Engine Recomendations?
Moderators: CaptPatrick, mike ohlstein, Bruce
Engine Recomendations?
Here is another topic I would like to pick everyone’s brain on. I’m looking for advice on engines for a B28. Before to many people harp on my about focusing on a B28 instead of the legendary B31 I will simply state that I have my reasons and that one of those reasons includes the higher price tag on the B31s which seems to result from the cult like following. Just remember that I have chosen to go Bertram.
For my engine question, I’m wondering what I should look for and/or plan on with a B28. Most of the ones I’ve seen within the price range I’m using have 350s and a few have peninsular Diesels. They all have various HP ratings, hours since overhaul/install, and ages. As much as I would prefer diesel, I have to wonder if the peninsular engines are worth it as I have read several poor reviews concerning their durability and lifespan. I’m also wondering what HP is recommended for good performance with a B28 and any recommendations on possible replacement engines as I would like to account for a future repower in my maintenance budget.
For my engine question, I’m wondering what I should look for and/or plan on with a B28. Most of the ones I’ve seen within the price range I’m using have 350s and a few have peninsular Diesels. They all have various HP ratings, hours since overhaul/install, and ages. As much as I would prefer diesel, I have to wonder if the peninsular engines are worth it as I have read several poor reviews concerning their durability and lifespan. I’m also wondering what HP is recommended for good performance with a B28 and any recommendations on possible replacement engines as I would like to account for a future repower in my maintenance budget.
- In Memory Walter K
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Hilary-For starters, no need to apologize for a B-28. We affectionately joke about them as 31 owners but many of the bretheren on the site are proud owners of them. They are fine boats. As far as power goes, hopefully some of our B-28 guys who have gone through the repowering process will chime in with specifics for you. As far as diesel power is concerned, the key is availability of parts and expert servicing facilities. Bertram owners have seemed to have settled in on Yanmars and Cummins for those reasons. As a rule, Cummins 6bt series are too large for 28's. Steer clear of "Peninsulars" as I honestly can say I have never heard of them or seen their name ever mentioned on the site. Do NOT trust what a salesman or owner says about anything. If you find a boat you are REALLY interested in, pay to have a good survey made. It will be well worth the cost, even if you DON'T buy it. Good luck and welcome aboard! Walter
- scenarioL113
- Senior Member
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- Joined: May 31st, '08, 09:00
- Location: Massapequa Park, NY
I just got my B28 in the water from a long repower project and am very satisfied with the results.
I am running 4BT Cummins 150HP. The boat performs good. The cruise with this setup will be about 20 knots. I do not have enough hours yet to see what the cruise RPM I will end up liking, 2400 is good and thats about 18knots and there is still room to push up a little. Like I said I have not logged enough hours with her yet still getting the kinks out.
I am satisfied with the setup although, if I had to guess 200 -225HP engines would really be ideal and probably get a B28 cruising at about 30 knots. Yanmar makes something that fits in that range and 4BT's do come in 250HP but I hear they dont have the same longevity as the 150HP version.
I did see (I believe a forum member) a B28 with 6BT's, a very tight fit but they were in there.
I am running 4BT Cummins 150HP. The boat performs good. The cruise with this setup will be about 20 knots. I do not have enough hours yet to see what the cruise RPM I will end up liking, 2400 is good and thats about 18knots and there is still room to push up a little. Like I said I have not logged enough hours with her yet still getting the kinks out.
I am satisfied with the setup although, if I had to guess 200 -225HP engines would really be ideal and probably get a B28 cruising at about 30 knots. Yanmar makes something that fits in that range and 4BT's do come in 250HP but I hear they dont have the same longevity as the 150HP version.
I did see (I believe a forum member) a B28 with 6BT's, a very tight fit but they were in there.
1971 28 Bertram
4BT Cummins
Frank
9-11-01 NEVER FORGET
4BT Cummins
Frank
9-11-01 NEVER FORGET
The peninsular engines are marinized versions of the GM diesel truck engine, from what I've been able to find its basically the same as what chevy used before the duramax but configured a little different and supposedly made to directly replace a 350 or 454.
I've always been a fan of Cummins, and John Deer engines, but thats from growing up on my family farm and spending vacations working my inlaws farm. I'be lost track of how many of those engines I've rebuilt or assisting with rebuilding.
