Cat 3116 350HP - Good, Yes or No?

There's really no reason to add any to Frank's post above, technically speaking, but from a practical standpoint, I thought I'd interject my own personal experience witha pair of 3126TA motors.

Fear is spread quite rampantly on internet boards, and boatdiesel is not immune. The same question posted hear by the OP is often asked on boatdiesel. It seems like the same folks always like to spread the same war stories without looking into the facts.

Below is a post I posted on boatdiesel after someone asked the same question. Special emphasis on the bolded red test....


Dominic: I´ll add my own experience and opinion....... I am on my 3rd season with a pair of 3126-TA 350HP motors in a ´big´ sea ray.....a 41´ express cruiser at ~2400lbs loaded. I am the second owner, and the original owner is a member here and I have come to know him quite well. The boat, like most boats, was overpropped from the factory. The original owner did run it overpropped for the first few seasons.....WOT just around 2750 RPMs. He eventually did take some pitch out of the props and was making just barely 2800 RPM at WOT under full load. When I bought the boat, after doing my due dillegence, and heeding the advise posted here, I sharpened the pencil a bit more, and had the props done more precisely. I am now able to easily spin up to 2865 RPMS with a full load. I have changed out the tachs to the Aetna digital tachs, so my numbers are exact....confirmed with a laser tach.....not just guessing from inaccurate factory analog guages. I can easily plane at 1900 RPMs....maybe less, but I´d have to check that out....maybe this weekend I´ll get some real numbers. Anyway, I typically cruise/run the boat at 2250-2350 RPMs while making 21-23 knots.....load and sea conditions dependant, while sipping fuel....I average over 1 sMPG....closer to 1.1 sMPG. The 3126 motors are slighter larger displacement than the 3116.....7.2L vs 6.6L....and have some other intrinsic differences...one of the biggest I think, is that the aftercoolers on the 3116 are closed cooling cooled and the 3126 aftercoolers are raw water cooled. Using the displacement numbers above, a 300 HP 3116 is 45.5 HP/Liter and a 350HP 3126 is 48.8 HP/Liter....both under the accepted target of 50 HP/Liter....a 350 HP 3116 will just break that earmark at 53 HP/Liter....but still in the ballpark.....when you move upto the 420HP 3126, you start to push the envelope at 58.3 HP/Liter....still WAY under the numbers for some of the current motors from various manufacturers.....some approaching and/or exceeding over 70 HP/Liter. My knowledge of the history of these motors is not hands-on. It´s all from reading here, reading on other boards, speaking with current/previous owners and internet searching the archives. The early years for both of these motors....3116 and 3126.....were shakey to say the least. However, there were and still are, TONS of these motors out there. The ones that were bad, have generally gone bad...early in their life...for a few reasons, but mainly from bad valves and soft blocks....not necesarily a design issue....more of a parts supplier issue. This is just my opinion, but I would think that if these motors are ´bad motors´, that there would be post after post here and on other boards about 3116/3126 motors failing..... and that´s just not the case. It surely was that way back in the 90´s, but most, if not all of those ´bad´ motors have been repaired or replaced. Sure, they have their issues, but what motor doesn´t?
 
3116 Soft Blocks. I am a technician and my people skills are not the best. I'm not trying to start anything with this or jump on a soap box of sort. I didn't go there with my first post because I failed to see a need. What Frank posted earlier I am all in up to 99.9%.

But ... There were a few 3116 soft blocks. I personally diagnosed and replaced a small hand full of them in trucks. I'm talking the very early 90's. We never seen any in boats up hear. I believe because the 3208 was still offered. At the top of the bore, where the top ring changed direction a cylinder taper occurred. This taper lost compression and burn pressure at the top 1/2" of stroke. ... What you seen was: unburn't fuel smoke at hot low idle. A steady plume coming from the fumes disposal tube. Under load these engines ran fine and you would think nothing was wrong.

As Frank said earlier: this problem developed early in the engines life. Most were replaced under warranty. The ones that slipped through Cat still stepped to the counter.

All these blocks can be salvaged sleeved and when done right is alike new bore again. There not throw aways!

As far as the comments above hp:cid ratio and other manufactures; that would be a great topic for another thread to include hp:lb ratio.

And the comment about overproped, only turning 2750! would be another great topic on performance tuning. cheers to all. ... HNY ...Ron
 
I wouldn't be worried about the cat motors. if they have 800 or so hours on them they should have developed any problems by now. if you can find out if they have had any factory work done and what if any service these engine have had. if there are no records then I would walk.I would not take just the word of David Pascoe. he thinks he know everything. he is pretty good but I have spoken with him and one he has a idea that he knows as truth you can not talk to him.
 
