Rebuilding an Alpha

[SneakyPete]

I am planning on rebuilding my alpha at some point, and using cryoed gears to give it a fighting chance with my 383. I am not very "outdrive" knowledgeable. Is this a major untertaking, or something I can tackle with a couple of special tools? What should I be doing to the drive, all new seals, bearing, etc? I was thinking about gettting a rebuild kit from Mercruiserparts.com but I wanted to check here first. I am not sure what is around (Ma, NH, VT) for good shops to do the work, and if I can buy the rebuild kit, and spend a few bills on tools and save paying big $$ to a shop, well that would be great.

 

[happy]

i would suggest putting a bravo drive on her.. seeing that your worried about the hp/alpha combo. easy, most likely would be the last drive you put on the boat..

as far as tooling goes, mine are old, and werent cheap then, i suppose they went down in price since, but the person behind the tool is more precious than the tool itself.

consider this, because it is probably your least expensive choice

 

[vinny p.]

Pete,

Your biggest problem is going to be finding someone or even a knowledge base that can help you with an Alpha. As I am sure you are aware, high performance boating with I/O's is a Bravo world. I wish I could help you with that drive, but I have no experience at all with them. If you wanted to do the swap to a Bravo, I can set you up real well.

That being said, you know me well enough to recommend you learn how to rebuild that drive yourself. I too was afraid of the voodoo mystery of what makes drives tick. Even though I had experience setting up automotive rears, drives intimidated me. Mostly because I didnt want any failures during our short north east season due to a set up screw up. Secondly, parts are expensive to waste. What I did, was get the Merc Bravo drive manuals and read through them ( there are 2) . From there, I made a list of tools I would need. There are a few tools that Merc makes that you absolutely need to set up drives properly. I got them from Marc Berman @ mercruiserparts.com, as I do with almost all Merc parts. Alpha and Bravo tools are different, sorry mine wont work or I would lend them to you. Along with the special tools, you will need basic hand tools, a good 1/2" Torque wrench, a dial indicator, a 3/8" torque-o-meter.

Whether you rebuild it or someone else, replace all the seals, bearings and races. If the u-joints are old, now is a good time to dump them. The gears, depends on what they look like. If the budget allows, a new set cryoed, is the way to go.

If you are apprehensive about it, try calling Chris Martin @ http://www.sterndrivespecialists.com/ I have ordered parts from him before. He has a good reputation.

 

[Big Dave]

Sierra also sells most of the tools, we bought the shim tools for the upper half and the spanner nut wrenches, and daren34 has rebuilt both of ours and a few for friends
even at the higher rpm and hp I am running, the alpha is working great... the kids use it almost every weekend pulling skiers and wakeboards 5 and 6 hours at a time

 

[daren34]

you can put a bravo gimbal in a alpha gimbal housing
you have to do a little massage work but i have seen it done at a mercruiser dealer

the big thing i would worry about would be if the x deminsion needs to change

are the drives the same length propshaft to inputshaft

i don't think you would want to run any deeper than you are now

just my 2 cents
daren

the alpha drives are pretty basic, not to hard to rebuild
get the special tools though

 

[SneakyPete]

The thing with a Bravo is the $. I am under the impression that it would cost me around 5k to do a swap. I also read here that a guy swapped to a bravo and couldn't keep the boat from porposing due to the added weight (altho I am running an aluminum top end on my motor) in the back. I also fear that the drive would run to deep. What are your thoughts on costs etc?

 

[vinny p.]

Pete,
Unfortunately, I cant offer much help when it comes to Alpha's. I would imagine that you could get a used B-1 for about $2k and a used gimbal and transom plate for about $1k. Then you have to pull the engine out again to do the swap. I am not sure about the cut out in the transom, is it exactly the same? I am not sure. The prop shaft height is another issue. I can help you with that one. My drive is off the boat and in pieces, but I can measure the distance between the drive and prop shafts. Then you can compare it to yours. Another consideration is, a Bravo eats up more HP than an Alpha. Not sure of exact numbers, but you will go a bit slower.
I think that if your Alpha is set up correctly and you treat it well, it will live.


P.S. It finally stopped raining here a few hours ago. I just lifted the engine out of the boat. Even though the boat is in the garage, I have to stick the bow out of the garage to get the engine under the crane. I didnt want to get it wet after I waxed it last weekend. Tomorrow, the lifters will come out and be sent to Isky on Monday. I am still unsure of whether I am going to put an Imco ring and helmut on my existing gimbal or just get a Merc HP gimbal.

 

[SneakyPete]

I would just assume stick with the alpha, and try and do the cryo gears. I have poured so much coin into an old boat as it is, and would like to keep the purse strings tight. This boat will be seeing river action mostly, with little in the way of waves, so I think time and money wise, getting the tools and knowledge on setting up the alpha is the better way to go for me. Vinny, snap some pics of the lifters if you get the chance. Unless you can find the HP stuff for a good price, the Imco sounds like the way to go.

