29scarab

I'm in the process of working a deal on a Stellings Ext. Box and components from a board member and have a couple of questions. I know the box will work with my Bravo outdrive. I'm not to saavy on how the hyd. rams mount on a Stellings application. From what I saw the IMCO has a couple of wing plates. The Stellings application looks like it calls for some ext. arms that bolt to the back of the transom for the rams to bolt too. I want to purchase the ext. arms from the OSO member also, but want to make sure their going to work with my application. The Ext. box is coming off a Active Thunder and I'm installing it on my 29 Scarab.

I'm attaching a picture of the components. Could one of you steering experts shed some light??

I hope to gain 3 to 5mph . Does this sound possible?

Also , besides some longer hydraulic lines and a few through hull fittings, what else will I need to complete this upgrade?

Thanks for any input!

29scarab

here's another pic

Cord

iTrader: (2)

Before you mount that box, consider taking it to a machinist. He can connect each of those holes. That way you can adjust your x-dim with a floor jack and don't have to tear everything apart. When I mounted my box, I had some super thick stainless washers cut so they wouldn't deflect when the bolts are tightened.

I put vasaline on the transom to make sure the gasket wouldn't stick. I didn't want it tearing when I moved the box.

Also make sure those transom bolts are really tight. I actually had the box move all the way up on me once and lost water pressure. Do keep an eye on your pressure. I found that mine fell to zero shortly after planing.

I see a couple of items missing from your pics. I don't see the water outlet pipe. This piece will be required to connect the 1-5/8" hose to the drive. I also don't see the inner transom plate. The stock merc plate cannot be used without hacking the hell out of it. Stellings makes a rather nice inner plate that I'd recommend. This plate does not allow for the stock steering valve to be used. There is also a piece of steel that will bolt to the back of the crank shaft. This is the adapter that goes between the crank and the drive shaft. Grade 8 bolts, lock washers and blue lock tight are a requirement. Wire ties are recommended, but not required.

You will also need some bolts to go through the transom. It would proably be the easiest to put the nuts inside the box. You proably have to do that for the bottom 2 holes anyways. I used standard grade bolts and nylon lock nuts. The first time I tightened them, I torqued it to the capacity of the bolt. Unfortinatly, I crushed the transom which moved the two mounting ears together so the engine couldn't be installed. The transom is still crushed to this day and I had to add some shims behind the plate to make up for it.

I see that somebody dissassembled the center bearing. That's very dissapointing. After assembling everything, I was unable to get the drive to align with the center bearing. I ended up tearing the whole thing apart and sending it back to Stellings for alignment. There are some shims that go below the bearing that are custom machined for every application.

Hydraulic steering is a requirement. I used the imco brackets which mount off the box. This has a significant advantage over the transom brackets. First they look cleaner. Second when you change the box height, the steering rams stay centered on the drive pivot. This is very critical as a bind condition will result with dual steering rams. I ran both of my steering lines into the box below the brackets. This makes it really easy to pull the box off, but makes for very tight packaging. That box sure is crouded in there! The one thing that I did not like about the imco brackets was their mounting system. You drill 6 holes in the box and then thread in some beefy studs. The problem is that you cannot get 6 nuts on the studs inside the arm. There just isn't enough room. I ended up with 6 studs but only 4 nuts. I hand drilled these holes, but it would be better if there was some way to do it on a mill. If you already have steering rams, just make sure they are compatable with the imco brackets.

I would attribute 3-5mph to the box and much improved planning. Don't forget that this box will effectivly lower your x-dim by 1". This is a function of the transom angle. Stellings says they adjusted for this in the design of the box, but just be prepared to raise the drive a little. They say that you can keep the engine at the stock location for all but the top and bottom 1" of travel. I've had the box all the way up and down and have never felt a drive shaft vibration.

29scarab

Cord,

I forgot to mention I already have an external pickup tube for the water inlet. They put that on when they installed the Whipple Charger.

I didn't know you had to change transom plates? I'm not sure I want to buy the steering brackets if the IMCO's will work better as far as possible bind.

It looks like have some more investigating to do on this project.

Cord,

Thanks for taking the time to explain in detail. I think I'm going to print this page out.

Shawn

Cord

iTrader: (2)

You don't have to change the plate. The problem is that merc designed the plate for a small splined shaft comming off the drive. You now have to pass the large knuckle of the drive shaft through that small hole. A sawzall will do the trick, but there is a lot of webbing that would need to be cut. It would just be a hack job which will significantly weaken the plate.

29scarab

I'm going to talk with my mechanic about the plate.

Do you know how much that transom plate would be. Also is there a website I can look at a parts list for the Stellings ext. box conversion.

Cord

iTrader: (2)

Stellings isn't on-line. I think I paid around $100 for the plate (unpainted) a couple of years ago. There's not much too it, so they are really making a killing at that price.

When you do call, don't be suprised if they do some head scratching at seemingly simple questions. A couple of years ago the owner died and left everybody in the dark.

29scarab

Thanks Cord!!!

29scarab

Anyone have any pics with both types of set-up.

Stellings with transom steering ext arms.

IMCO with wing mounted plates. ?????????????

cobra marty

Well said. The flange that goes thru the bearring carrier is where I can put my dyno/strain guage.