New to airboat - need advice

Airboat propeller discussion.
andyram1994
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New to airboat - need advice

Postby andyram1994 » Tue Aug 15, 2017 2:07 pm

Bought an airboat a couple months back, and the wood prop got damage. Was wondering if anybody can give me an idea or advice on how to buy an put a carbon fiber prop on it? It's a 1969 Cadillac 500 engine according to the guy who i bought the airboat from.

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kwanjangnihm
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Re: New to airboat - need advice

Postby kwanjangnihm » Tue Aug 15, 2017 2:54 pm

andyram1994 welcome to SA!
More info on your boat is needed. DD, gearbox, length, aluminum, fiberglass, make, poly, riggin, seats, etc. :salute:
" I don't care who you are back in the world, you give away our position one more time, I'll bleed ya, real quiet. Leave ya here. Got that? "

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Deano
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Re: New to airboat - need advice

Postby Deano » Tue Aug 15, 2017 3:42 pm

While all that is both needed and relevant information,
You really first need to take a little time and identify what the engine really is. There was no 500 made until '70.

If the year is correct and it's a '69, then it is a high compression 472.
If the 500 cid is correct, it could be anywhere from '70-76 and could be high or low compression.
Since you were already given inaccurate info, the possibility also exists that it is a '76+, 425 cid.

To identify what it is (all needed, listed in order of importance) :
..1) What is the block casting number (top, right side by the bell housing)
..2) What does the stroke measure (coat hanger through plug hole)
..3) What heads are currently on it? (number is cast on head, centered for and aft, under valve cover)

Given these three tidbits, and Kwan's hull info, picking a prop can be done pretty accurately.
There could be a big difference in prop turned. For instance, a 425 and a 500 w/902 heads are two entirely different scenarios.
"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."
- Carl Sagan

andyram1994
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Re: New to airboat - need advice

Postby andyram1994 » Tue Aug 15, 2017 4:53 pm

Deano wrote:While all that is both needed and relevant information,
You really first need to take a little time and identify what the engine really is. There was no 500 made until '70.

If the year is correct and it's a '69, then it is a high compression 472.
If the 500 cid is correct, it could be anywhere from '70-76 and could be high or low compression.
Since you were already given inaccurate info, the possibility also exists that it is a '76+, 425 cid.

To identify what it is (all needed, listed in order of importance) :
..1) What is the block casting number (top, right side by the bell housing)
..2) What does the stroke measure (coat hanger through plug hole)
..3) What heads are currently on it? (number is cast on head, centered for and aft, under valve cover)

Given these three tidbits, and Kwan's hull info, picking a prop can be done pretty accurately.
There could be a big difference in prop turned. For instance, a 425 and a 500 w/902 heads are two entirely different scenarios.

Thanks deano for getting back with me and helping me figure out what exact engine is on the boat, i was able to get the block number (1486200), but the rain came down on me, i will get the other numbers tomorrow or when the rain finish pouring and send it to you.

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Deano
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Re: New to airboat - need advice

Postby Deano » Tue Aug 15, 2017 5:57 pm

That is good news then . . . it ain't a 425. 8) .. It is worth confirming that 4th digit is a 6, could be a 5.
1486200 would be a later model, and consequently, lower compression (most likely) 500.
When you measure the stroke:.. If it's > 4 1/4 then its a 500 (4.30) .. If it's < 4 1/8 then it's a 472 (4.06).
Given that block number, odds are it has 493 or 552 (last 3 digits) heads, low compression either way, no problems there.

These are largely deductions, primarily based on what the factory initially did . . . still it is in your best interest to gather that info and report back. Bear in mind that many idiots could have come and gone under your valve covers over the last 40 years. Sometimes, things have been Frankensteined along the way (deliberately or not), and it is ALWAYS BEST to confirm what you have and are working with so as to not shoot yourself in the foot through no fault of your own. :idea:
"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."
- Carl Sagan

andyram1994
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Re: New to airboat - need advice

Postby andyram1994 » Tue Aug 15, 2017 6:04 pm

Ok thank you for getting back, tomorrow ill get all the info an get back to you as it is still raining over here

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Re: New to airboat - need advice

Postby eldorado » Fri Aug 18, 2017 6:26 am

Although I agree with most of the above, like for instance the 500 was exclusive and specific to the Cadillac El Dorado which they stopped making in 75 not 76. All of that aside try not to complicate what you are trying to achieve. I strongly suggest you call Water Walker props most likely it will be Andrew that answers the phone and I assure you he will help you, he is very easy to talk to. Most likely he will recommend a prop that will spin at 2850 to 2950 rpms because your boat is a DD. I know a little bit about this stuff because my boat is named El Dorado for a reason.

