Viewing 20 topics - 1 through 20 (of 84 total)
    • Cummins Marine Forum Topics
    • 1982 Bertram 38 Convertible – Engine Raw Water Thru Hull Location

      This topic has 3 replies, has 3 voices, and was last updated byRob Schepis 1 month ago

      February 11, 2024 at 9:56 pm Hi Everyone, I am working on the cooling system for this boat’s 6BTAs and doing it the “seaboard” way.   I’d like to make some space when you enter the engine room and attached is a pic showing the location of current 2.5″ strainers and also newer 2″ strainers further forward.  The third picture shows where the new 2″ thru hull might go.  I don’t have a picture showing axial position of the thru hu…

      Started by: Zac Schramm


      3 Replies
      February 16, 2024 at 1:14 pm They do both, flow and protection.  But as to which style, etc, there is no one size fits all. Where you boat, how long between haul outs, who does your maintenance, etc etc all come into play. My 6BTA’s have external squid screens only, nothing  internal/inline and been that way since 2002 repower. Zero issues with temps or fouling. 

      Last Post by: Rob Schepis posted: 1 month ago

    • Repowering ’62 Connie from 427 gas to 6BTAs

      This topic has 4 replies, has 2 voices, and was last updated byTony Athens 2 months ago

      January 17, 2024 at 6:30 am Hi all! I’ve got a ’62 45′ Connie that I am repowering from 427 gas to 6BTAs (JWAC). I am spit-balling that the performance should be acceptable, as I don’t run her hard at all, and don’t plan on changing that. I would love to hear what the brain trust thinks. Current setup is (2) 1969 Chris Craft 427s with Paragon 44s, 2.5 to 1 gears. I am swinging 22 x 22 modern 4 bladed wheels. Her weight is listed at 28000 pound…

      Started by: bwanaf111


      4 Replies
      January 17, 2024 at 5:42 pm “Aftercooler looked clean, so passed on that…  What does that mean? You must have x-ray vision? 160F Hi-flow thermostat is a must for this engine to get the temps  safe Mounting–front of the engine and the side on the transmission

      Last Post by: Tony Athens posted: 2 months ago

    • 1973 Aluminum Houseboat Repower

      This topic has 4 replies, has 2 voices, and was last updated byTony Athens 3 months ago

      December 3, 2023 at 6:18 pm Hello All! I’ve been preparing this post for about 2 years now. I have a 50 foot 1973 Pluckebaum Houseboat. I am repowering from the current twin Marine Power 454s (Late 70’s) mated to Velvet Drive V-drives with 3.14 reduction. This specific vdrive model have been out of production for a long time. As you see from the photos of the boat, it is an all aluminum hull and superstructure. It is s single level and has decent head clearance…

      Started by: Jamie Alberts


      4 Replies
      December 4, 2023 at 5:03 pm Jamie, This is way too complicated to do this way—You definitely do not want 302IV’s——————–Lets try 15 minutes or so on the phone–Drop me a note at [email protected]–your time zone is?

      Last Post by: Tony Athens posted: 3 months ago

    • Single diesel displacement trawler repower

      This topic has 2 replies, has 3 voices, and was last updated byTony Athens 6 months ago

      September 7, 2023 at 10:08 am Hi folks, I’ve got a 42 ft, 36,000 lb trawler with a Cat 3208TA and a TD507 2.54:1 in her.  It’s a Sunnfjord 42, they mostly build commercial boats and fishing boats but ours was built as a yacht. It’s go an 8″ wet exhaust going into a shower can style riser. Injection point is 48″ above DWL so they got that right. The Cat has 9000 hours, we plan to keep the boat long term so want to repower now rather than after it…

      Started by: Eddie Sheufelt


      2 Replies
      September 9, 2023 at 7:18 pm What RPM and vessel speed do travel at when going from Point A to Point B?   That will be a start as to whether  “much less engine” will be suitable. Your hull is probably a 6-8K easy to move WINE & CHEESE  cruiser..    

