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- Cummins Marine Forum Topics
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Disassemble QSM11 to fit in to boat – then reassemble
This topic has 5 replies, has 3 voices, and was last updated by
5 years ago
April 29, 2019 at 10:24 am In the early stages of researching to potentially repower my 6v92/550 powered flybridge express. Currently an ideal time to explore since my DD need to be overhauled. This would be an inframe overhaul. but doing research and due diligence on a Cummins QSM11/630 potential overhaul. The engine can not be “dropped in” as the clearances in to the cabin and then the below engine room just doesnt have the clearance. So whatever happens,…
5 RepliesApril 30, 2019 at 4:44 am Rob. Thanks for the link. I literally found those last night and have already printed them out. Looks like the Cummins is 23 in longer than the 6v92. But in reality Itās probably 13in as the last part is what sticks out from the exhaust blower over the transmission which isnāt a big deal. It is about the same width and a few inches shorter in Height. I got the engine block length of 37in but couldnāt get more accurate measurements Iād the widt…Last Post by:
posted: 5 years ago
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35 T Jason Repower
This topic has 5 replies, has 2 voices, and was last updated by
5 years ago
April 27, 2019 at 11:31 am Right now I have a 35 T Jason commercial lobster boat that is powered with a bf6m 1015 Deutz rated at 443 HP. I have a 2” shaft swinging a 28×34 wheel. I have a zf 325 2:1 gear. I am looking into a QSC 8.3 500. My Deutz is a 2100 rpm engine. Would I be able to keep my zf 325 at 2:1? The gear is only 2 years old with less than 2k hours on it.
5 RepliesApril 28, 2019 at 7:19 pm Thank you Tony! Fuel burn is not a concern. My concern was unfamiliarity with what the engine can handle, as it came in the boat when I bought it. Also not much support in this area. Most of the day is spends at idle hauling gear, and my runs are only 15-20 minutes average at cruise speed. Once Iām where Iām hauling gear i donāt hit cruise speed very often. I will run her a little harder and see where it brings me. Thank you for your help!Last Post by:
posted: 5 years ago
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Propeller Cupping – 38 Bayliner
This topic has 10 replies, has 3 voices, and was last updated by
5 years ago
April 2, 2019 at 8:53 am Hello…my name is Nick… I have a 1988 Bayliner 3870 repowered with Cummins 6BTA’s 5.9M’s, build 8206, Tranny gear at 2:1, WOT 2600…propellers 21x26x4 Nibral. My issue…I have some damage in the corner of the tunnel where the trailing edge of the prop has pitted a hole about 3/8″ deep apparently caused by water turbulence/cavitation. Right now I cruise at 2350RPM/16.5kts, WOT 2600RPM/22kts. I don’t w…
10 RepliesApril 8, 2019 at 2:48 pm Steve wrote: Sir, Are those the original propellers and were they adjusted when the boat was repowered? I had my prop serviced by Wilmington Propeller Service in Southern California. Talking with numerous others (including a Long Beach Harbor Pilot who has a fishing boat a few slips down), Wilmington Prop Service has a stellar reputation in the shipping industry. The owner there told me that generally all props in tunnels should be cupped. He ex…Last Post by:
posted: 5 years ago
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What size engine to use in a TJason 35?