From what I've found it looks like I would prefer something in the 200-260 range with gas being on the upper end and diesel on the lower. My goal is to cruise at 18-21 knots with WOT getting somewhere in the mid to high 20s.
I've always been a fan of Cummins, and John Deer engines, but thats from growing up on my family farm and spending vacations working my inlaws farm. I'be lost track of how many of those engines I've rebuilt or assisting with rebuilding.
From what I've found it looks like I would prefer something in the 200-260 range with gas being on the upper end and diesel on the lower. My goal is to cruise at 18-21 knots with WOT getting somewhere in the mid to high 20s.
If you go with gas the sad fact is you will have little resale value. There are a lot of the 28s out there and they can be for 10-15k. I rebuilt my 350 mercs to the original 260hp three years ago and I'm satisfied with the results, 22k cruise with 1kn fuel burn. If I had deeper pockets I would have gone with more horse power, the boat runs with a better attitude at about 25kn.
I would stay away from the penninsulars but only because of the reputation , I have no first hand knowledge of them.
If I could get the fuel burn numbers of ScenarioL113 I would gladly give up the 2knots of cruise since you'll only be doing 15-18 kn most days when you're out in the ocean, and with the diesel you'll have the extended range out of your 165gal tank.
Either way you go it's a great little boat, this is my 16th season with my 28 and she has never let me down.
I would stay away from the penninsulars but only because of the reputation , I have no first hand knowledge of them.
If I could get the fuel burn numbers of ScenarioL113 I would gladly give up the 2knots of cruise since you'll only be doing 15-18 kn most days when you're out in the ocean, and with the diesel you'll have the extended range out of your 165gal tank.
Either way you go it's a great little boat, this is my 16th season with my 28 and she has never let me down.
Don't lend a hand to raise a flag aboard a ship of fools!
-
- Senior Member
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There is a nice article on Boat Diesel about putting Yanmar 4LHA 240 engines in a Bertram 28.
This link probably will only work if you are a member ... ($50 or so per year) but lots of information there.
http://boatdiesel.com/Articles/Articles ... cfm&Y=2008
My research on the topic indicates the Yanmar 4 cylinder 240hp are the way to go.
This link probably will only work if you are a member ... ($50 or so per year) but lots of information there.
http://boatdiesel.com/Articles/Articles ... cfm&Y=2008
My research on the topic indicates the Yanmar 4 cylinder 240hp are the way to go.
1981 Bertram 28 Flybridge CruiserThird Strike II1984 Bertram 54 Big Buddy
http://cgi.ebay.com/Steyr-Motors-256-Ma ... 439f945fca
Found these browsing on EBAY. I can only dream how the 28 would respond with these. I have the 212 hp version of these. Same displacement in cubes but the different turbos, computer tune etc. You would need ZF 63 gears behind these and it would be a big project with upgrading running gear to handle the power. If you could get the 212 hp version stock 1 1/8 shafts and gear would work.
I just finished a 296nm trip with my boat. I burned exactly 200 gallons. There were 5 people, 5 coolers varying in size, every tool I may have needed, spare water, yamaha generator, spare parts, extra fuel, camping gear, secondary anchor etc. I estimate this 12000 pound boat easily had an easy 3-4 thousand pounds of fuel, gear and people on it. Still knocked down about 21knots on average. By far the heaviest I have ever ran this boat.
If you are happy with the 28 that is the important part. Like the guys say, you could get a nice 28 with wore out gassers and repower. By the time you get gears for the above listed engines and install them you are looking at 50K if you do it yourself. then add your purchase price of 15K or so for a boat. You just need to know how you want to use the boat and decide the best way to go for you. I personally could never go back to gas in this type of boat. I am finishing up my fourth year with these motors. So far just oil and filters. Engines just are not widely known like the cummins or yanmars. Still running the original belts.
You are in the right place to learn. With out this group of folks I never would have been able complete what I did. My biggest problem right now is figuring just how far I should push into the Bahamas with a 28 foot boat.
Found these browsing on EBAY. I can only dream how the 28 would respond with these. I have the 212 hp version of these. Same displacement in cubes but the different turbos, computer tune etc. You would need ZF 63 gears behind these and it would be a big project with upgrading running gear to handle the power. If you could get the 212 hp version stock 1 1/8 shafts and gear would work.
