800-hp range (C18, C32). I don't know their Euro engines very well, just not exposed to them much. I don't like when product ownership is split between companies.
Volvo makes some nice engines, as does Yanmar, but tend to be very expensive to buy parts and once engines get old, parts can be tough to get.
There is no one "best" engine mfr. You need to figure out what power you need, what the duty cycle will look like and start from there. There will be several mfr's that make a decent machine that meets the specs. I will only address current vintage engines as that's where my experience is and rather than a ranking, I'll address strengths as I see them.
MAN-I don't think you can beat them for the 800- hp range. The combination of size to performance and dependability. A+
CAT-I think in the US they're a bit overrated. Many long time boaters just think they are the only engine to have. I think they have as many issues as anyone plus they're noisy. I'd choose MAN over them. Now, I would give them a C except their warranty service is excellent (Unless you're waiting on Pantropic) so B.
Cummins-I'd almost give them a top rating just based on how they treated Dhays. Dependable, solid engines. A.
Yanmar-In the smaller diesels, we've found them dependable and trouble free on the whole. B+
MTU-MTU has all the upper horsepower business from hp up plus a part of the smaller engines. Because many of their engines are pushed to the limits and in ranges others don't offer, I do think they get a bit more negative response than deserved. A hp pressed to it's limit is likely to have more issues than a 600 hp. Their warranty service is strong so I'll give them a B.
Deere/Lugger and all the variations. I personally prefer the Lugger versions slightly having used them extensively in Northern Lights generators. There is no more dependable engine, in my opinion. A+
Volvo-Rating just the engine here and trying not to cloud it by IPS. Solid. Really gaining share with European and Asian builders. Their history of parts availability and service in the US hasn't been what it is in Europe but is improving rapidly. However, until it makes a bit more progress, I must do the opposite of what I did on CAT and reduce them from a B to a C+.
Mercury-Why? Now that Searay no longer builds larger boats will they die? With so many excellent engines, theirs are not. D
In smaller engines, there are many others out there who build fine engines but their service networks and general usage just isn't enough for me to evaluate. VW, Kubota, Suzuki are just some that quickly come to mind.
Also, it must be said that one can experience trouble with the best engine and one can have a lifelong wonderful experience with the worst. On the whole, all the engines are good, just some better than others, especially in their prime ranges. All good points. While new to marine spent my life in trucking and machinery. Each manufacture has its gem and also its turd. Old days with mechanical engines reliability was good and simple to keep running. Now with such high pressure injection electronically controlled with muti-fireing one needs a laptop to even get started.My Favorites have been cat , cummins big cam 400s ,international dt466, and the deer engines have all been good. We needed to move a deer dozer last week that has been sitting for 20 years. They dropped two battery's in it and it fired right up old fuel and all. Only problem was fuel running from rusted fuel lines so some duct tape and got it on a trailer. Right now were having a lot of trouble with cummins 15 liters dropping valves on number 6. 30k repair. They have just upgraded the head but its a good example of a manufacture having something wrong and then after some time they figure it out then come up with a fix. I have about a dozen ISX600s with one failure. My advise is to ask on the forum about a specific engine and what series.
Gardner. I might just buy the engine and then go look for a boat.
We went the other way
Our boat was clearly looking at a 6lxb when being converted (brochures and comparison numbers on file) but an NTA855m , same as previous engine was chosen and for that I am glad.
Reasons are
1) 6lxb would have been running hard in ours where as the 855 is at a fast idle
2) Parts and service for Gardner are difficult in most parts of the world, certainly not Cummins easy.
But, if I had no intention of venturing far yep, a Gardner is a pretty thing.
One thing I was 100% adamant about was no electronics and I would have preferred non turbo and.....the 855 would have the grunt in ours imho to be non turbo .
I will only address current vintage engines as that's where my experience is and rather than a ranking, I'll address strengths as I see them.Not really applicable to the discussion here, but Mercury owns the gas inboard and outboard market. Designing and building many of their engines in house from raw aluminum
MAN-I don't think you can beat them for the 800- hp range. The combination of size to performance and dependability. A+
CAT-I think in the US they're a bit overrated. Many long time boaters just think they are the only engine to have. I think they have as many issues as anyone plus they're noisy. I'd choose MAN over them. Now, I would give them a C except their warranty service is excellent (Unless you're waiting on Pantropic) so B.
Cummins-I'd almost give them a top rating just based on how they treated Dhays. Dependable, solid engines. A.
Yanmar-In the smaller diesels, we've found them dependable and trouble free on the whole. B+
MTU-MTU has all the upper horsepower business from hp up plus a part of the smaller engines. Because many of their engines are pushed to the limits and in ranges others don't offer, I do think they get a bit more negative response than deserved. A hp pressed to it's limit is likely to have more issues than a 600 hp. Their warranty service is strong so I'll give them a B.
Deere/Lugger and all the variations. I personally prefer the Lugger versions slightly having used them extensively in Northern Lights generators. There is no more dependable engine, in my opinion. A+
Volvo-Rating just the engine here and trying not to cloud it by IPS. Solid. Really gaining share with European and Asian builders. Their history of parts availability and service in the US hasn't been what it is in Europe but is improving rapidly. However, until it makes a bit more progress, I must do the opposite of what I did on CAT and reduce them from a B to a C+.
