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Parts Wanted WTB Rotax 447 B gearbox (2.58/1) UL engine

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MACOWA

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Apr 19, 2021
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Hello, Richard. I bought a new B-box @ 2.58/1 and installed the internals in a PROV 4 case to fit my hot rod 503. The PROV 4 box was a zero hours rebuild by Bill Larson A&P at OAD, which leaves me with a set of fresh internals (new 12 spring clutch} and a brand new PROV 8 case. these could be assembled and shipped. perfect for a 447.
 

Richard MacCrone

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Feb 8, 2020
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45
Hello, Richard. I bought a new B-box @ 2.58/1 and installed the internals in a PROV 4 case to fit my hot rod 503. The PROV 4 box was a zero hours rebuild by Bill Larson A&P at OAD, which leaves me with a set of fresh internals (new 12 spring clutch} and a brand new PROV 8 case. these could be assembled and shipped. perfect for a 447.
I appreciate the offer but it seems like 447 engines are rare and expensive!!! If I can't get the 447+gearbox for a reasonable price I may try a different route (Polini Thor looks interesting). I have a ways to go yet so I'll keep this in mind. Thanks for your reply.
 

MACOWA

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I appreciate the offer but it seems like 447 engines are rare and expensive!!! If I can't get the 447+gearbox for a reasonable price I may try a different route (Polini Thor looks interesting). I have a ways to go yet so I'll keep this in mind. Thanks for your reply.
 

MACOWA

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Hello, Richard. I get the impression that you are planning your first build. I have been flying 103 for almost 2 decades, my present build will be my third. Please understand that you are looking at a massive undertaking that will tolerate no compromise. (It's your butt in that seat !) Many have started only to end up with with an empty bank account and a broken heart. Find your local EAA chapter on the net and attend ! It will amaze you. Do not become discouraged, if you have what it takes you WILL succeed.
 

Richard MacCrone

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Feb 8, 2020
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Not really. I rebuilt a Baby Great lakes about 25 years ago and built 90% of an Airbike which I sold to another member on this board. I do like to have most major materials and systems on hand from the beginning. I am building the Kolb Ultrastar from scratch though, and would like to settle on my choice of engine before I get to far along. I got my Pvt in 1969 and A&P in 1979 so I understand the ramifications of compromise. All sage advice though and I appreciate you sharing it with me. My big obstacle is time! I'm hoping I have enough of it!!
 

MACOWA

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Apr 19, 2021
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Hello, Richard. Boy ! Is my face ever red ! We have probably both seen a few good folks disillusioned. I understand about the time. I am hoping to cruise through my remaining 70's with enough to complete a scratch built Ruckus clone. It's taken a while to gather up the major components, the last being a proper boom tube. Best of luck and thank you for being such a good sport.
 

Armilite

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Sep 5, 2011
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Location
AMES, IA USA
A 447UL is a Skidoo 440F only with Dual Ignition. 1993+ 380F/440F's/503F's has a Provision 8 case for the Gear or Belt Drives. A 440F is a 380F Big Bored. So both use the same lower ends. A 380HO with 11.2cr, a pair of 30mm Carbs with a Good Tuned pipe can make approximately [email protected], and a 440F can make about [email protected]
 

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Richard MacCrone

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Feb 8, 2020
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A 447UL is a Skidoo 440F only with Dual Ignition. 1993+ 380F/440F's/503F's has a Provision 8 case for the Gear or Belt Drives. A 440F is a 380F Big Bored. So both use the same lower ends. A 380HO with 11.2cr, a pair of 30mm Carbs with a Good Tuned pipe can make approximately [email protected], and a 440F can make about [email protected]
Wow, GREAT information!!!! I did not know this and appreciate you sharing it with us!
 

n3puppy

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Jun 25, 2019
Messages
257
Wow, GREAT information!!!! I did not know this and appreciate you sharing it with us!
I know this is drifting from your original wanted to buy post.
But before you jump on the 380/440 high horsepower bandwagon some things you should know.

