bravo III from alpha I swap

[garryowen]

hi; i am tired of problems breaking drive gears in my alpha behind a 454 in a '88' 230 weekender.
i am looking to switch to a bravo III and am wondering if any one can help me with what prop pitch and gear ratio you might be using on your boats.
most of our boating is at approximately 6000 ft elevation

 

[Lazy Daze]

You're aware there's a lot to do to make that switch, right? Among other things, everything on the outside of the transom needs to be changed.

Is your current prop the correct pitch for the boat? If so, what is that pitch?

 

[Tail Chaser 661]

The Gen 1 alpha's with V8 engines used 1.50 and now 1.47 GR in there drives.
My 26' boat has the 1.47 GR drive

Bravo 3 with a big block, fairly light boat 1.80 GR
They gear them Bravo 3 drives down a little due to the power needed to spin the large surface area of twin props.
Your 454ci has the power for the 1.80 GR
The 2.0, 2.20 GR is for heaver boats smaller engines etc
Prop shops will usually let you try out props B4 you buy
They should have a good starting point also.

If you want more top end speed.
I think freshwater guys are into that:huh:
It may be worth researching the Bravo 1 drive
That drive comes in a higher GR (Faster top speed)

A 454ci in a 24' boat should be able to push them taller gears nicely

Cruising at low to moderate speeds, I think the Bravo 3 is the better choice.

 

[Sundancer]

You might look at the drives available through Stern drive Engineering. They have a unit that is a direct replacement for the outdrive of the Alpha I. I don't know what kind of horsepower it can handle, but its a whole lot cheaper than switching to a Bravo.

http://www.sterndrive.cc/

 

[garryowen]

thanks for all the replies guys.
the other option i have would be to swap the 454 out for a 350 but to be honest i really have grown to like that BB thumping back there and have gotten as high as 3 mpg and can expect 2 mpg unless the conditions get rough.
the A-I thats on there now is a 1.65 to one
i run 17 pitch at 7000ft, 19 pitch at 6000 ft, and 21 pitch at 3600' and 1100'. this gets me 43 gps mph at all elevations with the biggest difference in the how quick she will come up on plane. it runs different rpms at the different elevations with different props but the speed has always been constant, i guessing this must be the speed for my hull and motor and while slower to get there at the higher elevations it is making power pretty consistently.
stern drive wont sell or warranty a alpha I drive for a 454.
i lunch a a-1 about every 20 hours and this last time it locked up and hydro locked my motor.OUCH. there easy enough to change and work on but i'm tired of getting towed in. if i could find one of the 1.32to1 or 1.50to1 heavy duty gear sets i might get it to hold up but i was just down at mead and tried and saw some B IIIs and liked every thing about them.
i realize the cost involved and what all needs changed. so far the best deal i can find is going to be around $6500. drive, new transom assembly, raw water pump, and the props.
as they come in the 1.80 2.0 and 2.2 ratios i didnt understand why so low ratios. i see now the props are all on the high side for pitch with 21 and 22 and 24 being the most popular??

 

[Sundancer]

I ran a 454 Magnum on our 250 DA and it had the original Alpha I when we sold it in 2007. We NEVER had a problem with the drive.

I wondered if SDE would have an option for for the 454 BB. I guess buying a new drive ever 20 hours makes the $6,500 look like a good deal. I think I'd just upgrade my boat and buy one with the Bravo already installed. Boats are cheap these days!

 

[Tail Chaser 661]

The Alpha Gen 2 is stronger then the Alpha 1
Still would not risk it with the 454 ci

I was told by a good mechanic that,
What really kills the Merc drives is taking off too fast.

It will flex the main shaft going from the lower unit to the upper unit. That will cause the gears /teeth to miss align in the upper unit and break due to the tq being applied.
Taking off slow will help the drive.
Under proping the boat will take some load off the gears also.
That should help the Alpha live longer.



I saw an adapter for changing to a Bravo not to long ago
Maybe Alpha Gen 2 to Bravo?
I think it said would not fit Alpha 1.
Dont know if you have a Gen 2 being a 1988?
May be worth doing a google search on

Duoprops are suppose to give 3mph increase in cruise speeds.
And 10% better MPG

 

