Yanmar 3YM20 vs Beta 20

[stormalong]

Originally Posted by nmccubbin

We have over 1000 hours on our Beta 60
No issues
It starts First bang, even when in the Arctic. We have used the heaters once only, to test them
Mechanically quiet and no black smoke staining the hull
The SSCA database shows much better reliability than Yanmars, but over a smaller user base

The above comments make sense and show diversity
There is not absolute guarantee but on balance I would go for Beta

Definitely avoid Volvo

nmccubbin: It is interesting that you do not preheat. When I was at the Beta factory inspecting my new engine they told me it would be best to always preheat before a cold start. I do 10 seconds normally but 20 seconds on very cold days. The engine always starts in less than a second and I credit fast starts with long starter motor life. My old Perkins 4-108 also started easily but never that fast. I hear about so many sailors carrying spare starters and think it is totally unnecessary. The Perkins never needed a new starter in 17 years and the same with the Beta - now 16 years old (knock wood).

Originally Posted by StuartWeibel

I replaced a Yanmar 1GM10 with a Beta 14. I did the installation on my own, a first engine installation. The experience was not without wrinkles, but the end result was satisfactory and having done it myself means that I have intimate knowledge of every aspect of the installation. This is good.

I am happy with the result: the engine is far smoother than the 1GM10, and I appreciate the extra power the engine has. Details of my experience are recorded in an extended blogpost at Re-powering s/v Ripple

Reading the responses to your post, the ones that struck me as most compelling are the few that actually reflect direct experience of both engines (as you requested in your query), and these posts lean strongly in favor of the Yanmar. While I am very happy with my new engine, I think a strong argument can be made for the Yanmar.

Best of luck

Stu, Your install writeup reminded me of my Beta 50 install. I am in the Seattle area now but replaced my Perkins 4-108 with a Beta 50 in England.

Working directly with the factory and the Beta Marine managing director made things go smoothly. The only external labor on my install was the craning out of the old and craning in of the new. One on the big advantages of Beta Marine is that they will do custom engine brackets. Maybe not cheap but they save so much labor that they are well worth it. I had to relocate the engine mount holes but that was easy compared to what many engine swappers go through with engine bed modifications. The tricky part was measuring properly which took me many tries with much concern about getting it right.

Part of my decision to go with Beta was the compatibility with the old Perkins. The fuel system and exhaust were a near perfect match. Now 16 years and about 4500 engine hours later I am still happy with the choice.

[Visarend]

Originally Posted by Cheechako

Compare RPM vs HP curves also. Yanmars are famous for rating at high rpm, thus making a lower HP engine appear to be higher HP. (Well... that's one way of saying it) I don't know about the Beta. I hated running my 3600 rpm Yanmars at 3400 rpm.

I had a look at torque curves, that I always find most interesting when dealing with non planing hulls. I see that Beta has a peak of 45 Nm @2600 rpm, while Yanmar has a flat maximum of 50 Nm from 2000 to 2400 rpm. According to those figures, it is probably interesting the possibility of choosing Yanmar and designing the drive train to obtain maximum (hull) speed at no more than 2400-2500 rpm, thus keeping a very good thrust at lower rpms. And I say that, notwithstanding the fact that I still keep in general a penchant towards Beta.

[drcat]

What gets to me is the original question and this discussion. It's like should I buy a Rolls Royce or a Porsche? What about a Ford or GM or Toyota?
If a Beta is just a Kubota diesel with an added water pump">raw water pump and a water to water heat exchanger/ exhaust manifold, why spend the many added $s for the Beta when you can get a Kubota plus aftermaket raw water pump and a water to water heat exchanger/ exhaust manifold. Or go with a 12v variable speed magnetic drive raw water pump and avoid the issues we so often hear about of broken impellors and leaking pump seals.
There are also simple marine diesels out of China that are 20-25% of the cost of a Yanmar or Beta and probably millions of boats running them in Asia. Look at Alibaba.
If you got the bucks go spend it on Yanmar or Beta. If you are on a tighter budget consider alternatives.

[Mauruuru]

I have a Yannar 3YM 30 that has been a great engine. I am going to replaceit when I convert to edrive but not because I ever had anyproblems with it just because I m convering to edrive. BTW my last boat was a 1970 Oday 30 with a single cylinder yanmar with lots of hours. Never let me down though there were some speeds where it would shake the bejesus out of the boat!

[Old fella]

Originally Posted by FlyingScot

Both the Yanmar 3YM20 and the Beta 20 are indirect injection.
http://www.betamarineengines.com/dow...C-SOM-0314.pdf
https://www.yanmarmarine.com/theme/y...heet_3YM20.pdf

I would not want common rail on a sailboat. The increased efficiency doesn't offset the complexity and increased difficulty of service.

