When you need a few more inches.....
 

Seems to be the story of my life. However, this time I could fix it. We are installing Stellings extension boxes on a 37 Outerlimits. We really need to get the boxes/drives as high as we can. Since the boxes are adjustable, we can move them up 2". However, that left us with a pretty steep driveshaft angle (10*). That is too much with almost 1000 hp. We have 2 choices to fix it. The first is to move the engines up. We are already sticking out of the hatch with the engines where they are currently. The owner doesn't want a scoop on the hatch ruining the hatch pad. So, moving them up isn't an option. The other option is to move them forward. By shoving them forward 4.5", I was able to get the driveshaft angle to 7*. The cleanest way to do it was to extend the mounting ears on the inner transom plate. I didn't think a rear engine plate was the way to go. Not only would it not look good, but it would be tough to work on with such limited space to the transom, since we are only moving the engine forward 4.5".

I thought ya'll might enjoy some pics of the fabrication process. I started with an IMCO inner transom plate. It is much stronger than the stock Merc unit. Not only that, but it doesn't have all the extra bs of the steering ram mount, etc. I did all of the mods with 1/4" and 3/8" 6061 aluminum.

These first pics are of the inner transom plate being cut, templates being made and mock up. We made up a temporary jig that duplicated the transom angle of the boat, the angle of the engine, etc, so that it would not only be right and fit in the boat, but so both of the transom plates would be identical.

Thanks for looking. Enjoy.
Eddie

More pics of it going together.
Eddie

Finshing up

I kept my stellings box install angle under 3.5 degrees because I wanted to be able to turn my motor 6200 (after talking to Guys there about the angles), I would be VERY nervous at 7 degrees Eddie. Make sure the front angle and rear angle match within 1 degree. I had a 4 wd jeep with a 15" rear driveshaft with 1200ft lbs at end of tcase with 10 degree angles at only about 3000 driveshaft rpms and it would snap 1350 ujoints like twigs, switched to 1410 and they bound even worse, ended up redoing everything to get angles calmer and problems went away. Looks like your working hard, Smitty. You also have to factor in driveshaft length- I attached some info I have went by for along time:
" When the transmission output shaft centerline and input shaft centerline are parallel, the u-joint operating angle permissible is length of driveshaft divided by five. Example: A short coupled driveshaft with a 15" length would be limited to 3 degrees maximum operating angle. A 30" shaft would be limited to 6 degrees.

DRIVESHAFT RPM

MAX. NORMAL OPERATING ANGLE
5000 3.25º
4500 3.67º
4000 4.25º
3500 5.00º
3000 5.83º
2500 7.00º
2000 8.67º
1500 11.5º

Did you consider gutting the stellings boxes , buying the long imco torsional shafts, angling the motors and running it that way (like a Imco), it seems to be the popular way to do it.
I used magnetic angle finders on both the crank button and Stellings flange and aligned motor till they numbers matched but I'm sure your already doing that, good luck, let us know how it turns out, Smitty

Thanks for the info Smitty.I spoke at length with a guy from Stellings. He claimed that 9* was the max and they regularly ran them in the race boats at 8+*. I really don't have much more room to go forward even if i wanted to. We can always lower the box down an inch if it causes a problem. We would prefer not to, but will if we have to.
Luckily this isn't a real high rpm deal. According to Stellings it should be no trouble at all. I guess we'll find out soon enough.Thanks Smitty.
Eddie

If we used the 3" up IMCO box, then we would have to move the engines up 3". the owner doesn't want big scoops. He would rather sacrifice the speed.
Eddie

Nice job Eddie. Thanks for sharing the pics.... Smitty are you an engineer? If not you missed your calling.

How are the Stellings boxes' design different than the Imcos?

how wil the move fwd affect the cg of the boat?

Yeah, Smitty knows his stuff. No doubt he is a very sharp guy.
The Stelllings boxes are adjustable vertically where the IMCO's are not. That is the biggest difference.


