BL Xray M18!!!
 

Hi all,

I'm having a little trouble with my M18's ball diff. I can't seem to set it to the right spot. I have a front one-way, Mamba 8K motor. The problem is when I apply some throttle it spins or swerves to one side. I'm trying to get it to work to try my new ESC that just rocks. This little ESC can handle up to 6S lipos or 7S A123 (or equivalent 3.6V cells) and it has an option for it too. This ESC seems to have the same MPU that the CC MM uses, but it has options for different timings. I will also test it with my Mini-LST after I get my ball diffs as I'm tired of buying and fixing my viscous. If anyone can lend a hand on how to set the Xray M18 ball diff, please let me know.

Regards.

let me guess, is swerves to the right?

It was actually swerving to the right at first. I did some adjusting and now it swerves to the left.

I had that problem as well. Don't have the M18 anymore, but if you go to the xray forums they might be able to help you better.

Lutach, what is happening to the viscous diffs? Are you stripping the ring and pinion or the spiders? I fixed the spider issues in mine and good shimming helped the ring and pinion. A lossely set center ball diff, like the mip will help the diffs last lonnger. I had TLT wheels and tires on my mlst and I think that they had a hand in killing my diffs!

The first set I stripped the ring and pinion and I had it shimmed. Now the second set the internal gears seems to be all garbage. The plastic is too soft. I'll try the ball diffs to see how they act. I think I got my M18 dialed again. I tried 6S lipos to see if the ESC could take it and it did. This ESC is just amazing. I might work on a mini to set a speed record.

what esc are you using? i see you hyping it up, but no mention as to what it is. also 7cell a123 wow, thats bigger than your truck.

when i had the issues your having with my 18th, i had to tighten my diffs up. problem is its unloading more power to one side. next problem you'll have is reduced turning ability with tighter diffs, and they seem to strip out quicker when tightened down.

I'm not hyping the ESC. Here are some picture. I might have the diff set up right.

More pictures.

Instructions pictures.

Some more LOL.

Here are some pictures of the MLST I'll be using to test the ESC.

I will do a write up of how to prevent the internal gears from stripping. I had the same problem and cured it easily. The viscous diffs are the best available for the mlst. All of the others I tried were junk. I have a bunch of mlst diff parts, pm if interested, I will let them go cheap as I have no use for them now. Give me a few hours and I will post up a tutorial on the viscous diffs.

Heres a little how-to on the viscous diffs. The reason the spider gears crap out is because of the o-rings that seal the output shafts. If you take apart the diff you will notice that the output spider gears are keyed to the diff output by means of a small pin, like how a hex is keyed to an drive shaft. The problem is that the thin steel washer that backs the pin is directly on top of the o-ring that seals the fluid in the diff. When the diff spins fast the thin washer is pressed on by the pin. The washer is too thin to stop the pin bending it, and when it folds up it cuts the o ring and lets the output shaft disengage the pin from the output spider gear. My fix was to remove the o-ring and repalce it with steel washers, this also allowed me to shim the spider gears so that they would mesh correctly. Of course this required the use of grease instead of silicone fluid since the diffs were no longer sealed. The washers I used were rc18t wheel washers, linked below. I used 2 per side of the diff to replace the o-rings and it set the mesh tight, but after about 5mins the gears wore in together and I never had a problem again. I used tamiya ceramic grease to lube it up.

http://www2.towerhobbies.com/cgi-bin...?&I=LXJHR8&P=7

That is exactly what I did to mine. I did buy ball diffs and I will install them as soon as they come in. I went through 2 sets of viscous and a few sets of that weak side gear all shimmed and greased. I'll let you know how the ball diffs are compared to the viscous.

Good luck, I wil stand by my reasoning that the mlst is junk, it is fine with the stock motors, but just can't handle brushless power. I sold mine for about a 1/4 of what i had in it cause I was just sick of fixing it. Loved the way the truck handled and looked, just had a crappy drivetrain.

I should have went to one18th.com to see all the complaints before I bought it. I also like the way the truck handles and looks. I will try the ball diffs and if that doesn't work, I'll put it in my basement until something good comes out.

