1:65:1 alpha one gen 2 behind a 5.7...

[bigblock454]

Well, my buddy (who is a I/O guru), informed me that my drive ratio is a 1:65:1, This is to go behind a 5.7 mercuiser in my 1993 Bayliner "Classic" 2452 that was originally equipped with a 5.0. He is recommending a gear ratio change for the ability to deal with the increased torque of the 5.7. He is going through the drive right now, to determine it's overall condition. He says "it appears that water as made it's way in there at some point, because he can see a little surface rust on the gears, but all feels good turning" as stated, he is in the process of going through it. He is also going to figure out what it will cost to swap the ratio over to a 1:47:1, to determine the best "course of action". Although entirely possible to run the current 1:65:1 behind the 5.7, he mentions that it will be a rough life for it. so the options are: go through my current drive I have with 1:65:1 ratio, replacing whatever internals it needs and run it as is... or rebuild and re-gear current drive with whatever internals it needs PLUS new 1:47:1 gear set... purchase a used "merc" 1:47:1... or purchase a brand new SEI 1:47:1 unit and just "plug it right in". If I hadn't read (a few) negative reviews, I would have already purchased the SEI drive, but I admit, I'm a little hesitant because of those reviews. I will be guided mostly by what my buddy recommends (who has installed SEI's in a lot of his customers boats with great success), but love to hear from others as well, to get a more broad potpourri of info from the experience here at iboats. I realize that I can prop the boat to obtain pretty much the performance expected from the 5.7, but also realize that the "bigger" the prop, the more stress on the "weaker" gears in the upper drive. What would YOU do? I've mentioned this in so many words in other posts of mine, but trying to get the best help by posting it in the appropriate place under it's own topic heading. Thanks guys.

Norm

 

[Faztbullet]

I myself would go SEI as I have sold at least 30 sterndrives assemblys and over a 100 outboard lowers and can count on 1 hand the failures or returns...

 

[bigblock454]

Thanks Faztbullet, that sounds like a great track record!! I'm reading a lot about "gear noise" and "break-in-procedures" and such, with some people stating "that should tell you something". Like I said, it's enough to get you to re-consider. But it seems the more I read/inquire, the less I'm finding the negative reviews on the SEI's! Can you elaborate on how good the paint holds up, or what can/should be done to an SEI drive that may be in the water for much of the season, incase I decide that trailering just isn't very easy with my 2452? Are they prone to being "noisy" and how good is the paint on them these days? Thanks for your time to post some good feedback!

Norm

 

[alldodge]

1:65 to 1:47 that isn't much change and torque is not IMO the issue. If your drive is fine right now I would be looking at changing props, not ratios. What is your current WOT GPS speed and rpm?

With that we can figure what your next prop should be

 

[bigblock454]

Man, AllDodge, I like the sound of THAT, because that would be the least expensive option! But I'm hearing that the difference is significant! I certainly don't have the expertise, experience, or first-hand knowledge myself, so that's why I'm reaching out, but I want to mention all that I am hearing and reading, I read that the 1:62 is "borderline" behind a 5.0 and not really recommended behind the 5.7 unless you "take it easy", now mine is a couple of ticks "worse" than that (1:65). Anyway, I got the boat this way, and have not had it in the water yet. Can only say that "she runs great" with the outdrive off. I don't run it long, as there's no coolant going through it, so just a minute or so. Actually, I'm taking gimbal assy apart now and have shift/throttle cable off, so not starting at all anymore until she goes back together. I'm replacing bellows, bearing and shift cable, as well as de-scaling and repainting the gimbal assy and drive when I get it back (unless I opt for the new SEI). Man, I'd love to just rebuild what I have and know that it will live a comfy life, but the problem, I'm told is the gears themselves are more "beefier" with the 1:47:1 versus the 1:62:1 gears, which I'm told are a bit more "chincy", and more prone to failure when more torque is applied to them. I'm listening though! Thanks!

Norm

 

[bigblock454]

I should elaborate by saying that I got the boat with the drive removed. P.O. seemingly abandoned the project in the middle of bellows exchange. So no idea how she performed. I can't wait to get her on the water and see! I have access to LOTs of props, so I'm not worried about "tuning" for diam/pitch, etc. Just want a reliable drive to start with.

Norm

 

[alldodge]

I'm told is the gears themselves are more "beefier" with the 1:47:1 versus the 1:62:1 gears, which I'm told are a bit more "chincy", and more prone to failure when more torque is applied to them.

IMO this is pure BS, gears are gears and the difference between them is next to non-existent.

Now if your using 1:65, turning 4800 rpm and using a 15 or so pitch prop then maybe we need to rethink this. My guess would be the prop is around a 21 pitch so this gives us some room to change. The difference as before between a 1:65 and a 1:47 is next to no change at all. Think of it as one degree of pitch.

