420 SD vs Tiara 4300 Sovran - help me decide.

I would try contacting Ed Hislop, I don't have his card in front of me but he definitely used to work for Cummins Bridgeway. I had heard that he doesn't anymore but another contact would be Rich Katt in Grand Haven 616-240-1530. He knows Detroits first and foremost but surveys a lot of engines for surveyors in the area. We have had him do a lot of work.
 
It is a known issue if the engine is in an overloaded state. I remember reading that thread and other like it and the consensus is the boat is overloaded and the prop pitch needs to be reduced. Placing too much load on the valve train of that engine, 480CE, results in damage valves and well you the items that were already replaced on your engines. You have to ask the question though, was the problem solved by Cummins Milwaukee or did they just replace the valve, head, pistons etc and send the PO on his way. My guess, they just replaced and sent him on his way but the boat to this day is still running in a overloaded condition. So, for 150 hrs it has been that way on the new engine ,but the old engine has 660+ hrs overloaded. If you proceed in purchasing this boat, first thing you are going to have to do it reduce load on engine and adjust props to achieve proper fuel burn below prop curves etc. All this information can be found on boat diesel and since I don't have 480CE's I don't have those documents. I would call Tony Athens from SBMAR.com or get on boat diesel and post a question just like above.

EDIT: As far as the lack of valve adjustment I thought the first scheduled valve adjustment was at 1000 hrs and this boat only has 660 hrs so no adjustments were needed unless the 480CE are different than my 6bta's?
 
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Tom,

Based on the Cummins maintenance schedule I got the valve adjustment and injectors job is due at 600hrs OR 1 year. It seams that most boats that had the trouble were due to the fact of being overloaded and owners ignore the 1 year recommendation. Everyone is just so focused on the 600hrs mark.
 
Alex F said:
Tom,

Based on the Cummins maintenance schedule I got the valve adjustment and injectors job is due at 600hrs OR 1 year. It seams that most boats that had the trouble were due to the fact of being overloaded and owners ignore the 1 year recommendation. Everyone is just so focused on the 600hrs mark.
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Oh ok. Mine is 1000 hrs period for 1st valve adjustment. I would still say boat is overloaded and that is what is predominate problem when looking at boat diesel. Remember, manufacturers prop a boat in a very light condition. Once you add all your stuff, the props need to be re-evaluated to again achieve rated WOT++. Read the Cummins service report and I didn't see anyplace where they adjusted props to even checked them to verify.
 
Thanks guys. So lets assume that Tom is correct, and the boat is over-propped which is overloading the motors. What is the procedure/cost of correcting this? Have any other 420 guys seen the same issue and taken corrective action such as this? The Boatdiesel forum certainly suggest that this is a Sea Ray problem on a number of models.

Alex: What is the approximate cost of the 1 year/600 hr valve adjustment and injectors job

Scott
 
trit21 said:
...If you proceed in purchasing this boat, first thing you are going to have to do it reduce load on engine and adjust props to achieve proper fuel burn below prop curves etc. All this information can be found on boat diesel and since I don't have 480CE's I don't have those documents. I would call Tony Athens from SBMAR.com or get on boat diesel and post a question just like above.
Click to expand...

Tom, Excuse my ignorance, but I want to make sure if I post to boatdiesel that the question is asked properly. How do you determine if you've achieved "..proper fuel burn below prop curves etc.". Can this be determined simply by the WOT RPM? Or is this something an engine specialist determines in conjunction with a prop shop? Maybe you could just clarify the question for boatdiesel and save me from looking like an a$$.

SB
 
Scott,

Of course every region has slightly different prices, but my cost was $250, which was added to the full 600hrs service.