      Last Post by: Tony Athens posted: 6 months ago

    • Thanks Tony and the Seaboard Cummins Forum!

      This topic has 3 replies, has 4 voices, and was last updated byLaurence Warden 8 months ago

      July 5, 2023 at 12:17 pm I just wanted to say thanks to Tony and participants of this forum. After 15 years in a giant shrink wrap tent, I splashed my 1969 Chris Craft Roamer 46 and had a pretty much incident-free 108 mile run to my new home port. As part of the refit, I repowered from Super SeaMaster twin turbo and intercooled gas engines to Cummins 6CTA M2 420hp engines that light off immediately. They ran great the whole way. I discovered some diesel in the bilge at …

      Started by: 1969Roamer46


      3 Replies
      July 8, 2023 at 7:02 pm Congratulations on the successful trials.  Followed this on another forum for years and it’s great to see it on the water. I can only imagine how satisfyingly that was.

      Last Post by: Laurence Warden posted: 8 months ago

    • CUMMINS 6BTA REPOWER AUTOMOTIVE

      This topic has 5 replies, has 3 voices, and was last updated byTony Athens 10 months ago

      April 24, 2023 at 7:43 pm I have a 1937 retired Canadian Fish Tug.  Currently powered by a Perkins 6.354 N/A.  The tug is keel cooled with dry exhaust.  I’ve purchased a 1993 Cummins 6BTA CPA 1579, with low miles/hours that I’m looking to repower with.  For the most part this conversion should be straight forward with already having dry exhaust and the keel cooler.  Where I’m hung up, is on the aftercooler.  Is the aftercooler required if I’m plum…

      Started by: andyvinkus


      5 Replies
      April 27, 2023 at 7:26 pm Original aftercooler on the engine was air to air or coolant cooled?  Some good pics on the engine would answer that for me.. Original engine rating was? (HP & RPM?)    What are you expecting to gain over the Perkins you have now?    Any good 6BT 5.9 with a good working turbo,  set up right can make  up to about 150HP in the 2400 RPM range without an aftercooler at cruise,  using about 8 GPH of you want to run that hard… 

      Last Post by: Tony Athens posted: 10 months ago

    • Shaft/Engine Re-Alignment

      This topic has 6 replies, has 4 voices, and was last updated bylpmcc 10 months ago

      April 19, 2023 at 7:47 pm 25 Years ago I had SS strust made by my prop shop and they have done well. When the 6BTA’s were installed they were remove and reset as part of the engine install.  That was back in early 2019.  All has been well. However, I took my extended family out to see the 4th of July fireworks back last summer (’22).  I anchored up with dozens of other boats just out of the intracostal and watch the show.   However, when heading back to the c…

      Started by: pwrobert


      6 Replies
      April 27, 2023 at 5:12 am Yes I have, and yes, I followed your directions.  I only really have one spot on the shaft to measure with a dial gauge and that is 4″ behind the coupler (v-drive boat).  My question is where the high & low spots are, and by how much, give you any guidance as to what adjustments in the motor mounts need to be made?

      Last Post by: lpmcc posted: 10 months ago

    • Searay 330 EC Re-Power Yanmar

      This topic has 3 replies, has 3 voices, and was last updated byRob Schepis 10 months ago

      April 24, 2023 at 2:14 pm I have a 1997 Sea Ray 330EC repowered with twin  rebuilt 2002 Yanmar 6LPA-STP 315HP. 2;1 gear and 18″x21 pitch 4 blades with cup. Listed below are the current specs: No load RPM 4200, loaded RPM’s 3600, top speed 24knts, boost is at 18 psi and I’m told on these engines 20 is tops. My issue is that the performance of my boat is far less than the performance of the sister boat set up with all the same drive gear. One variable I&#…

      Started by: John-Eric Buckheit


      3 Replies
      April 25, 2023 at 11:16 am 5 year difference in boat model year can change things, weight being a big one.  Have both boats been weighed on the same lift? The sistership has more prop diameter and more pitch and is turning more rpm’s than you? Have the tach’s on both boats been verified ? Your boat is overpropped and/or has a low power issue…    

      Last Post by: Rob Schepis posted: 10 months ago

    • Is 1 1/4 Raw water pick up enough for 6BTA 370’s?

