Bertram 33 FBC repower

lperedat · Post by **lperedat** » Thu Jul 05, 2007 1:17 pm

My original catÂ´s 3208T 260 HP need replacement, and I some help with one of my options: I would like to install 320 hp instead of the 260 hp engines. Do you think I would need to work on the shafting and struts, or I can live with my current 1 3/8 shafts, with the same ZF MG502 1-1:54 transmission? I will appreciate any coments. Tx.

IRGuy · Post by **IRGuy** » Thu Jul 05, 2007 2:49 pm

Luis... Welcome to this forum! You will find lots of help here! I don't think I am the best person to answer your questions, but I can shed some light on them. I am sure others will make comments as well. I am not aware of anyone here running Cat 320 HP 3208s, although there might well be some, but there are several of us with Cummins 6Bs and Yanmars in the 300 to 330 HP range, as well as at least one Yanmar with 370 HP I believe. There seems to be some debate about the best shaft size, with some of us having kept the original 1 3/8" shafts after repowers, while others of us have 1 1/2" shafts. (there seems to be confusion as to which shaft size Bertram installed in gas and diesel 33s back in the 80s) If you decide you want to move up to 1 1/2" shafts it is sometimes possible to keep your original 1 3/8" struts and simply bore the rubber cutless bearings out to 1 1/2", and then install 1 1/2" shafts, which will save you a lot of money. My 1983 FBC originally had Cat 260 HP 3208s, but was repowered with Cummins 315HP 6Bs. I think all of us with 300-330HP feel this power level is adequate, and provides 26-28 knots speed. The usual setup is a 1.5:1 transmission and props in the range of +/- 21"D and 21-23"P. You also might want to use the "Search" function at the top right corner of each page here to look for old posts where several members repower projects and performance results are documented. Once again.. welcome, and we are glad to have you aboard! Frank B - IRGuy@aol.com "Phoenix" 1983 FBC Wilmington, NC

lperedat · Post by **lperedat** » Thu Jul 05, 2007 5:21 pm

Frank, I appreciate your answer. It seems like you know enough about it having done it before. I will check on the link youÂ´ve mentioned. Tx again.

IRGuy · Post by **IRGuy** » Fri Jul 06, 2007 5:30 am

Luis... Actually my boat was converted from Cat 3208s to Cummins 6BTs by the previous owner, so I have not had to go through that process. Most of the repowers that have been done by regulars here have been from gas to diesel, and I am not aware of anyone doing a diesel to diesel upgrade. It would seem that you could find some higher HP rebuilt 3208s locally and replace your 260HP engines for less money than any other option, as long as you have good service support locally. I have no idea how strong Cummins support might be in Venezuela, and it would seem that Cat, being a huge worldwide company, would have the best support. This has to be balanced against the fact that at least here in the US Cat no longer makes the 3208 engine, and their 3116 and 3126 engines have bad reputations for several reasons. From what I have learned Cat has pretty much disappeared in the US from the sub 750 HP marine engine market. One more comment which I believe is a benefit of Cummins 6BTs in the Bertram FBC models. I can get against the hull of my boat and work on the outboard sides of both my engines.. it is certainly tight, and I am an average sized guy (170 lbs more or less.. usually more!). I can't imagine how tight it must be trying to work on the outboard sides of Cat 3208s in the FBC hulls.. the wide blocks must make it really tight. Finally, I would suggest you go to "www.boatdiesel.com" if you have not already been there. This is a forum specifically set up to provide info on marine diesel engines of all types and sizes. As a visitor you have access to recent posts, but for a $25 US fee you can become a member and read everything, have access to several good articles on specific marine engine subjects, and ask questions which will be answered by very knowledgeable people. Frank B - IRGuy@aol.com "Phoenix" 1983 FBC Wilmington, NC

