Gear Drive Help???

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Txairboat66
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Gear Drive Help???

Post by Txairboat66 » Sat May 07, 2016 12:20 am

What Ratio Gear drive do I need for a 350 Chevy motor? Also does anyone have a used gear drive for sale?
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SWAMPHUNTER45
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Re: Gear Drive Help???

Post by SWAMPHUNTER45 » Sat May 07, 2016 8:30 am

A lot depends on how the engine was built, what RPM you want to run and what prop you have. The three elements have to match to work properly. That said 2.0, 2.37 or 2.68 could all be possible choices depending on your sum of parts.

There are a lot of fellows on here with sbc experience. Post the engine specs. if you know them and what prop your going to use then I'm sure you will get some great advice. A little about the boat is helpful too.

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Des Moines Boater
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Re: Gear Drive Help???

Post by Des Moines Boater » Sat May 07, 2016 8:40 am

I do have a nice gearbox for the Chevy 350. It is a Precision 2:1 gear drive and includes the soft drive and flex plate. I also have a like new wood paddle prop that goes with it. I'd like to get $2000 for the pair. I'll even pay shipping. This came on my 383 boat and I upgraded to a Ballistic drive.
13' 6 Lazer, 383 SBC 425 hp, 2.7 Ballistic, 3 blade 80 NGR

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Deano
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Re: Gear Drive Help???

Post by Deano » Sat May 07, 2016 10:53 am

Swamphunter has given you good information. To expand and/or clarify what he said:

It will depend on the RPM range where said small bock makes its most power (CAM choice),
and on the RPM range where the prop you are using produces the most thrust. (PROP choice).
The best gear ratio will be the one that most closely links those previous two choices (GEARBOX choice).

What you are asking is a very fundamental concept that can't be answered without more info.
While that may not seem like many variables . . . they are all contingent on each other.

All that information is here for the reading. Your best bet is to learn how to use, and then exploit
the board's [Search] feature, which is quite powerful after you learn to use it.

Here is one example from a similar thread:
http://www.southernairboat.com/phpBB3/v ... um#p600087
"The suppression of uncomfortable ideas may be common in religion and politics,
but it is not the path to knowledge; it has no place in the endeavor of science."
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Txairboat66
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Re: Gear Drive Help???

Post by Txairboat66 » Sun May 08, 2016 11:12 am

Ok thanks everyone for the reply.. I have owned an airboat for several years and have learned a lot but I still have a lot to learn.

My Current setup is a 18' Panacraft hull with a 472 Caddy DD and a fiber Prop Dan from Stinger gear drive sold me the correct prop I need for a gear drive to fit the caddy but I can't seem to keep the caddy cool.. I have added a new radiator extra Fans and changed the carb a few times and it still gets hot.

Plus there is no one in my area that knows much about them. Plus I am the only one in my area that even owns an airboat.
.
Soooo My dad farms and has recently retired so we have several irrigation motors that were removed from service and one that is fairly low on hours is a 350 so I thought I would try that with a gear drive.

So now it seams I need to have it Dyno'd to see what its top torc is at what RPM. Before adding a gear drive.. I will also look at what prop I have and check back..

Thanx again for all your help
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Txairboat66
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Re: Gear Drive Help???

Post by Txairboat66 » Sun May 08, 2016 11:19 am

Another Question is Which is better the gear drive or the Belt drive or does it matter???????
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Blackcoffee
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Re: Gear Drive Help???

Post by Blackcoffee » Sun May 08, 2016 4:45 pm

I would find out what makes your boat run hot, pushing a 18' boat far on dry ground will probably make a lot of motors run hot. I don't think a 350 is going to do much on a 18 foot boat with any gear.
GTO 14' Deckover

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Deano
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Re: Gear Drive Help???

Post by Deano » Mon May 09, 2016 9:20 am

I agree with BlackCoffee on both counts. You are pushing quite a load.

Were it me, I would identify why that 472 is running hot and be looking around for a belt or gear drive in the 1.7x neighborhood. If at all possible, I would start by doing compression and leak down tests and confirm it didn't have a serious problem first, but then I would jump in with both feet. That having been done, it really isn't that difficult to diagnose and correct.