This topic has 9 replies, has 4 voices, and was last updated by
5 years ago
March 7, 2019 at 10:32 am I am planning on having a 35 foot TJason built I was hoping the guys on here could help me out. I am trying to decide which engine to use. The QSL9 450 or the QSC 8.3 500. Also what gear would be a good match The boat will be a cruiser/ fishing boat but mostly used for cruising, with the hopes of doing the great loop and to take it to the Bahamas for extended cruises. The TJason is a lobster boat I would like a solid 18 knot cruise. The boat wi…
9 RepliesMarch 13, 2019 at 7:44 pm Tony, Thank you for your help. I did not understand the performance curves and was reading them wrong. After reading the article you directed me to I get it now.. Thanks again. DonLast Post by:
posted: 5 years ago
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Thinking of re-powering from Cat to Cummins
This topic has 1 reply, has 2 voices, and was last updated by
5 years ago September 16, 2018 at 9:34 am Hey All: I’m new to this site. I have a question, I have a pair of T/3208TA 375 Cats w/TD 507 gears with approx. 4k hours. I have an opportunty to replace them with a pair of QSB 5.9 480hp with TD MG5061A 1.54:1 gears @ < 100 hrs. The boat is a 1988 37′ Topaz which I use for charter fishing,approximate displacement of 20k #’s. Im wondering what and if this would be a good move ? I like the idea of the smaller motor (inline) …
1 ReplySeptember 16, 2018 at 3:14 pm Post your current gear ratio w/ the CATS , your current WOT RPM and vessel speed, current vessel speed at 2300 rpm, and most important, your current prop specs and engine HP. I seriously doubt you could use a 1.5 R gear. For propping purposes, this engine need to see 3500 RPM. TonyLast Post by:
posted: 5 years ago
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Cummins repower
This topic has 2 replies, has 3 voices, and was last updated by
5 years ago September 13, 2018 at 11:14 am Hi, I have a 1989 26′ Boca Grande i am in the process of redoing. Boat weighs roughly 5500 lbs just the hull. 26′ long 9’6 beam. Boat currently has a volvo TAMD61a which weighs roughly 1800 lbs and puts out ~300 hp. Im looking to repower with a cummins around the 250-300 mark. Ive got my eyes on one that is a 270 hp. Any recommendations? i can pretty much do whatever i want with it because the hull is basically stripped. Ive th…
2 RepliesSeptember 15, 2018 at 6:34 pm Rob Schepis wrote: Thereās nothing not to like about the 270B. Lower RPM and JWAC so no salt water aftercooler maintenance regimen.. Do you have the serial number of the one you āgot your eyes onā ? Is it new recon or RTO or ?? And what does this mean ? āIāve thought about swapping the cam for a 370 hp marine cam into this 270 im looking at.ā any chance “the 270” is a non marine ? same question as Rob to the OP? ? “370 marin…Last Post by:
posted: 5 years ago
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Repower Question
This topic has 6 replies, has 5 voices, and was last updated by
5 years ago August 10, 2018 at 10:03 am I’m a new registered user, and I’d like to ask you a few questions and hopefully anyone can be of some help. sbmar website is great btw. I am interested in a purchase of a 1998 Maxum 4100 SCB, but it has 330hp Cummins 6BTA’s, and I think that is not enough engine for that weight boat. I could be wrong, but while I know some may say buy an express boat if you want something that does around 22knots, but I am leaning towards a Se…
6 RepliesAugust 24, 2018 at 10:56 am Carmen, Just as an FYI, I purchased a 2005 Maxum 3700 CY, Twin 6BTA’s 5.9 330hp. Not sure of the weight difference of the 41′ but they have ample power. I cruise at 2400rpm (22mph)Last Post by:
posted: 5 years ago
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Re-Powering 1999 26' Shamrock Express
This topic has 4 replies, has 3 voices, and was last updated by
5 years ago July 9, 2018 at 10:29 am Hi from the East Cost, I have been considering to re-power the 99 shamrock 26′ express from the 5.7 gas Sea max for long time to power Diesel to get more fuel efficiency per Gal and long range . what is the right eng application or the right fit for this 99 26′ Express. Is Cummins like 6BT 215hp~250hp with the current ZF to keep the existing 1 1/4 shaft will be the right fit for this project ? what is the cost associated with …