I spoke with Mike Fiore quite a bit about the boat. Originallly, he wanted me to shove the engines as far forward as i could and tighten up the drives to about 25" centers. The owner didn't want to give up the access in the front of the engine compartment. We are talking about moving them well over 1' forward. If that was ok to do and not mess up the CG, I can't imagine that 4.5" is going to affect it much. Not to mention, it's a big, heavy boat.
Eddie

Sounds like to me that you have a high-maintenance owner!

Looking good!

Thanks for sharing! Looking good and look forward to hearing some Awesome results!

Great job!

Did you relly paint that with spray paint in a can? Wow I'm impressed

Maybe just little bit!!:lolhit:





QUOTE=TCBoss302;3828468]Sounds like to me that you have a high-maintenance owner!

Looking good![/QUOTE]

Can't wait to see this thing when your done bro. So my engines appeared to have just an inch or 2 in clearance , how are you getting away with no scoops with the monsters your dropping in the bilge?

I assure you that wasn't what Eddie wanted. He pushed me to powder coat them our have them sprayed and I told him to "rattle can" them as they will not be seen. I am surprised you were impressed though........

The merc black rattle can paint looks a million bucks....... Until you touch it with anything, it scratches off real easy. I did an outboard mounting bracket with the stuff, it looked as good as that inner transome plate until I went to fit it!

What are you going to do about extending the input shaft 4" ????

I have Stelling boxes on my AT and the engines are moved forward a foot. My set up uses a rear plate for the mount. Mine uses the normal splined Stelling shaft and that inserts into a splined driveshaft extension.

Yeah, sometimes.:lolhit: But that's ok. The customer gets what they want.


As mentioned, not my first choice. We sanded it with 80 grit to give it some tooth. Then we primed it with an etching primer and painted it with Krylon Fusion. For a rattle can, it's pretty good stuff.

Hey Larry,

We are gaining clearance as we move forward. We're thinking inserts may work now.

The box has a the bearing carrier in it with a female spline on one end to accept the input shaft from the drive and the other side is a 1410 flange. There will be a similar flange on the flywheel. (no Merc coupler). We will have a driveshaft made with a 1410 yoke on each end. It will bolt up to both the flywheel and the bearing carrier.
Eddie

My wife says anymore inches and it would hurt too much.. just sayin..

:bunnydance:

what drives are on this boat?

Lookin good brotha!!!

Cool project.

talking about customize ! that's a real one right here!!!

IMCO SCX's with #6 prop shafts.

Thanks everyone.
Eddie

Aren't we all high maintenance owners????

Eddie, my 1st 37 had Stellings boxes with the set up that you are talking about. I ended up raising the motors an inch along with the inner transom plate in order to run the long driveshaft straight into the Merc rubber coupler. At that time I was running some modified bravos with about 800 hp. The rubber coupler set up seemed to be easier on the drives. Best of luck with this setup and HP. Tape his wallet to the throttles to remind him they are not 6s.

No, not 6's, but are you familiar with SCX's? They're a bit more substantial than the bravo alternatives you probably had at the time. There are a number of SCX's out there running more power than I will be with no problems. Of course, I've just set myself up for a failure now......

I would love to be able to run the long IMCO shaft straight into a rubber coupler, but that would mean raising the engines. We really could use a 3" up box, but that would require pretty large scoops. Not sure if you know or not, but these are carbed Whipples. Since they have a carb on top, they are pretty tall. The owner just doesn't want large scoops taking up the sun pad. Can't say I blame him for that. However, that means we have to sacrifice in other areas. I know it's going to cost us a few mph by not being as high as we need to be, but that's ok. It should still be plenty fast.

These SCX drives have been holding up exceptionally well with some power in front of them. It's still not a #6, but it's certianly not a Bravo 1 either. It should hold up just fine with the power.

Hope you and wife are doing well Gary. Talk soon.
Eddie