The highest power PRODUCTION 380HO was only about 48hp @ 7100 rpm, so maybe 43ish at 6500rpm. The 380HO was limited production sold to sno-cross racers only. Was not sold to general public because of potential reliability issues.

The 380/447 bottom end was never used in production engines over 50hp. The "Big Block" 503 held that spot, again for reliability (warranty) reasons. Even then, the 503 had to have some mods to handle 50hp.

To the best of my knowledge - Nobody has flown a 53hp 380 or 62hp 447 so you will be the true definition of "Test Pilot" if you decide to make modifications over the standard 35 - 40hp they made from the factory.

72A3D585-AD07-419D-9374-74847CC036F8.jpeg
 

Armilite

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AMES, IA USA
I know this is drifting from your original wanted to buy post.
But before you jump on the 380/440 high horsepower bandwagon some things you should know.

The highest power PRODUCTION 380HO was only about 48hp @ 7100 rpm, so maybe 43ish at 6500rpm. The 380HO was limited production sold to sno-cross racers only. Was not sold to general public because of potential reliability issues.

The 380/447 bottom end was never used in production engines over 50hp. The "Big Block" 503 held that spot, again for reliability (warranty) reasons. Even then, the 503 had to have some mods to handle 50hp.

To the best of my knowledge - Nobody has flown a 53hp 380 or 62hp 447 so you will be the true definition of "Test Pilot" if you decide to make modifications over the standard 35 - 40hp they made from the factory.

View attachment 113583
============================

N3, I call Bull ****! You and most of the USA/Candian Skidoo Hardcore Snowmobile and Ultralight People never even heard about a 380HO till I brought it up years ago. There are about 8 Billion people on this Earth and you have No fricking idea what they are using on their Planes around the World! The 380HO's were Sold in Alaska, Norway, Sweden, and other foreign Countries to the General Public!

It was rated Stock at 36kw at 7000rpm not 7100rpm. 36kw = 48.2768 hp! The Stock 380HO at 6500rpm = 44.5hp!

As the 380HO Dyno Sheet shows with an Aftermarket Tuned Pipe it made [email protected], and on that same Dyno Sheet, you can see it was making around [email protected] 368.4cc/7cc = [email protected]

The 503UL with R&D Aero's Tuned Pipe made 62.3hp a +12.3hp over the Stock 503UL Rotax Exhaust. The 503UL (72mm x 61mm) 496.9cc.

496.9cc/50hp = 9.938cc to make 1hp using a Megaphone Header/Muffler Exhaust!

496.9cc/62.3hp = 7.9759cc to make 1hp!

496.9cc/7cc= [email protected] is what it's capable of making with 11.5cr and proper Size Carbs with a Good Tuned Pipe Exhaust. Many People flew with R&D Aeros Tuned Pipes, some were great and some not so great.

Simonini Victor 1 Super [email protected] using 9.5cr with a 36mm Carb. 401.5cc/54hp = 7.4351cc to make 1hp!

Stock Skidoo 670 using 11.5cr is 669.2cc/[email protected] = 5.7839cc to make 1hp.

Stock Skidoo 583 using 11.5cr is 580.9cc/[email protected] = 5.9886cc to make 1hp!
 

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n3puppy

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Jun 25, 2019
Messages
257
Richard MacCrone- Sorry to thread drift your want ad one more time.
But as you can see from the previous post -
1) Nobody knew about the 380HO in the largest snowmobile markets - limited sales.
2) Apparently still no evidence of a Flying stock 380HO or 53hp 380 or 62hp 447
3) The 380/447 can make higher HP - unknown reliability in aircraft use over 50hp
4) 447 with R&D Aero pipe was about 46hp - under the 50hp of the 503 big block
5) The Simoni, and Ski-Doo 583/670 engines are liquid cooled to handle the additional heat of the extra hp per CC

Hope you find the 447 you are looking for. Great engine "As Is"
 
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Armilite

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Sep 5, 2011
Messages
3,613
Location
AMES, IA USA
Just Wow, just why would anyone come on this site anymore to be pounced on by You and your two other Amigos, one of which has mentioned he has never worked on a Rotax 2 Stroke but always has an opinion, who you three never really offers anything Constructive in 99% of the Threads you jump into, or offer anything new on the Market. You Jump into these threads to make Snide Remarks and to start arguments, but never offer anything of much Value. You just got done Posting False info on the 380HO.

