Alpha 1 Gen 2 Weak Link

[AShipShow]

For the experts that lurk here...
Does anyone know what the weak link is in these drives? I've heard they are typically okay to use up to 300hp and 5000rpm, but when you exceed that, what usually fails? I imagine its not always the same, but was curious if its typically a specific gear set, the clutch dog, the u joints, etc...

 

[Scott Danforth]

Weak links:

Dog clutch
Lower gear set
Upper gear set
Drive shaft diameter

Then on RPM, the oiling system

 

[Bt Doctur]

The weakest link is operator malfunction

 

[AShipShow]

The weakest link is operator malfunction

Haha... definitely #1 problem

 

[Lou C]

Or lack of maintenance

 

[tank1949]

For the experts that lurk here...
Does anyone know what the weak link is in these drives? I've heard they are typically okay to use up to 300hp and 5000rpm, but when you exceed that, what usually fails? I imagine its not always the same, but was curious if its typically a specific gear set, the clutch dog, the u joints, etc...

There are always exceptions.... However, I suspect unless OD and motor are "blueprinted," then sustained high RPMs will cause something to "hand grenade." Most Alphas were built before engineers used technology and figured out how to significantly increase V8 HP and market it. I remember back in the day, that if people wanted 350hp that they needed a big block. Now, they can get that easily from a 350 block (not HP). Amazing.

 

[Scott Danforth]

I know people with 383's putting 400-450hp into Alpha drives and doing is "successfully" in early 90's sausage boats on the great lakes. they are using kryo treated gears, however they have to watch the hole shot and use a rev limiter. successfully is also in quote, because one boat is on their 3rd set of drives.

normally the drives are ok unless the boat comes out of the water cresting a wave. the prop comes unloaded, the RPM's go up, then on re-entry, the upper gear set, vertical shaft and lower gear set all try to play musical chairs and swap places. this is where the rev limiter is a must

RPM limit is because the drive upper bearing and gear set is splash oiled and not designed for high-speed.

RLC performance did a complete custom low-x Alpha based outdrive for project triple digits about 10-15 years ago. I believe that one of the motors used was well in excess of 600hp to get to 100 mph. However it was a custom case, custom gears custom shaft, etc. the only thing stock Alpha I believe was the transom shield.

 

[AShipShow]

I know people with 383's putting 400-450hp into Alpha drives and doing is "successfully" in early 90's sausage boats on the great lakes. they are using kryo treated gears, however they have to watch the hole shot and use a rev limiter. successfully is also in quote, because one boat is on their 3rd set of drives.

normally the drives are ok unless the boat comes out of the water cresting a wave. the prop comes unloaded, the RPM's go up, then on re-entry, the upper gear set, vertical shaft and lower gear set all try to play musical chairs and swap places. this is where the rev limiter is a must

RPM limit is because the drive upper bearing and gear set is splash oiled and not designed for high-speed.

RLC performance did a complete custom low-x Alpha based outdrive for project triple digits about 10-15 years ago. I believe that one of the motors used was well in excess of 600hp to get to 100 mph. However it was a custom case, custom gears custom shaft, etc. the only thing stock Alpha I believe was the transom shield.

Good info here, thanks Scott.

I guess the torsional "impact" of the prop coming out of the water and going back in would well exceed the typical torsional stress seen under a constant load... I can see how that would grenade the drive...

Are there any aftermarket parts to up the limits of the alpha drives?? Sounds like per your previous post, guys have improved the drives, but I assume it was all custom work...

 

[Meames1]

RLC performance did a complete custom low-x Alpha based outdrive for project triple digits about 10-15 years ago. I believe that one of the motors used was well in excess of 600hp to get to 100 mph. However it was a custom case, custom gears custom shaft, etc. the only thing stock Alpha I believe was the transom shield.

Curious as to "why". Wouldn't it be easier at that point to just swap to a Bravo drive ? Is there some efficiency or lower parasitic loss the Alpha provides ? Just wondering, seems like a lot of $$ on custom parts.

 

[Scott Danforth]

Curious as to "why". Wouldn't it be easier at that point to just swap to a Bravo drive ? Is there some efficiency or lower parasitic loss the Alpha provides ? Just wondering, seems like a lot of $$ on custom parts.

in the case of RLP performance. it was because he wanted to

because if you want performance to hit 100mph in a 21 foot boat, you want a shorter X dimension (less drag) and a custom foot (less drag) and a stand-off box (better bite). not just a bigger/heavier drive like switching to a Bravo. you should locate the article project triple digits. its a good long read.

in reality, to go that fast, you actually want a surface drive with a transmission mounted at back of the motor and the motor moved forward. however that is a completely different setup.

 

[Scott Danforth]

Good info here, thanks Scott.

I guess the torsional "impact" of the prop coming out of the water and going back in would well exceed the typical torsional stress seen under a constant load... I can see how that would grenade the drive...

