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View Full Version : Newb needs Help on 18 classic Purchase!!!



blutegra1992
02-12-2009, 10:14 AM
Ok guys, thought I would ask for opinions from the people who know these boats best.

Looking at two Donzi Classic 18 2+3s.

1990 Classic 18 with a 454 BBC motor said to have 420hp with an OMC King Cobra outdrive. GPS'd at 73 mph.

and

1986 Classic 18 with 350 SBC ZZ3 motor and Alpha SS Drive 1:50 ratio. GPS'd at 70-71

The BBC boat is a bit more in price but also 4 years newer. Both boats have positives and negatives to me, the 90 has an extremely nice aluminum two axle trailer while the 86 has a regular steel two axle that could use repainting. The 86 however has a brand new interior and alot of money in the custom Gafrig gauges and little stuff to make it look nicer.

That last paragraph aside, I guess what I am getting at here is is there an advantage to going with a big block boat over a 350? Does it have alot more potential to reach higher speeds than 73? Which outdrive is better? Why is the 454 not "that much" faster than the boat with the 350. Obviously must have to do with prop combinations and outdrive ratios?

Just looking for some input so I can be happy with my purchase!!

THANKS!!:confused:

mattyboy
02-12-2009, 10:24 AM
either boat should make you happy


the sb is closer to the speed of the bb cause of the ss drive good for at least 5 mph
other things to consider new gauges and an interior would cost more than a new alum trailer
a BB 18 is cool
a SB will eat less gas
the king cobra is a strong drive stronger than an alpha
what color do you like
hope that helps

zelatore
02-12-2009, 10:26 AM
Others who know the 18's will pipe in with more knowledgeable opinions soon...

But it seems to me that most here would tell you the 'best' engine for an 18 is a stroker small block. Less weight, less size (more room to work on it), cheaper parts, better economy, etc. Heck, might even be cheaper to insure. And you can build plenty of power/speed.

And the s/s drive is highly prized as it's no longer built and a hard to come by part. For a smaller/lighter boat, it's like free speed.

The 454 certainly has more power potential, but exactly how much do you think you're going to build for an 18? So much you couldn't do it with a small block? The king cobra drive is a mixed blessing. They are well regarded around here, but in general most people would still prefer a Bravo on the open market - some are scared of parts availability or basically anything that's not a merc part.

As for which boat is the better deal, not enough info to say. But that's my $.02 on the engine/drive combos

Kirbyvv
02-12-2009, 11:21 AM
Others may know more, but I think a SBC is probably a better all around package in an 18.

mattyboy
02-12-2009, 11:29 AM
is the BB boat named genuine trouble or genuine risk ???

seem to recall a member had a late model factory BB 18 was all white with a black stripe??

zelatore
02-12-2009, 11:43 AM
Reading your post again, and bearing in mind I haven't seen either boat, don't know the asking prices, and don't even own an 18....

I'd lean toward the older small block for a couple reasons:

The ages are close enough to not make a big difference in resale down the road. Condition will trump age.

The older boat has the new interior and gauges - much more work than rebuilding/replacing the steel trailer it's riding on.

Better aftermarket support for the Merc. At that speed you might want to start thinking about things like external steering. Does anybody even offer that for a King?

If you go crazy on power and want to upgrade to drive (on either boat) you'd have a much easier time selling the S/S than the King.

Donziweasel
02-12-2009, 11:44 AM
IMO, the big block has alot of potential and is a rare configuration for an 18. 420 hp? Put a blower on it and you have close to 600. If you are nice to the Cobra, it should be fine.


The SBC boat with the Alpha ss is also rare with the SS drive. One thing to remember, if you grenade the SS, parts will be hard to find. This was a limited production performance drive from Merc that has not been around for a while.

Hard call, but personally, I would go with the BBC/ with Cobra. Really strong combo. Plus, a 454 can be massaged for way more power evne without a blower.

chappy
02-12-2009, 11:48 AM
The one with the big block sounds like RedDog's old 18.

mattyboy
02-12-2009, 11:54 AM
some other things to take into consideration

an 86 would have an alum tank and is not just about 23 years old and if the tank is not treated could be an issue.

a 90 might have a poly tank

as long as the drive is a king cobra parts are not hard to find and in some cases Volvo sx stuff will work .

if the SS should happen to go there goes 5 mph that will be hard to replace.

there are pluses and minuses on both sides.
without knowing the true condition of each it is hard to say both do sound like nice boats

txtaz
02-12-2009, 12:12 PM
My .02. Go for the '86 sbc for reasons stated above. Plus you don't need to go faster than 70 in an 18. It will take a lot of seat time just to feel comfortable at that speed. If you want to play race boat with some of the others, you are looking at the wrong hull. It will get squirrely above 75 and you need external steering.