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kwanjangnihm
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Re: New to airboat - need advice

Postby kwanjangnihm » Fri Aug 18, 2017 8:43 am

caddy engines are like a rain storm, see-alice or a pornstar: ya never know how many inches your gonna get or how long its gonna last! :toothy7: :stirpot:
" I don't care who you are back in the world, you give away our position one more time, I'll bleed ya, real quiet. Leave ya here. Got that? "

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Deano
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Re: New to airboat - need advice

Postby Deano » Fri Aug 18, 2017 9:58 am

eldorado wrote:Although I agree with most of the above, like for instance the 500 was exclusive and specific to the Cadillac El Dorado which
they stopped making in 75 not 76.
. . I know a little bit about this stuff because my boat is named El Dorado for a reason.

No intention to offend, but years ago there was a lot of conflicting Caddy info here, and it was difficult at times to weed through. While their numbers are decreasing over time, there are still those who could justifiably use this as a reference. Consequently, it is in the collective interest to make corrections when and where they are needed so as to avoid spreading disinformation.

At first I couldn't figure out where you read El Dorado is this thread . . . then realized, it wasn't there before your post.
Then I deduced that you must have been referring to the span of years I listed above. I can assure you that neither the 500 nor the El Dorado stopped production in 1975. Actually, their last years were '76 and '02, respectively. What stopped in '75 was the 500 being used exclusively in the El Dorado. The year after that (the last before its demise) it was in every Cadillac model produced except for the Seville. These were much easier, and far faster to pull, given that they didn't employ the FWD tans-axle.

I do agree with your recommendation about talking to Andrew. I'm willing to bet two pushrods he will say a 72" Signature Series 2 blade, which is likely the safest all around bet, and will work very well depending on intent. However, we still know nothing about the boat or it's intended use, which is more than passively relevant. If it's a really small, light boat and he lives to haul ass, that will not be the best suited prop for his purposes.

While I admit to being partial to Water Walker props to some extent, depending on what he has and how he uses it, there are very likely multiple alternatives. In fact, so many that I was waiting to hear more about his boat and use before commenting.

kwanjangnihm wrote:caddy engines are like a rain storm, see-alice or a pornstar:
ya never know how many inches your gonna get or how long its gonna last! :toothy7: :stirpot:

Have to admit, that was cute. :wink: But to a trained eye, there are ways to tell . . . And if it doesn't last as long as you
want it to, you probably let somebody play with it along the way that should have been denied access altogether. :shock: :lol:
"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."
- Carl Sagan

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Re: New to airboat - need advice

Postby eldorado » Fri Aug 18, 2017 12:32 pm

You did not offend me nor is it my intention to offend you. I agree there is a lot of misinformation which is why I did a lot of research on the 500 caddy before i bought my boat. I too I'm partial to water Walker and I totally agree with your comments about the size and type of the boat as well as intent. And how all that played a part in making decision for prop.

Back to the caddi 500.
When I Google Cadillac 500 there are many sites to go to that contain the history of Cadillac and the evolution of the 500.

Below is a clip from Wikipedia.

"The 500 was exclusive to the Eldorado until 1975 where the powerplant was standard in all Cadillacs except for the Seville, which was powered by a fuel-injected"

All of this is a lot of fun and I could go on and on about caddy 500 and in the right hands they're great airboat motor.
Like what is a true 500 caddy?
Why did the early airboat guys use the 500?
And on and on.

But.

Back to Andyram and the reason for this thread.
I'm sure that we both would also agree that he should call not just water Walker but sensenich and maybe some of the Airboat manufacturers to get their opinion as well.








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Deano
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Re: New to airboat - need advice

Postby Deano » Sat Aug 19, 2017 7:49 am

:? ... :scratch: ... I reckon, you can read and quote what google and Wikipedia says until the cows come home if you like.
Unfortunately, that isn't generally a substitute for practical experience, nor does it guarantee increased comprehension
or expanded knowledge of the given subject matter.

long ago, in a place far away, Master Po wrote:Ahh . . Grasshopper . . . When the source of your acquired Caddy knowledge is Wikipedia, you must first learn to decipher and
then gain complete understanding of the meanings contained therein, before you can successfully quote from the sacred text.
"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."
- Carl Sagan

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Re: New to airboat - need advice

Postby eldorado » Sat Aug 19, 2017 7:25 pm

Deano. Much of this thread can be answered in this link below.

https://www.southernairboat.com/phpBB3/ ... 42#p471754

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