      This topic has 3 replies, has 3 voices, and was last updated byTom Platt 12 months ago

      March 20, 2023 at 6:08 pm I’m sure this will be the first of many questions as I go down the road of repowering my 1974 35 Bertram convertible. Basic overview is the boat originally came with  big blocks. then at some point she was repowered with Cat 3208 NAs with aftermarket M&W turbos…. I  run the boat for  charter fishing…but it has come to the point where   I need a little upgrade in speed, fuel economy and Technology. I am repowering Her with t…

      Started by: Tom Platt


      3 Replies
      March 21, 2023 at 9:14 am Thank You Guys.. nice to confirm what i was thinking….. 

      Last Post by: Tom Platt posted: 12 months ago

    • Repower cruisers yachts 360

      This topic has 8 replies, has 4 voices, and was last updated bypwrobert 1 year ago

      January 15, 2023 at 11:32 am Hello i have a 2009 cruisers yachts 360 express currently equipped with mercury 8.1s with zf63iv ratio 2.5 and 1.5inch shaft i am repowering with twin diesel yanmar 6lpa stp2 and keeping same gearbox. The boat came from factory as an option with the following setup: yanmar 6lpa with zf63iv ratio 2.5 and 1.75inch shaft my question is : should i upgrade my shaft from 1.5 to 1.75 or i will be safe keeping my old shafts?  

      Started by: Richard Khawam


      8 Replies
      January 31, 2023 at 3:42 pm When I re-powered with 6BTA’s at 355 HP each from 200 HP Detroit 8.2L engines and went from 3 blade to 4 blade Nibrals (22X20)I kept my 1.5 inch Aq19 shafts after getting different suggestions.  My 38 ft boat is likely heavier than yours and carries 300 gallons of fuel and 80 gallons of water – about 24,000+ lbs. Transmission is 1:1.75 so shaft RPM’s may be similar but also consider mine are diesel and yours are gas.  Not sure …

      Last Post by: pwrobert posted: 1 year ago

    • Repower Cruisers Yachts

      This topic has 1 reply, has 2 voices, and was last updated byTony Athens 1 year ago

      November 3, 2022 at 12:32 am Hello, I am the owner of a 2009 Cruisers yachts 360 express powered by twin Gaz engines mercury 8.1 with ZF63IV (ratio 2.5) I am in the process of repowering my boat with twin diesel engines. I have contacted cruisers yachts and found that this boat model was powered with diesel engines from the factory with either Yanmar 6lpa-stp2 and zf63iv (ratio 2.5) or Volvo Penta D6-350 and ZF85IV (ratio 2) I am confused between repowering with brand new Y…

      Started by: Richard Khawam


      1 Reply
      November 4, 2022 at 3:08 pm IMO, prop your D6 350’s to 3600 RPM minimum with the vessel loaded for bear, and you’ll be just fine using ZF63IV’s that are in perfect shape or “as new” …  

      Last Post by: Tony Athens posted: 1 year ago

    • Bertram 28 new power prop sizing

      This topic has 1 reply, has 1 voices, and was last updated byFernando Perez 1 year ago

      October 24, 2022 at 8:17 pm Hi, a friend of mine is needing popellers size  recommendations for Bertram 28 1972 with Cummins 4bta 250hpRpm 600 to 3000Shaft 1-3/8 Wating on trans ratio   any one with similar set up?    