I think there is more going on with the story of the boat then what your being told, the ratio is not an issue IMO

 

[bigblock454]

I certainly appreciate (and respect) your opinions, as they are exactly what I was seeking! As far as the ratio being an issue... that isn't coming from the PO, but from me and my own (inexperienced) research, as well as listening to the shop (my buddy) that currently has the drive, Seems to me, that this boat was running with this drive and well... it ain't blown! So I'm truly all ears with what you (and hopefully others) are saying. I suppose I could go outside right now and look at the prop to see what size it is. It may shed some more light on what the PO was trying to accomplish. My friend said that he would be happy to bring what I already have "up to snuff", but is concerned by someone getting "ham-fisted" with it and perhaps putting to much strain on what he thinks is a marginally capable unit. He said "it could last you 10 years, or ten minutes, depending on the moon, stars, and idiot behind the helm"! Thanks again Dodge!

Norm

 

[bigblock454]

The prop that came with boat is a 1912P17. I guess that's a 17 pitch, right? How is the rest translated? I'm sure this is easily searched... but what the hey... we're talking (I'm learning) here! Thanks!

Norm

 

[alldodge]

Running a 17 pitch with 1:65 tells me I would not under any circumstance change to a 1:47. With running 17 with 1:65 tells me that if you go to 1:47 your prop will spin faster. Spin faster means you need to reduce pitch unless your increasing HP. Going from 5.0 to 5.7 is your increasing HP, that said you would want to be able to increase pitch instead of changing ratio.

 

[bigblock454]

Understood... I just ASSumed that I would be re-propping anyway. Especially changing ratios. If for no other reason but I'm not at all sure that this was the drive, or the prop that was run on the boat. It would SEEM likely, but I already figured a new prop would be purchased for it. Again... I only thought the ratio change was necessary to give me more "gear strength". You gave your thoughts on that... and I'd like to believe that to be the truth, as it means a simple "freshening up" of my current drive would be all that's needed to get me going!

 

[thumpar]

It is probably that ratio because of the size of the boat. The torque has nothing to do with it as long as you are running at the recommended WOT. You could run a 1.98 and the only thing that would happen is you blow the motor from running too high RPM. The drive will take it. You might want to find a new "guru".

 

[Bondo]

Again... I only thought the ratio change was necessary to give me more "gear strength"

Ayuh,... Tooth count has little to nothin' to do with gear strength,.....

'n as thumper says, gear ratio has Much to do with hull size,....

With a reasonably stock 350, I'd go with the drive ya got, 'n think you'll end up with a 21" prop to make up the difference,...

If it was runnin' a 21" or bigger with the 5.0l, Then ya might need the taller gears, as you'd be at the top-end of easily available prop pitches,....
Startin' at 17" with the 5.0l, gives ya some prop pitches to move up,.....

Goin' to the 1.47/ 1.50 ratio would probably put ya into 15", maybe the 17" props,....
If ya needed lower, you'd be pooched,....

Standard prop pitches run from 15" to 23",....
There ain't no 13" props, 'n 25" props are much harder to find,....

 

[bigblock454]

Very good! Looking at your post counts indicate to me that you guys have been around this stuff for awhile, and "know your smoke"! I believe I am inclined to run the drive that I have, with freshened internals, then drive it like a "big boat" and NOT a drag racing boat! It's no secret that the alpha is not destined for long term survival with high displacement/ high horsepower engines. Now if maintained properly, and run responsibly, I think I can get some good enjoyment out of what I got. My 5.7 liter is till wearing the 5.0 liter "externals", specifically the 2bbl carb. Can it be said that this in itself would keep horsepower down to modest levels, therefore taking it "more easy" on the drive? I'm liking what you guys are saying by saying that the "gear size/strength is BS"... but I've heard that from more than just the folks working on my drive. I am aware that there are a lot of "urban legends" floating around, and one certainly needs to do their homework with facts (which I don't have), so most are at the mercy of what they're being told, and the reasons given by the "experienced". It's easy to ask someone to simply "tell me what I WANT to hear", but in the end, that doesn't buy you much. I was told that the tooth count effects the amount of metal left on a given sized gear (or something that made sense when I heard it). Not that the gears were actually built stronger, but stronger "by their nature". it was said that the stoutness of the gears could be seen when held side by side... not true?? I've never seen the gears, so I have no argument, again... just learning from the "experienced". I do know that the more power my motor make, the more prop I can effectively turn and still get the boat on plane and experience the performance afforded by the increase in power, but I also know that this HAS to increase the loading of the gears, case, bearings, etc. It appears that the alpha is running on the edge with the V8 motors in general, and certainly with the higher horsepower ones. I love hearing that "so and so is running one just fine behind a 454"... it gives me hope that mine will give me plenty of good times in a Bayliner (not the heaviest of boats) 2452 Classic. Glad to hear from you guys!

