A certified Cummins mechanic should look at it ASAP.
Friend just had a problem with a Cummins in his 05 420 DA. Not sure what model Cummins motor it is but the problem was an exhaust valve seat on number 4 cylinder dropped.
Local Cummins service company knew exactly what the problem likely was as soon as he called them for an appointment to have a mechanic look at it.
Apparently it's a design issue with the heads on those motors and Cummins has redesigned them a couple of times since the engines were first manufactured.
It was an expensive fix that included a new head, piston, and cylinder sleeve. He got lucky in that the debris didn't work it's way in to the turbo, and he was able to get it all done in about a week in the middle of the season.
They found a crack in the number 6 cylinder exhaust seat too once they got it apart.
I think he is negotiating with Cummins to offset some of the cost.

 

A certified Cummins mechanic should look at it ASAP.
Friend just had a problem with a Cummins in his 05 420 DA. Not sure what model Cummins motor it is but the problem was an exhaust valve seat on number 4 cylinder dropped.
Local Cummins service company knew exactly what the problem likely was as soon as he called them for an appointment to have a mechanic look at it.
Apparently it's a design issue with the heads on those motors and Cummins has redesigned them a couple of times since the engines were first manufactured.
It was an expensive fix that included a new head, piston, and cylinder sleeve. He got lucky in that the debris didn't work it's way in to the turbo, and he was able to get it all done in about a week in the middle of the season.
They found a crack in the number 6 cylinder exhaust seat too once they got it apart.
I think he is negotiating with Cummins to offset some of the cost.

 

Dock mate had exactly the same scenario with a 1000 hr 6CTA in his Carver 450 Voyager. Dropped a valve seat, broke a rocker and injector tip, melted piston...Total rebuild for $38,500...He owned the boat 4 hours when it happened...

 

Both of those scenarios sound bad enough. I just talked to the owner and they are getting opinions from people who heard the engine running that it may just be an injector. Apparently that makes a horrendous noise when it fails.
Hopefully the mechanic can get to them tomorrow and make a definitive diagnosis and possibly repair it.

 

I want a twin engine diesel boat really bad for my next boating chapter. But these kind of stories and repair bills scare the hell out of me. On one hand diesel reliability is legendary and part of the end goal......on the other hand is the possibility of someone handing me a $38k repair bill. What's a guy to do?

I could maybe pull off $150k for a used diesel boat, but am I kidding myself?.... because I don't think I could weather a huge bill like that. I would have to sit at the dock quite awhile to resupply my wallet for repairs before the boat would move again.

 

As a rookie diesel owner and recent diesel boat shopper I completely understand your apprehension.
There are no guarantees in life, but with the right amount of research about the idiosyncrasies of the particular diesel motors you're looking at, and a proper pre purchase inspection and survey of them you increase the odds of getting some good motors in a great boat.
I'm still kind of afraid of diesels because of my absolute lack of experience with them, but I have to say that I absolutely love having them in my boat.
My friend had some grief with the Cummins in his boat, but once repaired, the boat performs amazingly.
I'm super jealous of the room he has in the bilge of his 05 420 DA. The mechanic did the job standing up like a gentleman, and was able to stand and walk around the motors to check things and record numbers throughout the test ride.
He and my friend were smart enough to plug their ears, I wasn't. Those things are loud as heck at WOT, and cruising speed ain't much better.

 

No. You really don't know about the maintenance/service history of any of the boats with war stories. I'll bet you that in each case the present owner really has no idea if all of the required maintenance was done or not.

I understand that Cummins was aware of the valve seat problem, but their usual pattern is to let the engine owner discover the problem on his own then negotiate a discount on the repair.

A bad injector can cause a noticeable knock, but it is in the top end of the engine and the valve and piston do their thing normally. A dropped valve sounds like what it is….a terminal event for the engine. The owner of this boat should absolutely not start the engine to let any well meaning by-standers see if they think the knock sounds familiar. The risk of trying to run an engine with a potentially more serious problem is large since broken parts can move in the intake and exhaust manifold to nearby cylinders and damage them or into the exhaust system and ruin a $2000 turbo.

 

No. You really don't know about the maintenance/service history of any of the boats with war stories. I'll bet you that in each case the present owner really has no idea if all of the required maintenance was done or not.

