XR to SCX conversion

[Boat 405]

Wanted to update a few folks on the swap. Info that some of which I found, some I had to do some digging.

First off the true weight difference of the two drives is 55 lbs. In perspective that is about 8 gallons of fuel or the average sized family dog. So really no big deal.

Full XR drive built from Max Machine with an IMCO SC -2 Lower with +12" driveshaft with all the goodies with oil. 131 lbs.

Full SCX drive from IMCO with dual downshaft -2 lower with +12" driveshaft with oil 186 lbs.

Somewhere I read 80 lbs difference... Not sure how that rumor came about.

You can run a 1 7/16" propshaft on the dual downshaft lower and keep your bravo props. IMCO sells a prop hub adapter to run a bravo style prop on a 1 7/16" shaft. (Had I known this I would have ordered the dual down shaft lower with the larger 1 7/16" shaft over the std 1 1/4" propshaft.

Other must have items, a helmet change, no big deal most people know this. An HP gimbal ring or IMCO's gimbal ring or their complete transom assembly. A larger oil reservoir. The scx drive with dual downshaft lower holds 5 quarts of oil. A complete XR with sc lower holds about 3.

You do not need to use a manual trim gauge when switching to an SCX drive. Teague sells a kit that makes so you can use your existing trim gauge. https://teaguecustommarine.com/em0011/digital-trim-indicator-actuator-kit-imco-scx You'll also need a 0-5 volt to Ohms converter box from Mercruiser. Mercruiser PN 884359T 1. It adapts 0-5 volt output to Ohms so your existing trim gauge works.

 

[EBT531]

Is there a reason you didn't go to the IMCO gimbal ring? I ask because whoever did the swap on my boat did not swap to the IMCO either. I saw the two side by side today and the IMCO is significantly beefier.

 

[Boat 405]

Is there a reason you didn't go to the IMCO gimbal ring? I ask because whoever did the swap on my boat did not swap to the IMCO either. I saw the two side by side today and the IMCO is significantly beefier.

The only reason was because I found an HP gimbal ring brand new old stock last season for a song.

 

[ToMorrow44]

Good info. How much power are you going to be putting thru it?

 

[Blackmagic94]

No wonder they break that isn’t shit for oil

 

[J.P.]

Thanks for posting the differences in the 2 drives. The dual down shaft looks like the real deal.

 

[Boat 405]

Good info. How much power are you going to be putting thru it?

Current power is 852hp and 760 ft/lbs.

 

[woodagain]

View attachment 760652 View attachment 760653 View attachment 760654 Wanted to update a few folks on the swap. Info that some of which I found, some I had to do some digging.

First off the true weight difference of the two drives is 55 lbs. In perspective that is about 8 gallons of fuel or the average sized family dog. So really no big deal.

Full XR drive built from Max Machine with an IMCO SC -2 Lower with +12" driveshaft with all the goodies with oil. 131 lbs.

Full SCX drive from IMCO with dual downshaft -2 lower with +12" driveshaft with oil 186 lbs.

Somewhere I read 80 lbs difference... Not sure how that rumor came about.

You can run a 1 7/16" propshaft on the dual downshaft lower and keep your bravo props. IMCO sells a prop hub adapter to run a bravo style prop on a 1 7/16" shaft. (Had I known this I would have ordered the dual down shaft lower with the larger 1 7/16" shaft over the std 1 1/4" propshaft.

Other must have items, a helmet change, no big deal most people know this. An HP gimbal ring or IMCO's gimbal ring or their complete transom assembly. A larger oil reservoir. The scx drive with dual downshaft lower holds 5 quarts of oil. A complete XR with sc lower holds about 3.

You do not need to use a manual trim gauge when switching to an SCX drive. Teague sells a kit that makes so you can use your existing trim gauge. https://teaguecustommarine.com/em0011/digital-trim-indicator-actuator-kit-imco-scx You'll also need a 0-5 volt to Ohms converter box from Mercruiser. Mercruiser PN 884359T 1. It adapts 0-5 volt output to Ohms so your existing trim gauge works.

I’ve seen your boat at KMG, he really
Did a nice job on it.
What gear ratio and prop are you planning to go with?

 

[Boat 405]

I’ve seen your boat at KMG, he really
Did a nice job on it.
What gear ratio and prop are you planning to go with?

Thanks, I'm really happy the way the cap turned out. Right now I have a 1.5 Gear ratio and a 30P prop.

 

[woodagain]

Thanks, I'm really happy the way the cap turned out. Right now I have a 1.5 Gear ratio and a 30P prop.

Have you ran it yet?

 

[Boat 405]

Not with the new drive. Hopefully this weekend.

 

[hawgty55]

Great info

 

[Boat 405]

Another tip. When you make the change. Always use the factory shift cable. I made the mistake of buying an aftermarket cable and it didn’t want to shift correctly. I put the factory Merc cable in. zero issues.

The new cable is on top. The factory Merc on bottom.

 

[River Dirt 2]

Not with the new drive. Hopefully this weekend.

any updates on how your boat like the DD shaft lower?
working on dialing ours in now.

 

[Boat 405]

Went back to an SCX/SC-2. Boat would not plane. Took forever and about 4000 rpm. Sc 2 planes instantly at 2600 rpm. Also lost 12 mph on the top end.