I just finished a 296nm trip with my boat. I burned exactly 200 gallons. There were 5 people, 5 coolers varying in size, every tool I may have needed, spare water, yamaha generator, spare parts, extra fuel, camping gear, secondary anchor etc. I estimate this 12000 pound boat easily had an easy 3-4 thousand pounds of fuel, gear and people on it. Still knocked down about 21knots on average. By far the heaviest I have ever ran this boat.
If you are happy with the 28 that is the important part. Like the guys say, you could get a nice 28 with wore out gassers and repower. By the time you get gears for the above listed engines and install them you are looking at 50K if you do it yourself. then add your purchase price of 15K or so for a boat. You just need to know how you want to use the boat and decide the best way to go for you. I personally could never go back to gas in this type of boat. I am finishing up my fourth year with these motors. So far just oil and filters. Engines just are not widely known like the cummins or yanmars. Still running the original belts.
You are in the right place to learn. With out this group of folks I never would have been able complete what I did. My biggest problem right now is figuring just how far I should push into the Bahamas with a 28 foot boat.
- CaptPatrick
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- Location: 834 Scott Dr., LLANO, TX 78643 - 325.248.0809 bertram31@bertram31.com
Hilary,
Just posted link on the other discussion but it may help you as well.
Some of these photos will give you an idea of how far you can go when you get the Bertram bug. Some pics give you good idea of how the Steyrs fit. Lots of pics show the progression of the project. I have about 100K into the boat and that was us doing 95% of the labor. Would I do it again.....no. Was it worth it........yes. Plenty of boats out there that are much nicer than mine was when I bought it for even less money.
http://s189.photobucket.com/home/1kevinmehegan/index
Password is Bertram
Just posted link on the other discussion but it may help you as well.
Some of these photos will give you an idea of how far you can go when you get the Bertram bug. Some pics give you good idea of how the Steyrs fit. Lots of pics show the progression of the project. I have about 100K into the boat and that was us doing 95% of the labor. Would I do it again.....no. Was it worth it........yes. Plenty of boats out there that are much nicer than mine was when I bought it for even less money.
http://s189.photobucket.com/home/1kevinmehegan/index
Password is Bertram
- CaptPatrick
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- Hyena Love
- Senior Member
- Posts: 309
- Joined: Jun 30th, '06, 09:54
Hyena Boats
Repowered mine with Yanmar 240's. Took good bit of work, but love them.
Then again, except for a slightly lower cruise and a higher fuel burn, I liked the Chevy 350's. Easy to work on, relatively simple, parts available at Napa and AutoZone. I'm convinced one could stand astride a chevy 350 and pour fuel out of a bucket into the carbs and still make it home.
Of course, once you hear the whine of the turbos and that hull rockets up on plane, you will be makin reefs out of small block chevy's. Just sayin.
Then again, except for a slightly lower cruise and a higher fuel burn, I liked the Chevy 350's. Easy to work on, relatively simple, parts available at Napa and AutoZone. I'm convinced one could stand astride a chevy 350 and pour fuel out of a bucket into the carbs and still make it home.
Of course, once you hear the whine of the turbos and that hull rockets up on plane, you will be makin reefs out of small block chevy's. Just sayin.
On some other sites I've seen mention that the B28s which came from the factory with diesels had a larger engine compartment allowing some people to fit the 6BT Cummins where as the ones that came with gas can't. Is this true and if so does anyone know what the design difference is? From what I've seen it sounds like the Yanmar's and Stehrs are the favorites and that diesel is the ultimate endgame goal.
I believe I'll basically be faced with one of two scenarios initially, either having a gas boat witch will eventually get converted over or a diesel boat with difficult service and parts for the engines. As I have a fair amount of experience rebuilding diesels I’m not too worried about the service, however parts and inherent/recurring issues would give me pause. With diesel as the ultimate endgame goal should I go gas and plan on a complete repower involving exhaust, shafts, etc. or go diesel and just plan on having to change the engines? How difficult or possible is it to change engines but still utilize the same shafts and related hardware?
My goal is to be able to go at least a few years before a repower allowing me time to start making the boat my own with other features such as electronics.
