If You're Thinking Yanmar, Think Twice

[sded]

I have actually used very few of the high priced Volvo parts on my 2003t after 4000+ hours (30000 miles or so). The engine has been very durable. I can get a rebuild kit for the water pump at a reasonable price, but was surprised that the whole pump was only $100 or so more and bought that instead. When this one finally trashes I would seriously consider another Volvo.

[S/V Alchemy]

Volvos are indeed good engines, but I would say you've been lucky. I have a small circle of friends who run Volvos, and the way they bitch and moan about the price of spares (which seems to occur at the eight to 10 year mark, but before a complete repower is justified or desirable)...well, it's been a little off-putting, frankly.

I would have bought a Cummins, myself, because it's big, stupid, overbuilt and torquey, what I want for a steel cruiser, but they stopped making them below 75 HP, and that would've meant a bigger shaft and a new prop. My Beta 60 is eight more horses than my W-52 that it replaced, which should do well with the fractionally larger prop and the two alternators.

Yanmars are indeed good engines, but I consider them lightly built in some ways, and I have no desire for the mechanical complexities of turbo/intercooler methods of squeezing more power out of a smaller block. Perfect for 90% of the motoring out there, however. I would recommend them for most coastal applications and certainly in most race boats.

[sabray]

Originally Posted by S/V Alchemy

Volvos are indeed good engines, but I would say you've been lucky. I have a small circle of friends who run Volvos, and the way they bitch and moan about the price of spares (which seems to occur at the eight to 10 year mark, but before a complete repower is justified or desirable)...well, it's been a little off-putting, frankly.

I would have bought a Cummins, myself, because it's big, stupid, overbuilt and torquey, what I want for a steel cruiser, but they stopped making them below 75 HP, and that would've meant a bigger shaft and a new prop. My Beta 60 is eight more horses than my W-52 that it replaced, which should do well with the fractionally larger prop and the two alternators.

Yanmars are indeed good engines, but I consider them lightly built in some ways, and I have no desire for the mechanical complexities of turbo/intercooler methods of squeezing more power out of a smaller block. Perfect for 90% of the motoring out there, however. I would recommend them for most coastal applications and certainly in most race boats.

My cummins is a 4 b 65 hp marinized by tad. Still available. your points are good thumbs up

[sdowney717]

would it possible to simply do this.
Buy the cheap new too short pump.
take off the gear from old pump.
get a keyed shaft collar, think of this as a pipe, slide it on shaft, other end get a stubby shaft attach (perhaps cut from old pump) to gear slide it on. pipe collar joins the 2 shafts.

I think you could do this and it would fit without any pump spacer needed
if it was but welded to the collar. You might need a pump spacer. depending on how it fits out.

the pipe collar that joins the shafts will need to be a tight fit as you want the gear to line up and not wobble. a machine shop can make that or you might be able to buy one, perhaps even make your own and drill it to the right size, etc...

how does the gear attach to the shaft?
perhaps you could weld the stubby shaft from old pump to the collar you make, then all you have to worry about is one keyed side.

[DotDun]

Originally Posted by Daedalusk

In 2004 I installed a 4JH4E Yanmar engine in a boat I built. After 7 years and 1,000 hours, the gear-driven cooling water pump began to leak through the ceramic seal, so I bought a kit and rebuilt it. So far so good, but rebuilding the pump is not something you can do on the fly, so I began to think this would be a good time to stock a spare pump. Think again. This gear driven water pump sells for $723 from Yanmar. This for an engine that costs about $8000.
Turns out the pumps are made in Sweden and I could buy one through my parts dealer for $260. But, Yanmar uses a proprietary version of the pump that is identical to the standard except the shaft is 1/2" longer. This means the gear on the standard pump will not mesh with the gear inside the Yanmar engine. You have to pay Yanmar $463 extra for that longer shaft.
My parts man was apologetic, but said I should be thankful I did not need a piston or connecting rod. It appears Yanmar does not want to keep its engines running, it only wants to sell new ones.

Try Depco - give them a call, real humans to talk to that actual know about pumps!

Depco Pump Company

(bottom of page 124 of the marine catalog)

[Daedalusk]

Originally Posted by sdowney717

would it possible to simply do this.
Buy the cheap new too short pump.
take off the gear from old pump.
get a keyed shaft collar, think of this as a pipe, slide it on shaft, other end get a stubby shaft attach (perhaps cut from old pump) to gear slide it on. pipe collar joins the 2 shafts.