BonBini,

The information I posted relative to soft blocks and the 3116 engine pertains only to Sea Ray boats and to engines marinized by Ringhaver Cat for Sea Ray. According to their warranty and service folks, they had no marinized 3116's with soft blocks and no warranty claims for Sea Ray owners for block replacements.

Since the 3116 and 3126 blocks came from the same factory I suspect you are right about the early 3116; I just don't know anything about Caterpillar's non-marine products, other then general diesel maintenance info.
 
Katricol

Your post stated 3116 3126 engines are "sought after". I can only tell you that every time that engine model number comes up, people worry about soft blocks, valve failures, etc. They are not "sought after" in North Carolina.... Nor are they sought after by SeaRay.
 
Isn't it interesting that the OP hasen't been heard from? We don't know if he has even read all this excellent bantering...
 
Terrific thread, great information and I learned a lot; thank you all.

Jeff
 
I want to thank all of you for posting your information. I'm seriously thinking about pulling the trigger on this boat and making an offer. Can anyone suggest a CAT surveyor in the Annapolis area?
 
Try this dealer locator:

http://www.cat.com/cda/layout?m=39542&x=7

Caterpillar dealers are different then Mercruiser or even Cummins. Your surveyor won't be a general diesel service guy in a pick-up truck, but will be factory trained,experienced on your engines and have acceess to Caterpillar's service records on the engines in question.
 
Have the 3116 350hp 1800 hrs on them 450 hrs this year in my boat a 1998 Sea Ray 420ac and have never had one problem with them. But read Franks post and had to go look both serial numbers are below 6000
 
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Go to boatdiesel.com. Excellent source. You can get top layer posts without joining--but if you run diesels you ought to join. The general consensus from what I have read is the 3116 and 3126 have a much higher potential for problems than the old 3208 or the Cummins b/c series. If you purchase, allow for some additional expense in your purchase price.
 
The General consensus may be as you state, but on boatdiesel, there are 3 or 4 HIGHLY regarded CAT SPECIFIC mechanics/owners who will NOT tell you to avoid these motors.

The problem with the General consensus folks, is that many are just repeating something that they've heard or read from a good amount of time ago and have no real hard core 'CURRENT' facts to suuport their stand. Sure, 8 or 9 years ago, they may have horror stories of 3116/26 motors lined up on the docks being replaced. But re-read my post above....that's not the case 'TODAY', IN SPITE of the fact that thousands of them are out there running quite well thank you, today.

Also, those motors that were replaced.....re-read FW's post..(actually re-read his post a few times if you are considering a 3116/26 powered boat)....CAT stepped up to the plate and did NOT leave their customers hanging....they acknowledged the problems and made good on the product.

As far as being prone to overloading....don't overload any (diesel) motor....period....It's not good for longevity.
 
I've witnessed several cat owner "hangings". My neighbor was handed a bill for over $5,000 of "yard fees" each time that his 3126's failed. He fought them and had those fees partially covered, but he still had to pay a good chunk out-of-pocket for the replacement of engines that he had maintained and run with extreme care.

He traded the boat when he discovered that both of the replacement engines were also faulty. This wasn't rare as rare as it should have been, and I believe that the repeated failures have given the notoriety some holding power.
 
dbriceno said:
I've been told by many to run from these cat engines, though I just saw a nice 1997 40 sedan with a pair of them with 860hrs. What do I do?
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A friend of mine has them in his 370AC. I think he has about 500 hours on them. They have treated hom well and he has had no serious problems with them.
 
I bought my 450 DA that had 3116 s with 700 hrs on them and put 600 additional hours on them and didn't have any problems. However I used the boat and maintained it as well. The pair of motors just sailed through an intense survey by the boats buyer.
 
twyant said:
Have the 3116 350hp 1800 hrs 450 this year in my boat a 420ac 1998 and have never had one problem with them. Have three friends with the almost the same boat 430hp Volvo in 1999 420ac, 420hp Cummings in 2006 420sb, 300hp cat 3116 in 1996 40sb , no problems 3800 hr one turbo failed on his cat. Both the others have had problems Volvo very minor but the one with the cummings called them and said that he thought he thought had the better engine but looked like cat outdid them! They did not want to warranty the motor 280 hr on Cummings 420 hp but they were cheep on parts. We run together allot and on fuel burn do not even come close they are a mile are two faster but cruise the same speed. Not race boats anyway, I think frank said allot don't back away from the cats but use cat to check them out about $1000 money well spent. good luck. And I know I'm going to catch hell cummings owners but that just how it is
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I'm sorry, I really can't figure out what you're trying to say.
 
Sorry posted from my new phone and guess I will never learn how to work this thing.
 
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