IMCO SCX Upgrade
 

Eddie Young built us an 800HP motor a few years back and we can't keep seem to keep a Bravo style drive alive for very long. Decided to go with IMCO SCX upper and SC lower. Eddie is installing the new drive now. Christmas came early this year. Here are a few pics from the week. Enjoy!

A few more...

Nice. Where do you boat?

Nice set up. I did the same set up on my 42 Fountain PR. I was pushing a little over 800hp and kept getting metal shavings from the lower (from the oil plug). Never broke the SC lower but I didn't take the chance and went to the SCX lower. Slowed me down...but never an issue again.

Good luck! SCX the way to go!

The boat lives on a trailer so we're mobile. Clinton Lake, LOTO, Lake Michigan (a few times), Lake Cumberland (annual family trip).

Nice!

You will love it!

Yes we're looking forward to it! Always worried about your drive makes you a passive driver. We went through 2 uppers and a lower in less than 2 seasons, not fun.

Now you have me thinking about the SCX lower, we'll see how the SC lower holds up.

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Very Good choice!!! I Pound mine. this is 3rd summer and NO problems! Before 2 to 4 XR rebuilds a year

For the price of a lower, buy another and keep it in your truck.

Sweet, thanks for the info!

Yes an option but if the lower is creating excessive debris won't that effect the life expectancy of the upper?

Other way around is not good but if your lower grenades it does not typically make it to the upper...I know mine didnt

Did you use the existing bravo transom assembly? I was just curious if this was a bolt on type of upgrade.

From what I understand the IMCO needs the merc HP assembly.

What makes the IMCO better than the bravo? Better design? Bigger/stronger components? Is there a loss or a gain in HP?

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All of the above you mentioned. There will be more parasitic drag.

Good to know.

I did lose some top end- but Reliability wins in My book. How much top end do you lose when the biioootch is sitting on the trailer b/c XR failure??

I'm not doing the work but Eddie explained to me we could use the existing Std. Bravo Transom assembly with some mods to it. The mods are drilling and tapping some new studs and replacing the gimbal ring w/ a HP ring. If I'm butchering the explanation someone please step in. He also mentioned he's upgraded the "Magnum" transom assembly as well and that was a little different but I wasn't paying attention since I didn't have one. I just learned all of this yesterday and I'm in no way an expert on marine engine and/or drive setup, hence why I'm having Eddie do the work.

Nice upgrade, Rob. Hey, don't be such a stranger. Give us a shout out if you are around town.

Only the IMCO SC upper uses the B1 gimbal. The SCX needs a different gimbal from what I have read. My SC Upper bolted right up to my B1 gimbal.

**Edit... I was not up to date on this thread. Looks like the B1 gimbal can be modded to fit the SCX. Cool to know. The guy I bought it from had the IMCO gimbals.

I heard that. I am always thinking the the back of my head since I have a single and still run the XR upper gear train in my IMCO SC upper I may have to get a tow. AND I don't have good cell coverage on a lot of the lake we have a house on. I have a handheld baofeng VHF radio though fortunately that I can get a tow from a couple of the marinas on the lake. If I had the money, I would be running an SCX upper with the -3 SC lower I have now and also be making about 150 more HP. I would love to wake my boat up like that sometime.

Will do!

The SCX requires changing the helmet (or bell housing as some call it). That is the part that the drive actually bolts to. In Rob's case, we also had to change the gimbal ring. Mercury has 3 different gimbals. They have the HP, Magnum, and standard. The HP uses SS pins to retain the helmet and has a thicker gimbal ring for increased power. It is used on the "blue" engines and most diesels. The magnum is basically a hybrid. It uses the HP ring but not the SS pins to retain the helmet. The standard gimbal uses a smaller ring and has 2 bolts that thread into the helmet to attach it. With the HP and the magnum, you don't have to change the ring to install the SCX helmet. However, the magnum has to have the ring drilled and tapped to attach the SS pins since it is setup for the 2 helmet bolts. The standard gimbal requires changing the helmet and the gimbal ring. This is what we did in Rob's case, since he had the standard gimbal. Even though we had to change the ring, it was a great idea to change it anyway. That ring is not recommended with that kind of power.

I've attached a few pics to try to explain it better.

The first pic is the threaded bolt used to retain the helmet in the standard and Magnum transom assemblies.

The second pic is the SS pin used to retain the helmet in the HP transom assembly

Next is a pic showing the difference in the Mercury helmet and the SCX helmet

This shows the holes that we drilled and tapped in the gimbal ring to accept the SS pins. You can also see the original 2 holes that were used to attach the trim sender. The HP gimbal doesn't have a provision to use the electric trim sender (at least not a direct bolt on), since most guys running an HP gimbal have a mechanical indicator.

Does anyone else worry about the upper pin in the transom assembly?

All of it :drink:

We have swapped out the upper pin for IMCO's pin on a few. We always check the gimble ring for play. In all the ones that I've seen that have some play, it's the ring itself that is worn out, not the pin. I've never seen a pin break before the ring. That's not to say it can't happen. Anything can and does happen.
Eddie

Thanks Eddie for taking the time to explain the process..... for those of us that haven't had to work on our transom assembly's but are always thinking about them. :eureka:

My pleasure. Don't hesitate to call if we can help you in any way, even if it's just to answer some questions you may have.
Eddie

Eddie, So that's a magnum ring you drilled and tapped? So the center hole is not threaded on a magnum like a standard? And the 4 stainless screws create a stronger fit that than the bigger bolt. So its a pin a 8 screws that hold the helmet to the ring?

Thank you for posting this information.

Joel

Actually, it's the helmet that is threaded. The head of the bolt just sits in the hole in the gimble ring to center it. In the case of the SS pin, the hole in the helmet is larger and is not threaded. The (4) 1/4" bolts just hold the pin from falling out.

In this case, we drilled and tapped a standard gimble ring. The Magnum transom assembly has the larger HP gimble ring. It would need to be drilled and tapped as well since it uses the bolt instead of the pin so that an electric trim sender can be used. The head of the bolt in what drives the electric trim sender.
Eddie

Thank you!

Does IMCO recommend replacing the helmet AND the gimble ring or just the helmet?

I just put scx uppers and all new imco gimbles on my tiger, the imco gimbles are a little beefier in all the right places than the merc hps. They shift like a dream and i have that piece of mind now.

You must replace the helmet in order to even mount the SCX. The ring is just for added piece of mind. As OSD mentioned, the IMCO ring is beefier and therefore stronger. Once you start putting a heavy drive that can handle the power, a bunch of HP, faster speeds, etc. the ring will be the failure point. If that ring fails while running hard, or running hard through a corner, you will be in for a BAD day. I have seen boats hook and roll after a gimble ring breaks.
Eddie

Correct, you also have an option of a stainless gimble ring. being as the scx is heavier, it doesn't make sense to hang a bigger heavier drive on a ring that's not designed for it. in the big picture, the ring will be the least expensive part of the equation, especially if the other one breaks. I did mine all at once because I didnt want 75k in upgrades to my boat to wind up on the bottom because i tried to save a little money.

Money well spent.