Thanks for the suggestion, but I think you do not understand how critical gear mesh tolerances are. Properly designed and meshed gears result in zero relative movement between the contacting surfaces. If the mesh is not exact, the mating surfaces will move relative to one another during contact (instead of rolling against one another) resulting in rapid gear wear. Following your suggestion, especially in regards to welding, would never produce the mesh tolerances required.

I am a Georgia Tech graduate with a degree in mechanical engineering focused on machine design. I am also a machinist. I could make a new, longer shaft, but this shaft is not a simple item to make. It is splined on one end to fit the pump rotor, has several critical diameters, snap ring spaces, and a keyed, threaded end for the nut holding the gear. The set-up time to produce one (or even several) shafts would be prohibitive.

However, a most practical solution is available. Simply do away with the gear driven pump. Cover the opening into the engine with a suitable gasket and plate. Attach a second pulley to the front of the engine, and fabricate a bracket to hold a standard belt-driven water pump">raw water pump. A second pulley is necessary as attempting to drive the new pump with the existing belt arrangement (longer belt of course) would result in a decrease in belt wrap on the existing pulleys and could cause belt slippage.

The positive in this solution is the ability to utilize economical, off-the-shelf pumps. The negative is engine modification. While warranty voidance is not an issue on my engine, this engine modification would most likely be viewed negatively by a surveyor for a future, potential buyer of the boat.

[Cheechako]

Originally Posted by gonesail

rebuild what you can with yanmars .. raw water pumps are 400 - 500 bucks .. i rebuilt the seal for 20. but yes i have scratched my head many times along with muttering a few profanities at the cost of yanmar parts.

Neither. Bad pistons. Cracked bottom land. One at 800 hours, other at 2200 hours. There's a reason you shouldnt run a diesel at 3600 rpms! Yanmar just doesnt realize it. JMHO. Yanmar mechanics tell you to run them up there too. If I was buying a new Yanmar, and I needed say 40 hp, I would buy the one that made 40 hp at about 2800 rpm. I know some people disagree, but let's face it... there is no real data where someone has taken multiple engines and tested them each way! However, I bet if you took two identical engines with some load, set one to run unattended at 3600 rpm and the other to run at 2600, the 3600 would blowup first. Automotive diesels, some of which have marine cuzins, dont run at max rpm all the time do they? OK... I'm off my rant!

[Daedalusk]

Originally Posted by DotDun

Try Depco - give them a call, real humans to talk to that actual know about pumps!

Depco Pump Company

(bottom of page 124 of the marine catalog)

Thanks for trying, but I wish it were that simple. I have that very pump on my bench ($260). Depco lists the pump as replacement part for Yamnar 4JH engines, but it will not fit 4JH4E serial #E000512. And that' a fact!

[sdowney717]

you could bolt a gear to a gear. Take old gear or new and line it up shaft wise so that the center is perfectly aligned.
Drill around periphery and tap holes. Bolt the gears back to back.
Without seeing them I am just offering ideas.

The other shaft collar idea, if the 2 shafts line up with a tight fit to the collar and it is robust, it will run true. Might have to cut back shaft of new pump to fit, I bet a machinist seeing these parts could make it function.

[Daedalusk]

Originally Posted by Cheechako

Neither. Bad pistons. Cracked bottom land. One at 800 hours, other at 2200 hours. There's a reason you shouldnt run a diesel at 3600 rpms! Yanmar just doesnt realize it. JMHO. Yanmar mechanics tell you to run them up there too. If I was buying a new Yanmar, and I needed say 40 hp, I would buy the one that made 40 hp at about 2800 rpm. I know some people disagree, but let's face it... there is no real data where someone has taken multiple engines and tested them each way! However, I bet if you took two identical engines with some load, set one to run unattended at 3600 rpm and the other to run at 2600, the 3600 would blowup first. Automotive diesels, some of which have marine cuzins, dont run at max rpm all the time do they? OK... I'm off my rant!

My Yanmar engine is the 54hp @3000 rpm version. When I placed the order the engine specs were 54hp @3600, but EPA would not approve the higher-speed-engine emissions, thus the change. I think my problem is the serial number (E-000512). Obviously this is an early model production engine. The difficulty with the raw water pump my be the result of a design change. This I have not been able to establish.