I believe I'll basically be faced with one of two scenarios initially, either having a gas boat witch will eventually get converted over or a diesel boat with difficult service and parts for the engines. As I have a fair amount of experience rebuilding diesels I’m not too worried about the service, however parts and inherent/recurring issues would give me pause. With diesel as the ultimate endgame goal should I go gas and plan on a complete repower involving exhaust, shafts, etc. or go diesel and just plan on having to change the engines? How difficult or possible is it to change engines but still utilize the same shafts and related hardware?
My goal is to be able to go at least a few years before a repower allowing me time to start making the boat my own with other features such as electronics.
- In Memory Walter K
- Senior Member
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- Joined: Jun 30th, '06, 21:25
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To the best of my knowledge, Cummins 6 bt series engines started appearing on B-31 repowers in 1989 and 90. I don't think they found their way into factory 28's at all but I may be mistaken. The diesels I know about in 28's are 4bt's, Yanmars and Stehrs, and their owners love them. If you can find one, they'd be worth the additional price. If in decent shape, your power is done. As far as running gear upgrades if you go from gas to diesel, you may or may not have to change your shafts and struts based on what you had in the boat, or what HP you're putting in. Just new props. I'm sure the guys who did it will chime in. If buying a gas powered one, make sure the tanks and all related fuel and vent lines have been changed to aluminum and ethanol-proof hoses. If they haven't, either pass or factor in those costs which you wouldn't have if it were a diesel. If you ARE changing tanks and your long-term thinking is diesel, have return line fittings put in now and just cap them. You'll be glad you did later.
Just to remind the Yanmar 4LH series engines are no longer available in the US for sale. There are ways around this though if you really want them.
The replacement BY series is a BMW designed totaly electronic engine and even though I never pulled a punch about products, now that I no longer represent Yanmar I wouldn't touch the piece of shi* series with somebody elses check book.
4LH engines were good engines and mostly found at this point as used takeouts upgrading in power. The early 230 or later 240(same engine) is the way to go. The 170 never really did produce enough power to make it useful IMO.
Cummins 4 BT's are good as are the Steyr line of engines as Kevin can attest to.
Its too bad the economy dumped just as they were comming on the market as I belive they are a good engine.
Peninsular is big heavy and low power. Cheap yes, but not worth it. I'd stick with gas over them.
The replacement BY series is a BMW designed totaly electronic engine and even though I never pulled a punch about products, now that I no longer represent Yanmar I wouldn't touch the piece of shi* series with somebody elses check book.
4LH engines were good engines and mostly found at this point as used takeouts upgrading in power. The early 230 or later 240(same engine) is the way to go. The 170 never really did produce enough power to make it useful IMO.
Cummins 4 BT's are good as are the Steyr line of engines as Kevin can attest to.
Its too bad the economy dumped just as they were comming on the market as I belive they are a good engine.
Peninsular is big heavy and low power. Cheap yes, but not worth it. I'd stick with gas over them.
- scenarioL113
- Senior Member
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- Joined: May 31st, '08, 09:00
- Location: Massapequa Park, NY
With the 4BT's I had a 2 prop guys tell me I could run 1-1/8 shafts with the 150HP.
I had to replace the shafts no matter what and ended up with 1-1/4 which was no problem the shaft logs and the factory struts are still being used.
Going the Yanmar route will require LOTS of work probably above and beyond logs and struts.
I am happy cruising in the Low 20's mph.
I had to replace the shafts no matter what and ended up with 1-1/4 which was no problem the shaft logs and the factory struts are still being used.
Going the Yanmar route will require LOTS of work probably above and beyond logs and struts.
I am happy cruising in the Low 20's mph.
1971 28 Bertram
4BT Cummins
Frank
9-11-01 NEVER FORGET
4BT Cummins
Frank
9-11-01 NEVER FORGET
To respond to Walter's explanation about the B31 repowers and the factory B28s. I was refferring to a post and photos shown on another forum in which a B28 had been repowered by the owner with 6BTs and several others indicated they had seen other B28s like them. That particular thread went on to explain that only the B28s which had factory diesels (I believe they said the factory diesels where volvos) had large enough engine rooms to fit the 6BTs, I am wondering if anyone here knows of or could explain the indications that there were significantly different engine rooms sizes on factory B28s. My main question here would be what effects the larger engine rooms had on the rest of the boat and should I consider looking for one?