I understand that Cummins was aware of the valve seat problem, but their usual pattern is to let the engine owner discover the problem on his own then negotiate a discount on the repair.

A bad injector can cause a noticeable knock, but it is in the top end of the engine and the valve and piston do their thing normally. A dropped valve sounds like what it is….a terminal event for the engine. The owner of this boat should absolutely not start the engine to let any well meaning by-standers see if they think the knock sounds familiar. The risk of trying to run an engine with a potentially more serious problem is large since broken parts can move in the intake and exhaust manifold to nearby cylinders and damage them or into the exhaust system and ruin a $2000 turbo.

Great advise on not running it again for sure. I'll let you all know what the verdict is tomorrow. It's a bummer no matter what it is. He just bought the boat and went thru hell getting it delivered and re assembled from Seattle. Last thing he needed is a major engine problem but he's been boating for years and knows the drill.

 

I wouldn't run it again. My friend got real lucky in that the damage was confined to the top of #4 piston and that cylinder wall. They were pretty beat up from the pieces of the valve seat banging around in there.
New head, piston, and cylinder sleeve and it was good to go. He had the injectors done while it was all apart.
The turbo was fine and no debris circulated or wound up in the pan.
I went along for the test ride after the repair was complete and the motor ran beautifully.
Quickest way to see if this common Cummins problem is the culprit is to pull the valve cover and check the height of the valves.
Mechanic mentioned that anyone looking at a boat with these motors (older than 2007?) should ask for proof that the heads were changed to the latest version, or knock 15k off of the price of a good running boat with original heads and have the heads changed right away.

 

Thanks JVM225!.......I think I hijacked this thread......going to un-insert myself now.

 

No worries Quint 4 its all about perspective! I didn't understand the fascination with diesels until I owned them. I shudder to think what the exposure might be,that's part of the fun of it. I love to learn all I can from others experience and do what I can to avoid problems by doing constant preventive maintenance. Seems like a lot of boogie for the relative few hours of yearly operation but it seems time soaking in seawater is the problem more than wear and tear hours.
Love to read the discourse.

 

Have they taken a look yet?

 

Make sure you get your insurance company involved. A lot of yacht policies include mechanical coverage.

 

Cummins tech is coming out tomorrow to have a look. Hopefully it's an injector and he will be on his way. I'll post an update.

 

CD, Good luck with the Tech. I hope all is well! JC

 

Here is the update on the knock. Looks like a dropped valve seat. Cummins tech showed up and removed the valve cover and rotated the crank until it locked up on the stuck open valve on number four cylinder. Looks like an engine pull and either overhaul or repair at the least. On these Searays with the Cummins the engine room is not tall enough to raise the engine to drop the pan for piston removal. Big job for sure. We are going to single engine it in t he morning about twenty miles to a yard that will pull the engine on Tuesday and get this party started.
Harold really wishes he had just kept his flawless 98 400 Sedan Bridge. He really just moved up to enjoy ownership of an updated boat with those reliable deisels. Real Bummer!!!
Any info from others that had Valve Seat failures and got Cummins to help out with repairs would be appreciated. The boat is 13 years old with 700 plus hours so dont expect much from Cummins unless it was considered a latent defect issue.
Ill update here with anything that is of interest as the repair progresses. As an owner of the same boat I am intensely interested in understanding these engines and root causes for any difficulties that might be avoided by routine service or inspection.
Have a great weekend on the water this weekend

 

Carpe Diem - I am in SF Bay Area also with the same dropped exhaust-valve seat on a Sea Ray. Were you able to find any information from others about how to deal with Cummins. So far they pretend ignorance. I would like to hold them to account. Thank you.

 

I have heard far too many problems with valves dropping. What engine and horsepower is this? Really tough news to hear

 

My suggestion is to try to find a back door to a Cummins TSB or dealer notice by using Google, other forums, search engines, etc. You Cummins guys are in a lot better position with Cummins if you can show that they know about the problem and have done nothing.

 

Engine is Cummins 8.3 480CE. By most accounts the engines are solid and reliable power plants for these boats. They are man made machines though and anomolies do occur. Just a tough break. This just reinforces the reality that you should not own any vessle of this caliber unless you are financially and mentally prepared to make serious investments in repairs and maintenance. The term "break out another Thousand' won't quite cover this though!