To me, you would be way better off in the end given the size and weight of the boat you are talking about.
There is a lot of Caddy info and help here. Additionally, that approach would very likely be more time and cost effective than stating over from scratch with a lesser and largely unknown quantity.

In the end, on a boat that big, the only difference between a belt and gear is what prop you will use. LH vs RH
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Deano
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Re: Gear Drive Help???

Post by Deano » Mon May 09, 2016 10:20 am

As far as your over-heating 472 goes, your problem may be related to the thermostat which is a slightly different setup than is found on other GM products. After reading the following thread, you may already know if this scenario is what is causing your problem. If so, the fix may be a very easy one.

If not, pulling the thermostat housing and confirming what you do or don't have should only cost you a cheap gasket and about half an hour. :)

http://www.southernairboat.com/phpBB3/v ... ze#p642132
"The suppression of uncomfortable ideas may be common in religion and politics,
but it is not the path to knowledge; it has no place in the endeavor of science."
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Txairboat66
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Re: Gear Drive Help???

Post by Txairboat66 » Tue May 10, 2016 12:42 am

Yes the heating problem is an ongoing thing. I have rebuilt the motor completely. I have drilled holes in the thermostat Ive put a lower temp and a higher temp in I have pulled the thermostat completely out. Ive changed carbs and all the adjustments. and now its so far out of whack it blows fire out of the carb Im guessing thats a timing issue. Just hard to find any help around here and I consider myself somewhat educated at it but still feel like an idot by not knowing what I'm doing. Just trial and error

Thanx for everyones help Ill keep plugging and try to get it right

I have a LH Sesnich 2 blade super wide not sure the length but Im thinking its a 72" Dan said I might need a 2.38 gear box but I just Don't know what to go with and don't have the funds to make a mistake.. I will go read the thread provided

Thanx Y'all
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Deano
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Re: Gear Drive Help???

Post by Deano » Tue May 10, 2016 10:32 am

First of all, let me say that there is no need or reason to feel like an idiot.
Not being overly quick to ask questions does not make you an idiot, it just
gives you incentive to ask questions a little quicker. :wink:

Just a couple of random thoughts . . .

If you were not using 'Cadillac' specific thermostats or did not plug the bypass in the block, that is almost guaranteed the source your overheating problem. The 'Cadillac' thermostat is constructed so it blocks that bypass when it opens, other generic ones will not. Without the bypass plugged, the coolant just circulates through the block and not the cooling system as a whole. You have to do one or the other, there is not a third option.

If you are attempting to run the SuperWide blades you spoke of on a direct drive, this would also contribute to an overheating problem (and deprive you of thrust). That's far to great of a load. If those are the blades you have, then you will either need to get smaller blades in order to run DD, or get a belt drive to properly use them. They will not work on a gearbox because they are left hand rotation and a gearbox needs right hand rotation.

What do the blades measure at the widest point? How long are they? Can you post a pic?
Not doubting you, just would like to think that Dan didn't sell you LH Superwide blades for a DD. :shock:

It is sounding like your problem(s) may be no more serious than a freeze plug and a mismatched prop.
"The suppression of uncomfortable ideas may be common in religion and politics,
but it is not the path to knowledge; it has no place in the endeavor of science."
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Re: Gear Drive Help???

Post by Blackcoffee » Tue May 10, 2016 8:11 pm

What are you doing when your boat runs hot
GTO 14' Deckover

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Re: Gear Drive Help???

Post by myronja » Tue May 10, 2016 10:53 pm

Where are u located at
TAA-436
15' panther 350dd 72"x30 Flordia Paddle 40mph-sold
16X7 Air Ranger 383 stroker 2:1 belt 78" powershift 3/8" poly 58.8mph had to let out

Striker543
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Re: Gear Drive Help???

Post by Striker543 » Mon May 16, 2016 10:02 pm

A picture of your setup would probably help everybody in diagnosing the overheating issue. It could easily be something as simple as radiator size or placement.

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Re: Gear Drive Help???

Post by Txairboat66 » Tue May 17, 2016 8:38 pm

Well i have been advised to stay with the 472 Caddy and a 2.09:1 gearbox With 3 super wide Q series props..

