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Looking for information on the following on Cat 3116TA vs Cummings 6BTA59M3. Model is Tiara 35 open.
Can anyone give me any info on the to power plants, pro's and cons ?
cats are very heavy and have a friend with a 36 tiara and they took the cat out and put diamond cummins in and got 6 knots with same hp. also cummins parts can be found at most any part store.
The only Cat diesel in that HP range that was a good engine for Cat was the 3208. The 3116 and 3126s have poor track records with regard to all the important parameters we as boat owners desire. The 5.9 L 6B engine in all of the HP configurations is a superb engine IF properly cared for and maintained as per Cummins guidelines. I would take the 6B Cummins 100/100 times if offered the choice between it and the 3116 Cat. Simplicity, reliability, ease of finding people to work on it, parts prices and availability all favor the Cummins. Buy a boat diesel dot com membership ($25 I think) and you will receive priceless advice and tons of reading material on the Cummins (and Cat too). Good luck!
certainly cat 3116/3126s have had their issues. 3116s had a bad run of blocks. and 3126s were tweaked to put out too much hp. however, it seems that most 3116/3126 failures were due to boat manufacturers poor installs - many problems stemmed from overloading and motors not reaching rated rpms.
we have 1998 3116s, 300 hp. we rerated them to 350 hp in 2002 and re-propped. approx 1000 orig hrs on them now. they have been bulletproof. only routine maintenence and recommended servicing (clean intercoolers, rack adjustments, etc). for every 1 3116/.3126 that had issues, there are hundreds (maybe thousands) that are running perfectly.
as for parts/service, you should look at where will you will keep the boat. most major areas are well covered for both. i dont think there is any difference between these two. yanmar and volvo are a different story both in terms of service and parts availability.
3116 Cat is crap in trucks so I would assume they are even worse in boat applications. The 3116 was orginally designed for the GM topkick trucks as a CHEAP engine. GM wanted cheap and thats what they got. Its a 6.6L engine. The 3126 is built quite a bit better and uses better quality parts and is 7.2L displacement.
First, if the block on the 3116 is one that was not cast in France and the motor has over 350 to 400 hours on it, chances are that you will not have a problem. Most problems with those cast in France were a result of a "soft casting" and problems showed up before those hours were reached. But, there is also a class action suit against Caterpillar that targets the 31 series motors, 3116, 3126, 3176 and the 3196 this has had a bearing on the marketability of boats with those motors and the resale values and time on market have suffered as a result. While you may be able to get a boat powered with a 31 series motor at a relative deal, you will have to live with that choice later on when it comes time to sell it. If it were me, and all other factors were equal, I would lean (and lean heavily) to the boat with the Cummins power.
what steveyacht said. I got 2 new short blocks for my 3126's from cat due to their soft block casting issue (still paid over $4k out of pocket). I also know of others who have had valve and turbo issues with 3126's. I know of other boating friends with 3116's with issues. My new boat has cummins (8.3L diamond C's)!! SeaRay since 2000 or so refuses to use cats in any of their boats due to the above (and the 3196 issues too as I hear it from searay dealer people). the 3208 cats do seem to have a better reputation as I hear it. I cant speak for that model of cummins engine, but I can for my cat 3126 experience. As said above go to boatdiesel.com if you want to hear an ear full. At an absolute minimum check with cat service guys on any engines you consider for the service / warranty history - after you get info from boatdiesel on what the recalls and service actions were. I know I'm not going back to cat.
Steve,
I believe you are talking about the class action lawsuit started by James Jaikins, which is mainly focused on the 3196 aftercoolers. I have not heard any mention of the the other engines as part of the class action lawsuit.
I believe the other CAT 3116/3126 issues were all resolved by 1993...
We repowered a a custom 35 express from Volvo TAMDEs to the Cummins 6BTAs in 370 hp config and absolutely loved them. Never had a single problem with them and the difference in performance was night and day, when we were re-powering we considered the CATs, but the more research we did, the more we wanted the Cummins, lower weight, less moving parts. The cummins are a higher RPM engine with less torque, but we babied them. we would cruise between 2200 and 2400, on really nice days 2500 which would push the boat a steady 27 knots. 370 HP config is really 355 at the wheel and they're designed to top out at 3000 RPM and were rated to cruise all day at 2800, but we never did, or only for short bursts. At 2400 RPM we would burn about14 gph per engine at 2200 less than 11. gave us a solid 1 mpg sometimes better. had a friend that re-powered a 37 Topaz at the same time with CATS and had nothing but trouble from day 1. One of 'em blew at 300 hours, If I ever own another diesel Cummins is my #1 choice. they made a believer out of me.
I read an article somewhere in the last day or two,(come to think of it, it was in the Boat US magazine,) detailing aftercooler probs and a lawsuit filed against cat b/c of the problem
Cummins is the way to go. I've owned several makes of diesel and all were OK but Cummins would take the abuse. One example I ran the old 555 Cummins, or "triple nickles" in a 1978 Post 42 for years with no problems past minor repair and normal maintenance. Reliability was outstanding. The new Diamond series is rock solid.
cat v cummings 
