Conservative performance?
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Conservative performance?
Hello folks, I've been doing a lot of searching and reading, but haven't found a whole lot of info on the particular type of powerplant I am thinking of building. Maybe you can help?
Why don't I lay out what I have, what I am looking for, what I expect it to do, and what resources I have available to me, and maybe you folks can point me in the right general direction...
What I have...
- 25 foot Bertram, a rather different type of hull than most of what I am seeing discussed in the majority of my search results. The boat has no motors or drives, she's a blank canvas.
What I am looking for...
- I am looking to loosely flesh out a component list of what would be required to build a 350-400 Hp powerplant for the above vessel. I intend to run a Bravo O/D (3?).
What I expect it to do...
- I would like to achieve respectable performance, good fuel efficiency, and (hopefully) excellent longevity while pushing about the above vessel (figure about 5000lbs). Average usage will likely consist of about 10-15% at or near to WOT, 30-40% efficient planing speed, and the balance at or near to idle (trolling). I would like to do all of this without breaking the bank.
What resources do I have...
- I am pretty handy with a wrench myself, and have a few friends who are much more so. These friends are ready and willing to help, very knowledgable in performance engine building, can hook me up with cheap parts and supplies wherever they can, but, have no marine engine experience.
I want to get a good idea of what my requirements are before approaching my pavement pounding buddies as I know from my reading to date that there are some major differences between the two worlds and what they require from an engine, and therefore what goes into a build.
I thank you in advance for any help you can give. Feel free to ask questions if I have left anything key out.
Why don't I lay out what I have, what I am looking for, what I expect it to do, and what resources I have available to me, and maybe you folks can point me in the right general direction...
What I have...
- 25 foot Bertram, a rather different type of hull than most of what I am seeing discussed in the majority of my search results. The boat has no motors or drives, she's a blank canvas.
What I am looking for...
- I am looking to loosely flesh out a component list of what would be required to build a 350-400 Hp powerplant for the above vessel. I intend to run a Bravo O/D (3?).
What I expect it to do...
- I would like to achieve respectable performance, good fuel efficiency, and (hopefully) excellent longevity while pushing about the above vessel (figure about 5000lbs). Average usage will likely consist of about 10-15% at or near to WOT, 30-40% efficient planing speed, and the balance at or near to idle (trolling). I would like to do all of this without breaking the bank.
What resources do I have...
- I am pretty handy with a wrench myself, and have a few friends who are much more so. These friends are ready and willing to help, very knowledgable in performance engine building, can hook me up with cheap parts and supplies wherever they can, but, have no marine engine experience.
I want to get a good idea of what my requirements are before approaching my pavement pounding buddies as I know from my reading to date that there are some major differences between the two worlds and what they require from an engine, and therefore what goes into a build.
I thank you in advance for any help you can give. Feel free to ask questions if I have left anything key out.
#2
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Location: Oshawa, Ontario, Canada
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Hello folks, I've been doing a lot of searching and reading, but haven't found a whole lot of info on the particular type of powerplant I am thinking of building. Maybe you can help?
Why don't I lay out what I have, what I am looking for, what I expect it to do, and what resources I have available to me, and maybe you folks can point me in the right general direction...
What I have...
- 25 foot Bertram, a rather different type of hull than most of what I am seeing discussed in the majority of my search results. The boat has no motors or drives, she's a blank canvas.
What I am looking for...
- I am looking to loosely flesh out a component list of what would be required to build a 350-400 Hp powerplant for the above vessel. I intend to run a Bravo O/D (3?).
What I expect it to do...
- I would like to achieve respectable performance, good fuel efficiency, and (hopefully) excellent longevity while pushing about the above vessel (figure about 5000lbs). Average usage will likely consist of about 10-15% at or near to WOT, 30-40% efficient planing speed, and the balance at or near to idle (trolling). I would like to do all of this without breaking the bank.
What resources do I have...