Mercury-Why? Now that Searay no longer builds larger boats will they die? With so many excellent engines, theirs are not. D
In smaller engines, there are many others out there who build fine engines but their service networks and general usage just isn't enough for me to evaluate. VW, Kubota, Suzuki are just some that quickly come to mind.
Also, it must be said that one can experience trouble with the best engine and one can have a lifelong wonderful experience with the worst. On the whole, all the engines are good, just some better than others, especially in their prime ranges.
Not really applicable to the discussion here, but Mercury owns the gas inboard and outboard market. Designing and building many of their engines in house from raw aluminum
Well, maybe in the US, but not everywhere. And for anyone that goes back to the 60's, 70's or even 80's they will know Mercury outboards by their other name: "black anchors". Earned, deserved.
But times change. These days you can find some Mercury around, and for race engines they may well be preferred. However, for both commercial and recreational users Yamaha have owned the market since the mid 80's in these parts. Then daylight, and a bunch of others with Mercury not near the front of that pack either. Reputations can take a very long time to rebuild.
As for diesels, 'nothing runs like a Deere'. In the case below, it was still running even after the train dis-assembled it a bit. Not relevant here - boats aren't going to encounter trains in normal use!
Attachments
After 25 years in the business I have limited opinions:Caterpillar = Crap-a-pillar or Clatter Tractor.
Cummins = Come-a-part.
Detroit Diesel = Dirty Diesel. (I don't prefer Screaming Jimmy or Screaming green leaker but that's just me).
MTU = EMpT You Pockets = Reflective of the operating costs...
For some additional flavor on Lugger branded marinization, the Tier III threshold stopped their pursuit of marine propulsion for a few reasons:
1-Komatsu entered an agreement with Cummins to provide their electronic engine/fuel system controls as a "black box solution" that made it expensive for Komatsu to do any aftermarket tuning on their industrial certified engines to allow for higher power marine ratings as had been done in the past. In the end, the cost to continue with the product dramatically outweighed the profit of the business (10%GM/10% of company sales revenue).
2-John Deere decided not to offer NL/Lugger their T-3 Industrial engine to allow Lugger marinization, instead offering the JD marinized engine which again restricted the opportunity for adding value.
Sad end as they were well regarded in the boutique marinization market.
Personally, I like EMD's the best today...but that's only because I know the strengths and weaknesses rather well. -HP but a little heavier than your high speed engines.
Not really applicable to the discussion here, but Mercury owns the gas inboard and outboard market. Designing and building many of their engines in house from raw aluminum
Interesting as that domination has seriously eroded. First, the I/O market has diminished greatly. So their percentage there is of a much smaller market. Then, on top of that, Volvo has acquired a significant percentage of that market. Part of that has been builder revolt although that has calmed some. At one time many builders switched to Volvo as a defense to Sea Ray and Bayliner and all their Mercruisers and what the builders felt were unfair advantages given to their in house brands. Mercruiser did more openly solicit others and now most other brands are about 50/50 Mercruiser/Volvo. Again, a problem for Mercruiser is the decline or Sea Ray and Bayliner stern drives. Another party that influenced the bowrider market significantly was Yamaha jets. Those took a huge chunk from Mercruiser.
As to outboards, Yamaha dominates that market outside the Brunswick brands which are sold only with Mercury. Of course, Yamaha now has it's boat brands too. It will be interesting to see what becomes of the share Evinrude held. Will it go to Yamaha and Mercury or does this open a path for Honda and Suzuki and others? With the rise in outboard market share, I'd see this as a good opportunity for others. Tohatsu also could take advantage. Then at the upper end, Volvo has shut down Seven, but their market share was miniscule to start with.
After 25 years in the business I have limited opinions:
Caterpillar = Crap-a-pillar or Clatter Tractor.
Cummins = Come-a-part.
Detroit Diesel = Dirty Diesel. (I don't prefer Screaming Jimmy or Screaming green leaker but that's just me).
MTU = EMpT You Pockets = Reflective of the operating costs...
For some additional flavor on Lugger branded marinization, the Tier III threshold stopped their pursuit of marine propulsion for a few reasons:
1-Komatsu entered an agreement with Cummins to provide their electronic engine/fuel system controls as a "black box solution" that made it expensive for Komatsu to do any aftermarket tuning on their industrial certified engines to allow for higher power marine ratings as had been done in the past. In the end, the cost to continue with the product dramatically outweighed the profit of the business (10%GM/10% of company sales revenue).
2-John Deere decided not to offer NL/Lugger their T-3 Industrial engine to allow Lugger marinization, instead offering the JD marinized engine which again restricted the opportunity for adding value.
Sad end as they were well regarded in the boutique marinization market.
Personally, I like EMD's the best today...but that's only because I know the strengths and weaknesses rather well. -HP but a little heavier than your high speed engines.
Lugger also used Komatsu engines, not just JDs. They simply got out of the propulsion business when Tier 3 requirements made it too expensive to qualify their engines. I do not believe it was a JD issue (though I'm sure there was some friction there too).
Peter
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