 

[River Dirt 2]

Went back to an SCX/SC-2. Boat would not plane. Took forever and about 4000 rpm. Sc 2 planes instantly at 2600 rpm. Also lost 12 mph on the top end.

Thanks, that’s what I’m experiencing as well. Was hoping there was a way to make it work...

 

[Boat 405]

I tried 5 different props. Zero change on planing ability.

Right now with the SCX and SC-2. I’m running 109 on GPS with a stock 30 bravo prop at 6300 rpm. Very happy overall.

Thanks, that’s what I’m experiencing as well. Was hoping there was a way to make it work...

 

[River Dirt 2]

I tried 5 different props. Zero change on planing ability.

Right now with the SCX and SC-2. I’m running 109 on GPS with a stock 30 bravo prop at 6300 rpm. Very happy overall.

Yep, tried 5 different props as well, too bad looks like a nice piece, just not the “missing link” we thought.

Did you find a new home for the lower?

 

[Boat 405]

Yep, tried 5 different props as well, too bad looks like a nice piece, just not the “missing link” we thought.

Did you find a new home for the lower?

Yes I did.

 

[Jonas Grumby]

I tried 5 different props. Zero change on planing ability.

Right now with the SCX and SC-2. I’m running 109 on GPS with a stock 30 bravo prop at 6300 rpm. Very happy overall.
[/QUOT

 

[ChrisV]

View attachment 762810

Another tip. When you make the change. Always use the factory shift cable. I made the mistake of buying an aftermarket cable and it didn’t want to shift correctly. I put the factory Merc cable in. zero issues.

The new cable is on top. The factory Merc on bottom.

Do you have to change the shift cable for the conversion?

 

[Boat 405]

No but you do have to cut the nipple off the end of the shift cable where the threads stop.

 

[ChrisV]

No but you do have to cut the nipple off the end of the shift cable where the threads stop.

thank you

 

[OC Daytona]

I tried 5 different props. Zero change on planing ability.

Right now with the SCX and SC-2. I’m running 109 on GPS with a stock 30 bravo prop at 6300 rpm. Very happy overall.

Was a 30 Merc labbed 4 blade one of the props you tried?

My Daytona always gets on plane smoother and faster with Merc labbed 36s and is also a good 8 mph on the top end.
The labbed props work better for me in every RPM range using Imco SC's and Merc -2 Sportmaster lowers

The only reason I put some standard 36's on was I pitched a blade during Covid and couldn't find a new set of labbed 36s

 

[Boat 405]

Was a 30 Merc labbed 4 blade one of the props you tried?

My Daytona always gets on plane smoother and faster with Merc labbed 36s and is also a good 8 mph on the top end.
The labbed props work better for me in every RPM range using Imco SC's and Merc -2 Sportmaster lowers

The only reason I put some standard 36's on was I pitched a blade during Covid and couldn't find a new set of labbed 36s

Yes. Two of them

 

[ChrisV]

Did you have to buy a new drive line shaft or used the one from the XR?

Extended Drive Line

Extended Drive Line

imcomarine.com

 

[WYRD]

I tried 5 different props. Zero change on planing ability.

Right now with the SCX and SC-2. I’m running 109 on GPS with a stock 30 bravo prop at 6300 rpm. Very happy overall.

I have a 600sci and scx/sc switched from a merc 4 blade to the max5....planed much better

 

[I Dig It !]

Sometimes you just gotta try another prop

 

[pkrrvr619]

I have a 600sci and scx/sc switched from a merc 4 blade to the max5....planed much better

How did the top end change?

I have a 25 and run a 32 4 blade and a few people have said to go 32 5 blade.

 

[WYRD]

I don't really know. It's a new boat to us so I have not played around with maxing it out yet. Previous owner and research here indicates the boat did around 87 mph with a Bravo 4 blade 28p. I did have it up to 80 with a little room left but I had the family on board so iwasn't really pushing it or trimmed out. Still getting to know the boat but I will say I was impressed with the max 5 28p.(except the cost)

 

[pkrrvr619]

I don't really know. It's a new boat to us so I have not played around with maxing it out yet. Previous owner and research here indicates the boat did around 87 mph with a Bravo 4 blade 28p. I did have it up to 80 with a little room left but I had the family on board so iwasn't really pushing it or trimmed out. Still getting to know the boat but I will say I was impressed with the max 5 28p.(except the cost)

Besides planing did you notice any other positive effects?

 

[WYRD]

Besides planing did you notice any other positive effects?

It was definitely smoother however the four blade I had was nicked pretty good so I'm sure there was vibration from that. Other than that probably just placebo effect because I spent a lot of money on it.

 

[Rkc]

Is there a specified break in period for the scx? I’ve tried to search but came up empty. Under certain rpm for amount of hours etc? Or is it just install and let her rip

 

[pkrrvr619]

Is there a specified break in period for the scx? I’ve tried to search but came up empty. Under certain rpm for amount of hours etc? Or is it just install and let her rip

Hammer down! Jk I didn’t break mine in for any specific time but I didn’t go out and flog it either for a few trips.

 

[Rkc]

I guess I don’t search as well after beers all night vs clear headed in the morning haha.
Found this through imco if anyone else needs it.