Alpha 1 upper destroyed

[i_build]

I purchased a new SEI upper and lower and last year because of the o-ring not being where it should have been after servicing I was cruising along and the upper gears shredded. As soon as I heard it I immediately shut down and got towed in. I since have been using another original Alpha 1 with the wrong gears in it for my setup just to finish off the season.

I contacted SEI and they do not do rebuilds. The SEI drive worked great... so I am going to buy another... but my question is should I buy upper and lower or just upper. The lower pretty much accounts for half the 1,800$ price tag and I would flush my original lower out extensively before using it... but I read some posts that say the metal shards may have already damaged the lower... not sure what to do cause the budget is tight. I also dont want to buy the new upper bolt it to the older lower and then ruin it if the lower gives out... then I would have to buy both again.

Please let me know if you have had or seen similar experiences and have advice.

Thanks.

 

[i_build]

Alternative to the above also seems to be that I change the gears in the Alpha 1 drive I have bolted up now... or possibly take the Mercruiser Alpha 1 lower from and bolt it to the SEI upper... if that is even a possibility.

 

[kghost]

If the upper gears came apart then the metal most likely made its way to the lower. This means the lower would need to be completely dissassembled, cleaned thoroughly and reassembled.
Of you can do or have that done, then you can vet away with just and upper.

To do the upper gears to the correct ratio will cost about the same as a new upper if you have a shop do it.
OEM gear sets, bearings and seals will costs are fairly high.

What version of Alpha, gen 1 or gen 2? What ratio do you have in the running drive and what do you need?

 

[kghost]

Where are you located?

 

[Bt Doctur]

thought they had a 3 year unconditional warranty

 

[i_build]

I'm in Clearwater FL, and its Alpha 1 Gen 1 hooked into a Mercruiser GM 250 on a 1966 Ann Capri 22'. Bt Doctur I hear you with the warranty, I just feel like getting it done right first time though, I'm mid 50's now so its not so easy to deal with getting stuck and waiting for a tow.

kghost I see "Mass" in your sig... so I am guessing we are a long ways apart. I'm not afraid of some physical work... I still rebuild engines and I am a software architect by trade... but if you have a hookup please let me know.

 

[i_build]

I will get the ratio of the new drive in the a.m.

Could it be possible that I might just need to swap props?

 

[kghost]

The ratio for an inline 6 cyl is 1.65:1.

(Opinion)
What in the world are you messing with a boat that old for especially in Florida?
By the time you get this resolved you could have purchased a used bigger and very much newer and powered by at a minimum a V6 if not a V8 for about the same money.......

Old technology boats are certainly easy/fun projects but parts for a 60 yr old boat become very difficult to find.

You say the drive is a gen 1 Alpha.
So you are saying the boat has been upgraded from its original drive (OLD) to the 1980's Alpha series?
If this is the case, then at least Alpha Gen 1 parts are readily available still...

 

[i_build]

 

[i_build]

I really like the Hull design and the Carolina flair. You can see the SEI drive there and that was a 1.81 so its really odd that 1.65.1 is what you are saying and what I saw for an inline 6. I think I read that SEI gears are different somehow. Yes it was converted over to Alpha 1 Gen 1. I pulled the back to back seats out and I will be putting in pedestals. I had a "newer" Cobia, Mako, and Stamas... and for some reason... known to an engineer for Anna Capri (out of business in Miami at one point).... this thing is a TANK. You can see the bump out on the transom. Super solid dry ride.... Plus a ton of space for the grand kids to fish and a little step down with room for a porta potti and privacy between the windows. The platform off the back is nice also.... not to mention after a double organ transplant money is a little tight... but life is much brighter now.

 

[kghost]

So,
Based on all the newly updated information,

The ratio may not be 1.65:1 originally based on boat/hull design/size/weight. Only way to tell is what the original drive was when you purchased it.

To start, Need a lot more info.

1. Have you had it at wide open throttle with the drive trimmed up for max performance and if so what were you RMP?

The inline six is most likely 4400-4800 rpm. So if you were able to run as described above you should be in that range.

If you were over 4800 rpm then we need to know by how much and the same if you were unable to reach the min of 4400 rpm we need to know by how much.
This is the really only way to determine if the ratio or the prop are even close to what is needed.

99% of boats small and medium are designed to run a 19 pitch 3 bladed prop. Normal variations could require pitch changes from 15 pitch all the way to 23 pitch would be typical based on all kinds of factors.
So for a heavy boat with an under powered engine and based on size and weight of the boat, it may require a smaller pitch to get the boat to plane off correctly and reach max RPM. In some cases they change the gear ratio in the lower unit to compensate. This could change a standard drive ration of 1.50:1 to 2:1. Common in high altitude.

Now this is a very basic explanation so dont take it as the rule.

For Alpha 1 Gen 1 the "typical" outdrive ratios went like this.

Inline 4 cyl 120-140 hp, 1.94 or 1.98:1
Inline 4 cyl, The infamous 165/190/470 Merc engine used 1.84:1
V6 used 1.84:1
Small block V8 used 1.50:1
Big Block V8 used 1.32:1.
Those are typical and there were many variants for different purposes/boat designs/power package designs.