- Hyena Love
- Senior Member
- Posts: 309
- Joined: Jun 30th, '06, 09:54
As I understand it, there are three basic B28 layouts: the low step cockpit, the high step cockpit, and one with a longer engine box. The longer engine box ones might even be myth or legend. At a minimum, they are far less numerous.
I don't know what I had originally, and I have never seen any of the units with the longer engine boxes.
Look, you can make just about anything work - at some level of time and money.
If you want a boat with 6BT's, I would suggest money would be better spent with a B31. No way around that.
I don't know what I had originally, and I have never seen any of the units with the longer engine boxes.
Look, you can make just about anything work - at some level of time and money.
If you want a boat with 6BT's, I would suggest money would be better spent with a B31. No way around that.
This thread from The Hull Truth has a couple pix of my 28 w/ Cummins 210's.
http://www.thehulltruth.com/boating-for ... power.html
This Bertram31 thread includes my performance figures.
http://bertram31.com/newbb/viewtopic.ph ... 23bb40932f
http://www.thehulltruth.com/boating-for ... power.html
This Bertram31 thread includes my performance figures.
http://bertram31.com/newbb/viewtopic.ph ... 23bb40932f
i am not sure of the stategy here. i am a little confused ; you say the 31 ' bertram is more money then the 28' but you going to buy either in gas knowing you are going to replace with diesel power.ok----then who or why the hell do you care what power is in them ,could be a trained monkey turning the shaft .they are coming out!!!! buy whaler`s 1967 fbc for 11,000 the work of removing the engines are done for you.shaft,structs are meaningless there are coming out anyway .for 37,000 you have warranty 2011 cummins with gears ----what am i missing?? your going for diesels anyway and your dicking around with wana be diesels in a lesser value boat as a finish product .for the same money.don`t you think it is prudent to go the extra mile.
capt.bob lico
bero13010473
bero13010473
- scot
- Senior Member
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- Joined: Oct 3rd, '06, 09:47
- Location: Hurricane Alley, Texas
- Contact:
The hours of enjoyment on this board, Price: Voluntary donations to the good Capt.
The expert advise Price: Voluntary donations to the good Capt.
Having Bob explain various engine options....
Thanks Bob, that one stuck.
The expert advise Price: Voluntary donations to the good Capt.
Having Bob explain various engine options....
Priceless.could be a trained monkey turning the shaft
Thanks Bob, that one stuck.
Scot
1969 Bertram 25 "Roly Poly"
she'll float one of these days.. no really it will :-0
1969 Bertram 25 "Roly Poly"
she'll float one of these days.. no really it will :-0
-
- Posts: 52
- Joined: Jun 13th, '11, 09:47
- Location: Vessel: Stock Island, Fl; Me: Malibu, CA when not on board
B 28 stock TAMD 41 "B" with MS4A tran's
Hi all, reading and enjoying old posts. Wanted to pick anyone with knowledge re: stock Volvo drive train. Mine is unbeleivably original and in amazing shape... like out of the factory. I haven't been able to get too much info on the stock transmissions; however, having run many vessels in my career, I'm not impressed with the way these engage. That said, they operate perfectly. At 3,200 rpm, I'm doing 18 knots with original trim tabs all the way down (wonder if I could get more trim, if the speed would increase- my guess is the factory did not compensate for the additional weight of the diesels and she's a little stern heavy) and per the survey, she tops out at 28 knots at 3,850rpm. My gut tells me with the power coming from the mains, she might be a little under propped... anyone know if these rpm/speed numbers seem to spec? My gut also tells me that these tranny's may not take additional load shifting at idle... to me, these transmissions feel like the weakest link of the entire drive train...
Started voyaging off and on in Pensacola about a year ago... currently in Venice, Fl and continueing S. in a few weeks... would love to say hi and meet any B owners out there... pls join us for drinks if in the local...
Best to all and clearly a wonderful giving group of folks on this site,
Capt Rex
Started voyaging off and on in Pensacola about a year ago... currently in Venice, Fl and continueing S. in a few weeks... would love to say hi and meet any B owners out there... pls join us for drinks if in the local...
Best to all and clearly a wonderful giving group of folks on this site,
Capt Rex
HilaryS,
Welcome aboard, whether you have a 31 or Knot.