4 RepliesJuly 10, 2018 at 5:30 pm I have a friend that has that has that same boat with a cummins 6b 210. They came as a option. To me putting a diesel in a boat like this is a great project. Is it always the right choice?? Going from gas to diesel requires a lot of work. Some of these boats with a diesel in it might be a better way to go. Not trying to burst your bubble just putting it in perspective. I would do a little research and there is a owners club with a ton of info.Last Post by:
posted: 5 years ago
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Unspported Shaft Length
This topic has 1 reply, has 2 voices, and was last updated by
5 years ago May 19, 2018 at 9:01 pm Hell Tony and All, I’m considering a repower of a fiberglass keel boat. My calculations show a 28″ to 30″ length of shaft between the hull shaft log forward to the shaft/tranny coupler. Figure 380 QSB 5.9 Recon power, 8 degree ZF85A gear, 2:1 gear swinging a 22X19 four blade more or less. TBD . Prop shaft diameter 1.75 inch. 20/40 rule apply here ? No less than 20 X shaft diameter between bearings? = 35″ No more tha…
1 ReplyMay 20, 2018 at 1:46 pm Am missing total shaft length? Flexible or rigid engine mounts? Flexible or rigid shaft seal/log? TonyLast Post by:
posted: 5 years ago
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Transmission Clearance to Hull
This topic has 2 replies, has 2 voices, and was last updated by
5 years ago
May 12, 2018 at 8:10 pm I am currently in the middle of a repower project. In order to get good shaft alignment, I need to have the engine sitting low in the boat, with the corner of the ZF220A only clearing the bottom of the boat by about 3/8″ on the outboard side. Is this too close? Is there a rule of thumb or a standard for this? Appreciate any input. -Mike-
2 RepliesMay 14, 2018 at 9:01 pm Tony, A fiberglass boat, a 37′ SeaRay. The stringers looked wimpy to me so I added 3/4″ of plywood that was glassed in, transom to forward engine room bulkhead. Mounts are 1/2″ aluminum “L” channel with 1/2″ backing to sandwich the top of the stringers, each bracket being 12″ long. I used new Barry mounts I got from Cummins. Sorry, no pictures, my phone dropped and ceased working today!Last Post by:
posted: 5 years ago
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1997 Bertram 36 Repower
This topic has 13 replies, has 8 voices, and was last updated by
6 years ago December 27, 2017 at 3:03 pm We are considering a purchase of a 1997 Bertram 36 with Cummins 450 Diamond engines. Approximately 1800 hours. Engines appear to be in good shape (sea trial and inspection pending), but the current owner has told us its not very fuel efficient above 1800 RPMs. Displacement is 30,000 lbs dry. Owner says at 1850 RPMs it is 17 knots and ~24 GPH, which seems a bit higher than the published power curves for the 450C Fuel efficiency, no smoke/fume…
13 RepliesMay 2, 2018 at 8:12 am I’m a little late to the party here by the looks of it! I figured I would chime in anyway . I just completed a repower of my 36 Bertram Moppie. The boat originally had 430hp Volvos in it. I repowered with a set of 550hp QSB6.7’s. From my experience your fuel burn numbers at 1800 don’t seem too far off. This hull does not like speeds below 20 knots, it’s like it is fighting itself to plane out. With the Volvo’…Last Post by:
posted: 6 years ago
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Possible shamrock repower
This topic has 1 reply, has 2 voices, and was last updated by
6 years ago March 22, 2018 at 5:55 am Thinking of repowering a 1987 26′ shamrock stalker…..used mainly in freshwater lake but would like to trailer the boat to the coast for some fishing and diving adventures I was thinking about 380 ish hp. Boat weighs about 6000 pounds dry with the 350. Would like to gain speed, fuel efficiency, and dependability Currently has port and starboard fuel tanks 54 gal each Also have some concerns about prop clearance shaft size runnin…
