Newbie .21 conversion help needed

[chadds]

Hi, I recently ordered a Cyber-Maxx chassis, and I'm still waiting for it to arrive. I WAS going to use the stock TRX 2.5 in the Cyber-Maxx for awhile, but after another day of tuning problems, and another melted spur gear...I've decided to spend the money and get the .21 now!

First of all...what type of .21 do I need??? I'm looking at the XTM 24.7 and the O.S. engines. I want a reliable, easy to tune engine...what engine is the better choice if these are my main concerns, an O.S. or the XTM?

Next...what kind of shaft do I need? I see the XTM 24.7 is offered with a threaded shaft, or an SG shaft. I'm not even sure what O.S engine I should be looking at, the RG-X looks decent, and it has a Pilot shaft. Do all of these shafts need to be shortened, or is there some that can be used as is?

I think I'll be OK on the mechanical end of it...but I want to make sure I get the right engine, with the right shaft.

Next...what header and tuned pipe do I need for these engines?

What other accessories do I need to complete the conversion, do the conversions use the stock clutch bell, or do I need something else?

If someone could be so kind as to link to the parts I need on either Tower Hobbies, or Stormer Hobbies, I would be VERY greatful. There is nothing more frustrating than ordering the wrong parts, or realizing you don't have everything you need.

Thanks A LOT!

Chad

 

[SkyMaxx]

Can't help you with the conversion business...but I will address the spur gear issue. Most likely your mesh is off, and thus setting your spur gear up for failure. Going to a bigger engine without researching proper mesh and tranny set-ups could let you in for some more disappointment.

I'll let those with .21 conversions talk you through the tranny upgrades, and I'll use this quote from a previous thread to answer the mesh question:

"From another SkyMaxx post"

Setting gear mesh is very important to the longevity of both gears and the components driving and being driven by the gears.

Here's how to do the mesh check.
1. Loosen the screws that hold the motor mounts to the chassis plate (don't take them all the way out).

2. Make sure you have both spur gear and clutch gear on properly (since you've mounted the spur and the clutch is attached to the motor, you probably have little to worry about here).

3. Take the plastic bag that the spur gear came in (a ziploc bag will work just as well) and place one thickness of the plastic between the two gears.

4. Push the motor back into place so that the two gear compress on the plastic.

5. Tighten the motor mount screws (making sure that the motor mounts are as square to the chassis as possible...you want the gears to have as even a surface to surface contact as possible).

6. Pull the bag out. The gears should rotate freely and mesh together just right.

Hope this helps...

 

[chadds]

Thanks for the tips SkyMaxx, but that wasn't the problem with this spur. This one was my fault...I'm using a Robinson Racing setup, and didn't loctite the screws on the spur, and one of them backed out on me, and the spur got wobbly.

The tuning issues on the 2.5 is my biggest gripe though, I'm ready for a .21! :devious:

I still need some help though guys! Please give me some tips if you have done this conversion. Thanks

Chad

 

[alkyula]

i have ran both the OS .21 rg-x and the xtm 24.7 mills in my .21 conversion. i did not have to cut the crankshaft on either of the mills, which were both pilot shaft style cranks. the OS .21 rg-x is a great motor to run in your cybermaxx conversion. it is easy to break in, very easy to tune, and will hold a tune forever (i think I've only moved the needles 3-4 times in about 2 gallons..now thats holding a tune!!) and are supsoed to last 5-6 gallons with correct mantinence. as for power, i can honestly say it has about as much as you need, had the ability to pull wheelies with my 10lb 5oz t-maxx (stock maxx is 9lb 5oz) pretty easily with 20/72 gearing. and definatly has more power than the trx 2.5 all over the powerband. as forthe XTM 24.7, it has enough power to tear up every component in your drivetrain, and will flip the truck over in a pissed off matter when traction is there, and have your truck going full speed in about 2 seconds. the xtm I'm my experience was also very easy to break in, holds a tune very well, i will go as far as to say almost as well as the OS, and runs very cool, about 200-215 while making awesome power. (make sure if you choose them xtm that is the newer one with the big cooling head) IMO id would go with the OS unless you want to spend alot more money on drivetrain components, which the XTM will shred before you finish one tank of gas. the OS will still have ALOT of power, but for me has been alot easier on the drivetrain. (was able to run with all stock tranny/diffs/xtm cvd's no problem) so in all its up too you, but you can't go wrong with either mill, jsut that the xtm will cost more in the long run for upgrades. peace--

 

[chadds]

Thanks a lot alkyula! I think I will go with the OS, the XTM sounds fun...but I like the idea of not having to immediately upgrade the drive line.

Can you tell me what type of header, and pipe I should choose for the O.S.?

Also, will I use the stock flywheel on the O.S., or do I need to purchase a different one? Thanks!

Chad

 

[alkyula]

i have always used the pipe and header that came with the xtm conversion kit, as it seems to work well and has a nice sound i never had need to try another. but i have heard good things about this header/pipe combo

http://www2.towerhobbies.com/cgi-bin/wti0001p?&I=LXCPX0&P=7

and with the OS rg-x you will need this

http://www2.towerhobbies.com/cgi-bin/wti0001p?&I=LXU639&P=7

you may need to shave some of the aluminum off the header for it to fit with the rg-x, as the os's pull start is very big and has some clearance issues, this is no big deal very easy to do.

you can use the stock t-maxx flywheel. but you will need some of these

http://www2.towerhobbies.com/cgi-bin/wti0001p?&I=LXNT03&P=7

shims to put behind the flywheel for the bell to line up properly. although i think rc-solutions has a special made collar for the conversion, give a call and find out. hope this helps, once you finish this project you wont regret going big-block. peace--

 

[olds97_lss]

I agree with alkyula to use the O.S. 21 RG-X(P). It has all the power you need, but doesn't put an excessive amount of strain on your drivetrain.

I bought the XTM 21 conversion. It has worked out for me for the most part.

I have also replaced every gear i could in the trans with steel RRP gears as well as the spur gear. I don't know how long they will last as i only just put them in about a half gallon ago.

 

[MaxxMan-X]

You'll be Very impressed with the O.S. motor. I've been running it for just under 5 gallons and still going VERY strong. It holds a tune VERY well and NEVER overheats no matter what. I'm still running the stock tranny but I don't do much jumping. The diffs need a little work now and then (I have a rear spool) but the rrp gears last around 4+ gallons.:LoL:

I like this smilie:w00t: LOL