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LS motor in a boat?

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Old 07-30-2012, 09:28 PM
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Default LS motor in a boat?

I am thinking of building a custom wooden boat in the next few years and was thinking of putting a modern LS motor in it. I dont know a lot about the newer motors and have a few questions.

1.Do the newer motors have the same bell housing as the older ones? I am planing on using a Borg Warner velvet drive transmission and need to know if they will even bolt together.
2.I want to keep things as light as possible and would like to know what motors are all aluminum? I want something with around 400hp with a carb conversion done to it. And what is the weight of the complete long block of the motor? I think what im looking for is a 5.3l motor, but am not 100%.

This is what i am looking to build.
http://www.glen-l.com/designs/inboard/crackerbox.html
Old 07-30-2012, 09:36 PM
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Originally Posted by bkhadley
I am thinking of building a custom wooden boat in the next few years and was thinking of putting a modern LS motor in it. I dont know a lot about the newer motors and have a few questions.

1.Do the newer motors have the same bell housing as the older ones? I am planing on using a Borg Warner velvet drive transmission and need to know if they will even bolt together.
2.I want to keep things as light as possible and would like to know what motors are all aluminum? I want something with around 400hp with a carb conversion done to it. And what is the weight of the complete long block of the motor? I think what im looking for is a 5.3l motor, but am not 100%.

This is what i am looking to build.
http://www.glen-l.com/designs/inboard/crackerbox.html
Dont think there are any performance oriented 5.3's beside the ls4 that would meet what youre looking for with the alum block, ls4 is fwd. I believe that the bellhousing will work, but im not sure, i may have read somewhere that it changed with the gen 3 engines. thats all the help i have to offer lol
Old 07-30-2012, 09:44 PM
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The 5.3 is just what I was thinking I might use. If there is a more suitable
one please share your opinion.
Old 07-30-2012, 09:47 PM
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if your looking for medium displacement than an ls1 would be suitable, its a 5.7 and there are plenty of threads that deal with carb'ing one. dont quote me on the bellhousing situation though!
Old 07-30-2012, 10:39 PM
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All but one bolt hole will line up and you'll be fine just leaving it out. I'm guessing that boats use an automatic transmission flex plate, if so you'll need something like this.
http://www.jegs.com/p/Chevrolet-Perf...35483/10002/-1
Old 07-30-2012, 10:53 PM
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I think there are some companies like Indmar that specialize in marinizing the LSX engines. You might check them out, but I'm not sure they do much other than engines for competition ski and tow boats.

Another plus about that is that it would likely come with the transmission included, so you wouldn't need to worry about having the right bell-housing, direction of rotation, flex plate, etc.

EDIT: I know Indmar marinizes the LSA engines also.
Old 08-03-2012, 12:55 PM
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carb or EFI? You might have issues with the o2 sensors in water cooled exhaust, if so.
Old 08-04-2012, 11:54 AM
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I sold Malibu boats for most of the last 15 years. during which time we had several LS engines as options. Most were LS1's being sold in their GM licensed "Corvette boat" which had many corvette cues down to the tailights , drivers seat ,emblems ,etc.

the LS1 could also be optioned in their other offerings such as their direct drive ( center engine location) Response ,Sunsetter , as well as "V" drives (rear mounted 180* with 2 transmissions one to redirect power to the shaft and strut in typical inboard location underwater) VLX , Sunscape etc...

more recently they offer the supercharged LSA from the cts V and a 410 hp L96.

My experience initially with the ls1 engines from a watersports towboat angle as this is Malibus target audience was not as great as you think it would be... The LS1 as we know does not make great power at low rpm thats why we in the car hobby recommend a stall convertor as a very effective place to start modding , especially in a wakeboard boat where they are expected to pull a boat load of people along with a thousand pounds or more of ballast up onto plane directly driven - no convertor ! a traditional SBC with less power known as the Monsoon by indmar in 325/335/340/350 hp over the years would plane out much quicker than the 375 hp LS1 would.

Toyota tried to get into the boat business about 12 years ago with their "Epic" boat which had a 300 hp Lexus sourced engine in a direct drive ( simplest form of propulsion in existence) it suffered from similar issues to the ls1 smooth running great power once the boat was up top but failed miserably when trying to plane a wakeboard boat loaded with ballast we took one in trade and me and a few buddies took it out and loaded it up , everyone had to go up in the bow to plane it , it was an "epic" fail lol

We also had more LS1's have catastrophic failures than we did Monsoons even though we sold more monsoons ! I dont think this was the LS1's fault though - I blame that on the mentality of the buyer that was typically of the "status buyer" type that wasnt typically our core watersports enthusiast buyer but rather the type of knucklehead that would run WOT for 10 miles straight on the limiter. Wanted to say " look its got a Corvette engine let me show you what it can do "

The LSA is the opposite its an absolute workhorse out of the hole the SC works fabulous for that power under the curve to get a boat up on plane with a heavy load making gobs of torque by 2500 rpm

That is enough of the history lesson for you in regards to putting one in a boat the LS1's that went in Malibus looked just like the ones under the hood of a corvette - search yahoo images for Malibu boats LS1 and you can see the different installations . They were run by a standalone MEFI controller that indmar paired with the engines so yes they were factory multi port efi , coil on plug , turnkey engines!

the transmissions during those years were by ZF and Hurth so those could be sourced to bolt on an LS engine.