Corrective actions to make sure that the engines are properly loaded is simple:
1. Do a seatrial with loaded boat to get current WOT numbers (RPMs and speed). Make sure the RPMs are measured with digital photo tach, and not just your analog tachs (they're usually slightly off).
2. If both engines get to 2680-2700 or better, then the corrective action has been taken. But, if the RPMs are closer to 2600, then the prop tweaking (most likely reducing the pitch) is necessary. When the props will get to the professional prop-scan shop they'll give you their best recommendation after doing the scan. Scanning should be free, but prop tuning will cost you few hundred ($400-$500 or so).
3. You'll need to redo your WOT seatrial test again to make sure that all is fixed. This might take more than one run to the prop shop and of course means that you'll either need a haul-out or have a diver take/off and put back the props.

At this point, I would expect a seller to take care of this, in the event if the prop tuning is required.
 
I agree with Alex as that is the way to ensure proper prop pitch and load. Just make sure you are 'loaded for bear', as much stuff on the boat as you will have when you are running to (for us anyway) to the Bahamas for 2 weeks. Obviously you aren't able to do that all the time so take people with you for a cruise and tell them to hold on, were doing a WOT test. Fuel burn number below the prop curve: Basically you take fuel consumption readings every 100 RPM all the way to WOT. You then look at the prop/fuel burn curve that is provided by Cummins and verify all numbers you took are below that chart. If so, you are NOT overloading the engine at any RPM. If it dips above the curve, then you ARE overloading. Not sure if the boat has fuel burn gauges, smart craft which I understand is only a proximation of actual, but that is another way to determine overloading. Again, not familiar with 420DB with 480CE so excuse my ignorance.

With that said, if the port engine had the problem, what is the state of the starboard engine at this time? (Don't remember which engine had the problem and can't read it as I am in the middle of this post). Do the engines had EGT (exhaust gas temperature) readouts and boost gauges? If so, what do they read? Typically on an overloaded engine EGT is high (over 1000-1000 F).

You have the maintenance records cool:
-When was the last time the entire raw water was looked at including, pump cam and impeller change out, fuel cooler cleaned, after cooler serviced, heat exchanger, trans cooler.

One major thing everyone on boat diesel will ask is for photos showing the exhaust layout,especially where the raw water dumps into the exhaust via the exhaust shower. It really needs to be on the down slope of the exhaust and I am continuously amazed as manufacturers that don't do it right. I AM NOT SAYING SEARAY DID IT WRONG, as I have no idea what the engine room even looks like but it should be verified to ensure you are not getting any splash back of salt water in the back side of the turbo OR the exhaust has a potential design flaw and it will rust out internally allowing salt water to enter the backside of the turbo. Again, if all it ok, which at this time I would suspect it is, then no problems at all.

I am not trying to scare you but in the 3 years I have had this boat, I have learned a lot of good and bad and wish I knew this when I purchased my boat. I also wish I had a mechanic that works on these boats look at the boat and NOT A SURVEYOR. Surveyors are almost useless at this point. Mechanics know how to fix these things and know what to look for as they have seen the problems. Surveyors just want your money.

One more thing, you did get oil analysis correct? Blowby test? How did they fair out?
 
At the bear minimum I would ask for fuel and water tanks to be full for the sea-trials.
 
Alex F said:
At the bear minimum I would ask for fuel and water tanks to be full for the sea-trials.
Click to expand...

So Alex - with the 420, how would you accurately check the fuel burn? Would you use the smartcraft readings, or is there something the motor can report through a special Cummins interface?

SB
 
My opinion is you should contact Tony Athens and see if he can explain this issue and/or get on boat diesel and post. Calling Tony would be quicker. sbmar.com
 
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sb in gp said:
So Alex - with the 420, how would you accurately check the fuel burn? Would you use the smartcraft readings, or is there something the motor can report through a special Cummins interface?

SB
Click to expand...

Scott,

Since my boat is powered by fully mechanical 450C Diamond Series it doesn't have SC. However, I would think that just like you have it on 320DA, the SC would be the first data I would try getting the fuel flow info from. I know that the SC version I had on my 320DA had Instant fuel flow data, so you need to find out if the SC version on 420DB for 480CE has the same mode.

I looked at a sample of survey report and I don't see the fuel flow data other than the restrictions. So, I can't say for sure that this type of data is coming from the same feed that this report was generated. I think it's best to ask Cummins tech. Anyway, here's what the report looks like.