Da Taz<---I should have kept my 18 after all. Ahhh hindsight sucks sometimes.

blutegra1992
02-12-2009, 01:21 PM
Wow lots of differing opinions. Helpful though.

So far as for the outdrives, you guys have said that both outdrives are hard to get parts for.

chappy
02-12-2009, 01:27 PM
A lot harder to find parts for the Alpha ss as opposed to the King Cobra.

glashole
02-12-2009, 01:52 PM
buy Jerry's

just posted

awesome boat

can't go wrong

Trueser
02-12-2009, 02:21 PM
buy Jerry's

just posted

awesome boat

can't go wrong


Agree......................... great deal. and well taken care of!

This one.....
http://www.donzi.net/forums/showthread.php?t=55973

blutegra1992
02-12-2009, 03:03 PM
Nice boat but the interior color is not for me.

ITTLFLI
02-12-2009, 04:38 PM
Nice boat but the interior color is not for me.
I have had both white and the off white interiors. I would take the off white over the white anyday. Actually its pretty subtle in person....:)

gcarter
02-12-2009, 06:03 PM
Nice boat but the interior color is not for me.
A new interior is a lot cheaper than an outdrive.

RedDog
02-12-2009, 06:25 PM
I used to own the one with the 454. I bought it from RickR and sold it to Balckie. Have you seen this boat it person? I'm sure Blackie has maintained it. This boat is rigged to perfection. Nothing half-asses. Nail the throttle in it and the acceleration is incredible.

I'd buy it in a second as my second boat except for my lack of a stimulus :nilly:

http://www.donzi.net/forums/attachment.php?attachmentid=43214&stc=1&d=1234484668

RickR
02-12-2009, 06:37 PM
If it is Blackie's boat, I owned her before Reddog.
I do not know you or what you want the boat for BUT when I was shopping for an 18 I had a pretty serious need for speed.:eek:
It just took me mashing down the throttle one time to know she was the boat for me. She drives like a 400HP jet ski.
Drive them and you will see a HUGE difference.

Tony
02-12-2009, 06:44 PM
There's a lot to be said for mid-range thrust. I don't know much about the SS drive, but like RedDog said it is impressive to punch it at 30 and be at 60 mere moments later. My old Ski Sporter could flatten you back in your seat pretty good, plus it was fun to use the responsive throttle thrust to launch it off waves.

I might have a hard time "being careful" with a drive...if that is what you'd have to do with the SS.

:beer:

BUIZILLA
02-12-2009, 06:55 PM
what's the price on the 454 boat?

blutegra1992
02-12-2009, 06:58 PM
There's a lot to be said for mid-range thrust. I don't know much about the SS drive, but like RedDog said it is impressive to punch it at 30 and be at 60 mere moments later. My old Ski Sporter could flatten you back in your seat pretty good, plus it was fun to use the responsive throttle thrust to launch it off waves.

I might have a hard time "being careful" with a drive...if that is what you'd have to do with the SS.

:beer:

So you guys are saying the 350 is not going to pull as hard?

What is meant by being careful with a drive anyways? Obviously waiting til the engine is completely at idle to switch from drive to nuetral or reverse... but beyond that, what is there?

Yes, it is Blackies boat I am considering. I did see it in person, while it is an absolutely amazing boat, there are things lacking about it to me. The interior is in good shape, BUT needs to be replaced to be perfect. It also needs to be updated on the dashboard.

The other boat is all done already, while I LOVE modifying my toys, my pocket book at the moment does not.

mattyboy
02-12-2009, 07:08 PM
the other things to worry about are hard holeshots and getting air and re entry
some drives need to be eased in on both accounts and some don't . like Tony's old 16 mine with a volvo basically took what i gave her the alpha is not so tough

the torque and mid range response is hard to beat with displacement

RickR
02-13-2009, 10:38 AM
"THERE IS NO SUBSTITUTE FOR CUBIC INCHES"

HP and top speed on Blackie's boat are limited due to the exhaust.

COG is different, so MINIMUM cruising speed wo/tabs is >40. SBC in an Alpha/18 will cruise in the 20s. I HAVE NOT BEEN IN A SS/ALPHA boat.