1 ReplyMarch 22, 2018 at 8:46 am I take it you want to put a diesel in it. I’m a big fan of shamrocks. They put a lot b series in the 26 shamrocks. Most were 210 hp. Big difference from that and 380 hp. Personally I think I would look for one of those. You have a ton of issues to deal with. Exhaust, fuel returns, shaft sizing, will it fit, prop clearance to name a few. This site has a lot of info on shamrocks https://forum.classicshamrock.net/ Great project though goo…Last Post by:
posted: 6 years ago
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Repowering 1990 luhrs 320
This topic has 9 replies, has 3 voices, and was last updated by
6 years ago March 2, 2018 at 6:59 pm Hello everybody my name is Cesar Correia from Rhode Island i work on alot of diesels i work for an oil company full time servicing everything they have from diesel vans and gas jobs to large freight liners and kenworts. Lots of diagnosing also. That said i will be doing 90 percent of the work to try and keep my bank account in one piece..Originally the boat had twin 454 crusader 350hp models with 1 3/8 shaft. Originally with 454s 350hp model at …
9 RepliesMarch 17, 2018 at 8:01 am Ceasar, You seem to have a great hands-on background in working on engines & equipment, but you are not understanding my responses. 1) The total operating WEIGHT of your finished vessel will be the main factor as to meeting your performance goals vs the HP you have to put into the props. Have you weighted your vessel and thought about what it will weigh after you are finished with the restoration/repower? Every extra pound you add will re…Last Post by:
posted: 6 years ago
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Jersey Dawn Repower
This topic has 6 replies, has 3 voices, and was last updated by
6 years ago February 14, 2018 at 12:33 pm The boat in question is a 36 or 42 jersey dawn. Most 36s come with 3208 cats at 320hp and most 42s have 6-71s TIB 485s. From my research they are 18/19knt boats. My question is it is even possible to get these boats to that 27/28knt cruise with the newer technology? I am also aware that some of the older hulls don’t perform well at higher speeds so any information there would be appreciated as well. Ultimately, I don’t think I would …
6 RepliesFebruary 16, 2018 at 3:53 pm Did something like this conversation occur over on BoatDiesel.com a while ago? In any case, if that’s the boat you want, and those are the engines you want, go for it. Life is too short to own an ugly boat, or is it Life is too ugly to own a short boat? Something like that, in any case, keep us informed about your quest. I for one would very much like to hear more about this project. Believe me, I spent many hours pondering the same questi…Last Post by:
posted: 6 years ago
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3.9 stern drive repower?
This topic has 2 replies, has 2 voices, and was last updated by
6 years ago
December 28, 2017 at 11:51 am We inherited a 2958 Bayliner last year with twin 350’s & omc Cobra’s. After throwing some time into it, we have decided it needs repowered with engines & drives. The beam is 10.5 making the 350’s very difficult to work on. I work in heavy equipment repair & hate spark plugs. My neighbor at the marina has a 2001 sea sport with twin 3.9’s and Volvo drives, was wondering if this is a option? Thanks for any advic…
2 RepliesDecember 29, 2017 at 6:08 pm Thanks Tony, we will probably fix what’s in it and use the boat for awhile till something pops up that has a good diesel package. Alot of nice boats out there with really outdated engines installed, hopefully that changes in the next few years. Paul.Last Post by:
posted: 6 years ago
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Repowering a Baja
This topic has 1 reply, has 2 voices, and was last updated by
6 years ago October 12, 2017 at 6:34 am Let me preface this by saying I have not purchased any boat to do this in yet, this is just a really wild idea in my mind that I really want to make happen, and would like some input as to what your thoughts or concerns would be. I am looking at getting a 26-30 foot Baja Sport powerboat if you will, going to get one with a 454 BBC or bigger in it with a Bravo drive to it at minimum. Now I have always been a diesel guy and would love to do a dro…
