Engine Swap / Conversion HELP NEEDED!
#1
Thread Starter
Tech Rookie
Joined: Dec 2012
Posts: 16
From: Illinois
Well I Have 3x Revo's And I Decided To Buy A .40 Airplane Engine Instead Of A Traxxas 3.3. For The One I Blew. There's A Huge Price Difference (saving about 80.00) And Getting Bigger Engine!
Well Now I Am Going To Have To Find A Way To Make A .40 Airplane Engine Fit Where A .20 Was.
Has Anyone Ever Done This Before? What All Might I Need. I Just Bought The Engine On Ebay Today So I Haven't Seen What All I Am Going To Run Into. Just Looking For Some Heads Up.
Thank You All In Advance.
If All Works Out Well I'll Post Some Pics And Videos Online So Yall Can See!
Well Now I Am Going To Have To Find A Way To Make A .40 Airplane Engine Fit Where A .20 Was.
Has Anyone Ever Done This Before? What All Might I Need. I Just Bought The Engine On Ebay Today So I Haven't Seen What All I Am Going To Run Into. Just Looking For Some Heads Up.
Thank You All In Advance.
If All Works Out Well I'll Post Some Pics And Videos Online So Yall Can See!
#2
It's going to be hard to find a clutch that will work. Just look at the cranks on the two engines.
Maybe you can get some ideas on this forum.
http://www.rctech.net/forum/offroad-...velopment.html
Maybe you can get some ideas on this forum.
http://www.rctech.net/forum/offroad-...velopment.html
#4
Thread Starter
Tech Rookie
Joined: Dec 2012
Posts: 16
From: Illinois
They Do But I Am Wanting Something Different. I Like The 3.3 But Want To Try Something Else. And Besides I Got The O.S. .40 LA Brand New For 59.99 + S/H
#5
you'll probably be disappointed. You'll have to change your gearing cause i dont't think that engine can run the rpm's not to mention, trying to keep it cool. You have a big task in front of you. good luck...
#8
Thread Starter
Tech Rookie
Joined: Dec 2012
Posts: 16
From: Illinois
I Think I Am Just Hard Headed. And I Like A Challenge. When Someone Says It Can't Be Done I Try To Make A Way. I Just Think It Would Be Neat. Mabe Not The Fastest But Tons Of Raw Power. The Engine Should Come In Soon So I Can See What I Am Up Against. Kinda Like Putting A Semi Motor In A Geo! I Do Have Lots Of Metalworking, Machining, And, Engine Experience So I Can Only Hope. Oh Well FUN TIMES AHEAD!
#9
Joined: Apr 2009
Posts: 2,049
From: Long Island, NY
When you get the engine see if the Trx flywheel nut will thread onto the OS crank. If it does Then you can get a Trx Pro .15 flywheel nut/clutch shaft that the clutch bell bearings can ride on. You'd also have to make sure the flywheel collet fit the OS crank properly without play. If that all checks out the Trx Revo clutch can go on the OS crank with the OS flywheel, but you'd likely have to cut the crank down a bit.
Mounting will be another story. The OS will end up longer and wider than the Trx. Depending on how everything lines up some simple spacer/adapter may be able to be used with the stock mount. Picture bolting 4mm thick strips to the stock mount, having them extend to the rear to the OS mounting pads where nuts and bolts could be used. Another option that might make things easier is a Big Block Conversion Kit from Traxxas or another source.
The real hard part will be a starting system since the OS has no provisions for any. The clutch and flywheel will be in the same location longitudinally. But without a custom mount the engine and flywheel will be higher in the chassis which may prevent the use of a starter box. You may have to use an electric motor with a wheel attached and hold it to the flywheel by hand to start it.
Cooling could be an issue, a small electric motor with a fan blowing on the engine would be a good idea. Some have made custom flywheels with a belt groove to drive a small fan with an O-ring used as a belt. Search YouTube for different 4stroke conversions to get ideas for clutch and cooling solutions. Keep us posted!
Mounting will be another story. The OS will end up longer and wider than the Trx. Depending on how everything lines up some simple spacer/adapter may be able to be used with the stock mount. Picture bolting 4mm thick strips to the stock mount, having them extend to the rear to the OS mounting pads where nuts and bolts could be used. Another option that might make things easier is a Big Block Conversion Kit from Traxxas or another source.
The real hard part will be a starting system since the OS has no provisions for any. The clutch and flywheel will be in the same location longitudinally. But without a custom mount the engine and flywheel will be higher in the chassis which may prevent the use of a starter box. You may have to use an electric motor with a wheel attached and hold it to the flywheel by hand to start it.
Cooling could be an issue, a small electric motor with a fan blowing on the engine would be a good idea. Some have made custom flywheels with a belt groove to drive a small fan with an O-ring used as a belt. Search YouTube for different 4stroke conversions to get ideas for clutch and cooling solutions. Keep us posted!
Last edited by Overdriven; 02-16-2013 at 06:46 AM.
#11
Tech Initiate
iTrader: (1)
Joined: Jan 2011
Posts: 28
Firstly LA 40 is a very low spec engine ,about 10,000 with prop
It uses bushing instead of bearings ,
Secondly the carb does not have LSN. Transition will be really rich .
Thirdly the cooling fins need to be enlarge.
If you want to make it work at least go for a heli engine eg; o.s. sx50
sz 50.good carb, much higher rpm and hp ,comes with enlarge cooling
fins. Just my 2 cents worth !
It uses bushing instead of bearings ,
Secondly the carb does not have LSN. Transition will be really rich .
Thirdly the cooling fins need to be enlarge.
If you want to make it work at least go for a heli engine eg; o.s. sx50
sz 50.good carb, much higher rpm and hp ,comes with enlarge cooling
fins. Just my 2 cents worth !