450C_Survey_Report_Sample.jpg
 
The 480CE is was an in between version of the C series engine which has some electronic controls but not a fully electronic version. From what I understand, 6cta (which I think is the 450C correct me if I am wrong Alex), then they came out with the 480CE, then the QSC engines in varying HP ratings. 6CTA (450C among others) are fully mechanical, 480CE has electronic controls and sensors basically an electronic version of the mechanical version 6CTA, and then the common rail fully electronic and controlled QSC's.

Which is better? Well better for what? Better economy is the QSC. Better to work on for yourself I would say any of the fully mechanical versions since no computer is needed to hook up to determine problems. 480CE again is a cross between the two.

Any engine can be overloaded, mechanical all the way to fully electronic QSC's. No one is better or worse in that regard. Overloaded is overloaded.
 
Tom,

You're absolutely correct. The 450C (450HP) is the basic and fully mechanical engine with 8.3L block (6CTA). Then, Cummins came out with 480CE electronically controlled and equipped with SmartCraft 480HP, which uses the same 8.3L block used in 450C. Then, they advanced their technology and decided to squeeze 500HP from the same 8.3L block and QSC500 (Common Rail) was burn. If I'm not mistaken, there's a new version QSC600 that was recently introduced. Again, this is squeezing all these extra HP from the same block used in 450C.

I like your "which is better...better for what" Q and A. This is exactly the questions I asked myself when I was upgrading. Since I do all the maintenance myself and try to address most of the repairs myself as well, I knew that I better keep it as simple as possible new to me diesel engines. Having great deal of experience with previous boat equipped with bunch of sensors and SC and reading all the stories how the electronics go bad, I wanted the simplest possible engines. This is the time when I listened to the advice of more experienced folks (Frank W) and will never forget his explanation/example, when he asked what will you do when you're 50-100NM offshore and your electronically controlled engine and sensors don't play nice to each other? Or another example of QSC500s limping home in a "guardian mode". Thus, my personal decision was to give up some performance in exchange for simplicity and reliability, knowing that I had plans on taking this boat for very long trips. When I say give up some performance, I refer to the fact that my boat would be the slowest between the 420DB with 480CE or 44DB with QSC500 as they cruise 1-2kts faster. But, this extra 1-2kts doesn't make much of a difference for me personally.

In all fairness, please don't get me wrong.The other engines like 480CE and QCS500s are great engines with good history. As Tom said, an overloaded engine is an overloaded engine regardless of the model.

IMO, it's all Cummins fault for providing misleading information. What kind of approach is this, they came out with official performance matrix having 2600RPMs as rated WOT. Then, after they realized (of course after number of engines are having huge failures and poor boat owners are stuck with a huge bill) that they left very little room for error, and only then they decided let's come out with a bulletin (correction) that we really need to see 2700RPMs at WOT. In the meantime thousands of boats are leaving the factory with manuals that call for 2600RPMs and when a manufacturer does a quick test with half empty boat and seas the number they're happy. Obviously, the minute this boat finds a home it'll never be "half loaded", hens from that day on the marine of error is only getting smaller and smaller until an owner somehow FINDS (God forbid someone would reach out to the boat owners with an important message) this bulletin and quickly runs to the shop for corrections before it's too late.
 
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I didn't think the 480CE was common rail? I thought it was an electronically controlled injection pump similar to the ones on the mech version only with wires sticking out the side? I could be wrong so don't quote me on that but that was my understanding.
 
trit21 said:
I didn't think the 480CE was common rail? I thought it was an electronically controlled injection pump similar to the ones on the mech version only with wires sticking out the side? I could be wrong so don't quote me on that but that was my understanding.
Click to expand...

Tom, I think you're right. It's the QSC500 that's the common rail. I'll change my earlier post.
 
Thanks to all, especially Alex and Tom. I have withdrawn the offer on this vessel, and I will wait for spring and determine if I want to do a new offer with a full engine survey to get a clearer picture of any lingering issues.

My education continues, great stuff.

Scott
 
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