CAT 3116T 300 hp

Kevin · Post by **Kevin** » Oct 18th, '11, 19:33

I remember that there were some models to stay away from. I can't recall which ones the faithful do not like. Are the 3116T good engines?

I might be looking at a boat with these engines for a friend. Less than 1200 hours. If these are the lemon models I will tell him not to waste the time.

Anything to look for with these?

bob lico · Post by **bob lico** » Oct 18th, '11, 22:15

the bad ones never made it beyond 100 hours "block made in france" so don`t listen to "he said,she said".

IRGuy · Post by **IRGuy** » Oct 18th, '11, 22:15

Kevin...

The Cat 3116 engines had some serious block QC problems when I believe Cat contracted out their fab to a French company. These blocks are known as "French blocks" or "Soft blocks", and Cat suffered a lot of failures and "bad press" after their response to worried owners was in the line of "We don't know if your engines will fail or not, so just run them until you have problems".. not a thing an owner wants to hear.

As far as I have been able to learn, the 3116s that made it through the first couple of hundred hours are probably fine.. if they were going to fail due to the above problem it was supposed to happen early rather than later. Eventually the 3116 engine line was followed by the 3126 line, but they don't seem to be discussed very much these days.

Lots of guys run them today and say they are fine, but Cat's reputation was so badly hurt they never recovered in the 250 to 500 HP marine market. Lots of people would not touch the 3116s, a problem at resale time.

RussP · Post by **RussP** » Oct 19th, '11, 03:25

Kevin,
3116's are also known to crack exhaust manifolds, don't overheat them. The 3126's are a better choice. I just attended Cat School and there are dozens of versions of the 3116, if they made it this far they are runners and should be fine. Contact your Cat dealer or service center with the complete serial # and they might let you know the build date, sub series and service history. Drawing oil samples and having them tested is a great way to see whats going on.

RussP

Capn' Tony · Post by **Capn' Tony** » Oct 19th, '11, 07:28

I concur with all things stated above. I have a pair of 3116's in my 33' Bert with 2000 hours and they are great. I also have 2 friends with the same engines in 35's and they love them. As long as you do your home work and all checks out don't be afraid of them.

TailhookTom · Post by **TailhookTom** » Oct 19th, '11, 07:49

My dockmate had them in his 31 Cabo -- great motors -- they looked so pretty every time the guys from H.O. Penn came to replace them -- sometimes it was 2 times the same month! But, they sure looks spiffy coming in and out!

Ironman · Post by **Ironman** » Oct 19th, '11, 09:47

3126 has some AC problems.. re designed 4 or 5 times..

Kevin · Post by **Kevin** » Oct 19th, '11, 20:16

Thanks, I now have a much better idea on how to approach this. I learned today that these engines where rebuilt by CAT at 5 or 6 hundred hours. Something cracked, but CAT rebuit both. I wonder why. I need to go check the boat out in person.I will have to get the serial numbers and see if dealer will give me history.

Tony Meola · Post by **Tony Meola** » Oct 19th, '11, 21:34

Kevin wrote:Thanks, I now have a much better idea on how to approach this. I learned today that these engines where rebuilt by CAT at 5 or 6 hundred hours. Something cracked, but CAT rebuit both. I wonder why. I need to go check the boat out in person.I will have to get the serial numbers and see if dealer will give me history.

Kevin

Not sure what happened to those engines, but my Sister had a problem on her boat with the 3116 with about 500 hours on them. Sea Water pump went bad, shaft snapped in the engine causing a gear of some type to tear everything up. $20,000 later the engines never ran better. Luckily she did not destroy the crank. But they ahd to basically rebuild that engine.

The Diesel Mechanic claimed it was a factory defect but it was out of warranty. So while he was at it he did rebuilt the other pump to make sure it did not happen on the other engine.

34Hatt · Post by **34Hatt** » Oct 21st, '11, 09:31

Tony Meola wrote: Kevin

Not sure what happened to those engines, but my Sister had a problem on her boat with the 3116 with about 500 hours on them. Sea Water pump went bad, shaft snapped in the engine causing a gear of some type to tear everything up. $20,000 later the engines never ran better. Luckily she did not destroy the crank. But they ahd to basically rebuild that engine.

The Diesel Mechanic claimed it was a factory defect but it was out of warranty. So while he was at it he did rebuilt the other pump to make sure it did not happen on the other engine.

The water pump problem was because they have the same crappy Sherwood pump that the Cummins B series have. But now there is a better pump available for both of them. I would suggest upgrading the pumps if your buddy buys it.

Kevin · Post by **Kevin** » Oct 31st, '11, 15:35

I looked at the boat and it was in need of a good bit of work. Too much for my buddy to get into. All engines had dead batteries including the genset. Broker did not have any real good information on engines as to what the problems were. Lots of maintenance that never got done. In my mind that is worse than running a boat hard. On to the next one!

ed c. · Post by **ed c.** » Nov 1st, '11, 20:47

Kevin,, if there is not a written diary with dates and hours when something was completed on the engines " WALK AWAY"
Good Luck

bertram31.com

CAT 3116T 300 hp

CAT 3116T 300 hp

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