I agree, it is common place for ford rangers and holden Colorados and others that there injectors **** themselves at only 70,000 k, and at a grand a peace, you can have that, plus in my boat I like things I can fix myself.

[limte]

I'm a bit confused by the terminology used in this thread. Please correct me if I am wrong, but it is my understanding that direct vs. indirect fuel injection does not imply the same distinction as mechanical vs. electronic injection, nor the distinction between common rail and unit injectors. Also, I think that all available marine diesel engines with common rail injection are also direct injection with electronic control.


For example: my Beta 38 engine has indirect mechanical injection with unit injectors (not direct common rail with electronic injection).


In regard to the Beta engine, the support from Beta for owner installation was outstanding, and they were willing to make custom mounts for the engine, which saved me the great deal of work which would have been needed to remake the engine beds.



Regards,
Bob S

[Wotname]

Originally Posted by limte

I'm a bit confused by the terminology used in this thread. Please correct me if I am wrong, but it is my understanding that direct vs. indirect fuel injection does not imply the same distinction as mechanical vs. electronic injection, nor the distinction between common rail and unit injectors. Also, I think that all available marine diesel engines with common rail injection are also direct injection with electronic control.


For example: my Beta 38 engine has indirect mechanical injection with unit injectors (not direct common rail with electronic injection).


In regard to the Beta engine, the support from Beta for owner installation was outstanding, and they were willing to make custom mounts for the engine, which saved me the great deal of work which would have been needed to remake the engine beds.



Regards,
Bob S

Me too Bob

As I understand it, mechanical injection is simply what it says. A mechanically operated high pressure injection pump that injects diesel into the cylinder via the injector. A single shot of diesel is injected every compression stroke. It may go directly into the cylinder / head space or it may go into a pre combustion chamber located immediately at the end of the injector nozzle where it begins to ignite before the flame front moves further into cylinder / head space.

Common rail and EFI are (to my mind) synonymous terms and describe an injection system that operates at a much higher pressure and is electronically controlled. The fuel can be injected many times in the one compression stroke and in varying amounts at varying times.

A64pilot has described the process very well upthread.

I will leave it to others to explain direct and indirect injection differences ('cause I'm not totally sure)

[Snowgoose35]

Well this has gone very off topic and as usual not really tried to answer the original question confined to those who had direct experience of both the Beta 20 and the 3YM20 - but I appreciate all the replies nonetheless

Just to be clear neither are common rail injection, neither have a black box (ECU whatever) and neither are hard to get to service parts - part of the reason I specifically asked about direct experience was to avoid comments that were irrelevant like that Yanmar on a 40 year old design had a silly place for the water pump (I've dealt with that one for 7 years) - the new Yanmar's have moved the water pump, moved the fuel filter and whilst the oil filter is still a little inaccessible if you need to get a full sized wrench on it, it is doable .

In the end I have ordered the Yanmar's - it was a close run thing as both are considered very reliable and the specs are close but the Yanmars make a bit more torque and are a direct fit in place of my existing ones. They also came out 15% cheaper than the Betas (despite getting a trade deal on the Betas) which frankly amazed me but that will pay for an awful lot of overpriced Yanmar oil filters if needs be The other useful advantage of the Yanmars is that they come as standard with 125a alternators and a digital control panel whilst the Betas have 40a and a very old fashioned looking panel

So once again thanks to all for the information both right and wrong (no offence but quite worryingly wrong from a claimed Yanmar dealer!!) but the decision is made now and the payment sent - just a 6 week wait for them to arrive and I can usher in an age of quiet vibration free engines which in my whole sailing career I have never known (having only had 3GMs in all my boats) .

[Sputnik]

Good choice to go with Yanmar.
I have two friends who have fitted Beta 20......both have had massive problems with vibration issues after even though they have been fitted correctly and iaw the destructions.

Good luck, fair winds.

Neil

[crankysailor]

I have a Yanmar btw and I just googled for a replacement panel and saw some list prices of $3000... someone is having a laugh and I guess eBay might yield options specially if one is willing to get a used one but the point is it seems to me that parts prices are rather high.. YMMV and if you have infinite bucks sure, you probably can't go wrong with the Yanmar.

[longjonsilver]

Originally Posted by drcat

If a Beta is just a Kubota diesel with an added raw water pump and a water to water heat exchanger/ exhaust manifold, why spend the many added $s for the Beta when you can get a Kubota plus aftermaket raw water pump and a water to water heat exchanger/ exhaust manifold.

i won't just tell you about it, i'll give you linx.

https://www.pumpvendor.com/sherwood_...ing_pumps.html

https://www.brazetek.com/shell-tube-heat-exchangers

jon

[Dockhead]

Originally Posted by Wotname

. . . I will leave it to others to explain direct and indirect injection differences ('cause I'm not totally sure)

It's simple -- indirect injection uses a pre-chamber, and direct injection does not.



