Airboat Engine Builds - Automotive

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kwanjangnihm
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Re: Airboat Engine Builds - Automotive

Post by kwanjangnihm » Wed Feb 14, 2018 2:58 pm

CarMotorBarge wrote:5 years ago on Memorial Day weekend I ran across Gardner's marsh from Big Hole in the wall all the way to North Cove. There wasn't any water in the marsh. Didn't see any boats at all. Motor had stock block, stock heads, stock intake, stock lifters, stock rockers, stock oil pan, etc. Motor ran 160 to 180 degrees and turned 4000 RPMs all the way. Give me another 12 pack and I would do it again. LOL
CMB did this stock motor have a stock tune or airboat tune? Where is this motor now? :scratch:
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Re: Airboat Engine Builds - Automotive

Post by OneBFC » Wed Feb 14, 2018 6:19 pm

Just because you type the words out on the screen doesn't make them true. You need to provide some basis for your assertions.

I and others have given examples and some math to illustrate. I am not so convinced by "your wrong because I say so and you should call and talk to someone else about it."

Just saying here, not making much ground with that counter view your presenting.

So far noone has addressed the fact that cruising at 30mph a typical Airboat is using pretty close to the same fuel that a truck with trailer uses. Same fuel is same load, no way around that fact.

Also, all vehicles save perhaps an aircraft vary their throttle (or, mor correctly, load). That is not any different or special to an Airboat.

Perhaps someone should suggest a minimum number of hours a theoretical engine should be able to attain in Airboat service so we can have a non moving baseline of what is "good"?

I will submit that if you get 1000 hrs out of your engine you are doing well. Open to other suggestions there.
ladyblackwater wrote:ONEBCF that is your opinion but I can tell you it's not true. There is nothing harder on a motor than an airboat. We have bad Harmonix, turn big props and in and out of the throttle on an airboat. Now this is just a few things. If you dig deep we put way more stress on a motor than you can even imagine. Everyone is entitled to their opinion but why don't you call an builder like MAS that has been building motors for 40 years for pretty much every application and ask him who is the toughest on a motor. An airboat motor has to be custom built way different than other motors in the race industry. Build a motor the way you build one for any race car and see how long that last you. I've been there done that and learned my lesson.
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kwanjangnihm
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Re: Airboat Engine Builds - Automotive

Post by kwanjangnihm » Wed Feb 14, 2018 6:46 pm

from a SA motor reliability thread:
Waterthunder wrote: We have a ton of motors out there with well over a 1,000 hours. I have a few commercial ones with over 3,000 hours. The main issue is primary use and the style of boat. If you have a boat that requires 4,000 RPM's to cruise you need a big HD BBC. Most of our motors fall in the 82'' 4 blade R prop range. Our current 418's typically turn a 4 blade R at the 3rd mark around 5,400. Our Current 550HP motors a 3 blade R is not enough prop. Cages and rigging will also effect this. However if you turn a 4 blade R on the 3rd mark 5,400 and you need more than 3,300RPM's to cruise you either have a very heavy boat or a hull that is not working well. We just had a 5 SEATER 16ft Hamant go out that cruised at 2,800RPM's hauling ass no doubt that was very impressive but I cant take all the credit the hull just ran AWESOME! Sorry got side tracked anyway the boat size and weight and cruise RPMs effect lifespan more than anything else. I also cut off a few hundred hours if you run a 2to1 ratio. 2.38 is better and 2.68 is the easiest on the motor.
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Re: Airboat Engine Builds - Automotive

