SC V6 or MPI V8?

About inboard or outboard motors.

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Denon Osterman
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Post by Denon Osterman »

Serious project.

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Mr Hot Rod
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Post by Mr Hot Rod »

For sure, you've got a lot of questions, but you're going to have to do some reading ! Most of your questions concerning stringer widths and engine installation can be found in the following books :

Boatbuilding with Plywood by Glen L. Witt

Inboard Motor Installations by Glen L. Witt and Ken Hankinson

You're going to need a trailer to haul your new boat, so you may as well order this one too :!:

How to Build Boat Trailers by Glen L. Witt

These and other reference books covering all aspects of the boatbuilding process can be ordered at Glen-L's Bookstore.

Like boatbuilding, engine building is a 'Learn By Doing' process. If you are mechanically inclined and have lots of time and patience, you should be able to build your own engine or know enough about it to have one built for you. Magazines are a great source for engine building ideas. Next time you're at the magazine rack, look for <i>Popular Hot Rodding</i>'s <i><b>Engine Masters</b></i> Summer 2008 edition. If you can't find it, they can probably order it for you. Of particular interest to you, their 454 BBC buildup starts with a stroked normally aspirated engine (645 HP @ 6400, 578 lb-ft @ 5200) which is then supercharged with a Vortech centrifugal supercharger (936 HP @ 6400 RPM, 757 lb-ft @ 6400). The <i>Stage</i> 1 engine's static compression ratio of 8.25:1 could be built and run as is. The supercharger could be added at a later date when your budget has had time to recover from the <i>Stage 1</i> build :!:

Parts used in this buildup could be toned down somewhat to suit your budget, but the general idea of building a relatively low compression engine which can be supercharged at a later date certainly gets you thinking !
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Nova SS
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Post by Nova SS »

Learn by doing, I like that idea. For me it was the only way. I would read everything I could get my hands on about what ever it was I wanted to do and then I would dive in and do it. be it engine building, painting cars, etc, etc there was always an intense period of research followed by hands on doing. Sometime it worked well the first time and sometimes it didn't but I can tell ya this. By the time I did it a couple of times the end result was pretty decent if I don't say so myself.

Nothing beats the education you get by doing. Even if done wrong you are still learning what not to do and that is just as important as learning what you should do.

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Caber-Feidh
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Post by Caber-Feidh »

novass wrote:Learn by doing, I like that idea. For me it was the only way. I would read everything I could get my hands on about what ever it was I wanted to do and then I would dive in and do it. be it engine building, painting cars, etc, etc there was always an intense period of research followed by hands on doing. Sometime it worked well the first time and sometimes it didn't but I can tell ya this. By the time I did it a couple of times the end result was pretty decent if I don't say so myself.

Nothing beats the education you get by doing. Even if done wrong you are still learning what not to do and that is just as important as learning what you should do.
Besides, the battle scars are great conversation starters.

How many times I have bought all the stuff to do something, then when it came, I realize it was all the wrong stuff. Oh, well... that's where we get "spare" parts for later, right?

I don't really like magazine article information. They have to please the advertisers. Too often I have seen completely dysfunctional items called the greatest build in the world, then 3 pages later you see the mfgr's full page advert... No, there is no bias there.

Best pump is an outboard bowl, Ya, it looks like a boat-on-a-stick when you are done, but the advantages of the motor almost against the transom, having the cleanout outside the boat, and being able to maintain the pump without without pulling the transom adapter, seals, yada-yada is worth a lot of ugly. That is a bad job. Yuck, it takes at least 6 pints of IPA to even roll the toolbox over to that one.

Most commercial motor mounts are going to be 26" for BBC engines. (plate type). I would avoid the cheesy ones that mount to the original mount pads used in cars. They are horrible! They center the load on 2 6x6 pads, fine for a steel cat frame, but expecting 12 lag screws to hold the better part of a thousand pounds in place... while getting beat in whitecaps, is a stretch.

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Mr Hot Rod
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Post by Mr Hot Rod »

What would a complete parts list look like for the 454 with aluminum heads, ready to drop in, hookup, and run?
Couldn't find a Parts List for Big Blocks, but I did find info for Small Block crate engines. The link below will allow you to download GMPP crate engine replacement Part Lists into Microsoft Excel. Click on the hyperlinked part numbers to see pricing information. With a bit of work, the spreadsheet can be reworked to include pricing for estimating engine build cost.

GM Performance Part Crate Engine Active Replacement Parts Lists

While you're at it, check out their catalog and agressive pricing :
Pace Performance On-Line Master eCatalog

Click on Product Index, Crate engines and start dreaming !
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csaggio
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Bobtail

Post by csaggio »

I've seen it mentioned a few times in the string of posts, an in engine dealer sites...but what does "bobtail" mean exactly?

Thanks, for the help, Chris

Denon Osterman
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Post by Denon Osterman »

Bobtail means just the rare(running) engine. no transmission.

some engines some with F-N-R transmissions, or stern drive attachements, etc...these are NOT bobtails

hope that helps.

