BL Xray M18!!! - RC-Monster Forums

lutach · **BL Xray M18!!! -** 09.22.2007, 08:05 PM

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.

09.22.2007, 10:32 PM

let me guess, is swerves to the right?

lutach · 09.22.2007, 10:40 PM

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

VintageMA · 09.22.2007, 11:37 PM

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.

lincpimp · 09.23.2007, 01:17 AM

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!

lutach · 09.23.2007, 09:23 AM

Quote:

Originally Posted by lincpimp

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.

tashpop · 09.23.2007, 12:52 PM

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.

lutach · 09.23.2007, 01:52 PM

Quote:

Originally Posted by tashpop

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.

lutach · 09.23.2007, 01:53 PM

More pictures.

lutach · 09.23.2007, 01:55 PM

Instructions pictures.

lutach · 09.23.2007, 01:56 PM

Some more LOL.

lutach · 09.23.2007, 02:42 PM

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

lincpimp · 09.23.2007, 03:01 PM

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.

lincpimp · 09.23.2007, 04:36 PM

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

lutach · 09.23.2007, 05:21 PM

Quote:

Originally Posted by lincpimp

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.