My Yanmar 3TN74 driving my generator is indirect. My Yanmar 4JH3 HTE main engine is direct. Both use Zyxel mechanical fuel injection.


Direct injection engines are more thermodynamically efficient (less thermal losses), but noisier, and easier to start. They are more demanding of injection pumps and injectors.



The thing I like best about direct injected diesels is they are much easier to start. My 4JH3 HTE starts if you just look crossways at the starting key -- does not require even a full revolution even in subzero weather. I have never used the air heater and I'm not sure it even works.


Previous indirect injected diesels I've owned have been more challenging to start, and required the use of glow plugs.



See:


https://learnmech.com/what-is-direct...ect-injection/

[a64pilot]

IDI motors gained widespread acceptance in I guess the 80’s for automobiles, they can be lower compression and therefore lighter weight motors and I believe they can be less harsh that a direct injected motor, and also they are easier to make pass emissions, or used to be anyway.
They can also turn much higher RPM, my old VW Golf would turn 5,000 RPM I think.

Common rail really unfortunately isn’t any more efficient, you would think it would be, and maybe if it’s tuned to ignore emissions it could be I don’t know.
Passing emissions on a Diesel is tough, real tough, and expensive, that’s why so many automakers (it wasn’t just VW, they ALL cheat) ,if you cheat you can save a lot of money.

Anyway very precise control of fuel is required to pass strict emissions, and that means common rail, it or maybe a similar technology is going to happen if emissions come anything close to US automotive standards, only way out will be buy an old boat.
https://carbiketech.com/indirect-injection/

A major problem with making a Diesel pass emissions isn’t the type of ignition, but the type of fuel.
I predict we will soon see hybrid gas/Diesel engines, that is gasoline engines that are compression ignited, this will of course require high pressure direct injection (common rail if you will)

You see one of the major differences between gas fuel injection and Diesel is that a gas motor’s injector can spray continuously on the back side of the intake valve, then when the valve opens the fuel air mixture is drawn into the motor, and it doesn’t ignite until a spark plug fires because the compression is so low, higher compression gives you more power but requires higher Octane fuel or the whole fuel charge instantly burns, called detonation, and detonation is not valve rattle, detonation destroys an engine pretty quickly, usually Knocks a hole in the piston. The Holy Grail for a gas motor would be high compression with low octane fuel, and I think that’s coming.

The heat of compression is so high on a Diesel that combustion begins the instant fuel becomes present when the engine is up to temp and running under a load, for this reason only a tiny fraction of a second is available to get all the fuel in and flow stopped, this more than anything else limits the RPM of a Diesel, Jack up the fuel pressure to say 50,000 PSI and that time shortens a whole lot, and now you can have a hot rod Diesel with common rail.

So, take a gas motor, jack up the compression to gain efficiency etc. and direct inject the fuel so that the moment fuel becomes present the burn begins.
You have a hybrid gas/Diesel cause I’d suspect it will still have spark plugs for cold weather operation and starting etc.

[Compass790]

Originally Posted by Snowgoose35

Well this has gone very off topic and as usual not really tried to answer the original question confined to those who had direct experience of both the Beta 20 and the 3YM20 - but I appreciate all the replies nonetheless

Just to be clear neither are common rail injection, neither have a black box (ECU whatever) and neither are hard to get to service parts - part of the reason I specifically asked about direct experience was to avoid comments that were irrelevant like that Yanmar on a 40 year old design had a silly place for the water pump (I've dealt with that one for 7 years) - the new Yanmar's have moved the water pump, moved the fuel filter and whilst the oil filter is still a little inaccessible if you need to get a full sized wrench on it, it is doable .

In the end I have ordered the Yanmar's - it was a close run thing as both are considered very reliable and the specs are close but the Yanmars make a bit more torque and are a direct fit in place of my existing ones. They also came out 15% cheaper than the Betas (despite getting a trade deal on the Betas) which frankly amazed me but that will pay for an awful lot of overpriced Yanmar oil filters if needs be The other useful advantage of the Yanmars is that they come as standard with 125a alternators and a digital control panel whilst the Betas have 40a and a very old fashioned looking panel

So once again thanks to all for the information both right and wrong (no offence but quite worryingly wrong from a claimed Yanmar dealer!!) but the decision is made now and the payment sent - just a 6 week wait for them to arrive and I can usher in an age of quiet vibration free engines which in my whole sailing career I have never known (having only had 3GMs in all my boats) .

FYI you have no need to use the genuine yanmar oil filters AFTER the warranty has expired, you can just find a baldwin or other crossover filter.
Good bonus getting 125A alternators. Hope you update the post to tell us your impressions after you install the new engines tho it will make me grind my teeth with jealousy if you say it's quiet & vibration free as we have a Yanmar single

[a64pilot]

You don’t have to use “genuine” Yanmar filters or oil from day 1, but you may have to prove you followed service intervals and used an oil of the correct grade.