Couldn't tell you much about what is better in a 28...but can say if your going to dig deep for diesels without a long term commitment to the boat you may want to consider resale. Good bad or indifferent the Peninsula Diesels have a bad wrap and that makes the boat harder to sell at a decent price if you need or want to down the road.
If you get them at a steal...then you make the call...but keep in mind service and parts.
Steyrs are a bolt up choice. Light, smooth and economical. Although the parts and service lack. Dad has the 236 version in his 28 Hatteras, a heavy boat and is in the 2mpg area. It was .9 with the 440 gassers.
Welcome aboard, whether you have a 31 or Knot.
Couldn't tell you much about what is better in a 28...but can say if your going to dig deep for diesels without a long term commitment to the boat you may want to consider resale. Good bad or indifferent the Peninsula Diesels have a bad wrap and that makes the boat harder to sell at a decent price if you need or want to down the road.
If you get them at a steal...then you make the call...but keep in mind service and parts.
Steyrs are a bolt up choice. Light, smooth and economical. Although the parts and service lack. Dad has the 236 version in his 28 Hatteras, a heavy boat and is in the 2mpg area. It was .9 with the 440 gassers.
I saw one in dads marina with worked 502's.
Guy who owned it donated the boat to a Marine Champlain Society or something along those lines. Anyway the transaction happened at dads marina and the first thing they did after taking ownership was to yank the motors.
Boat lunged even at lowest idle when put in gear, top end scared the crap out of everyone who went out on it...no numbers, speeds or burn.
Guy who owned it donated the boat to a Marine Champlain Society or something along those lines. Anyway the transaction happened at dads marina and the first thing they did after taking ownership was to yank the motors.
Boat lunged even at lowest idle when put in gear, top end scared the crap out of everyone who went out on it...no numbers, speeds or burn.
- conchy joe
- Posts: 153
- Joined: Jan 15th, '11, 03:06
I have a 76 28 FBC, that I have had for three years. I have done two very long trips throughout the Bahamas (two weeks in Andros & then 3 weeks in the Abaco's) over the past two years living on the boat with three adults both times. Other than getting 1.1 nmpg I could not be happier.
I am repowering with 150 hp cummins 4BT's and ZF220 transmissions. I chose these motors for a couple of reasons. Primarily the increased fuel economy. At between 4-6 gph per motor fuel burn, it sure beats the 10-11 gph, I was getting with the 351W Fords.
Sure it won't be a rocket ship, but I am doing the motor rebuilds myself, ceramic coating the pistons, dry lube on the skirts and bearings. I will likely have the injection pump turned up a bit and hope to get 175-180 HP out of the motors.
I am recessing the transducer in the hull along the centerline, per Capt Pat's building tip, getting rid of all the unnecessary thru hulls and generally plan to make the hull as clean and efficient as possible.
The other main reason I went with the Cummins is the price to purchase, rebuild and ease of getting parts.
Good luck, let me know if there is anything I can do.
I am repowering with 150 hp cummins 4BT's and ZF220 transmissions. I chose these motors for a couple of reasons. Primarily the increased fuel economy. At between 4-6 gph per motor fuel burn, it sure beats the 10-11 gph, I was getting with the 351W Fords.
Sure it won't be a rocket ship, but I am doing the motor rebuilds myself, ceramic coating the pistons, dry lube on the skirts and bearings. I will likely have the injection pump turned up a bit and hope to get 175-180 HP out of the motors.
I am recessing the transducer in the hull along the centerline, per Capt Pat's building tip, getting rid of all the unnecessary thru hulls and generally plan to make the hull as clean and efficient as possible.
The other main reason I went with the Cummins is the price to purchase, rebuild and ease of getting parts.
Good luck, let me know if there is anything I can do.
Troy & Daria
28 Bertram FBC, 3.9 Cummin BT's
Conchy Joe "ITS THE BOAT'S NAME, NOT MINE" -
Hypoluxo Point, FL
28 Bertram FBC, 3.9 Cummin BT's
Conchy Joe "ITS THE BOAT'S NAME, NOT MINE" -
Hypoluxo Point, FL
-
- Posts: 52
- Joined: Jun 13th, '11, 09:47
- Location: Vessel: Stock Island, Fl; Me: Malibu, CA when not on board
Re: Engine Recomendations?