Where this is looking to be a long term project maybe spend some time studying salvage channels for totalled boats and maybe buy a complete boat with everything you would need to swap the entire running gear , harness , pcm , and guages ??

if not a 6.0 or 5.3 with the truck intake and a cam should make the power down low a boat will need....

with aluminum block or heads you would need to go closed cooling rather than basic raw water cooled to have it survive well in the marine environment even in fresh water , this adds expense as well as complication over a traditional SBC all iron engine

A guy I know built a real nice wooden runabout a couple years ago as a winter project , Mercruiser based SBC 300 efi , direct drive , he is a fiberglass repair guy by trade and it came out awesome , I had sold him a used inboard trailer and a motor box from a malibu he had re upholsterred during his build good luck with your build

*edit*as for what killer ls1 brought up about 02 sensors above: Indmar only went "closed loop" in the last couple years having to add o2 sensors when mandated to install catalytic convertors on boats previous to that the controllers were pretty simple and ran in open loop with no feedback being provided by o2 sensors since therewere none - Alpha N tuning as I recall from my tuning books

Last edited by murphinator; 08-04-2012 at 12:07 PM.
Old 08-09-2012, 08:41 AM
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02-09 Trailblazer/Envoy trucks (all GMT360 based for that matter) that had the V8 where all -aluminum RWD 5.3s.
Old 08-09-2012, 12:42 PM
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I've looked at building the Glen L crackerbox with an aluminum 5.3 L33 motor. As stated above, not exacly an Olds 455 on bottom end but the crackerbox is a very light boat. 310 stock hp, 350 hp easy with just a cam.
For marine starter (spark arrested), check with crusader. Their 6.0 starter will work on the 5.3, 5.7, etc. Same for alternator.
There are a few companies that make water cooled exhaust manifolds. The lightweight solution is the aluminum jet log style for 351C engines. You'll need to drill and tap a hole or 2 but the ports line up.
For bolting up a trans, The LS motors bolt up the same as a SBC/BBC. However the distance is 0.4" farther from the crank to trans. The sachs 1050 flywheel is 0.4" longer and has a bolt pattern for an 11" BBC clutch plate. I'm thinking that's the same bolt pattern used by GM drive plates for Velvet Drive, Hurth, etc transmissions. If weight is a consideration, check out a crash box, half the weight of a velvet drive.
Old 08-09-2012, 01:29 PM
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The LS4 FWD motors use a different bellhousing pattern which IIRC matches up with a 60 degree V6 bellhousing.
Old 10-04-2012, 08:55 PM
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Well My Winter Project is an 87 Chris Craft .
Doing a 5.7 LS1 with Truck Cam , and Truck Intake.

Will Start a Thread when I get a little further.
Old 10-05-2012, 10:02 AM
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Yes. the FWD / LS4 is of a different pattern.. as compared to the Standard GM/Chevy V8 pattern.. see attached picture. The pattern has a odd-sided hexagonal shape

The only advantage to going to a LS4 would be size, it is shorter in front to back in lenght to be crammed into a FWD engine Bay.

Starter location can be different on the FWD vs RWD engines

BC
Attached Thumbnails LS motor in a boat?-220px-gm_60deg_v6_bellhousing.jpg  
Old 10-05-2012, 10:18 AM
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To do a velvet drive in the boat it would be best to use a RWD motor , it will bolt right up to the bellhousing that adapts to a velvet drive . On my boat I used a regular BBC rear four point bellhousing and it works perfect . I also have an extra set of exhaust logs for a marine application that I am going to sell if anyone is interested .
Old 10-05-2012, 10:25 AM
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Murphinator has a lot of sage advice. If you can't afford an LSA, it sounds like you'd still want a supercharged build oriented toward low-end grunt. Here are some aluminum block LSx donors a lot of people don't consider because they're not your normal powerhouse cars: Buick Ranier, Isuzu Trooper. Engines from them should be relatively cheap, compared to LS1, LS7, LSA, etc.
Old 10-05-2012, 10:32 AM
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There have been at least several LS1 boat projects, here, that I recall.
A search should turn them up.
Old 10-06-2012, 11:59 AM
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Here's mine: https://ls1tech.com/forums/conversio...efi-power.html

We couldn't get the engine warm enuf until a closed loop cooling system was installed. Most expensive part of the whole swap were the Marine Power manifolds; however they work kick ***. We did have a pinhole leak in one of the castings but we quickly TIG'd that closed.

I would suggest a 6.0 for the extra torque if supercharging is out of the question. It was for us simply due to cost. A 5.3 is a little soft out of the hole; however we have no problems getting people out of the water. We don't carry any water ballast unless you count a lot of beer and crazy stereo

We installed an LS6 cam, ported TB, and professional tune which really woke it up. Biggest power improvement was the crossover exhaust tube which helped low end power. The stock truck cam around 4500rpm falls on its face. In perfect conditions we have seen 48/49mph... which is limited by hull design I'm guessing.

The nice thing is that if this engine ever pops you can replace easily with another one for under $1K used.
Old 10-06-2012, 05:59 PM
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Very nice build^^^!



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