      Started by: Fernando Perez


      1 Reply
      October 25, 2022 at 5:11 am Ratio is 1.56:1

      Last Post by: Fernando Perez posted: 1 year ago

    • Yanmar 4lha-stp, lack of power

      This topic has 1 reply, has 2 voices, and was last updated byTony Athens 1 year ago

      August 15, 2022 at 9:14 pm I’ll keep it short and to the point. I did a motor swap from a Volvo d3 to a yanmar 4lha-stp. I’m running a Volvo dps-m Outdrive with 195 gearing boat is 21’ and about 5500 loaded. problems- No power going up the trailer(rpm no higher then 1600). Lope between 900-1100 rpm, boat only gets 24knts wide open at 3500 plus. Put bigger props and lope is at idle(real bad) and 1k rpm going up trailer.  motor info. Injector pump rebuilt, injectors re-set,…

      Started by: Ellison s


      1 Reply
      August 17, 2022 at 5:27 pm What the past history of the motor?  Didn’t you run it before the install?   Why did it need a injection pump rebuild?.. Certified shop?  The loping could be a bumper spring issue ..   Get a 0-30 PSI accurate boost gauge on the engine, and get your tach accuracy verified at a steady 3000 RPM in neutral

      Last Post by: Tony Athens posted: 1 year ago

    • What am I missing?

      This topic has 7 replies, has 3 voices, and was last updated bypwrobert 1 year ago

      February 1, 2022 at 3:47 pm I have a 37 foot 11.5 beam 20,000 pound Roughwater that is currently powered by twin 250 HP Detroit 8.2s. After a fire in a nearby marina I was able to purchase the motors from a 2007 Meridian that had external damage from the fire, it was not the boat that burned but moored next to it. ( check your shore power connections in winter!) I got two low hour, very well maintained 330 HP, 6bta s with ZF 80 A – 2 gears at 1.5:1, the mixing elbow,…

      Started by: Steven Borcherding


      7 Replies
      August 9, 2022 at 9:56 am Here is an overlayed picture of the Detroit 8.2L (Red) with 502 Trans with a Cummins 6BTA with ZF 220A (Black).  By superimposing the scaled diagrams in Photoshop and lining up the Faceplates of the transmission output flange you can see how they stack up.  Same degree of down angle.  Detroits are wider and the Cummins are a couple of inches longer.  The Cummins/ZF packages save about 1500 lbs on the install. Only other somewhat issue was the Cu…

      Last Post by: pwrobert posted: 1 year ago

    • Repower Considerations

      This topic has 4 replies, has 3 voices, and was last updated bypwrobert 1 year ago

      December 8, 2021 at 2:41 pm We have a 37 foot, 16,000 pound 1987 Roughwater 37′ that is currently powered by twin Detroit 8.2 350 hp engines with TD 506 gears. We love the boat and want to repower. It has newer fuel tanks, 1.5 shafts, new logs, cutlasses and struts. The steering system is also updated. The bottom was just compleatly stripped and re done. Currently with the 8.2s, we cruise at 8-9 knots at 1750 RPM 14-16 at 2,200 and exceeed 20 knots WOT. We are not ri…

      Started by: Steven Borcherding


      4 Replies
      August 9, 2022 at 9:33 am Are you sure they are 350 HP engines.  These look just like mine – standard Detroit/Allison Turbocharged which were rated at 205 HP..Only J&T and a couple of others made Aftercooled or twin Turbo and Aftercooled engines with the 350 HP.  I don’t see any of that hardware in your pictures. What is your fuel burn at 16 kts and at 20 kts? My 38 ft Chris Craft with the DD 8.2L weighs more and at 18 kts it burned 18-19 GPH.  I repowere…

      Last Post by: pwrobert posted: 1 year ago

    • Genset exhaust routing

      This topic has 6 replies, has 3 voices, and was last updated by1969Roamer46 1 year ago

      July 15, 2022 at 6:19 pm I realized a while ago that the port side of my project boat is getting heavily loaded compared to the starboard side. To balance the boat better, my best option is to relocate the Fischer Panda 12k genset from the port main engine stringers to the main stringers on the starboard side. This is a 1969 Chris Craft Roamer 46, and the genset exhaust thru-hull is welded to the hull. The Awlgrip paint job is done, so I’m not willing to make new …

      Started by: 1969Roamer46


      6 Replies
      at

      Last Post by: Anonymous posted: 1 year ago

    • Prop set back from face or transom

      This topic has 6 replies, has 4 voices, and was last updated byTony Athens 1 year ago