Are there any aftermarket parts to up the limits of the alpha drives?? Sounds like per your previous post, guys have improved the drives, but I assume it was all custom work...

there are some kryo gear sets on the market. the rest is custom work.

 

[tank1949]

I know people with 383's putting 400-450hp into Alpha drives and doing is "successfully" in early 90's sausage boats on the great lakes. they are using kryo treated gears, however they have to watch the hole shot and use a rev limiter. successfully is also in quote, because one boat is on their 3rd set of drives.

normally the drives are ok unless the boat comes out of the water cresting a wave. the prop comes unloaded, the RPM's go up, then on re-entry, the upper gear set, vertical shaft and lower gear set all try to play musical chairs and swap places. this is where the rev limiter is a must

RPM limit is because the drive upper bearing and gear set is splash oiled and not designed for high-speed.

RLC performance did a complete custom low-x Alpha based outdrive for project triple digits about 10-15 years ago. I believe that one of the motors used was well in excess of 600hp to get to 100 mph. However it was a custom case, custom gears custom shaft, etc. the only thing stock Alpha I believe was the transom shield.

I have blown up more that one V8, but they were in cars or trucks and were easier to tow home or to a shop. Your above information is why on my LAST boat restoration, I wanted Bravos. They are stronger. I fish offshore (or used to) and wave crashing happens frequently along with accidents. I don't like accidents 100 miles offshore! THX!

 

[AShipShow]

I totally agree that given the choice when buying a new-to-me boat, I would prefer a bravo drive 100% of the time... I was just trying to get an understanding of what the weak link is in a alpha drive... Basically, curious if some individual parts, whether it be gear sets, clutch dog, shafting, u joints, yoke, etc could be replaced with a higher strength component to increase the nongrenadability (new word) of an alpha drive.
Basically, if my motor ever craps the bed, and I decided to put in a stroker or upgrade to a higher horsepower option than my stock 230ish stock motor hp, I wanted to see if theres an option that is cheaper than trying to find an entire bravo drive and transom assembly...
I wouldn't be surprised if you're looking north of 5 grand for an entire bravo assembly in good shape. That being said, you could probably have a machine shop make you custom shafts, yokes, and even gear sets for significantly less than that...

I might be totally wrong, and I'm not saying this is my plan... I'm just throwing around the question to see what the practicality of it is.

 

[Lou C]

Also keep in mind this cuts both ways, yes the Bravo is stronger & shifts better but replacement cost is nearly twice as much as an Alpha. Comparable to the cost of a VP drive. I’d say with a small block V8 with good maintenance you shouldn’t have premature failures with the Alpha.

 

[JASinIL2006]

 

[tank1949]

I totally agree that given the choice when buying a new-to-me boat, I would prefer a bravo drive 100% of the time... I was just trying to get an understanding of what the weak link is in a alpha drive... Basically, curious if some individual parts, whether it be gear sets, clutch dog, shafting, u joints, yoke, etc could be replaced with a higher strength component to increase the nongrenadability (new word) of an alpha drive.
Basically, if my motor ever craps the bed, and I decided to put in a stroker or upgrade to a higher horsepower option than my stock 230ish stock motor hp, I wanted to see if theres an option that is cheaper than trying to find an entire bravo drive and transom assembly...
I wouldn't be surprised if you're looking north of 5 grand for an entire bravo assembly in good shape. That being said, you could probably have a machine shop make you custom shafts, yokes, and even gear sets for significantly less than that...

I might be totally wrong, and I'm not saying this is my plan... I'm just throwing around the question to see what the practicality of it is.

Indeed.... Used Bravos components, or a transom assembly, are difficult to find or VERY expensive. At least they were when I needed them. Perhaps not anymore....

 

[Scott06]

Alphas get a lot of shade thrown their way but the reality is they work great for its intended purpose smaller (less than 23 ft) boats less than 300 hp. Light, easy to maitain, and inepxensive comparatively to replace- perfect for typical bowrider marker.

Take care of them and they will outlast the boat with a few impellers and seals after 15-18 years.

 

[Lou C]

And parts are everywhere, as are techs who know them.

 

[AShipShow]

I wonder if anyone knows or knows of a resource that has the specific information on materials used for the internals of an alpha drive.. If they are already using super high end alloys and heat treatments off the bat, obviously there isn't much headroom for improved custom parts, without major modification of the designs... However, if all the shafts and gears are run of the mill low carbon steel shafts and gears with low yield strength materials for the sake of keeping manufacturing costs low to pump alpha drives out the door.

 

[tank1949]

I wonder if anyone knows or knows of a resource that has the specific information on materials used for the internals of an alpha drive.. If they are already using super high end alloys and heat treatments off the bat, obviously there isn't much headroom for improved custom parts, without major modification of the designs... However, if all the shafts and gears are run of the mill low carbon steel shafts and gears with low yield strength materials for the sake of keeping manufacturing costs low to pump alpha drives out the door.

Or, now made in China and junk?