Sean B · Post by **Sean B** » Sun Jul 08, 2007 7:23 am

Luis, I've looked at these issues a lot over the years and Frank's advice is right on the money. I'd like to add a few things though - although CAT no longer sells new 3208's, there are mountains of parts available and they still manufacture new parts as well, and also fully support the 3208s. There are too many of them around not to. The 3208 is kind of the small block chevy of the diesel world... they sold LOTS of them and they are very well tested and durable. I wouldn't worry about parts and support for them, as long as you have access to knowledgable mechanics and parts suppliers in your particular area (that goes for whatever engine you choose). All that being said, I would hate to have a pair of them under decks. They're just too damned big. All that iron is great for longevity (6000-8000 hours are the normal lifespan) but makes them heavier and larger than anything else in their class. I have the 33SF model with flip-open engine lids which removes the access problem. If I had a FBC with 3208's under the floor I'd absolutely hate working on it. The Cummings 6BTA's afford a lot more room and are a lot lighter too. The CAT 3116's have a bad rep because, so the story goes, of a bunch of them had blocks that were made in France that were substandard and failed. So people will say that if you do your research and get a 2nd generation 3116 that was manufactured after they found and fixed the problem, they are fine engines and lots of people have them and are completely happy with them. For me, resale value because of the bad rep, and also the access issue makes them a non-viable candidate anyway. I thought the 3126 engine was generally considered good but I could be wrong. It's still a big engine though, and still has access problems. If your 3208's are not in need of pulling then you can ramp them up to 320 HP without adding aftercoolers. Anything over 320 HP requires the addition of an aftercooler and is probably not worth doing. You mentioned ZF 502 gears... I think you mean that you have the Twin-Disk MG 502-1 gears with your 260 HP 3208's (I have same, it is the stock Bertram factory setup). Those gears are only rated at 255 HP, so increasing the HP on the engine brings that and also the 1.375" shafts into question. I too want more engine power, but for lack of a driving reason to mess with things (it all works fine now) and with the gear and shafts possibly being too small to handle extra power.... I have for now selected the do-nothing approach. If money were no object I'd be installing lighter and stronger engines, probably 6BTA's with gears and shafts rated to handle them. I asked Twin Disk about having 320 HP on the gears, and the guy said it would probably be okay, that the MG 502-1 is "a good old gear," but their official answer would be don't do it. So you'd be in a grey zone there. As for the 1.375" shafts, another grey zone... I'm of the school of thought that the 1.375 inch shafts are too small for 300+ HP. Their are opposite opinions to that here, and generally come from those who have the higher power engines with the 1.375" shafts... i.e. biased opinions, sorry guys

. All I can say about the issue is that I called two re-power specialists and talked to them about installing 315-330 HP 6BTA's and both said I definitely need stronger gears and at least 1.5 inch shafts. Also the shaft calculator on boat diesel leads you to 1.5 as a minimum, 1.75 preferred. I've read that the 1.75 shafts are not "self-centering" like the 1.375 & 1.50 inch shafts tend to be, to some degree... and so maintaining perfect engine alignment is a must. Also my shaft logs are too small for 1.75" and I suspect yours are too. Not being a fiberglass man, cutting out those and replacing them is not a trivial task. So if I were doing it I'd probably get the best alloy 1.5" shafts available, either the A22 or (and I don't know anything about these) the "Temet 22." And yes, there are thin-walled cutlass bearings that you can install that would allow you to keep your existing struts and have 1.5" shafts. You'll be pulling and re-aligning your struts anyway with an engine family change though, so that isn't as big a money saver as you might think it is. Since changing the engine requires all the labor involved in strut and shaft R&R anyway (and unless your lucky, probably a modification to shaft length too) why not spend a little more, put in the bigger shafts and feel comfortable about it. But... if you keep the 1.375" shaft, keep your props tight, don't hit anything, don't ever shift into reverse hard, don't over-pitch your props, and don't overstress the 1.375" too much (don't climb up the backs of huge swells at 24 knots)... they might serve you just fine. As I said: grey zone. Hope that helps Sean Burlingham "Island Time" 1987 Bertram 33 SF Melbourne, FL SBurlingham@cfl.rr.com [img]http://www.bertram33.com/photogallery/p ... d_Time.jpg[/img]

lperedat · Post by **lperedat** » Sun Jul 08, 2007 9:03 am

Sean, Thanks for that insightful answer. Do you know what is required to go from 260 hp to 320 hp on the 3208Â´s? Is this an easy change? If I decided to go with the cummins 6BTA, how difficult is the instalation process? How much is there to change or to redo? Thanks again for your help.

