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Flywheel Differences

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TeamLosiNXT

TeamLosiNXT

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Is there different flywheels for ps and non ps engines? I got a gallon of 20% nitro and a Ofna starter box for 2 bucks at a car parts swap meet. Anway the starter box seems like the wheel is too big for my chassis. Is the starter box wheel supposed to fit into the hole in the chassis or is the flywheel supposed to come down to the hole?

Here are pics of the GTX
TeamLosiGTXFlywheelandchassis.gif

TeamLosiGTXonStarterBox.gif

TeamLosiGTXBottom.gif

Here is the Ofna Starter Box
OfnaStarterBoxTop.gif

OfnaStarterBox.gif
 
Usually engines with pull starts sit higher for clearance on the pull start. This also raises the flywheel. "pro" versions that are bump start only usually have an engine mount that allows the engine to sit lower for the bump box. In some cases manufacturers will have larger diameter flywheels to allow for both a pull start and bump box.
 
My eninge does sit up on a set of risers from the engine mounts on the frame. Ill try taking them off the risers. Thinking in my brain this will make the clutch bell further away from the spur gear. I know that i can move the mounts around. I will try tomorrow and see if lowering the engine helps.
 
In the case of the original RC10GT, the RTR (pullstart) version had a larger diameter/thinner flywheel, coupled with taller engine mounts (for clearance for the pullstart housing).

The Bumpstart version had a smaller diameter yet thicker flywheel, with lower profile engine mounts.

The exhaust headers were also different.

The Losi flywheels may be different, but I'm not sure. You can check the RTR and CR manuals for different part numbers (the XXXNT flywheel should fit your NXT).
 
Yes the XXXNT and NXT/GTX are the same, Ill look and see if there is a different engine mount for PS or NPS. With the lower engine mount was there a difference in the way the bell was to the spur?
 
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The engine has to set a little more rearward (since it meets the spur gear a little lower on the circular plane), otherwise, they should use the exact same chassis mounting holes. You should not have to mod the engine mounts or chassis at all, assuming your current setup is workable.
 
Alright, Ill lower the engine and see if i can get the bell to meet. Ill put some pics and let you know how it goes. Thanks as always.

Ok i took out the spacers and put the engine in, It looks like my starter box should be able to spin it, but the bell is not too far from the spur. I can't get it to meet. If i was to make the holes a little biggen on the engine block i could make it meet.
TeamLosiGTXenginelowered.gif
 
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You could take the mount off of the chassis and use a dremel to lengthen the slots for the mount screws. That would allow it to be brought back.

Either that, or install one or two tooth-larger clutch bell. (I'd go the clutch bell route before the chassis cutting route)
 
I modded the engine block so the engine could spin closer to the spur. Now i just have to get a rotarty carb instead of a slide carb. The way the linkage is on the Losi I can't use the pull carb that came with the engine.
TeamLosiGTXenginemodded.gif
 
Got it to work, Got the box to spin the engine, gears mesh nice, and engine runs. can't believe it. Still need to get the propper carb. Has anyone used a pull carb on a XXX-NT and still had the brake? How does the linkage. With the pull carb to open the carb its the same way as when the brake applies. Thanks again
 
If I remember right, several of the people I used to race with ran slide carbs on their XXX-NT's. The procedure is actually covered in the owners manual for the XXX-NT. You may, however, need a linkage kit, but that part number should be listed in the manual, if you need it.
 
Using some old linkages I had, i was crudly able to make them work. I need to get some propper set or new straight peices so I can bend them to the way I need them. Ill check the owners manual and see how they have it. Here is my "getto" way:
TeamLosiGTXLinkagesetup2.gif

TeamLosiGTXLinkagesetup.gif
 
Your LHS might have what you need. It's a Traxxas part that was needed to convert the .15 with rotary carb to the 2.5 with slide carb. It's a tower with an L shaped bell crank on it.
 
That linkage setup looks fairly close. I cannont remember if the XXXNT brakes require being pushed or pulled by the servo, or if either direction will work.

If they're anything remotely like the RC10GT's, they probably require being pulled to actuate effectively.

Looking at the pictures, is there enough clearance to rotate the carb 180 degrees? I seem to remember the XXXNT trans case as being low-enough profile for that type of setup.

Rotating the carb would allow you to mount both throttle and brake linkages to the same pole on the servo horn, reverse throttle throw, and have a much cleaner setup.

Edit; no, you're spot on with the carb setup above; Page 57 of the XXXNT Sport manual on Rcdocuments.com shows the exact setup (minus the curvy brake link) that you have.
 
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If you're going to redo your linkages I would make a new brake linkage as well. those [2] 90 degree bends are going to be prone to flex during braking, thus stealing torque away from your brake pad. You can make that connection with only 1 bend.. probably about a 35-45 degree angle. Eliminate the bend closest to the servo and take the linkage directly to the area of the second bend. The closer to the spur gear you make the bend, the smaller the angle, and stronger and less prone to flex the linkage will be.
 
Without seeing the transmission from the "driver" side (by the back side of the engine, looking at the back of the spur, with the carb in the picture), I'd _almost_ say the best route is to flip the carb around. Clearance is all it boils out to. If you have enough clearance for the slide to actuate, I'd go that route, since you can run both linkages parallel to each other.
 
The brakes pull on the GTX, ill go down to the hobby store today and see if they have any sorta linkages. This was just for mock up. If I flipped the carb then it would be pushing the slide instead of pulling? The XXXNT is a little differsnt then the GTX, the spur isnt so massive on the XXXNT, so thats why there are 2 90's on the brake linkage to go around the spur, and it was already bent like that so I didnt want to unbend it too much. Rolex I did have one of those Traxxas bell cranks but I can't find anywhere to put it. It came with my .15 to 2.5 conversion for my TMaxx. I also have been watching a rotary carb from an OS engine on ebay so if it doesn't get to expensive then ill try to win it. Then ill just use my orig linkages.
 
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If you don't win it, I've got one. It's just the post and pivot assembly, no screw to hold it to the chassis or linkage. It also has a groove in it. Shouldn't affect the overall operation of it at all.

By flipping the carb around, it'd be "pushed" open, instead of pulling. That would enable you to connect the brake and throttle linkages on the same "arm", next to each other.

I forgot that the XXXNT uses a slightly different internal ratio.
 
I was looking at it more and if i flip the carb around it can't open all the way. The trans comes up to high. Ill have to make linkages look better lol.

Alright I got the XXX-NT likage kit from LHS and think I have it setup better and it def looks alot nicer. Thanks for all the help. As always, can't be done without your help.
TeamLosiGTXlinkagefinal.gif

TeamLosiGTXLinkagefinal2.gif
 
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