I am still worried about the heating issue though, I have not cranked the boat all winter so not sure how it will act now.. I think I have a timing issue and the carb thats on it is the stock quadrate that came on the motor in 69.

I would like to get a high torc starter. But where? I am learning motors but still consider myself a novice.

I remember reading something about plugging off a port in the intake but not sure which one??

And now short on funds with buying the new gearbox and blades..
Trying to add pics from my phone but keeps giving me an error that the pic is too big

Thanx in advance for your help I really do appreciate it.
Brent
:texas:
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Txairboat66
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Re: Gear Drive Help???

Post by Txairboat66 » Tue May 17, 2016 9:08 pm

Here are some pics
Attachments
image.jpeg
image.jpeg
image.jpeg
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Re: Gear Drive Help???

Post by Txairboat66 » Tue May 17, 2016 9:11 pm

Here are some more
Attachments
image.jpeg
image.jpeg
image.jpeg
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SWAMPHUNTER45
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Re: Gear Drive Help???

Post by SWAMPHUNTER45 » Tue May 17, 2016 9:22 pm

Was that boat built in Florida ?

Txairboat66
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Re: Gear Drive Help???

Post by Txairboat66 » Tue May 17, 2016 9:25 pm

I think so. I bought it from someone on the west coast. I believe it was Bay Town FL
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RazorsEdge
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Re: Gear Drive Help???

Post by RazorsEdge » Tue May 17, 2016 9:36 pm

Nice looking rigging. I know that having that s/s grate over the back of your radiator will kill you air flow big time. I know first hand.
:old_glory: :florida:

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Deano
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Re: Gear Drive Help???

Post by Deano » Tue May 17, 2016 9:40 pm

Brent, you have made a good decision to keep that engine and add a gearbox.
You have a big boat and will not regret having made that choice.
SWAMPHUNTER45 wrote:Was that boat built in Florida?
Right off of 470 just a bit north of Lake Panasoffkee. :)
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Txairboat66
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Re: Gear Drive Help???

Post by Txairboat66 » Wed May 18, 2016 12:21 am

RazorsEdge wrote:Nice looking rigging. I know that having that s/s grate over the back of your radiator will kill you air flow big time. I know first hand.
:old_glory: :florida:
Ok so what do you suggest? I put that on there because I got stranded up the river because i let a jug get loose and the prop slung it through the radiator. Had to have a Jet ski pull me home.. Just trying to protect the new radiator.. maybe a piece that has bigger holes??
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Re: Gear Drive Help???

Post by Txairboat66 » Wed May 18, 2016 12:24 am

SSSSOOOOOO does anyone know where I can get an aluminum Hull? I suppose these are much lighter?? Or where do I get the material and I will build it myself???
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Re: Gear Drive Help???

Post by skinnypockets » Wed May 18, 2016 6:24 am

"I remember reading something about plugging off a port in the intake but not sure which one?"

The hole you're referring to is under the thermostat. Pull the thermostat housing and thermostat, the hole is directly under the thermostat. I don't remember the size but it's somewhere between 1 and 1-1/2 inch. Be sure to drill a 1/8 inch hole in the plug so any air can bleed out. Install the plug and a 180 degree thermostat and re assemble.

With the original thermostat, this hole would be closed off when the engine warmed up and open when the engine was cold to make the engine warm up faster. If you can find an original cadillac thermostat, you can use that instead of plugging the hole, just be sure it's the correct "two way" thermostat for that engine.

Be sure you have a bleed off petcock or plug at the highest point of your cooling system to remove all the air. Hope this helps, Rich
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I'VE DONE SO MUCH WITH SO LITTLE FOR SO LONG, I CAN DO ANYTHING WITH NOTHING!

13.6 Alumitec, 350 Chevy, Rotator Gearbox and 6 Blade Warp Drive

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Deano
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Re: Gear Drive Help???

Post by Deano » Wed May 18, 2016 8:39 am

You tell 'em, Rich. :lol: :lol: For some reason he doesn't want to believe me. :scratch:
Heck, I even posted a link to a picture.
We could have fixed it in less time than we've spent typing about it. :roll:

Not being one to easily give up, I will make one last attempt.
Here is another, more self-explanatory and more inclusive picture:

Image
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