Post by CarMotorBarge » Wed Feb 14, 2018 7:33 pm

kwanjangnihm wrote:
CarMotorBarge wrote:5 years ago on Memorial Day weekend I ran across Gardner's marsh from Big Hole in the wall all the way to North Cove. There wasn't any water in the marsh. Didn't see any boats at all. Motor had stock block, stock heads, stock intake, stock lifters, stock rockers, stock oil pan, etc. Motor ran 160 to 180 degrees and turned 4000 RPMs all the way. Give me another 12 pack and I would do it again. LOL
CMB did this stock motor have a stock tune or airboat tune? Where is this motor now? :scratch:
Still on my boat today. Back then it had a Water Thunder ECM and tune. Today I am using a Holley EFI tuned by me. There really is no difference between an airboat tune and a car tune. In either case you control the timing and AFR. What varies primarily is how aggressive or how safe you make the tune. For example I am running 12.5 AFR and 23 degrees of timing at WOT. These are both conservative. BTW, didn''t see any A/C boats in the marsh that day either. :stirpot:
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Re: Airboat Engine Builds - Automotive

Post by lorick » Wed Feb 14, 2018 8:04 pm

That's because I didn't go out but day

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Re: Airboat Engine Builds - Automotive

Post by CarMotorBarge » Thu Feb 15, 2018 6:24 am

Just started my fifth 12 pack. It is 5 o'clock some where. So take your truck driving 70 MPH pulling your airboat. Now take your airboat and drive 30 MPH. The load (gph) will be very close between the 2. This is what OneBFC is saying. You look at the load and not MPH to do a proper comparison.
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Re: Airboat Engine Builds - Automotive

Post by SWAMPHUNTER45 » Thu Feb 15, 2018 8:16 am

I think my original point was to qualify that an airboat engine experiences a "severe duty" application. Personally it's simple math to me. I would not dispute that some towing vehicles see severe duty use. There are some apples and oranges among this comparison as the airboat never experiences an easy day. It is going up the mountain all day long. The ultra lite boat or extreme hp to weight application would see less stress. In that realm one could argue but in the larger or heavier boat world the demand is extreme.

There is nothing to debate here it is an application beyond that with which it was designed, being made to perform in a extreme environment at a high power level.

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Re: Airboat Engine Builds - Automotive

Post by loudmouse » Thu Feb 15, 2018 8:30 am

While I don't believe an airboat engine is an example of a severe Duty application, the constant elevated rpms without being tuned properly causes lots of problems. If the valve train is up to the task and the tune is on par the bottom in doesn't care how many RPMs it's turning.....
Last edited by loudmouse on Thu Feb 15, 2018 10:18 am, edited 1 time in total.
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Re: Airboat Engine Builds - Automotive

Post by CarMotorBarge » Thu Feb 15, 2018 9:07 am

SWAMPHUNTER45 wrote:I think my original point was to qualify that an airboat engine experiences a "severe duty" application. Personally it's simple math to me. I would not dispute that some towing vehicles see severe duty use. There are some apples and oranges among this comparison as the airboat never experiences an easy day. It is going up the mountain all day long. The ultra lite boat or extreme hp to weight application would see less stress. In that realm one could argue but in the larger or heavier boat world the demand is extreme.

There is nothing to debate here it is an application beyond that with which it was designed, being made to perform in a extreme environment at a high power level.
I think you need to try a GM motor built in the last 20 years. American auto manufacturers have really stepped up their game on engine HSP and dependability. The all aluminum blocks have also made a big difference.
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Re: Airboat Engine Builds - Automotive

Post by SWAMPHUNTER45 » Thu Feb 15, 2018 9:58 am

My old 70's era high nickel alloy will be going long after the aluminum crumbles...lol

CMB is WaterThunder not the master builder of the airboat LS technology?

It was he who said, if your running a large boat (15ft threshold) or heavy load go with a big block.

Maybe one day but for now we will keep the LS3 platform in the Camaro. It has a tune by the way and with the 6 speed gets 20.5 mpg average all conditions. It's an impressive engine. Maybe down the road when not the wife's daily driver anymore Mouse can turbo it :cheers: :salute:

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Re: Airboat Engine Builds - Automotive

Post by loudmouse » Thu Feb 15, 2018 10:23 am

Now that sounds like a fun project. You probably would never get the chance to drive it :dontknow:
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Re: Airboat Engine Builds - Automotive

Post by OneBFC » Thu Feb 15, 2018 3:01 pm

:banghead: :dontknow: :salute:
-Russ
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Life begins at 2 BAR, Just a good ole boy

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Re: Airboat Engine Builds - Automotive

Post by SWAMPHUNTER45 » Thu Feb 15, 2018 4:20 pm

On another note very few of you actually have seen just how much power a Branch roller Cadillac has and just how easy it can spin those 4 big S blades. Once you did you would know why I have not changed platforms. Kwan has seen it in the black cement mud and green sticky grass on a 95' day.