1 ReplyNovember 16, 2017 at 9:59 pm I guess this is another one that got missed.. Sorry.. Before I get into the “has anyone done this” , (I have) let me ask you this……………..Do you have a general “budget” for such a project and do you have a general sketch or some pictures of what you have now vs, what you want to end up with.. That would make it a lot easier to comment effectively.. TonyLast Post by:
posted: 6 years ago
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CAT 3126 420 to Cummins 6CTA 430
This topic has 6 replies, has 3 voices, and was last updated by
6 years ago October 25, 2017 at 8:26 am Posting this for a guy on down east boat forum. I’ve asked him to join……”hell it’s free” !!!!! “hey bill I know your a cummins guy and are very knowledgeable in this are Iām thinking for down the road I have a cat 3126B 420hp now with a td2.5:1 gear if I put in a recon 6cta 430hp could I use the same gear the cat turns 2800 wot the cummins 2600 wot” The boat is a beautiful 36 H&H down east lobs…
6 RepliesOctober 29, 2017 at 12:49 pm Propped right, the 6CTA 8.3 will turn at least 2750 and can run all day at 2400 RPM.. If you are working the motor super easy, just add 1-2″ of pitch to get the R’s down to 2200 or so to get your happy vessel speed. Don’t confuse MINIMUM rated RPM or test cell data with how this engine really likes to be propped in the field under real ocean/working conditions. . TonyLast Post by:
posted: 6 years ago
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Jersey Sportfish Repower
This topic has 8 replies, has 5 voices, and was last updated by
6 years ago
October 9, 2017 at 6:38 pm The boat is a 42′ 1993 Jersey Dawn III sport fish. The engines are 6-71 TIB’s, 485HP, that have about 1000 hours on them since full rebuilds. They run fine, but they are noisy, dirty, and smelly. It’s a great boat, and my wife and I both love the interior layout and it’s livability. We are now retired and are contemplating the options of running this boat back and forth from RI to FL vs staging it down there and buying …
8 RepliesOctober 22, 2017 at 8:16 am Rick good luck in your repower and in making the tough decisions. I just want to emphasize Tony’s comments regarding sub system upgrades/improvements. Having done a single engine repower myself in the past and having done most of it myself I found an awful lot to do as soon as the old engine was out. Old thru hulls? Now I have good access so time to install new ones. Old water system plumbing? Gone and a new system installed with proper a…Last Post by:
posted: 6 years ago
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Repower Options ?
This topic has 6 replies, has 3 voices, and was last updated by
6 years ago September 1, 2017 at 7:09 am Iām posting this question for a boat owner friend who has a 32 H&H (Osmond Beal down east) lobster boat. Right now the boat is powered by a 1999 Isuzu 6 cyl. Model A-6BG1T 230 hp rated @ 2500 rpms. The engine is keel cooled with dry stack exhaust. Tranny is a ZF63A 2:1 gear, 1.5ā shaft with 24X22 #3 cup prop. Weight is a guess @ 12,000 lbs +-. Owner stated the boat is āheavyā for the sea trial. I sea trialed the boat this past week and phot…
6 RepliesSeptember 3, 2017 at 8:07 am Rob, I’m confident the repower of this older 32 H&H will be no more than a ReCon engine.Last Post by:
posted: 6 years ago
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QSC propping to engine load
This topic has 2 replies, has 2 voices, and was last updated by
6 years ago June 14, 2017 at 6:03 pm Hi Guys, I am after some input on engine load to propping. I have just swapped out a pair of 3208’s to qsc 540’s. I think I may be close but everyone wants more speed if they can have it. The props were calculated on the 490 hp curve to keep within the shaft limits for survey( I am using marinex hs22 2.25). I can post the full numbers but at 2400rpm I get 19.5 knots @ 120 LPH and 52% load. At 2600 I get 22 knots and 74%. The engine …
2 RepliesJune 25, 2017 at 2:56 am Thanks Tony, It makes sense when you say it like that. The sea water sides are on my list to strip and clean. thanks LukeLast Post by:
posted: 6 years ago
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Disassemble QSM11 to fit in to boat – then reassemble
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