Engine Weights

Automotive powered airboat discussion.
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cajun_ag
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Engine Weights

Postby cajun_ag » Mon May 24, 2010 12:22 pm

I'm looking to find out how much of a weight difference there is between an LS motor and a big block 454 & 502. Also what's the weight defference between and AL & iron big block. I don't know much about engines so if I'm leaving some critical info out let me know. I will be upgrading to an 18x8 airboat bowfishing rig soon and a concern is that when you get 3 ~200# guys on the front of the boat that the rear tries to come out of the water with a small block. This causes it to draft deeper in the front and also makes it very difficult to steer especially in a little wind. There are some that use the big block just for a counter weight ,but it seems to me a ballast tank could be built to offset the weight difference. When you get ready to go just pump it empty and you get the performance back. On a 18x8 barge all this may be a mute point. :lol:
"Red Rocket" 2007 18X8 Air Ranger Rhino Edition, 540 ci chevy

mudkat
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Re: Engine Weights

Postby mudkat » Mon May 24, 2010 9:01 pm

we just weighed a 400 small block alum heads,waterpump and intake. no starter or dist. with oil ,399.8 lbs with rotator 475

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JAMES
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Re: Engine Weights

Postby JAMES » Mon May 24, 2010 10:00 pm

U WILL NEVER GET ANYONE TO TELL THE EXACT #'S BECAUSE THEY ALL ARE WEIGHTED DIFFERENT AS IN - AND + ACC. ECT
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muffled500hp
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Re: Engine Weights

Postby muffled500hp » Tue May 25, 2010 8:42 am

The aluminum WaterThunder Performance LS engine weighed 396 lbs. with all accessories including starter, alternator, pulleys, and flywheel. I believe it was a fuel injected 550 hp version. The 502 aluminum head GM crate engine with accessories tipped the scales at 707 lbs.
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Waterthunder
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Re: Engine Weights

Postby Waterthunder » Tue May 25, 2010 9:05 am

I have been weighing motors for years. I must start by saying we use a load cell on a strain gauge on our scale. It get's calibrated once a year and has never been off yet. Every complete small block Chevy I have ever weighed was more then 500lb's without a gearbox. I weigh all motors 100% complete. I use to post weights all the time but I got tired of having every post turn into a debate. In my pic or posts you will see GPU's, 540's, 470's, 180's, 500 Caddy's, 502 BBC, and a bunch more. I will say if you have a 18x8 Texas boat and you haul freight with it I would only go with a BBC mostly because everyone in Texas run's 2to1 or 2.38 belt drives. When you have a very big and heavy boat that you load down with 1,000's and 1,000's lbs of gear and people there is no reason to worry about a motor weighing less.
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cajun_ag
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Re: Engine Weights

Postby cajun_ag » Tue May 25, 2010 10:33 am

Thanks for the replies.
The boat I have planned will be layed out internally similar to WarriorP's boat viewtopic.php?f=48&t=23967&hilit=texoma as far as deck, lights, seating, genny mount. I want a quiet as reasonable boat as well so probaly 2:68 & S blades, full exhaust ect
By Florida standards it's a tank, but I plan on having it built by GTO or Diamondback so it should be somewhat lighter than Preston's above. The lights & genny will always be on the boat, but most of the time I'll just be hauling the wife and kids that might total 200# combined. There will be occasions when it has to haul 1000# extra but that's maybe 5% of the time and I'm not really designing around that. On the rare occasion that we get to shoot 1100 fish in a night I'll be content if she still floats and idle back to the ramp. :bounce: :lol:
I'm not heart set on a SBC, but being new to AB's I'm not sure if roughly 400#s is going to get measurable results in a boat so big. Obviously I'm not building a hotrod so what would you consider a workhorse day in day out engine. A lot of guys around here run a 496 or 502. I'll stick with CI's and won't state hp #'s for obvious reasons.
Thanks again for the help
"Red Rocket" 2007 18X8 Air Ranger Rhino Edition, 540 ci chevy

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HuntingBigun
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Re: Engine Weights

Postby HuntingBigun » Tue May 25, 2010 10:48 am

Each OEM has different specs on the build to compensate for weight & placement of all your goodies. GTO builds the deckover like mine but the setup is different between aluminum engine or cast iron. So for my 10 cent with a 18 foot barge I go with a FI BBC :D
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Re: Engine Weights

Postby Joe » Tue May 25, 2010 11:17 am

On a boat that big a BBC would probably do you the best for longevity and reliability. Give both those manufacturers a call and talk it over with them. Both have a good engines they use if your not making a hot rod.
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