In fact he didn't even need to "butt scooch" that day.

We have another build started and have been chasing piston rings. The new engine is going to be a 555 inch with a little wilder spec than the 542 on it now.

30mph @ 3,000 rpm all day long

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Re: Airboat Engine Builds - Automotive

Post by CarMotorBarge » Thu Feb 15, 2018 4:46 pm

So how much HSP is the 542 making?
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Re: Airboat Engine Builds - Automotive

Post by SWAMPHUNTER45 » Thu Feb 15, 2018 4:57 pm

Never put it on a dyno CMB

It spins 4 Sensenich "S" blades 81.5 inches long pitched at a solid 2 mark via a 2.37 ratio drive

We keep the rpm down low around 4,200 rpm

It has a wet plate nitrous system 150 shot with the spray 4.500 rpm

It idles like Aunt Mickeys old station wagon and has zero lag time to spin up. The power is near instant.

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Re: Airboat Engine Builds - Automotive

Post by CarMotorBarge » Thu Feb 15, 2018 5:13 pm

How much torque at 4200?
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Re: Airboat Engine Builds - Automotive

Post by SWAMPHUNTER45 » Thu Feb 15, 2018 5:31 pm

As stated this engine had not been put on a dyno but that said Mr Branch has had a variety of builds over the years he has tested. Using comparative data he feels it would yield 650 to 680 foot pounds around 3850 to 4150 and stated it is likely to be higher.

The 555 build will have a totally different blueprint and will see a higher max rpm as the main bearing clearances will be set to allow that. The crank was installed today as a matter of fact and he was very pleased.

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Re: Airboat Engine Builds - Automotive

Post by CarMotorBarge » Thu Feb 15, 2018 5:38 pm

Assuming the engine makes 680 foot lbs of torque at 4200, the engine is producing 544 HSP to turn the prop. Does that sound correct?
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Re: Airboat Engine Builds - Automotive

Post by SWAMPHUNTER45 » Thu Feb 15, 2018 6:30 pm

Maybe Darrin can pull data to see how much horse power is required to spin that combo.

The next one will be a bunch more power but really all I care about is how it spins the prop.

The cool thing is it's so reliable and the power is nearly instant.

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Re: Airboat Engine Builds - Automotive

Post by CarMotorBarge » Thu Feb 15, 2018 9:42 pm

Here is an interesting article for doing an LS3 cam upgrade:

http://www.superchevy.com/how-to/engine ... boomerang/

In this article, cam 2 is a relatively mild LS cam. So here is where I am going. The 542 Cadillac is spinning the 4 S blades at 1,764 RPMs (4200/2.38). It is making roughly 540 to 550 HSP (680 foot lbs at 4200 RPM).

Now take a stock LS3 and put cam 2 in it with the valve spring upgrade (you could also use cheap 6.0 truck engines with the L92 heads and get similar results). The LS3 with the cam 2 upgrade will make approximately 540 HSP at 5800 RPM (you can see this in the graph for cam 2). Run the engine at 5800 RPM with a 3.26 gear ratio and you will spin the same 4 blade S at 1,779 RPM with the same ptich.

Here are the advantages of the nearly stock LS3 over the custom built 542 Caddilac:

1. The LS3 will get superior fuel mileage. Especially with the EFI.

2. The LS3 will be several hundred pounds lighter. This would be like kicking two 150 lb people off your boat.

3. The LS3 is making comparable HSP despite being nearly stock and only spinning 5800 RPMs. There is nothing special in this build. A custom built LS could do far more.

