3116 or 3126?

[quality time]

Do you guys have any reason that I should exclude '99 380's with 3116's from my search? I believe that 3126's were offered on the 380 in 2000 (or was it partial year 99's?) Anyway what are the major differences or are there any problems with the 3116? I'm hoping Frank will weigh in on this.

 

[fwebster]

They are essentially the same engines except the 3126 has a larger displacement by 37 cubic in. The injectors and pump are also a little different. There are no systemic problems with either engine that should be a worry now as Caterpillar has already repaired all those affectd by the 1-2 things that happened in the 97-2001 period. PM me if you are intrested in the history, but none of those things should be a concern now in 2007.

One of the "famous" Caterpillar engine problems, i.e. soft engine blocks cast in France, affects the 3126, but not the 3116. That shouldn't be material, however, since by now any 31126 with soft blocks would be obvious to an engine surveyor if they had not already been fixed under warranty.

The real difference between the 2 engines is in output, but my feeling is that the extra power is only helpful at a point in the power curve where you least need it, at WOT. Most of us with Cats run our boats under cruise rpms anyway. Caterpillar engines have huge torque and swing big props so a boat like a 380DA will stay on a plane down to about 1800 rpm. If I'm going to run at 2200 rpm instead of rated cruise of 2400 RPM ...costs me 2 kts, but cuts fuel burn down to 19 gph from 26 on 3126's, do I need the horsepower advantage of 420 over 350? Nope............

I would certainly not discount a 3116 boat if I found the right boat and it had those engines.....and that is a key point. Your biggest challenge is going to be finding the right boat. I would worry more about finding one that had a known and documented service and maintenance history and had been well cared for and not "ridden hard and put up wet" than whether it had 3116 or 3126 engines.

Hope that helps...........

 

[quality time]

Thanks Frank! That's exactly what I was looking for.

 

[Girlfriend III]

Quality Time,
Have 3116's in my 42 Sea Ray Aft Cabin, good engine so far, lots of torque and The Sasafras Harbor is Authorized Cat Repair Shop if needed. See Joe !

 

[VASAMIAM]

I am just getting ready to do a sea trial/survey on a 2000 380 AC with 3126's. Bost has been stored under cover and most everything looks pristine. Your post gives me confidence about the cats. What should I expect for general maintenance expense on the engines with normal use? Also, are there key things I should look for with the surveyor? Loved to hear about gph! I am moving up to this boat from a Four Winns with 5.7l gas motors that burn the same amount! Hopefully survey goes well......I cold be in the boat next weekend!

 

[JC3]

Vas, You should PM Frank about the engine survey NOW! There are some things that will need to be done on your engine survey
that Frank can tell you about. I only felt confident after Frank told me WHAT/WHEN/WHY to survey and then went over the findings with me.
4 years later and Thank the Lord its still running strong. Good Luck, JC

 

[searaycruisn]

I have a 2000 380 with 3126 CATS. I average 18 GPH (take hours since last fill up and devide by gallons purchased), but that is pretty consistent whether I idle a lot, or am at cruising speed (2400 RPM and 21 to 23 knots depending on sea conditions). I use only genuine CAT parts / oil on my boat. Normal annual maintenance (oil change, engine zincs, fuel filters, racor filters and oil filters) will run you about $700 for parts for both engines and the diesel generator. If you have to change impellars, they can be expensive also (I think $80 a piece?).

I have heard several people (including myself) that had propellar shafts break and needed replacement (total cost with one new prop was about $3,500). I have done several upgrades (new canvass $4,000, new cockpit carpeting $700, new guts in the fridge $800, and just recently replaced the salon carpeting with hardwood floor $$$$$).

Anyway, those are the big ticket items you need to think about. And of course the big one....I had to replace one of the CATS $45,000....but luckily a good lawyer was able to get my insurance company to pay for that. You can do a search in here, and read all about it....but I believe this was the exception rather than the rule for these engines.

Great boat.....go for it....or make me an offer?

 

[Gimme Time]

I am just getting ready to do a sea trial/survey on a 2000 380 AC with 3126's. Bost has been stored under cover and most everything looks pristine. Your post gives me confidence about the cats. What should I expect for general maintenance expense on the engines with normal use? Also, are there key things I should look for with the surveyor? Loved to hear about gph! I am moving up to this boat from a Four Winns with 5.7l gas motors that burn the same amount! Hopefully survey goes well......I cold be in the boat next weekend!

We have the 2001 420AC version with the 3126 and love them. We to only run Cat parts and the specific oil that Cat calls for based on the engine Serial number. Don't cut corners and take care of the boat and engines and you will have many great hours aboard. Were on every weekend year round and keep her in a fully covered slip as well. If it's worth having it's worth taking care of.

 

[HUMPH]

Have the surveyor pull some of the zincs in the after coolers and inspect for corrosion. I am very happy with my 3126's and plan on them performing well for many years to come.

 

[VASAMIAM]

thanks for all the replys! Looking forward to the sea trial on Wednesday! Boats gets hauled at 10, then sea trial around 1. Should be a good learning experience.

 

[quality time]

I burn 26 GPH per Floscans @ 2350. I seriously doubt Eric is only burning 18 GPH at cruise speeds.

We are also talking about DA's, where your AC may burn a little more and may not cruise as fast due to weight.

 

[Phlorida]

Eric indicates that he is taking the number of gallons at fill up and dividing it by the number of hours since the last fill up. How could that be less accurate than your gauges?

I burn 26 GPH per Floscans @ 2350. I seriously doubt Eric is only burning 18 GPH at cruise speeds.

We are also talking about DA's, where your AC may burn a little more and may not cruise as fast due to weight.

 

[osd9]

I burn 26 GPH per Floscans @ 2350. I seriously doubt Eric is only burning 18 GPH at cruise speeds.

We are also talking about DA's, where your AC may burn a little more and may not cruise as fast due to weight.

Eric indicates that he is taking the number of gallons at fill up and dividing it by the number of hours since the last fill up. How could that be less accurate than your gauges?

One is an 'Average' and the other is 'Instananeous'.

An "Average" is just that....it includes the average GPH which will include idling at the dock, idling while setting an anchor, slow speed cruise into and out of port along with fast cruise speed. Average will always give you better GPH numbers.

Instananeous, when measured with accurate metering devices like Flo Scan or Smartcraft are exact numbers at each RPM at a given time under a given load. Instaneous fuel flow numbers will be more consistent than average numbers.

 

[quality time]

Exactly.