Pre Alpha when the inline 6 was used there were four typical engine versions.
150 hp 230 cubic inch,
160 and 165 HP 250 cubic inch
200HP 292 Cubic inch.
(Do you know which is yours?)

The typical 250 ci was found in most 20ftish and smaller pleasure boats and typically had the 1.65:1 ration drive.
Your boat is not typical so the original gear ratio may be difficult to determine without the original drive.

In the Alpha gen 1 drive manual they have a listing for 165 and it shows a ratio of 1.84:1. I believe this is pointing to the Merc inline 4 cyl engine which was rated a 165 hp. NOT the inline 6 rated at the same horse power. This is most likely where SEI got that ratio for you boat.

Now with all that said. 1.65 and 1.84 are not that far apart and I doubt you run the boat at wide open throttle, maybe 3/4 throttle some times based on my experience in salt water. So the 1.84 may be fine with the right prop diameter and pitch.

So if you have data for wide open throttle RPM and prop pitch and diameter with the SEI drive that would help.
If you have the same data for the prior drive that would also help.

Other wise someone with more design experience may be able to help.

 

[o2batsea]

Loved my old Anacapri. I had to send it to the landfill but it was nice while it lasted. If I still had it, I would cram a BBC in there with a Bravo 3. It would absolutely rip.

 

[i_build]

WOT trimmed properly I was in the 4600 rpm range with the 1.81 SEI drive and I am not sure what Pitch prop that was running but I still have that prop so I can check. The paperwork I have says the motor is 160HP Serial # 2233574 Chevy Straight 6... 250 Cubic Inch. I also need to get the numbers from the mercruiser outdrive that I have on it now with the prop that was on the 1.81 drive... with the mercruiser drive I feel my rpms are much higher to reach the same speeds (I know that is too ambiguous to make any calculations from) I will get the info from the mercruiser drive as well as the prop tomorrow its been a wash out this weekend here in Clearwater.

o2batsea... I know I like the way my Anacapri looks and rides... so I am trying to keep her going. Not trying to break any speed records with the inline 6 though.

 

[kghost]

No need to get any additional data.
If the SEI drive ratio and the prop used with it gave you 4600. You are good to go!

Now focus on the drive repair/replacement.

 

[kghost]

Remember, getting your WOT data is a way to determine if you drive ratio and prop are correct for your boat.
It is not saying you should run the boat at WOT.

If it is slow plaining off you can drop one pitch say from 19 to 17 to get a better hole shot so to speak. But if you try to run at WOT with the smaller pitch you will now have higher RPM. So your 4600 will become ~4900 RPM.

Based on what you said about the original drive and the higher WOT RPM, it may be exactly what i described with prop pitch and the prop pitch was reduced to get on plane better or the ratio is different which could give the same result.

 

[Dieter]

I'm in Clearwater FL, and its Alpha 1 Gen 1 hooked into a Mercruiser GM 250 on a 1966 Ann Capri 22'. Bt Doctur I hear you with the warranty, I just feel like getting it done right first time though, I'm mid 50's now so its not so easy to deal with getting stuck and waiting for a tow.

kghost I see "Mass" in your sig... so I am guessing we are a long ways apart. I'm not afraid of some physical work... I still rebuild engines and I am a software architect by trade... but if you have a hookup please let me know.

Im confused - the drive is still under warranty right? How will they honor the warranty- if they dont do rebuilds will they send you a new drive? Would think based on what what you said - missing quad ring have them honor the warranty and bolt it back on

I just went through resealing my drive and putting new bearings in the upper. If you have access to a press and buy the shimming tools it is very doable my reasonably skilled home mechanic.

 

[i_build]

Its not under warranty. I confirmed with SEI that the lower that is on my original Mercruiser with the wrong upper gears will bolt right onto the Upper they sell with the gears that worked great with my setup. The prior owner purchased the SEI drive lower and upper way beyond the 3 years they give you under warranty. When I had it for the first season she got up on plane and cruised at 4500 RPM really nice... until I had bad luck and lost lube and my gears in the upper... Once that happened I found a used Mercruiser Alpha 1 geared for what I thought was correct based on a bunch of sites saying what a GM 250 should be geared at... but when I bolted it on... found out that it was taking much more RPM to keep me where I used to be... So I have a good lower in the genuine Mercruiser drive... a potentially good lower from SEI that needs to be cleaned out... and all I need to do is buy the 1.81 upper and I bolt that to my genuine Mercruiser Alpha 1 lower ( I found the PO original SEI receipt saying 1.81 and saw the tag on the upper)... with that I should be back to where I started and I was happy... 900$ for the whole upper with a 3 year warranty is better than having to get the tools and do the job for something I probably will do only once... I have a few presses but I just dont really care to fidget with it for the difference in cost. Thanks to all for the advice.

 

[i_build]

https://photos.app.goo.gl/e6p2UwpgHbn6Liu2A

My pics went to admin heaven above... but in case you are wondering what I feel is worth the effort... here is a link to my drive.