4. The LS3 is easier to build and get parts for if something breaks.

I am also willing to bet that the LS3 spinning at only 5800 will be more reliable than a Cadillac spinning at 4200. :stirpot: GM has made a few improvements over the last 50 years since the original Cadillacs were built. 8)
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Re: Airboat Engine Builds - Automotive

Post by loudmouse » Thu Feb 15, 2018 10:06 pm

There is a reason that gm went to the LS in the Caddys :stirpot:
15' Alumitech deckover LSX TT Oxbox 84" JX 4-blade
Gas required Water optional :dontknow:
Built and Tuned by Me
14'X8' JW, Chevrolet 122CID LNF Turbo Engine, Ox box, 80" NGR 3 blade

Life is short, eat your dessert first! :downtown:

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Re: Airboat Engine Builds - Automotive

Post by CarMotorBarge » Fri Feb 16, 2018 7:06 am

The funny thing is that the 542 Cadillac makes substantially more torque, but doesn't turn anymore prop. :stirpot:
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Re: Airboat Engine Builds - Automotive

Post by SWAMPHUNTER45 » Fri Feb 16, 2018 7:52 am

Here is the difference CMB your talking about spinning 4 S blades with a LS, but I actually do it with the old 542 inch Cadillac!

On my boat there is no need for hearing protection, the neighbors don't complain and the ride is relaxing. This engine was built to net fish not for max power, we idle up on the schools and throw the nets then kill the power, cull and restart. This boat was a direct drive 514 when originally built as that was all we really needed. Deano saw the old DD set up and it was no slouch (76 NGQ pitched@3) but now we fish less and run a lot more dry loaded up. This created a need for big power and a retrofit to a gear drive was undertaken for which "Blue" knocked it out of the park with his craftsmanship. Without his assistance, I would probably be very limited with the ground game. (Thanks Brother)

Seems over my way there is a PoorBoys boat spinning 4 Maximus blades.....oh ya it's a Caddy and a big DB with 4 83 inch S blades, yep a Caddy also!

Any LS boat owners spinning 4 S blades feel free to pile on, would enjoy riding with you to compare. I am 100% pro LS like I said earlier we own an LS3 car and the purpose of this thread was to educate not hate. Mouse shares some good opinions on how with his experiences the tune and valve train are the critical base for that platforms survival on a boat. That can help others considering a salvage or crate build to prevent a problem. My belief is forged pistons are a must, but he is showing that for the budget minded a take out stock rotating assembly can work if the TUNE AND VALVE TRAIN are correct and all the systems around it are without fail or flaw. You LS guys who are running take out engines with FI on an unaltered auto profile EMC had best use this info and find a tuner.

OneEye is having great success with a carb version 5.3 and doing it having come from a DD Caddy platform.

For me right now the Branch built (Cadillac Performance Engineering) Cadillac engines offer everything I want and need with excellent technical support. My wife likes the ride quality and don't gripe about noise so I'm winning with that guys. I feel comfortable heading off knowing that Caddy is gonna bring me home without a hassle. Hell that engine owes me nothing, any LS stories about a freak oil pickup fail where you rode back home loaded, lifters clacking and didn't burn up the engine. I lived it, shared the story and pics. No bullshit that's a tuff and well built engine. When that happened Mr Branch said bring me that engine! It was not under a warranty but he tore into it, pulled the mains and inspected everything ZERO damage. Only cost was the gaskets and rear main seal. That is a engine builder I would recommend. For the record the oil was the home brew not an expensive synthetic or race oil!

You want more power, wait for the 555 to get completed, I will start a build thread soon.

Any Ford or Chrysler or Diesel guys want to jump in? Would welcome your input on those platforms and any required or suggested mods.

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Re: Airboat Engine Builds - Automotive

Post by Capt steve » Fri Feb 16, 2018 12:07 pm

Been following this thread. Learning a lot! Keep it up guys. This is interesting stuff for us newbies.
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Re: Airboat Engine Builds - Automotive

Post by Wild Bill » Fri Feb 16, 2018 5:23 pm

Don't you need brass freezeplugs too?

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