The composiste STOCK balldifs for the M18T is bulletproof if you take care ofthem, neer ever stripped out a diff like that, after 6 Xray cars, and only thoose diff+ org CVDs...Glue the "D" rings on he plastic outputs. shimm it well, not to tight,not to loose..then ya go!

Not try to step on anyones toes, but the stock 18t diffs will not stand up to high rpm use. If the truck lets one tire go and thre diff heats up, the stock plastic will melt. I found installing the steel diff outdrives cured this problem, as stell does not melt easily

They handled my 8000x11.1 and 14.8x8000. :) Havnt melted my diffs yet, but you are right about it, they will propably melt, but havnt that kind of problem. :)

Geeeze - I'm only running 2S with my LMT 1015 (6667kv) in my M18T with either a 12 or 14t pinion (not sure which right now) and it is screaming. I've been wanting to put my 3S TP 1320mAh pack in there, but I am scared.

BTW - a 8000kv motor with 4S would spin at 118,400 rpm. Castle rates them up to 80k rpm. I don't think you would even max out the speed on that without the motor literally destroying itself from the centripital forces on the internal magnets.

also - taking a closer look at those pics lutach it looks like those are 2/3A cells, not A123 - big difference.

I said the ESC has a setting for A123 cells, I never said the cells in my M18 was A123. Look at the pictures, it shows that instruction manual for the ESC. Someone mentioned I was hyping the ESC and I just took a few photos of the manual. I have a few lithium cells that are about the same size as a AA and it is rated for 3.6V. The A123 setting on the ESC makes the cutoff just right for the cells with a 2V minimum. This ESC handles 6S lipos and 7S 3.6V cells.

I got the Mini-LST ball diffs, Solid center spool and GPM pinion today and I'm breaking them in. So far they are better then the viscous. The ESC is working great with the Hyperion motor. I will run it some more to see how the diffs behave.

Hah! LOL - I knew there was something wrong with the way I was reading it.:lol:

I was envisioning a M18 with a brick tied to the top of the car:oh: Doh!

Cool that they are starting to put the A123 cutoffs in the esc's. I have tried them recently and I have to say I am not so impressed compared with a LiPo. The safety factor is there, but I've only had one brand of lipo ever go bad on me and swell (hmmmm.... can we say FDM?), never a problem with Maxamps, TP, Orion/Kokam and I just got my first TrakPower/FlightPower in the mail today. Until the A123 technology matures and the weight and size of the cells shrink in a few years it's just not worth the trade-off for runtime for the cells.

Yep, you are absolutly right about that, they hit 80k rpms...But i have a few shots Argh...at that time it was in my AE RC18T ( so sorry, but 118400 is still no problem,have it on video )

I have air trottle full wit out any problems m8, the issiue is to get the car o all 4 wheels... :), i have ran many packs on 4s lipo, the key is to let the motor to cool down after 5-6 runs (50 m away and then back)

Air trottle 4sLipo/8000
http://s123.photobucket.com/albums/o...t=S5032101.flv

1st test 4slipo 8000rpms/v

http://s123.photobucket.com/albums/o...4sspedruns.flv

4s lipo 8000rpm/

http://s123.photobucket.com/albums/o...ospeedrun2.flv

That last video is great - thx for sharing. Damn that thing is quick - the foams are the only way to go with that much speed!!!

Good luck man, I hope that it works for you. I tried the center spool and grenaded both diffs in two runs. I eventually removed it and tried a MIP ctr ball diff, worked much better that way, and helped keep the wear on the ft and rr diffs down. I tried all of the different pinion gears and none worked as well as the viscous setup.

The ball diffs with the center spool is working great so far. I'm finally having a blast. I just have to do some final adjusting of the ball diffs.

I found the problem with my Mini LST. The diff input shaft is bent and it making the pinion eat the diff ring. It is only in the front tho. I will do some up grading on my Mini LST. I wanted to test the ESC with the 11.1V 1600mAh KongPower battery pack, but that have to wait now.