Norm

 

[Bondo]

My 5.7 liter is till wearing the 5.0 liter "externals", specifically the 2bbl carb. Can it be said that this in itself would keep horsepower down to modest levels

Ayuh,.... That'll give ya maybe 230 hp,....

The Alpha series of drives have been runnin' behind 260 hp 350s since the late '70s,....

Personally, I'd slap a 4bbl. Edlebrock onto it, 'n go have fun,.....

 

[bigblock454]

Too cool... Love it!!! That is music to my ears!

Norm

 

[bigblock454]

I have no desire (well, not much ) to treat this cabin cruiser like a Scarab. It is my means to get out and drop anchor in a cove for the night. I hope to finally be able to take up some fishing with her! I have a 2000 Bayliner 2052 cuddy with a 5.0 (1:62 gen 2), that has plenty of performance for me. I navigate in the Upper Chesapeake region around the Baltimore area. It can get rough out there for the little 2052! I know that the Bayliner "Classic" is anything but a deepwater offshore boat, but hoping that it "smooths out the chop" just a little over the cuddy. I got a very good deal on it, she's solid, pretty clean (see other posts) and ready, except for the drive. Heck, in the position I'm in, I could easily rebuild, run what I have, and listen to what the boat tells me. If she deserves a different outdrive after the next season... no problem. I'll be where I am now with (hopefully) a good drive to use as a back-up, or to sell, give to a buddy in need, etc. I go out most of the time with a buddy, or my brother in another boat, knowing that there's a chance that one may need to be towed back. If not, our "hand-shake" agreement says "friend in distress, get enroute". If one of my friends or relatives calls, I will not waste a minute to go out and find them. I hope they feel the same. If not... 1-800-TOW BOAT and (hard) lesson learned! :argue:

Norm

 

[bigblock454]

Again... just wondering out loud... I'm thinking that there's a possibility that folks swap out their motors for bigger, more powerful ones, then start propping bigger to use this power increase, therefore overloading the drive. Seems quite likely that the gears may be the "weak link". Perhaps when going to a higher (numerically lower), they do not need to prop higher. This then wouldn't be putting the increased loads on the drive that the "bigger prop" people are seeing, giving the appearance that the 1:47 gears are "stronger" than the 1:65 gears. So the guy with 1:65 behind a 5.0 (I myself haven't seen that combo offered from factory, but is what my boat came to me with), swaps in a 5.7 and notices now that his holeshot is better, his boat now "jumps" out of the water, and with in no time, seeing 6000rpms on the tach! Sooo, a trip to WM to buy a bigger prop with more pitch, etc. Now he's back to "normal" boat launches, lower rpms at WOT, and better fuel economy... but the increase in load on that drive, just went way up, right? Now he grenades the drive and blames the munched gears. Meanwhile the guy who ops for a set of 1:47 gears in his drive isn't needing to "prop up" because he's doing it with a gear swap. I guess with slippage and all, the gears are "seeing" less stress?? In the end, your getting the same numbers, but by different ways... and I guess one way is easier on the "weakest link" than the other... or maybe it's just MOVING the weakest link! Am I close?

Norm

 

[bigblock454]

It seems also that I could prop her with a 14 x 17 prop designed for a 4cyl. It would probably achieve plane about as fast as you could move the throttle lever, drink gas as fast as you could pour it, and have a top speed of 20mph before the motor blows (the new "weak link")... but the drive would be living a life of luxury (no stress), right? It's that "happy medium" where you have to start weighing options and figuring out costs, strength, design limitations, prop availability, etc. Man... a Bravo is starting to sound good! :facepalm: . Sorry... whole new thread!

Norm

 

[alldodge]

Norm, don't know how we can provide anymore clarity, but the drive will not last any longer with either of the ratios. The HP/Torque combo you have will not have any effect on the drive. The only way it would be damaged is "IF" there is a problem with the drive before it is used.

From bblades prop calculator using 10 percent slip
17 prop, 1:65 ratio, 4800 RPM = 42.15 mph calculated
17 prop, 1:47 ratio, 4800 RPM = 47.31 mph calculated

19 prop, 1.65 ratio, 4800 RPM, = 47.11 mph calculated

This shows ratio has same effect as 2 degrees of pitch, in theory (all boats have differences due to weight/hull). Remember you are on the low end of the drive ratio, so you are in a good place to play with props for getting more out of hole shot and WOT.

The only way even in the go fast world for breaking drives is dropping the hammer, grabbing air, or having a motor with more power then the drive is designed to handle. The drives that are damaged are in most cases are due to much HP and to large a prop along with grabbing air.

Edit:
A 14x17 prop is not made for a 4cyl, it is a prop made and installed on a boat which has a 4cyl and a different ratio drive