Enjoying reviewing this old post of mine... the saga continues
I am now on the Atlantic side of Key West with cruising generally a little more spirited than in the Gulf. At 3,200 RPM's I have lost a couple knots since the original post and do 16 knots. The props have been sent in in the past and supposedly tuned- this week I took them off again and shipped them this time to a reputable prop shop in Miami. Stock they were 18, 18's. Yesterday I was told one prop was pitched at 18, the other 18.5. Since the original posting above, I rebuilt the turbos and despite their reputation to always smoke, these Volvos (TAMD41B's) barely smoke now and definitely have increased horsepower... the best repair/upgrade I've made to the boat, what a difference and no more dark black smoke.
The original B 28 manual/notebook for my vessel has RPM/Speed graphs for gas engines but not the factory Volvo diesels in my boat. With the better than new rebuilt turbos, I don't top out at a max RPM's- I got up to 3,700 RPMs on both mains and pulled back in fear of blowing the engines and they still wanted to do plenty more (3,700 RPM's only doing 22 kts). My last fueling, combination trolling and cruising, I burned 5.6 GPH- no complaints! The prop shop made some calculations and suggested a pitch of 23 based on accidently telling them 4700 rpm instead of 3,700- theory max RPM's out in the high 3000's. As I like the fuel economy, my inclination is to keep things near as they are plus I still feel the weakest links of the drive trains are the MS4A transmissions- they already clunk pretty hard just shifting in and out of gear at idle and adding more pitch/resistance I suspect can only make worse.
The other component I mentioned on the original post are the trim tabs-a they are stock. My speed always max's out at full tab and again my guess is that these were designed for the much lighter gas engines. Perhaps my upper speed efficiency is poor because I'm not getting the bow down enough...
I took a stab at re-doing the props at a 19 pitch to see if I can get my speed up a tad without putting too much additional load on the transmissions and hopefully still preserving fuel economy. Tried it out in rough seas- didn't notice any difference. If anyone has or knows someone who has the same power and trans combination or B28 factory diesel trimtab input, would love the hear.
Best to all, Rex
I am now on the Atlantic side of Key West with cruising generally a little more spirited than in the Gulf. At 3,200 RPM's I have lost a couple knots since the original post and do 16 knots. The props have been sent in in the past and supposedly tuned- this week I took them off again and shipped them this time to a reputable prop shop in Miami. Stock they were 18, 18's. Yesterday I was told one prop was pitched at 18, the other 18.5. Since the original posting above, I rebuilt the turbos and despite their reputation to always smoke, these Volvos (TAMD41B's) barely smoke now and definitely have increased horsepower... the best repair/upgrade I've made to the boat, what a difference and no more dark black smoke.
The original B 28 manual/notebook for my vessel has RPM/Speed graphs for gas engines but not the factory Volvo diesels in my boat. With the better than new rebuilt turbos, I don't top out at a max RPM's- I got up to 3,700 RPMs on both mains and pulled back in fear of blowing the engines and they still wanted to do plenty more (3,700 RPM's only doing 22 kts). My last fueling, combination trolling and cruising, I burned 5.6 GPH- no complaints! The prop shop made some calculations and suggested a pitch of 23 based on accidently telling them 4700 rpm instead of 3,700- theory max RPM's out in the high 3000's. As I like the fuel economy, my inclination is to keep things near as they are plus I still feel the weakest links of the drive trains are the MS4A transmissions- they already clunk pretty hard just shifting in and out of gear at idle and adding more pitch/resistance I suspect can only make worse.
The other component I mentioned on the original post are the trim tabs-a they are stock. My speed always max's out at full tab and again my guess is that these were designed for the much lighter gas engines. Perhaps my upper speed efficiency is poor because I'm not getting the bow down enough...
I took a stab at re-doing the props at a 19 pitch to see if I can get my speed up a tad without putting too much additional load on the transmissions and hopefully still preserving fuel economy. Tried it out in rough seas- didn't notice any difference. If anyone has or knows someone who has the same power and trans combination or B28 factory diesel trimtab input, would love the hear.
Best to all, Rex
Last edited by Capt Rex on May 21st, '15, 10:57, edited 1 time in total.
Re: Engine Recomendations?