[garryowen]

tail; that makes sense.every one i have failed has been the top gear set breaking teeth. i have had the motor out once changing rear motor mounts and looking for transom problems trying to solve this, so pulling it to change drive ect isht a problem. after looking i realy think the b3 is what we want. we are happy to cruise at 30 mph but like to do that speed for awhile as we boat flaming gorge, powell, and last winter mead. it takes awhile to get around and we like to get as far from the marinas as we can and then camp. every time i have lost a drive its been after we were on plane at 30 or so mph for over 30 minutes. i installed a drive shower on the last one thinking that might help, but still no luck


well buying a different boat is a option. we have looked at a few. there is a dealer down in vegas that has a new 24ft 07 maxim carry over for 50,000 with a trailer. it has a 5.0 bravo 3. the fuel injection would be nice where we change elevations a lot. there were some things that killed the deal for us. aft bunk,4 ladder steps into cabin, 102" beam and dry weight is 700 lb more than our 230. i have a disabily and the steps both in the cabin and up to the swim platform and then no easy way to board from the side of the boat in to the cockpit made it not so good for us. that plus we realy like this old sea ray and the 96" beam. when we got it we had been looking at newer boats at the time but the cabin,cockpit,and helm lay out just seemed to fit what we wanted. the best way i can put it is like putting on a old comfortable pair of shoes that look like #### but man do the feel good compard to shiny new pair of dress shoes that hurt your feet after awhile.

that said, we figured when we bought it we would try it for a while and trade if we didnt like it or repower and update what ever we needed to to keep it. my biggest concern in this is the weight it will add to stern of the boat and getting it proped right. it weights 6800 to 7000 pounds with the trailer with a full fuel load and lines and rigging. i tow with a gmc serra and a gmc yukon xl and am right at my tow limit with them now.

dancer; the guy that had the boat befor me started messing with the gear ratios and had it in the shop 5 times in 7 years. the 2 years it wasnt in the shop the lake was low and the boat sat. it was golden before he started messing with it. then he would get ticked at the shops so its been in 4 different shops in 2 different citys.
of coarse i did'nt find any of this out untill we bought the boat and started having trouble

 

[Tail Chaser 661]

garryowen,

Seems I may have gave you bad info.
I talked to someone that really did his homework running 454ci and 502ci engines on 26' Low to Mid 80's Sea Rays.

He said they perform better with the 2.2:1 gear ratio or even bigger gear ratio with the 454ci. Then you run lots of prop pitch. 26" pitch on my boat with the 8.1 engine
The person I talked to has the 502ci.
He cruises 30 mph at 3000rpm.
I assumed he was running 1.8:1 GR he runs the 2.2:1 GR

Your lucky you have the big block.
I just talked to a mechanic that just did a 8.1 repower. he pulled a 350 mag with only 20 hrs on it. A 24ft boat.
That owners happy now.
Check out www.perfprotech.com.
They have fuel injection kits for the 454ci engines.

Just thought I might add. Was told,
Them 26' Sea Rays with the big blocks and bravo drives have been holding up since 1995/1996

 

[26sxl]

Gary, are you buying new drives,reman. or is somebody rebuilding them for you??? You have more drive problems than anybody I have ever heard of, bbc or sbc!!!

 

[garryowen]

tail chaser; thats sounds like a good plan. gear down so you can run a lot of pitch. the 454 should have plenty of torque to move a lot of water with the higher pitch prop. 3000 at 30mph would be perfect. we run 3200 to 2700 at 30mph depending on which prop and lake were on.


26slx; as far as i can find out this boat had no trouble till the first regear in denver. the first time was the orignal drive and a regear. second--broken regear- repair orignal. the third--my first was orignal drive and repair gear set. my second was new drive as i thought the orignal might have problems and that we would eleminate with a new drive.the next was a repair the new one i bought. it allso took a new upper case, this split when it blew. at this time i put in a new gimble bearing pulled engine and installed rear motor mounts and looked for any thing wrong that could be causing problems. i also installed a drive shower and ran the drive for 5 hours after install then pulled to double check drive aliment and make sure was'nt it shifting. all was fine.
all drive work has been done by mercuriser shops. each time the upper was rebuilt the lower was striped and cleaned and reasealed. only work i have done was pulling motor and swaping drives, checking drive alinement and changing gimble bearing ect.and motor alinement was checked by one shop just to be on the safe side.

 

[Tail Chaser 661]

garryowen
You just have one of them few years that Sea Ray had great hulls, came out with a great engine.
But learned the hard way, there drives could not handle the power.

Reminds me of when Dodge put the 6cyl Cummins diesel in there PU trucks back in the 80's.
They were blowing auto transmissions, twisting axles, breaking differentials all the way till 1996.
In 1997 they finally got everything beefed up enough.
The year I bought one. :grin:


The dealer selling me the 496ci recommends the 2.0 GR for my boat.
Just want to have factory prop options going either direction. Avoiding going custom.
The Bravo 3 props may be 1000.00 :wow:

Noticed perfprotech.com has a OEM 2.0 GR Bravo 3 drives for like 4000.00
The other ratios were like 4800.00
Check out that transom adapter plate they carry. May get lucky.
Just remember a new 24' Sea Ray has got to go for more then 50K. Personally, I don't even like the new Sea Rays.
Smaller fuel tanks, less room, Maybe balsa wood cored hulls etc,
So 6500.00 for the complete bravo drive. Dialing in a good older boat. Is not a bad deal. IMHO
Your getting a lot more then just a stronger drive also.