- I am pretty handy with a wrench myself, and have a few friends who are much more so. These friends are ready and willing to help, very knowledgable in performance engine building, can hook me up with cheap parts and supplies wherever they can, but, have no marine engine experience.
I want to get a good idea of what my requirements are before approaching my pavement pounding buddies as I know from my reading to date that there are some major differences between the two worlds and what they require from an engine, and therefore what goes into a build.
I thank you in advance for any help you can give. Feel free to ask questions if I have left anything key out.
Why don't I lay out what I have, what I am looking for, what I expect it to do, and what resources I have available to me, and maybe you folks can point me in the right general direction...
What I have...
- 25 foot Bertram, a rather different type of hull than most of what I am seeing discussed in the majority of my search results. The boat has no motors or drives, she's a blank canvas.
What I am looking for...
- I am looking to loosely flesh out a component list of what would be required to build a 350-400 Hp powerplant for the above vessel. I intend to run a Bravo O/D (3?).
What I expect it to do...
- I would like to achieve respectable performance, good fuel efficiency, and (hopefully) excellent longevity while pushing about the above vessel (figure about 5000lbs). Average usage will likely consist of about 10-15% at or near to WOT, 30-40% efficient planing speed, and the balance at or near to idle (trolling). I would like to do all of this without breaking the bank.
What resources do I have...
- I am pretty handy with a wrench myself, and have a few friends who are much more so. These friends are ready and willing to help, very knowledgable in performance engine building, can hook me up with cheap parts and supplies wherever they can, but, have no marine engine experience.
I want to get a good idea of what my requirements are before approaching my pavement pounding buddies as I know from my reading to date that there are some major differences between the two worlds and what they require from an engine, and therefore what goes into a build.
I thank you in advance for any help you can give. Feel free to ask questions if I have left anything key out.
Good Luck!
Michael
#3
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I would seriously look at a single [or pair] of diesels, you AREN'T looking to run 100mph or Poker run the boat, the diesels will live almost forever, idle all day, low rpm, low maintainance and get great mileage. I am sure others who have forgotten more about this stuff than I will ever know will chime in, but, if it was me, I would look at Diesel power
Good Luck!
Michael
Good Luck!
Michael
Don't get me wrong, I'd love to plop a diesel in there for a few specific reasons, but it just isn't in the cards right now. I figure my other options are outboards, or I/O's (or perhaps a jackshafted version thereof). I am leaning towards the jackshafted I/O's. I had been reading elsewhere about the Mercruiser 383/350, and this did not seem as though it would be a terrible fit, good torque #'s to go with that HP. and given that I have the resources, interest, and a sickness for DIY, I might try crafting my own version somewhere along those lines.
- One additional point I forgot to mention in my first post regarding my "resources" is that I work in manufacturing (machinist), am very capable, and have access to just about any type of machine tool, as well as personnel to perform any sort of manufacturing tasks I am not proficient in.
#5
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What you're looking for is within the capability of just about any modern BBC-based Mercruiser. Are you thinking EFI or Carb? Sounds like you want to build it up?
#6
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I am half way thinking EFI, with the assumption it will give me better economy per pony, easier starting, and more all around reliability/less hassle. What I am unsure of though is at what expense it will come, and if it is a manageable project for a rookie.
If at all practical, yes. Number one, there is the aforementioned DIY sickness. If I can do it myself, generally speaking, I do. Second, there is cost. I am betting, with a bit of help in component selection from you guys, some hands on help from my race car wrenching buddies, and my manufacturing abilities, there is a buck or two to be saved in there.
Last edited by Dave McReeferson; 01-09-2011 at 07:43 AM.
#8
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Install a bracket and hang a 300X on it and be done. I'm a die hard BBC guy but for all the work involved starting from scratch with no rigging, thats the way I would go. My 2cts worth.
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Sometimes, for me, it is "all the work" that makes something worth doing. It's a sickness, and I don't try to hide it. Nothing gives me more satisfaction than stepping back and saying "I did that!". I am too far gone, no point trying to talk sense into me.