Sean B · Post by **Sean B** » Sun Jul 08, 2007 10:40 am

quote:Do you know what is required to go from 260 hp to 320 hp on the 3208Â´s? Is this an easy change? Luis, I think I was mistaken when I said you would have to R&R the struts in every engine family swap... that is what I would have to do because my shafts are not perfectly aligned with my shaft logs. One is about a 1/4" off and you can see the packing gland hose bending in a slight S-shape to compensate, which I definitley don't like. It is seemingly a factory screw-up. So I feel I would have to remove and realign my struts as part of the job, because if I was tearing into it all I would want that fixed too. Also I would want to install big backer plates and new sealant, because of the possible known leaks and weaknesses there, which is explained best here: http://www.bertram31.com/proj/struts/strut_backing.htm Anyway, so maybe you might not want or need to remove and replace the struts... an engine swap doesn't necessarily require it.... I would do it to fix my particular problem, and just to refresh the seal and backer plates for 20 more years... but that's just me. As for the HP upgrade, I did a search for my posts about my mechanic's research a couple years back and found this: Turbo 3208's range from 260 HP to 320 HP ratings. I've got the same 01Z block 3208T's (in a 1987 B33 SF), but mine are rated for 260 HP. From what I've read from different sources, the HP rating on those motors was all over the chart and doesn't really mean too much. To modify my particular engines (1W5070 arrangement) to a stock Caterpillar 320 HP setup, I've learned from my mechanic that the following is needed: The governor springs need to be changed, the pump groups in the injection pump need to be changed to increase fuel delivery and the full load fuel setting must be changed to 5.40mm. The hi idle adjustment will also be increased. The injectors are the same. All this only adds a slight amount of fuel delivery to the engines, and mostly at the top end of the power curve. Just after I got my boat I had my injectors swapped out for new and the valves adjusted, and was quite happy with the results. I've also got the 1.375" shafts, which broke once for the previous owner who replaced them with the current 1.375" Aquamet 22's. I'm scared to upgrade fuel settings or put on too big a prop because of the small shafts, even though they are the A22's. Currently running 20x22 3-blades, which give me a 21-22 knot cruise at 2500 RPM (I run a little higher RPM than I should because the boat wants to plane there, and as a result the engines are actually loaded lighter at that RPM). The engines top out at 2900 RPM, 25-26 knots. Definitely under-propped but also safe with that stock Bertram setup. As I recall it was going to be about $5,000 an engine for the upgrades, the biggest expense being the new (rebuilt) fuel injection pumps. Your Venezuelan Bolivars may go further than my US dollars these days, so you should price it there, may be much cheaper. There is more info here: http://www.bertram33.com/forum/topic.asp?TOPIC_ID=140 As you can see, I've kind of beat this issue to death. quote:If I decided to go with the cummins 6BTA, how difficult is the instalation process? How much is there to change or to redo? I would think that for the FBC, for physical access you need to open the entire cabin deck and remove the rear cabin bulkhead, but Doug L. just went through it and can tell you more. After gaining engine access it's a matter is disassebly and reassembly, with new engine mounts on the stringers. Electrical re-work too. At least your fuel systems or exhausts shouldn't need too much changing. There will be a bunch of other things to do like clean and paint the bliges, R&R the raw water intakes and backer plates, re-tab any loose hull braces, renew bonding connections... stuff like that which is 100 times easier to get done while there are no engines in the way. Swapping engines is a big job and I've never done it myself, so I wouldn't speculate more than that for fear of giving you bad advice... except to say that unless you are very experienced or very adventerous, hire someone in-the-know to do it (or to at least help you do it). Sean Burlingham "Island Time" 1987 Bertram 33 SF Melbourne, FL SBurlingham@cfl.rr.com [img]http://www.bertram33.com/photogallery/p ... d_Time.jpg[/img]

Post by **dougl33** » Sun Jul 08, 2007 5:18 pm

quote:Originally posted by IRGuy (there seems to be confusion as to which shaft size Bertram installed in gas and diesel 33s back in the 80s) Sorry Frank. There's no confusion: ALL diesel 33's came with inch and 3/8's shafts from the factory (unless specifically ordered with inch and a half as it appears yours was). ALL gas powered 33's from 1977-1986 came with inch and 3/8's shafts and 1.9:1 transmissions. From 1987 through the end of production, the gas powered 33's came with inch and half shafts and 2.5:1 transmissions. Regards, Doug L. 1986 33 Bertram FBC Queen Elizabeth Marblehead, MA [img]http://www.bertram33.com/photogallery/p ... sabeth.jpg[/img]