 

[vinny p.]

I agree, I am leaning towards setting up my gimbal with Imcos' ring and helmut. I should have it taken apart this week. I'll keep you posted. Also, I'll post a picture of the lifters and my new T&D's tomorrow.
I got very pissed off at Bob M. and the lifter manufacturer ( I dont want to post their name, but you know whos I am running ). These lifters were supposed to be the best ones out there. Then, my friend had a failure. It was blamed on his rather unusual set up and not enough spring pressure. Now, miraculously, it was offered to both my friend and myself to get another set of wheels that are suppose to be indestructable. The best part, no charge!! My question is, why the hell werent they on there the first time. I dont think I have any failures, but tomorrow will tell the tale for sure.

 

[vinny p.]

I got everything apart today. Luckily, my lifters look like new. I see no signs of wear at all. I dropped my borescope on the cam lobes, they look great as well. Seems I have finally been spared from a disaster. I am still sending the lifters back for the new wheels. Attached is a picture of the new T&D shaft rockers I just got. They look great, excellent machine work. In my opinion, better than Jesels. Setting them up, is going to be tedious and time consuming. However, once done, I am expecting good results.

I removed my gimbal also. The damn thing is in great shape. I am thinking of E-Baying it and just getting a brand new Merc HP Gimbal. When factoring in the $$ I can get for my used gimbal, buying a new one vs replacing my standard helmet and ring with Imcos, the amount it will end up costing me is about the same.

Anyone need a good used Mecr Bravo Gimbal??

 

[Mark A]

I went from an Alpha to a Bravo 1 on a 1986 convincor recently. I am 99.9% sure the cut out is the same.

The x dimension will not change going from an alpha to a Bravo.

You will loose some top end going from Alplha to a Bravo. It is a larger profile in the water and increases drag.

Bravos are heavier. I believe a small block with alplha package weighs 200 lbs less than the same set up with a Bravo package. 200 lbs does not seem like a lot but on the stern of your boat it really is.

Porpoising is a pain to deal with and tricky to really understand. It has to do with weight distribution and the dynamic balance of your boat. The balance of the boat is always changing though so it is really tough to deal with. On my boat I do not recall any porpoise with the alpha drive. I went with a small block as I had but from 260 HP to 320HP and I had a porpoise problem with the Bravo installed. So, adding wieght to the stern of the boat is OK if you are adding enough power to compensate for it. It would be close with the 383 engine.

Everything I have read and heard from more knowledgeable sterndrive guys is that you will be fine with the alpha gen II so long as you drive it right. I think if I had it to do again I would go with a big block and a bravo or, a small block and alpha gen II. The alpha is so much less expensive than a bravo.

 

[SneakyPete]

Christ on a Bike!! After almost 3 years on this site, I just noticed in my profile under my avatar I have the model of my boat spelled wrong....I wish that was the least of my problems.

 

[checkmate DOH!!]

LOL-----"ENCHATER"-----

 

[bigsbetter]

Pete. When I had problems w'/ my alpha ,I was in the same 'boat' you're in. I rebuilt mine myself. It was simple. I bought the special tools and spanner wrenches and all the stuff to measure the clearences. It's like a differential on a car, everyone knows they have to be set up just so, or they make noise and go bad, but it's simple to do if you have the tools. I actually ended up buying my gears from ebasicpower.com./ They are not made in the USA, but they have a different design that uses a smaller bearing to allow for a more beafier thicker gear on top of the drive (the weak point in alphas) The parts are cheaper and they sell the tools also. Mine held up to a supercharged 350 in my old 21' Scarab.

 

[SneakyPete]

Thanks brother, can you list the tools I will need?

 

[vinny p.]

Thanks brother, can you list the tools I will need?

Dont forget the service manuals..

 

[bigsbetter]

OK lets's see here, this has been so long ago that I did this. I found my whole box of stuff with all my tools and some old parts and some new parts leftover from when I rebuilt mine. I didn't buy all the special tools the manual said I needed, But I did buy the main ones and the ones to measure the upper gear clearences. For the upper gear clearences you need tool number (GLM) 90180 and 90170. Then I also bought some of the big 'spanner' wrenches, numbers are, 90190 and I don't have the box for the last one and there's no number on it. The hardest part about the whole job was getting the driven gears' race out of the upper half of the unit. I used a slide hammer, but there's not very much room at all under the race to grab it and it's down in the drive about 8 inches or so. There's shims under it. What year is your outdrive? I remember in 1985 there was a middle of the year revision and they went to reverse cut gears or something. The reverse cut gears were much stronger.I used the Clymer manual for the rebuild. It was very specific and every boat place carries them.

 

[SneakyPete]

My drive is an 1983, although the previous owner had some problems with it years back, and I think rebuilt or replaced it twice, so I am not sure if it is the the original 83 or a newer one. Is it possible to use the reverse cut gears in the old unit? I also heard that at some point they did away with a grove for an o-ring some where that also helped strengthen the unit...