 

I have a sympathy gut-ache for you - that really sucks.

I posted the opinion about financially preparedness as they relate to marine diesels in another thread about my neighbor who just doesn't strike me as wealthy enough to absorb huge repair bills. Update: maybe I'm not as smart as I think I am. His engine has been repaired to the tune of $38,000, but insurance covered it because his impeller was intact! Apparently the logic was that the intact impeller suggested reasonable maintenance, so the overheat was considered a covered incident. It wouldn't have occurred to me to call my insurance company, but again, maybe I'm not so smart.

 

My neighbor's 05 44DB had the same issue with only 200 freshwater hours. Warranty was just out on years. In the end either Cummins or Sea Ray split the bill with him. I still think he was out $15K

 

#4 cylinder. Same exact thing that happened to my buddy two weeks ago. Mechanic called either #6 or #4 before he even pulled the valve cover. Sure enough it was #4 that dropped, and once the head was off he found that #6 was cracked and not far from the same fate as #4 suffered.
He got lucky that it was all contained in the cylinder and they had enough room in the 420 Sundancer to get the pan out of the way to get to everything. No damage to his turbo either.
Hopefully you're friend has the same luck.
The good news is that once the job was done the motor runs flawlessly.
If he gets a certified Cummins guy to do the job they might be able to point him in the right direction for info about getting some money out of Cummins.
My friend is hoping they at least make good for the price of the head.

 

#4 cylinder. Same exact thing that happened to my buddy two weeks ago. Mechanic called either #6 or #4 before he even pulled the valve cover. Sure enough it was #4 that dropped, and once the head was off he found that #6 was cracked and not far from the same fate as #4 suffered.
He got lucky that it was all contained in the cylinder and they had enough room in the 420 Sundancer to get the pan out of the way to get to everything. No damage to his turbo either.
Hopefully you're friend has the same luck.
The good news is that once the job was done the motor runs flawlessly.
If he gets a certified Cummins guy to do the job they might be able to point him in the right direction for info about getting some money out of Cummins.
My friend is hoping they at least make good for the price of the head.

Did your friend have them pop the head off the other motor to check for cracking there as well?

 

Thanks! I'll pass that along.
Rusty

 

Not yet at least. Unfortunately there is not enough room to do the repair in the engine room. The engine will have to come out. For now he just wants to get this one fixed. I wonder if the cracks could be detected by bore scoping the engine thru the injector bores? Did your Freire have any pictures of the cracks?

 

Sorry my question was directed to JVM225. I can certainly see why Carpe's friend wouldn't want to pull an engine just to check.

 

Actually it's my apology that's in order, need to pay closer attention to the thread quotes. No harm done I suppose, the price is right for this form of entertainment

 

From what I have read here and boatdiesel.com the main cause for 480CEs dropping valves is over-propping causing EGTs that are too high. If this boat is still running the props fitted by Sea Ray it will almost certainly need 1-2" of pitch taken out to bring the loads back to Cummins specs. It might be worth your friend considering a new head for the other engine while everything is apart in case it is close to the same fate.

https://www.sbmar.com/articles/propping-cummins-6cta-8-3-480ce-vs-430450-diamond-engine/

 

PH321, wow, that's good intel. He does have the original props and his boat cruises faster than mine at lower RPM. I've got 2inch smaller diameter props with the same 27 inch pitch. I'm definitely under loading my engines while burning more fuel trying to keep up. I've been struggling with whether or not to replace mine with the larger props. I'm thinking now I'll spend a little more in fuel and save my Powerplants!
Thanks for the heads up and the link.
Rusty

 

Its stories like this that remind me to back down a bit and be happy I lost some speed when I reduced pitch this winter.

 

Hi Rusty,

I did notice your other thread about the props. My understanding with modern diesels is they use x amount of diesel to produce a given amount of horsepower whether that horsepower is produced at 2200rpm or 2400rpm. In other words you should use the same amount of diesel to cruise at 20knots regardless of what props are on. Just that your engines will be much happier under-propped than propped at their limit.

There's plenty of reading on the topic at www.sbmar.com . Tony there has experience with these engines in fishing boats with 10,000+hrs so definitely knows what's involved in keeping them reliable. If you're happy with your speeds in the 2200-2400rpm range then I would just leave the props.

Paul

 

Dang. That's quite a shame.