Broken crankshaft

kloudie1 · Mar 15, 2012

Did the front pulley come off, or is it an internal break? A loose pulley can break the tip of the crank off.. A bent crankshaft can result in internal breakage many hours after the bend happens. The crank can be bent as a result of a hydraulic lock . If water worked its way into the cylinder(s) during a time when the engine was being cranked but not running, as when bleeding air out of the fuel system, for example. One or more instances of the previous owner locking it could set it up for a crack after many hours.
Not going to be cheap to fix. good luck

petersea · Mar 15, 2012

reworb said:
I just recently bought a new to me boat. The boat has/had a 2GM20 Yanmar with 190 hours. On the way to my home the engine started making a loud noise and was immediately shut down. The boat was towed to a marina. A day of so before failure the previously correctly installed alternator had worked itself loose. The engine is out of the boat with a broken crankshaft, I'm waiting to find out if there is any other damage,

Anyone have any ideas what could have caused such a failure in an engine that was full of of oil at such low hours.

The GM series of engines has been around quite a while now (since early 80's)and 190 hours is no hours to speak of if it is 190 ORIGINAL hours or 190 on a rebuild ?? what year is the engine ?? Sometimes parts (while unusal for a crankshaft) just go bad............ it happens but I think that somewhere the engine may have been hydolocked (as piror post suggest) and may have had stressed the crank shaft. Might think about a new short block or possible new engine (depending on how long you plan on keeping this boat). If engine has had a rebuild and either a "rebuilt" or reground crankshaft that could be a problem. As far as the alternator coming loose I don't think it would cause the crankshaft to fail my guess is that a mounting bolt was not tight and it worked loose. After the engine is apart might give better clue as to what happen.

navigator97 · Mar 15, 2012

If the 190 Hours is from an Engine Hour Meter, it may well be that the Engine Hour Meter had failed and was replaced 190 hours ago. Since the 2GM20 has not been made for a while, 190 hours on it seem extremely low. My Engine Hour Meter failed at 1297 Hours and I replaced it. The new one shows only 211 Hours, for a total of 1508. I typed out a label and glued it just under the Engine Hour Meter stating that Total Engine Hours is 1297 plus Eng. Hr. Meter reading, so that I always know, and next owner will know. My 2GM20F is in a 1990 H-33.5 boat. Just a caution about the actual hours on your engine.

juslookin · Mar 15, 2012

2gm20

These engines are about as reliable as anything made. While anything is of course possible, I would be very surprised if some other cause for the failure is not found. I don't believe that a crankshaft would just break. Something as simple as an oil passage stoppage, or a loose balancer pulley will be found.

Steve Dion · Mar 15, 2012

I am sure we have not heard it all on this website, but this is the first time I had ever heard of anything like this.

I would contact Yanmar. I would think that they would like to look into this type of a failure.

Rick D · Mar 15, 2012

Had A Rod Bolt Crystalize

I had a 3GM that broke a rod bolt ay about 300 hours. It did require a rebuild, but I would have been smarter ordering new since in the rebuild, there was a hairline crack at the journal and then they found a crack in the block, so I had to replace the block & crank anyway. The engine surveyor said his inspection revealed an over torqued bolt which gave way at the head.

FastOlson · Mar 18, 2012

No cheap solutions....

reworb said:
Contacted Yanmar and they gave me the run around. Very poor customer service organization frankly one of the worst I've dealt with.

I do not know of anyone in the last 20 years around our moorage that has chosen to do a major rebuild with a problem similar to yours. Even with charging zero for your own labor hours, the parts are Very expensive. Also, the further your delve into that used engine you may find other bits that will not pass inspection. As others note, that hour meter may or may not tell the whole truth.

In the NW, the leader in replacement engines, by far and away, is Betamarine. Excellent Kubota blocks, and well-engineered marinization. Excellent warranty support on the few times it was needed, in my observation.
If our good-running Universal ever breaks any major parts, that's the replacement route we would take.

On the subject of the broken crank, I do have one small data point to toss in --
several decades ago a friend of mine had a Volvo diesel break a crank when just out for a day sail and returning to dock.... no warning. Upon inspection there was a tiny internal casting flaw. Outside of ultrasonic inspection ($$) of every new cast and machined part, such flaws are invisible.
Matter of fact, I had just finished a multi-hundred mile offshore delivery on that same boat, and the little Volvo ran like a top.

While Volvo diesels have a great reputation for longitivity, sometimes "stuff happens" and it's just awful when it's you or me....

Good luck on coming up with a fix.
LB

quietriot · Mar 21, 2012

The crank shaft breaking could be a result of a few things. The metallergy of the crank could have been at fault when delivered by the supplier. The harmonic balancer could have been bad for a long while. One of the main bearings coud have seized or you could have gotten water in one of the cylinders but then you should have a bent connecting rod or some other signs.

kloudie1 · Mar 22, 2012

reworb, sometimes if you go through a local Yanmar distributor, you may have better luck.. especially if you have a letter from a metallurgist with a couple of pictures of the crank and the crack face .. would be great if you could get to the engineering guys but in the US, the tech service rep for your area is the guy.. They probably won't spring for the labor, but ya might be able to negotiate a new crank or a significant discount on the new parts.. I wouldn't threaten with legal action unless completely stonewalled.. Ya may want to talk to the insurance folks as well since if this was a defect, as shown by the metallurgy, ya may have a claim and they'd go to Yanmar with it.. ?? I dunno.. Good Luck

petersea · Mar 24, 2012

kloudie1 said:
reworb, sometimes if you go through a local Yanmar distributor, you may have better luck.. especially if you have a letter from a metallurgist with a couple of pictures of the crank and the crack face .. would be great if you could get to the engineering guys but in the US, the tech service rep for your area is the guy.. They probably won't spring for the labor, but ya might be able to negotiate a new crank or a significant discount on the new parts.. I wouldn't threaten with legal action unless completely stonewalled.. Ya may want to talk to the insurance folks as well since if this was a defect, as shown by the metallurgy, ya may have a claim and they'd go to Yanmar with it.. ?? I dunno.. Good Luck