Denon

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Dave Grason
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Re: Bobtail

Post by Dave Grason »

csaggio wrote:...but what does "bobtail" mean exactly?
Denon's right. A bobtail has the drive shaft connected directly to the flywheel. This means that when you fire the engine, you're moving. If you want to stop, you shut the engine off. You have to either paddle or be towed in no-wake zones. And there aint no reverse .....except with the paddle. Take a look at the Crackerbox.
Denon Osterman wrote:Serious project.
Hey, Denon. I sure hope you didn't think I was being critical here. I just want to see this show up at the Gathering. :lol: It sounds very very cool, indeed.
Last edited by Dave Grason on Thu Jan 29, 2009 2:52 pm, edited 1 time in total.
Isn't it amazing!! The person that never has the fortitude to pursue his own dreams, will be the first to try and discourage you from pursuing yours.

Nova SS
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Re: Bobtail

Post by Nova SS »

Dave Grason wrote:
csaggio wrote:...but what does "bobtail" mean exactly?
Denon's right. A bobtail has the drive shaft connected directly to the flywheel. This means that when you fire the engine, you're moving. If you want to stop, you shut the engine off. You have to either paddle or be towed in no-wake zones.
I guess the towing part in no wakes zones would be dependent upon your idle rpm right, or would just about any motor put you faster then 5mph or whatever the speed is?

Denon Osterman
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Post by Denon Osterman »

Denon's right. A bobtail has the drive shaft connected directly to the flywheel. This means that when you fire the engine, you're moving. If you want to stop, you shut the engine off. You have to either paddle or be towed in no-wake zones. And there aint no reverse .....except with the paddle. Take a look at the Crackerbox.
unless you use a jet!(then reverse/"neutral" are part of the pump, and so even though the bobtail constantly spins the pump, you can still achieve directional control by the reverse gate/bucket redirecting the thrust). and if you're planning on buying a v-drive with a transmission in it, i suspect you'de only want a bobtail engine for that application too. that beeing said, a bobtail engine might cease to become a bobtail once its hooked up to a tranny...not sure if the term applies to the engine as received, or as installed.
Hey, Denon. I sure hope you didn't think I was being critical here. I just want to see this show up at the Gathering. Laughing It sounds very very cool, indeed.
No worries. Dunno about showing up at the gathering any time soon...gotta finish it first! it will depend on where i end up going to university...if it's on the west coast(fingers crossed!), then I'll definitely be attending the next 4 years(but wait...what if i don't have a boat? ahh)! but if not... :?

Denon

Denon Osterman
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Post by Denon Osterman »

http://www.gmhorsepower.com/ZZ454-440.php

last bullet point... "Not intended for marine applications."

I'm assuming this doesn't matter because of the thermostat?

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Mr Hot Rod
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Post by Mr Hot Rod »

If you're going to run an auto crate engine, don't forget to add a thermostat kit as Caber stated previously. Personally, I'd look for a crate marine engine. It's going to cost about the same and you'll get the forged parts and correct marine clearances to boot.
Here's a few examples : Blueprint Marine Engines from JEGS

If you want to see their custom GM Crate engines, specs and pricing, go to their website : Blueprint Engines
Click on the Popular configurations tab to see other GM marine engines.

It would be nice to know what your budget is for this engine :!: :?
These base engines are going to need some parts to finish them up. This can add up quickly. If you don't have a sufficient budget, it might be more productive to start looking for a running truck or take-out marine engine.

Here's a 454 real close to home : Chris Craft 454

No doubt that's an ugly engine ! Here's what our 283 looked like when we dragged it home :

Image

We threw most of the heavy parts away and ended up with this :

Image
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Last edited by Mr Hot Rod on Wed Feb 04, 2009 1:58 pm, edited 2 times in total.

Nova SS
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Post by Nova SS »

Denon you seem to like to research things so now is the time to research exactly what you need to build the motor you need/want. Then build it yourself. You might just save a few bucks in the process, get an education, and have lots of fun to boot. To me its a win win situtaion.

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Dave Grason
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Post by Dave Grason »

Mr Hot Rod wrote:..... and you'll get the forged parts and correct marine clearances to boot.
Ok, but what really happens if you DON'T go with a "marine" engine? I mean, my copy of "Inboard Motor Installations" is rather old and there's nothing in there about using an engine specifically for marine applications. This may have changed on the newer books but mine doesn't say that. So my questions are: If you just use, for example, a stock 2-bolt main 350 Chevy from a Caprice Classic and you set it up to use in boat, where are you going to run into probs as long as you follow the book's directions? Also, and I'm not talking about a race application here, but if you wanted to use this motor in something rather mundane like a Belle Isle or Tahoe and were perfectly happy with a modest V-8's horsepower, wouldn't that be fine?

I know you folks are talking about HOT Rod motors with high horsepower/torque and high expectations. Is that what makes the real difference?
Isn't it amazing!! The person that never has the fortitude to pursue his own dreams, will be the first to try and discourage you from pursuing yours.

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Mr Hot Rod
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Post by Mr Hot Rod »

Ok, but what really happens if you DON'T go with a "marine" engine?
Boom :!: :shock: :evil: $$$

Seriously, you're right, Dave, any automotive engine will do as long as you follow the book's directions, namely install a wet exhaust, marine distributor, camshaft, carburetor, flame arrestor, starter and alternator. When building a marine engine to run at over 6K all day everyday, stoutness and clearances become more critical. You don't want to be blowing up engines on a regular basis ! Caber knows all about this :P

If you're really curious, here's a table of engine clearances we'll be using for Bruce's 283 buildup. Marine specs were taken from the Chris-Craft Parts Book. This is a stock restoration rebuild, so we'll be building it up By the Book. We'll snap some photos along the way and post them in another thread if there's any interest.

Image
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