I just read a test on a 05 26' Sundancer with the 8.1 375 hp engine. Thing sucked
4000 rpm for 30 mph cruise? 2500rpm was like 13 mph getting awful mpg. Bad year for Sea Ray or bad test?
My dinosaur engine package performs better then that.
Boat test.com actually gave the 05 Sundancer a good review.
But I think the performance and mpg were awful on the 05 test.
The CSR members 83 26' Sundancer with similar power does
30 mph at 3000rpm getting 2.3 mpg

There was another test on the 04 26' Sundancer with the 5.7 350 mag
3600 rpm got 24 mph 2mpg Those numbers look correct.
8.1's usually post similar numbers but at 2500 rpm

Looks like boattest.com has a typo error or is pushing small block engines
I have never once seen the small block outperform the big block engine on fairly heavy boats.
I have never read anywhere with someone being unhappy with the power of there big blocks. (lots of hrs internet researching)
I did notice about 50% of people unhappy with there smallblocks when there boats weighed over 7000 lbs

Guess I'm venting this because,
I'm suppose to drop a 10,300.00 check in the mail today for my 8.1 Mag.
The first bad performance/mpg numbers ive ever read about with the 496 ci just turned out to be on a 26' Sundancer :wow:

Anyhow,
Time to go research Bravo 3 props now.

Good luck

 

[garryowen]

well tail; this is where i stand today
looks like i can get into a b1 with every thing for the install for $5533. the only thing were having trouble finding in this package is the top tension baracket for the raw water pump.

add to that 400 or 500 to up grade to the b3. i would have to buy props and prop wrench for b3 on top of that. easy $1500 or more to go b3

either unit would be a quick silver cpo with a one year warrenty.

now i have to make up my mind how bad b3. i have a couple of mirage-plus props that are bravo props and can use all my extra hub kits and alumineum props

how bad do i want a b3:huh:i need to sleep on it see if i'd be happy spending the extra $$$

 

[Tail Chaser 661]

Is your Alpha broken now?
Maybe try underproping a little.

A while back I was specing out the 454ci
Trying to get an idea of how much prop pitch I could add over my 5.7 260 hp on a 7500 lb boat.

The 1.5 GR alpha 1 drive with both the 5.7 and 7.4 engines used the same prop.
Guess they underprop the 7.4 engine.

When I dropped the weight of the boat down below7k or more.
Then the 7.4 speced out with more pitch then the Alpha.
Try some full synthetic gear oil also.
Amsoil makes some good stuff.

 

[garryowen]

yes its broken now. by the way i did check out the perfpro web sight and saved it. thanks tail chaser. i need to take the time and go over what i need and price it there before i buy.
my wife likes this boat pretty well and has been in other boats that ride different or take the waves different and made her uneasy. she feels safe in this old searay and wants to keep it too.
i just wish i could find out what the heck causes it to break the top gears so quick. i have an idea if i could come up with the orignal 1.32 or 1.50 heavy duty gear gear sets mercuriser put out for these when they were new i'd be good to go.
i'm not heavy handed on the helm and have seen lots of boaters hammer and run there boats harder than i ever consider, with no side effects.
at this point the b3 is the way to go. prop it for 6000 feet and when we go down be carefull not to let it run out at max rpm. and the dule prop should have enough bite and 454 long enough legs to work higher. the only time i have ever run at max rpm was to check it for proping any way.

i wonder if i'm trimming out to far when we cruise and stressing the drive? i trim the bow up till it starts to porpoise and trim down till it just stops, with no trim tab. this is where i get the most speed for rpm going by the gps. the only time i use the trim tabs are once in a great while to level side to side in a cross wind or if we get loaded heavy on one side or the other.


by the way good luck on your repower. looks like were in the same BOAT and your right, i am happy i dont need a motor too

 

[Tail Chaser 661]

When I bought my new Alpha 1 five yrs ago.
I was told 1985 V8 Alpha 1 Models came with 1.50 GR
The new drive I bought in 04 was 1.47 GR.
Was told the change was made to make them stronger:huh:

I believe as the gear ratios change, Like going too 1.6, 1.8, 2.0, etc
The gears have more teeth. With the limited space. They have to make them thinner. Causing weaker gears.

May give it one more try. SEI drive? With 1.47:1 gear ratio.
My OEM Alpha had a two year warranty.