I personally do not think (at the same speeds) the SBC burns much less fuel. I get exceptional mileage in our 22 with the built 502. Unless, or course you throw the hammer down:eek:


The most fun we had in the 454/18 was in a 2 to 3 foot swell, gassing it on the face, flying and landing on the back side of the next 20 or 30 feet later, YEEEEHAAAAAA!!! Prop on that boat has spent A LOT of time out of the water:yes:

Can't do that in the 22. Power to weight is wrong and she hits really hard due to it's wide reverse chines.

Just Say N20
02-13-2009, 01:09 PM
I'm going to go out on a limb, and say you decided on the 1986 w/SBC and Alpha SS.

If so, Congratulations!

glashole
02-13-2009, 01:36 PM
on a side note

does the big block boat jump funny? by that i mean stern heavy with relation to the small block, or is it even noticable when playing in the rough stuff

RickR
02-13-2009, 04:24 PM
gashole
The farther back the COG, the greater speed needed to maintain a horizontal attitude while the hull is in the water (sweet spot is farther back).
I did not feel any difference in attitude after she left the water.
In the rough, I had to use the tabs at slow speed.
In the 22 I put as much weight as possible aft(batteries, pumps, ignition....) , and installed bigger tabs. I am happy with the way she rides except for the big reverse chines. The 22 lands like a flat rock compared to the 18 :(

The difference between a 18C w/BBC, big drive and aftermarket exhaust compared to a SBC/Alpha with cast iron is less than 200lbs BUT it is all in the stern.

The SBC 18C is a much better all around boat. What can I say, I'm an adrenalin junkie ;)

Or resident Naval Architect, CDMA could explain it better. May be he'll see the post.

RickR
02-13-2009, 04:57 PM
Poodle
OK, OK, OK I am getting old.
I ment MINIMUM cruising speed. I'll change my reply.

blutegra1992
02-13-2009, 09:45 PM
gashole
The farther back the COG, the greater speed needed to maintain a horizontal attitude while the hull is in the water (sweet spot is farther back).
I did not feel any difference in attitude after she left the water.
In the rough, I had to use the tabs at slow speed.
In the 22 I put as much weight as possible aft(batteries, pumps, ignition....) , and installed bigger tabs. I am happy with the way she rides except for the big reverse chines. The 22 lands like a flat rock compared to the 18 :(

The difference between a 18C w/BBC, big drive and aftermarket exhaust compared to a SBC/Alpha with cast iron is less than 200lbs BUT it is all in the stern.

The SBC 18C is a much better all around boat. What can I say, I'm an adrenalin junkie ;)

Or resident Naval Architect, CDMA could explain it better. May be he'll see the post.


Was that a typo or did you actually say the SBC boat is a better all around boat, I thought you were VERY for the BBC boat.

You were the prev. owner correct?

RickR
02-13-2009, 11:52 PM
blu
A Toyota Camry is a better all around car than a BMW M3. Same overall size, number of gears, cylinders, creature comforts....... Or a better comparason would be between a BMW 325ci and an M3. It depends on what you a looking for.

How about a little biography. How old are you, family, what car/ bike do you drive, are you an experienced boater, where do you plan on boating, can you turn a wrench...??????

A SBC 18C is a much better all around boat. A Sea Ray would be even better, if that is what you want. The BBC/18 is a Performance Boat. Mine had a good idle but if you want a boat to take the family, friends and the dog they are not going to be happy cruising at 40+MPH. "The Boss" and I had a blast riding around at high cruising speeds and WOT. I wish I had the 18 too, she was a lot more FUN than the 22.

Poodle
Freezer is FULL, BUT with the limit changes we are thinking of selling "The Other Boat". Thing is, we have caught our limit EVERY full day fishing or 2 years and they say the Gags are in decline??????? Don't get me started on the circle hooks :(

zelatore
02-14-2009, 11:02 AM
A Toyota Camry is a better all around car than a BMW M3. Same overall size, number of gears, cylinders, creature comforts....... (

Dude....have you actually DRIVEN a Camry?

After your M, you'll find that Toyoder down right DANGEROUS!

blutegra1992
02-14-2009, 12:22 PM
Lol. 25 yrs old, addicted to power, no family, just a gf of 6 years, who is also addicted to fast cars and toys.

At the moment I drive a supercharged Honda S2000, my list of cars is long, everything from an M3 to a Corvette. I can turn a wrench very well and have never used a mechanic on anything in my life, never would, don't trust the work unless it was done by me. As for boating, I grew up around what I would call occasional boating, my parents had a 20 foot wellcraft basic speedboat setup. Went about 40 mph top speed. Nothing performance based. I am not worried about learning to drive a real boat though, just take things slow and easy until you learn the characteristics of how she handles in the water.