      May 17, 2022 at 2:15 pm    Is there some sort of formula for the distance from transom face to closest prop. blade?   How do I know how far under the hull the prop should be?   The picture shows the prop blade being 2 1/2 inches from the face of transom. In this position I can take the prop off without removing the rudder. The rudder is a transom mount rudder.   I am more concerned with being too close to the transom face.  How do I know where the prop should be positi…

      Started by: Darren Kinvig


      6 Replies
      May 30, 2022 at 4:25 pm Darren,   I really do not think there is a cut & dry answer to your question.. All has to fit, allow clearance for the prop to R&R it ( hopefully without pulling the rudder), all tip clearance, allow a minimum space between the prop hub and a cutless bearings, etc. Every boat is different..   I grabbed of few pics –As you can see, the mountings/setups  are all over the place. 

      Last Post by: Tony Athens posted: 1 year ago

    • Yanmar 6lp… replace, repower, or rebuild?

      This topic has 5 replies, has 3 voices, and was last updated byRob Schepis 1 year ago

      March 29, 2022 at 10:40 pm I have a 33’x12′ boat that does it’s job exceptionally, so I’d like to keep it going. It originally had Volvo 41s and was repowered in 2001 with Yanmar 6lps and Bravo 2s. I bought it shortly afterward and after a brief fight with drives and valves have had a decent relationship and built a good business with the Yanmars. I take care of them like my life depends on it, because it does, and despite their limitations and nee…

      Started by: matt1


      5 Replies
      April 1, 2022 at 4:39 am If you have six engines on hand that “could” be rebuild it sounds like you have your own parts department right there.  There’s a ton (actually 2.7 tons) of value in that stockpile.

      Last Post by: Rob Schepis posted: 1 year ago

    • Prop clearances/distance. Two questions.

      This topic has 4 replies, has 3 voices, and was last updated byDarren Kinvig 2 years ago

      January 9, 2022 at 10:21 pm    Can someone clear up these clearances/distances for me.   What is the recommended clearance from the prop to the underside of the hull.  Also. I have a transom mounted rudder. I understand the idea of having enough clearance from prop to rudder to change the prop without removing the rudder. What is the distance from the prop to the face of transom. Is there a Min. that should be observed?  Will there be cavitation issues if the prop is too c…

      Started by: Darren Kinvig


      4 Replies
      January 11, 2022 at 10:00 pm      Ventilation?  is this a condition where air can enter the prop wash/ prop from the end of transom into the prop? Looking at some drive examples where props on some boats appear to be close to the face of the transom, I have seen that the transom has been extended in the area above the prop. Is this a solution to prevent Ventilation?    Thanks for your advice and knowledge.

      Last Post by: Darren Kinvig posted: 2 years ago

    • Repower

      This topic has 2 replies, has 2 voices, and was last updated byDavid strout 2 years ago

      December 13, 2021 at 6:39 pm I have a 32 foot 12.9 beam Atkinson novi solid glass hull. I’m Guessing around 14000 lb. 3 ft draft with keel. Anybody who knows more accurate numbers don’t hesitate .. Im Changing out the Detroit 471 I have a 89 I believe 8.3l Cummins engine I believe 220 hp maybe 250 once I put marine turbo paired with a 1.8 to 1 transmission Questions I have is, it has a 1.5 inch shaft will that work And what size of a prop would be roughly …

      Started by: David strout


      2 Replies
      December 14, 2021 at 10:48 pm s/n 44272339 6ct 8.3 Rated hp 207 hp at 1800rpm It has 4000 hours been well maintained in a generator. No blow-by and no black smoke of course I didn’t have load on it. but it sounds tight. The coolant looked clean like a slimy film on the side of the hose when I drained the coolant . I think it’s been governed at 1800rpm All info is welcome. My biggest concern is my shaft on the boat is 1.5 inch I can’t seem to find any in…

      Last Post by: David strout posted: 2 years ago

Viewing 20 topics - 1 through 20 (of 84 total)

You must be logged in to create new topics.