IRGuy · Post by **IRGuy** » Sun Jul 08, 2007 8:33 pm

Doug... Thanks for clearing that up for me.. this is the first time I have seen this explanation. Luis... Sean touched on something I forgot to mention anywhere above... engine weight! The 3208's weigh about 800 lbs EACH more than the Cummins 6Bs.. so just taking 1,600 lbs out of your boat allows for more efficient operation (better speed, better fuel economy). The previous owner of my boat claimed that when he repowered from 3208s to 6Bs the aft end of the boat came up enough that the head shower drain did not work as well. I have the small (aprox 3" diameter) exhausts in the transom with the VelociJet side mounted (we call them "mailbox slots" here) gas exhausts. The bottoms of my 3" exhausts are about 2-3" above the water. I suspect they were right at water level with the original 3208s. You asked about ease of installation of the 6Bs.. since this had already been done before I bought my boat all I can say is that the installation looks clean.. the engines fit close to the fwd engine room bulkhead (the fwd belt guard covers have been removed), and since I can pretty much drop down through the removable cabin floor hatches to get outboard of them I do not need to use the doors in that bulkhead (although the stbd side is quite restricted because of the cabin counters being on that side). The aft end of the transmissions (I have Twin Disc 5050As) allows a couple of inches of shaft to show ahead of my dripless water lubricated shaft seals. I suspect Doug and Bill have the same situations. Frank B - IRGuy@aol.com "Phoenix" 1983 FBC Wilmington, NC

buzzk · Post by **buzzk** » Mon Jul 09, 2007 2:25 am

I have a 1988 FBC. It was a gas boat converted to diesel. I thought my boat came with 1 3/8" shafts. It now has 1 1/2". When I changed my strut bearings one of the bearings had been turned down to accept the 1 1/2" shaft, the other strut boring was the correct size. So I removed the strut and had it bored to accept the right bearing. Maybe it came this way from the factory with two different size holes in the struts. I don't know because I didn't do the conversion. Buzz buzzk 1988 Bertram FBC Buzz Off Morehead City, NC

Brian Davin · Post by **Brian Davin** » Fri Jul 13, 2007 11:24 am

I had the 1 1/2" shafts with my gas '90 and upgraded to 1 3/4" with new struts when I repowered to 370's. We didn't have to remove the rear bulkhead to remove old gas or install new 370's. We removed Starboard cabinets from the refrigerator back, but left the countertop in place. Brian '90 Bertram 33' FBC Never Say Never Guilford, CT (Homeport) Kinnelon, NJ (Home)

lperedat · Post by **lperedat** » Sat Sep 15, 2007 11:52 am

Well, A little update. I bought recon engines from cummins dealer in Miami area, Miami Yachtworks and they were about 4 weeks late delivering the engines and never returned any calls. Service at this place really sucked. It will take me about 2 weeks to receive them in Venezuela and to start having fun withy the installation. will keep you up to date.

IRGuy · Post by **IRGuy** » Sat Sep 15, 2007 6:15 pm

Luis.. Good luck with the installation.. take pics and document things if you can.. I am sure others who want to repower in the future will want to see what you have done. Frank B - IRGuy@aol.com "Phoenix" 1983 FBC Wilmington, NC

smanni · Post by **smanni** » Sun Sep 16, 2007 7:30 am

Nice - I love it when you guys do this stuff - gives me motivation to start saving for it.

No Yacht Yet · Post by **No Yacht Yet** » Fri Sep 28, 2007 1:53 am

Hi All, I haven't been on here for a while. We have been enjoying the 86 FBC we bought in the spring. It has 1450 hrs on gas mercs. Eventually I will be repowering. Looking at Yanmars and have been told by a few installers that it is a differant boat with the diesels. My question to those of you that have gone this route what are those differances? Is it just he speed and reduced fuel consumption or does it enable the boat to ride better at speed in big seas.Most of my boating is out from the west end of the canal in Buzzards Bay