I guess that would answer the question on which boat to get... lol


blu
A Toyota Camry is a better all around car than a BMW M3. Same overall size, number of gears, cylinders, creature comforts....... Or a better comparason would be between a BMW 325ci and an M3. It depends on what you a looking for.

How about a little biography. How old are you, family, what car/ bike do you drive, are you an experienced boater, where do you plan on boating, can you turn a wrench...??????

A SBC 18C is a much better all around boat. A Sea Ray would be even better, if that is what you want. The BBC/18 is a Performance Boat. Mine had a good idle but if you want a boat to take the family, friends and the dog they are not going to be happy cruising at 40+MPH. "The Boss" and I had a blast riding around at high cruising speeds and WOT. I wish I had the 18 too, she was a lot more FUN than the 22.

Poodle
Freezer is FULL, BUT with the limit changes we are thinking of selling "The Other Boat". Thing is, we have caught our limit EVERY full day fishing or 2 years and they say the Gags are in decline??????? Don't get me started on the circle hooks :(

Couple of my past toys to support my "biography" you asked for. lol

http://img.photobucket.com/albums/v126/blutegra1992/Picture081.jpg
http://img.photobucket.com/albums/v126/blutegra1992/1085.jpg
http://img.photobucket.com/albums/v126/blutegra1992/1151Large-1.jpg
Hahah.. this is the closest I have been to boating in the last year.
http://img.photobucket.com/albums/v126/blutegra1992/1286Large.jpg

RickR
02-14-2009, 02:20 PM
blu
You sound like a BBC/18 guy to me:yes:
Email if I can help.

BTW: the 90 does have a poly tank.
There is a big difference in drives. The King on the 90 is similar to a Merc Bravo with a "Cone" clutch, which is smoother and is capable of a lot more HP than an Alpha. The Alpha has a "Dog" clutch" BUT,the King is bigger and has more drag.

If you want more speed out of the BBC/18 the exhaust will need to be set up "Drier". Performance engines w/wet exhaust sometimes have "Reversion" issues. Although I do not think my set up had reversion issues the exhaust is still very "Wet" which makes it quieter/less efficient.

zelatore
Well, mabe the M handles a little better ;)

blutegra1992
02-14-2009, 02:22 PM
You sound like a BBC/18 guy to me:yes:
Email if I can help.

BTW: the 90 does have a poly tank.
There is a big difference in drives. The King on the 90 is similar to a Merc Bravo with a "Cone" clutch whick is smoother and is capable of a lot more HP than an Alpha. The Alpha has a "Dog" clutch" BUT,the King is bigger and has more drag.

If you want more speed out of the BBC/18 the exhaust will need to be set up "Drier". Performance engines w/wet exhaust sometimes have "Reversion" issues. Although I do not think my set up had reversion issues the exhaust is still very "Wet" which makes it quieter/less efficient.

When you say wet exhaust, does that mean the exhaust exits are under water? I thought they sat low when I checked out the boat.

Is the poly tank a good thing or a bad thing?

zelatore
02-14-2009, 02:45 PM
When you say wet exhaust, does that mean the exhaust exits are under water? I thought they sat low when I checked out the boat.

Is the poly tank a good thing or a bad thing?

He's talking about water-cooled exhaust. You can still exit it above the waterline. The engine cooling water is picked up through the drive (or in some cases through a dedicated pick-up) and is pumped through the engine then is dumped in the exhaust where it cools the pipes/hoses on it's way out the back of the boat. If you've got a lot of duration in the cam, you have to dump the water in waaaay back from the riser to prevent the water from being sucked back into the motor. I'm sure you can figure out what would happen next...

Dry exhaust doesn't dump the water into the riser. Dry will let you get away with all kinds of engine choices you couldn't do with a wet exhaust, but it will be far louder. Loud enough to attract attention from the wrong people in most areas.

The poly tanks are generally a good thing. Any metal tank will eventually fail due to corrosion (although the life is usually measured in decades, not years), and it's a real PITA to change them. Since we are usually dealing with older boats on this site, tank replacements are a recurring theme.

blutegra1992
02-14-2009, 04:20 PM
RedDog, do you have anymore "inwater" pictures of it. From the behind maybe too?


I used to own the one with the 454. I bought it from RickR and sold it to Balckie. Have you seen this boat it person? I'm sure Blackie has maintained it. This boat is rigged to perfection. Nothing half-asses. Nail the throttle in it and the acceleration is incredible.

I'd buy it in a second as my second boat except for my lack of a stimulus :nilly:

http://www.donzi.net/forums/attachment.php?attachmentid=43214&stc=1&d=1234484668