Most People are intimidated enough on here to not trying to rebuild their own Engine, let alone make their own Tuned Pipe, or do any of these Engine Coatings or to Port their own Engines, etc. It's a FACT, that R&D Aero made some Tuned Pipes for Rotax's UL Engines in the 90's and it's a FACT, they also Dynoed some of the same Engines and Posted them on their website. It's a FACT, a 503UL 50hp made 62.3hp a +12.3hp Increase used at the same Factory rpm! 50hp +24.6% = 62.3hp! Which +24.6% is a very mild Tuned Pipe. 496.9cc/62.3hp= 7.9759cc to make 1hp. You can use a Percentage like Max 40% for Airplane use, so for 35hp + 40% = 49hp using 9.6cr, 40hp + 40% = 56hp using 9.6cr, so for a 50hp +40% = 70hp using 10.8cr, or you can use the Simple 7cc Rule of Thumb and using 11.5cr with the proper Size of Carb. 496.9cc/7cc = 70.9hp. But I'm sure you want to argue over the .9hp variance. Some of them Engines have lower than the stated 11.5cr and too Small of Carb for the 7cc Rule of Thumb. It's also a FACT the 277UL rated [email protected] actually Dynoed Max [email protected] and with their Tuned Pipe it Dynoed [email protected] a +5.1hp. 25.4hp + 20.1% = 30.5hp. So was also a very mild Tuned Pipe.

You and your (2) Amigos don't seem to have any problems with a Polini 250 turning 8000rpm to make 36hp. But then again you don't have many people on here even using them on Planes here in the USA/Canada, just on Trikes and mainly used overseas!

Kawasaki 440 436cc. [email protected], [email protected] uses lower than 11.5cr.
 

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n3puppy

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Jun 25, 2019
Messages
257
Richard MacCrone - As you can see, lots of passion concerning the wisdom of modifying Aircraft two strokes for more power than the factory felt was reliable.
Just to clear up a few facts -
1) 380HO sold to Sno-cross racers in Europe was 35.5kw (47.6hp) @ 7150 rpm.
2) At 6500rpm the 380HO would be only about 43hp.
3) The 447 R&D pipe generated 46hp. (15% increase)
4) Thousands of 447s have been reliably flown at 40hp.
All those numbers are less than 50hp of the Big Block 503

Not knowing your application - you may decide that the 447 you are looking for needs to be modified for more hp than the flight proven 46hp from the D&D Aero pipe. Or the reliable 50hp of the big block 503

If so, I would seek out someone who has actually ported, piped, raised the compression etc of the 447. Be sure that same person has also flight tested the modified engine. Or at least swung a prop in ground testing to see if it can survive 2 hours or so in flight.

Not trying to be dramatic, but your life literally depends on the reliability of the engine after modifying to high HP numbers the factory avoided for many reasons.

A3DF6267-A655-4767-9B8E-4CF3A936A833.jpeg
 
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Richard MacCrone

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Feb 8, 2020
Messages
45
Folks, I enjoy hearing about technology that "pushes" the boundaries, doesn't mean I want to do the same. I do find it interesting that a 447 will produce that much power!!! In an aviation use I'd prefer the de-rated power output of a stock engine for longevity. I feel badly that you folks are angry with each other and hope you can meet on common ground.

That being said I'm still looking for a low time 447 with a B gearbox a reasonable distance from NW Florida.
 
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