I was specing Merc props for my new 496ci Bravo 3 this AM
Looks like I'll be 43 mph at 4500 rpm. Thats specing with Gross wgt of 9100lbs 2.2:1 GR with 15.25"D X 26"P prop
I wonder what the MPH is at 3000 RPM? :huh:

I had noticed that, Just going to the 6.2 Merc.
Merc upgrades to the Bravo drive.

 

[26sxl]

Gary,It shouldn't be doing what its doing.I've been running alpha's for decades with out problems(other than self inflicted).Do you know what gear ratio it came with? Do you run stainless prop?Alphas have a updated upper brg. and housing(bigger and stronger). Also jasper sell alphas with a warranty.Have some friends who own marinas will run your problem by them.Unless you are into performance I personally don't see spending the major $$$ for a new set up.

 

[Tail Chaser 661]

Gary,It shouldn't be doing what its doing.I've been running alpha's for decades with out problems(other than self inflicted).Do you know what gear ratio it came with? Do you run stainless prop?Alphas have a updated upper brg. and housing(bigger and stronger). Also jasper sell alphas with a warranty.Have some friends who own marinas will run your problem by them.Unless you are into performance I personally don't see spending the major $$$ for a new set up.

Look at post #5

Merc uses the Alpha 1 Gen 2 with 5.7 350 MAG Puts out like 355 ft lbs of tq
6.2 engine comes with Bravo drive. That engine only puts out like 375 ft lbs of tq
I only typed this stuff out for for reference.
Obvious Merc Still doesn't want a lot of power pushing there GEN 2 Alpha either.
Sure there's lots of people who's Alphas hold up well. There good drives.
Nice to know which components are poor, fair, or xlnt for your application.

I'm bored of my slow, Drive saving 16Dx14P Alum prop ive used the last four seasons.
Vessel Assist is payed up.
Going to throw my 15D x 17P Stainless back on.
Hope there's not a big swell if my Alpha drive lets go.

 

[garryowen]

Gary,It shouldn't be doing what its doing.I've been running alpha's for decades with out problems(other than self inflicted).Do you know what gear ratio it came with? Do you run stainless prop?Alphas have a updated upper brg. and housing(bigger and stronger). Also jasper sell alphas with a warranty.Have some friends who own marinas will run your problem by them.Unless you are into performance I personally don't see spending the major $$$ for a new set up.

yes it came with the 1.32 to one and was good with that ratio. it wasnt till after a regear to 1.5 that all this started. i have been told that unless i get the heavy duty gear set that mercruiser came up with back in the day to make these drives live that i'm spinning my wheels.
if i had done this instead of buying a new alpha drive for 25 or 26 hundred + the gear sets and labor and seal kits i could have paid this for this mod and saved money in the end.
i dont mind the problems with the drive so much as breaking down on the lake and getting towed in. this realy puts a dampner on a trip.
as far as self inflicted i have no problem listening but so far all we have gotten is bills and spent money at shops that knew for sure what our problem was and could fix it for us.
yes i have and have run ss props but not on the last drive thinking that could be part of the problem.
we have spent the price of this upgrade and pulled the motor once looking for transom drive or any other out of alinement or broken parts.
if you have any idea as to what the problem could be i would be more than happy to listen but to be honest i'm not taking this back on the lake again with a alpha drive. i'll put a trolling motor on it and use it that way first. its just to dangerous when it breaks. so far we have been lucky but it could break in a wind storm leaving us trying to fend off the rocky shores we have or one of the remote canyons on powell or flaming gorge.

realy getting rid of the clunky shifting and getting the cruising efficiency of the b3 can make this a good up date on that alone
as far as trouble free thats not realy true either. i ran into a fellow at powell that had the same boat as mine. he had bought his new and had trouble with the 1.32 drive being to high and had proping issues. he went through 2 1.32 drives and then got the 1.5 gear set all under warrenty. he had the boat 7 or eight years and it was still running on the 1.5 gear set when he traided it. his and my boat came from the same dealership and he had known of my boat when it was new.all the boats that came from that dealership with the 7.4 and alpha drive had at least one or more gear set change under warrenty.

 

[Tail Chaser 661]

To much money 2595.00 to risk blowing another Alpha.

Check www.marinepowerservice.com
PN# MERCAL- 130 seems thats the 1.30:1 GR youre looking for.
I doubt they use a stronger steel with these gears.
I bet using these overdrive ratios. They have less teeth on the gears So the teeth that are on the gears are thicker.

Im guessing, But I'm 90% sure of this.
Figure it this way, You have a 3 1/2" bearing race and cup the bearing and gear sit in.
Say a 1.30:1 drive has 100 teeth on the gear.
The 1.65:1 drive has 150 teeth on the gear.
The only way to get the 150 tooth gear in the 3 1/2" Race/cup is to make the gear teeth thinner.

All this does you absolutely no good.:lol:
But there is some 1.30:1 drives out there.