First, welcome and don't worry about the 28 Bertram... I don't have a 31 either... And there are plenty of 28' owners here...
OK, FWIW, personally I'm a marine engineer... I've worked on diesels that were bigger then 6 x 40' containers stacked 3 high next to each other, HP was 50,000 IIRC... I also have a naval background dealing with smaller engines (16V92 Detroit Diesels, HP was about 1,200 HP and MTU 16V956 TB91 with 4,000 HP)... I'm also not very enamored with gasoline on board vessels...
Having said all that, David Pascoe (a well known marine surveyor) published a couple of good articles on the subject of diesel vs gas engines on pleasure boats: 1st article: "Power Options: Gas Versus Diesel" and 2nd article: Power Options: Gas -vs- Diesel Part II...
My basic disagreement with David Pascoe is that I put the borderline where gas inboards are no longer practical (due to size/weight of the boat) lower then he does... Your Bertram 28 is below that borderline IMHO...
To surmise David Pascoe, unless you're going to use the boat far more then the average 100-120 hours per year money wise you're better off with gassers... However, safety (gas is explosive under the right conditions) and resale value are considerations you should take into account (which David Pascoe doesn't)...
Talking about engine ratings (true for both gas and diesel), manufacturers will often market what's basically the same engine with low, medium and high ratings... Sometimes even low, med-low, med-high and high ratings... The differences being achieved through different turbos, intercoolers, injectors etc)... But, there are no free lunches in life and there's always a tradeoff... Higher power rating equals more engine wear and tear... That, in turn, means more maintenance and a lower useful life expectancy... Let's take as a specific example the Detroit Diesel 8V92:
OK, FWIW, personally I'm a marine engineer... I've worked on diesels that were bigger then 6 x 40' containers stacked 3 high next to each other, HP was 50,000 IIRC... I also have a naval background dealing with smaller engines (16V92 Detroit Diesels, HP was about 1,200 HP and MTU 16V956 TB91 with 4,000 HP)... I'm also not very enamored with gasoline on board vessels...
Having said all that, David Pascoe (a well known marine surveyor) published a couple of good articles on the subject of diesel vs gas engines on pleasure boats: 1st article: "Power Options: Gas Versus Diesel" and 2nd article: Power Options: Gas -vs- Diesel Part II...
My basic disagreement with David Pascoe is that I put the borderline where gas inboards are no longer practical (due to size/weight of the boat) lower then he does... Your Bertram 28 is below that borderline IMHO...
To surmise David Pascoe, unless you're going to use the boat far more then the average 100-120 hours per year money wise you're better off with gassers... However, safety (gas is explosive under the right conditions) and resale value are considerations you should take into account (which David Pascoe doesn't)...
Talking about engine ratings (true for both gas and diesel), manufacturers will often market what's basically the same engine with low, medium and high ratings... Sometimes even low, med-low, med-high and high ratings... The differences being achieved through different turbos, intercoolers, injectors etc)... But, there are no free lunches in life and there's always a tradeoff... Higher power rating equals more engine wear and tear... That, in turn, means more maintenance and a lower useful life expectancy... Let's take as a specific example the Detroit Diesel 8V92:
- Stock (OEM) 400 HP NA (Naturally Aspirated - there's really no such thing as ALL 71/92 series DD's have a supercharger - a.k.a. as the blower)... Put this engine in a 45'-50' commercial trawler and it will probably run 6, 7 and possibly more then 8,000 hours between overhauls... And there's practically no way you could over stress the engine in this application...
- Stock OEM 575 HP TI (Turbocharged and Intercooled)... Put these in a 46' Bertram and you're looking at 2,000 to 2,500 hours between overhauls assuming they are properly maintained and not over stressed...
- Non stock non OEM 750 HP marinized by the likes of Johnson & Towers (a.k.a. Junk & Trash)... Put these in a 56' Bertram and you'll be lucky to get 1,200 hours between overhauls and less then that if over stressed (heavy boat, lot's of WOT etc)...
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Re: Engine Recomendations?
I had a 28 with 305 Chevys, Mercs. 17 kts. 21 downhill. If I had to choose, I'd but in some efi 350s keep it simple easy, cheap. No changing engine beds , starts, shafts, tweet the props and enjoy the $10000 investment. Read Kevin's post again. I repeat, read Kevin's post.
Bill
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