[S/V Alchemy]

Originally Posted by sabray

My cummins is a 4 b 65 hp marinized by tad. Still available. your points are good thumbs up

My understanding when I was shopping around 12-18 months ago is that the smallest naturally aspirated Cummins for marine use was 75 HP rated, as in this line (Cummins MerCruiser Diesel | TDI 2.5L), whereas I do recall that at one point they had a 65 and a 50 (I would've bought the 50, likely).

Now they have a 40 HP diesel...news to me!(Cummins MerCruiser Diesel | TDI 1.9L)

I don't recall this site; a more basic Cummins site is what I accessed when I was shopping. (Products > Auxiliary > 6B)

Too late now, of course, but thank you for the information.

[S/V Alchemy]

Originally Posted by Daedalusk

The positive in this solution is the ability to utilize economical, off-the-shelf pumps. The negative is engine modification. While warranty voidance is not an issue on my engine, this engine modification would most likely be viewed negatively by a surveyor for a future, potential buyer of the boat.

You may find it interesting in the context of your proposed solution to read of my reasons for specifying a double PTO on my new Beta 60.

The primary reason was so I could run two alternators of a smaller output (75-100 amps) instead of one big one (150-200 amps). This was chosen to avoid excessive wear on the drive train due to a single offset pull of a wide serpentine belt; to give me the ability to carry cheaper spares; to reduce the chance of a single point of failure, and to shunt power output selectively (one alt feeds the large house bank, the other to the start bank in concert with variable external regulation).

A secondary reason was that I wanted a cheap and dirty solution to raw water pump failure in the form of a "bolt on solution" as you cite.

The last reason was if I ever wanted to move to an engine-driver compressor for refrigeration or to an engine-powered emergency bilge pump. The second PTO was necessary to these various schemes, and I have the length in the engine bay to pull it off.

Good luck.

[S/V Alchemy]

Originally Posted by Cheechako

Neither. Bad pistons. Cracked bottom land. One at 800 hours, other at 2200 hours. There's a reason you shouldnt run a diesel at 3600 rpms! Yanmar just doesnt realize it. JMHO. Yanmar mechanics tell you to run them up there too. If I was buying a new Yanmar, and I needed say 40 hp, I would buy the one that made 40 hp at about 2800 rpm. I know some people disagree, but let's face it... there is no real data where someone has taken multiple engines and tested them each way! However, I bet if you took two identical engines with some load, set one to run unattended at 3600 rpm and the other to run at 2600, the 3600 would blowup first. Automotive diesels, some of which have marine cuzins, dont run at max rpm all the time do they? OK... I'm off my rant!

When I cite "big, stupid and torquey" as desirable traits of marine diesels, this is what I mean. "Big" means "cruise at 2,100 rpm/5.5 knots for literally days while transiting the Doldrums...don't touch the throttle and change the oil afterwards". By "stupid", I mean naturally aspirated and with few electronics to melt or fail when wet. By "torquey"...see "big".

There are reasons to choose a racehorse, and reasons to choose a plowhorse.

[Rakuflames]

Originally Posted by Cheechako

Neither. Bad pistons. Cracked bottom land. One at 800 hours, other at 2200 hours. There's a reason you shouldnt run a diesel at 3600 rpms! Yanmar just doesnt realize it. JMHO. Yanmar mechanics tell you to run them up there too. If I was buying a new Yanmar, and I needed say 40 hp, I would buy the one that made 40 hp at about 2800 rpm. I know some people disagree, but let's face it... there is no real data where someone has taken multiple engines and tested them each way! However, I bet if you took two identical engines with some load, set one to run unattended at 3600 rpm and the other to run at 2600, the 3600 would blowup first. Automotive diesels, some of which have marine cuzins, dont run at max rpm all the time do they? OK... I'm off my rant!

3600 is redline on my Yanmar ...

[sandy daugherty]

I was surprised to learn (by following your link, Alchemy) that Cummins has taken over support and distribution of the Volkswagen TDI 1.9. Is this a marinized Golf Engine? Its rated at 40 bhp at 2600 rpm and 75 bhp at 3600 rpm. All with the same warranty? That says something about the old "low rpm engines last longer" saw! It seems to me that if an engine is adequately lubricated and cooled to run at a specific rpm, and balanced for that speed, it could last as long as any other, and benefit from higher gyroscopic stability to reduce errant harmonic vibration!