Maybe it is just me but I am a little surspized that alot of you think Yanmar should stand behind this broken crank even suggesting legal action if it can't be resolved thru Yanmar customer service. First this engine is a 2004 so it has 8 to 9 years of use. It is well past any warrenty. Other then it has been said there is 190 hours on the engine no one knows for sure as the prior owner could have been less then honest about running time or as suggested replaced the hour meter, or even never had one for several years then added one. The current owner has no first hand knowlege of any history on the engine other then what he was told. . No other manufacture would cover this under warrenty as the warrenty expired years ago. The current owner is not even the original purchaser. So my question is how long "should" a manufacture be expected to cover its product ?? even out of warrenty ??

reworb, Just curious did you every discovery why the alternator worked loose ??? was it a original equipment alternator or an aftermarket upgrade ?? Also not sure why you think it would be so much more expensive to repower with another brand have you checked in to the Betamarine engines ? (this assumes your are repowering with another yanmar rather then a rebuild)

kloudie1 · Mar 24, 2012

If this break is truly a defective casting/forging.. which can be determined by a metallurgical examination/evaluation.. then Yanmar is responsible outside the warranty..It is not a normal thing to break a crank.. and that can be done by abuse as noted prior.. but I am talking about a verified defect in a supplied part that was defective when it was supplied..
Yanmar can elect to ignore him or they can acknowledge that they provided a defective part (if indeed they did) and help him .. he can push the issue if he and the metallurgist feel strongly and can document the defect.

petersea · Mar 25, 2012

reworb said:
The engine is being rebuilt by a Yanamr dealer he could not find anything wrong other than the broken crankshaft; Yanmar does not have any of the replacement engines till June. I don't want to wait that long as the Boat is in a marina 500 miles from my home and I'm paying a daily rate, in addition it is about 2 to 3 thousand less for the major rebuild than the new engine.

I believe a company with a good reputation should stand behind their product for the designed life of the product assuming there is no misuse or abuse. A crankshaft is designed to last for the useful life of the engine.

Just imagine as a manufacturer you have a suspect batch of casting but you surmise that the defect will not manifest until after several 100s of hours of use, knowing that many sailors do not like to motor, you determine that a lot if not most of the failures will come after the time limit of the warranty has expired therefor it would be more profitable for you to use the defective parts than discard them, as once the warranty has expired you can stonewall the claimants. A classic Ford Pinto gas tank case without the personal injury. I'm not even addressing the applicability of the Warranty of Merchantability to a case such as this

A responsible manufacturer stands behind their product for it designed useful life no matter what their legal obligation. I'm not saying they should provide an entire new product but some concession should be made. In addition I would think they (Yanmar) would be interested in looking at the part to find out the cause of failure and use what they learn to improve their future products.

The alternator is the original and no one is sure why it came loose.

OK maybe I'm in a minority here but would you ask ford or chevy or any other engine maker to cover a 8 year old product ? especially since the the original purchaser is not in the picture anymore. If your home refrigerator died (that you purchased second hand) from compressor failure after 8 years and you thought the useful life was 15 years what do you do ?? How is usefull life determined ? ?
I have a fire extinguisher on my boat that is two years old and has lost its charge, it was warrantied for one but use life should be more then one years so is it a manufactures responsibility to replace? does the "Warranty of Merchantability" apply here ??
Broken crank shafts are not a yanmar "regular" occurance and we still don't know if it was defective or not. I would be very interested in the report from a metals test. There are a lot of reason why this crank could have gone bad.

I guess what bothers me is that some are so quick to assume it was defective (and we still don't know if it is) and that if yanmar won't help that maybe legal action might be an option or go to the insurance company and make a claim. Really ??

As quoted from FastOlson " sometimes "stuff happens" and it's just awful when it's you or me...."

Reworb, I don't want to appear uncaring or cold about you engine problem but I just don't see where you have any recourse against yanmar quite frankly even if it was proven to be a defective part it did last eigth years (well past warrenty) and you were not even the original purchaser. As I recall the Ford Pinto gas tank issue it was a design problem not a defective manufactured part, I don't think it is a like comparison. Have you talked to the prior owner and told him of the problem and what if anything did he say ???

Bob S · Mar 25, 2012

Is the crankshaft pulley the original? I am modifying mine and read this that made me rethink how I would do it.

http://en.wikipedia.org/wiki/Harmonic_balancer

kloudie1 · Mar 25, 2012

Petersea.. consider production numbers.. If GM or Ford had a defective crank, it would have showed up in quite a few.. there would be maybe "Hidden Warranty" stuff where it would be made good for the owner, even though out of warranty and not original owner.. Many fewer Yanmar cranks for that particular engine .. I figure that a reputable company with good customer relations would WANT to stand behind the product .. Again.. I am talking about documented analysis by experts on the part to show that it was indeed a defect and not abuse. Example: Honda Accord.. first year of production, (1976?) mine failed a head gasket at about 25000 miles .way out of warranty. The failure cut the head between two cylinders and the water jacket. I did all the work myself, including welding up the aluminum head and refacing it.. Wrote a letter to their customer folks with pictures and receipts.. I was reimbursed fully for the work.. About a year later, there was a factory recall to fix the problem .. That is the kind of customer service I expect from reputable companies.. I doubt Honda would do that same thing today, however..