Play in RCM Losi 8ight mount - Page 2 - RC-Monster Forums

DwightSchrute · 05.21.2010, 07:49 AM

i've never heard of anyone having to shim the center diff on a new build, but if it works, it's not gonna cause any harm as long as the conversion was done right.

can you maybe take a close up video of the motor mount, the center diff and the rear drive shaft and demonstrate the issue? i'd like to see exactly where the play is coming from. i have a brand new 2.0 sitting next to me and mine dosen't do that.

as far as the front and rear diffs.....the 2.0 comes with extra diff shims. the 1.0 didn't that i could remember. some drivers like to run a tighter diff setup side to side.

some drivers say it seats things better in the longrun after the diff breakin. every diff is going to shim a little differently. it's really nothing to be concerned about.

also, your drive train sounds new and perfect. like BrianG said, it's absolutely normal.

as far as the 2200, it depends on the track. right now, our points leader is winning every damn race with a 2200 on 4S hyperions geared 48/14.

i run a 2650 on 4S and i'm right there with him, he's just a better driver some days.

some people say the systems tend to run hotter that way and you ought to run a lower kv motor with it, but my temps rarely see anything over about 165-170.

obviously,if you live in nevada, then i would recommend a lower kv motor.... as running a 2650 in 115 degree weather is gonna make it run hotter than 2650 in 80 degree weather, but i've had good results on the 2650 and the 2200.

ptt81 · 05:46 PM

well in that case I will stick with my 2200kv and 48/14 since thats what I already have and it sounds like it is a good setup as well. I'm just a basher, no racing on track so I think 2200Kv is better for me as far as temp goes, I live in TX so its also hot here during summer.

Ok here is a vid showing the play problem. The same problem remain on or off the chassis. This has nothing to do with the front or rear shaft, just the mount and center diff itself.

http://www.youtube.com/watch?v=6biZnoiiH9U

I found that the grove where the bearing goes into is cut a little too deep on the RCM, stock mount does not have any play. May be i got a defective mount? because no one that have RCM mount seems to have the same problem as me.

DwightSchrute · 07:26 PM

Quote:

Originally Posted by ptt81

well in that case I will stick with my 2200kv and 48/14 since thats what I already have and it sounds like it is a good setup as well. I'm just a basher, no racing on track so I think 2200Kv is better for me as far as temp goes, I live in TX so its also hot here during summer.

Ok here is a vid showing the play problem. The same problem remain on or off the chassis. This has nothing to do with the front or rear shaft, just the mount and center diff itself.

http://www.youtube.com/watch?v=6biZnoiiH9U

I found that the grove where the bearing goes into is cut a little too deep on the RCM, stock mount does not have any play. May be i got a defective mount? because no one that have RCM mount seems to have the same problem as me.

EDIT: all of mine have that play in the center diff. no biggie. i've been racing them like that for a year and 2 are brand new.

i'll video it. i misunderstood what you were saying...what you have is normal.

ptt81 · 05.21.2010, 07:37 PM

Quote:

Originally Posted by DwightSchrute

EDIT: all of mine have that play in the center diff. no biggie. i've been racing them like that for a year and 2 are brand new.

i'll video it. i misunderstood what you were saying...what you have is normal.

i guess i'll leave it like that then. but I still think for quality wise, they need to fix it for future customers so at least it is like the original mount and there would be no play at all.

DwightSchrute · 05.21.2010, 07:38 PM

here you go:

http://s247.photobucket.com/albums/g...=fghfgh002.flv

ptt81 · 05.21.2010, 07:51 PM

Quote:

Originally Posted by DwightSchrute

here you go:

http://s247.photobucket.com/albums/g...=fghfgh002.flv

Ok thanks man, i guess i worry too much, i'll finish the build now.

Stoomstrijkijze · 05.22.2010, 04:52 AM

The 2200kv is OK if you are just bashing, but it's too much on the track :( I have the 2200 too and you need to be very smooth with the throttle. I'm going for a Tekin 1900kv buggy motor this summer and maybe the tekin ESC too.
Friends are driving the 2050kv buggy motor and the temperature is ok, but it's more controlable then the castle neu 2200.

Ryu James · 05:48 AM

hey pt881,

you are fine to use that 2200kv motor on 4s in your buggy. it will be perfect. extremely fast and cool temps. i have had 3 losi 8ights and ran all of them on 2200kv on 5s and even tried 2700kv. the 2200kv on 4s is a great setup.

as for the ratcheting noise in the rear...that is "ok" if there is no binding but there is a way to minimize that sound or eliminate it. those shims you used for your center diff are actually able to be used in the rear diff bulkhead also to adjust the gearing mesh of the rear diff and pinion. you can use shims to adjust the mesh just right to eliminate that noise....and get smoother power transfer. but here is the most simple thing to do to eliminate that noise:

it will require you disassemble the car so you can access the rear bulkhead. once you have the rear bulkhead open take out the diff. then remove the rear cvd from the pinion gear. now, put fresh threadlock on your set screw that holds the cvd onto the pinion gear shaft. from inside the bulkhead push on the pinion gear as hard as you can. while doing this put on the cvd and lock down the set screw with the cvd as close to the bearing and bulkhead as possible. make sure there is absolutely no play in the pinion gear to move inward or outward. now put the rear diff back in and try the engagement. notice it any quieter? this should do the trick almost every time. does this make sense? let us know if you have questions.

ptt81 · 05.23.2010, 02:05 PM

Quote:

Originally Posted by Ryu James

hey pt881,

you are fine to use that 2200kv motor on 4s in your buggy. it will be perfect. extremely fast and cool temps. i have had 3 losi 8ights and ran all of them on 2200kv on 5s and even tried 2700kv. the 2200kv on 4s is a great setup.

as for the ratcheting noise in the rear...that is "ok" if there is no binding but there is a way to minimize that sound or eliminate it. those shims you used for your center diff are actually able to be used in the rear diff bulkhead also to adjust the gearing mesh of the rear diff and pinion. you can use shims to adjust the mesh just right to eliminate that noise....and get smoother power transfer. but here is the most simple thing to do to eliminate that noise:

it will require you disassemble the car so you can access the rear bulkhead. once you have the rear bulkhead open take out the diff. then remove the rear cvd from the pinion gear. now, put fresh threadlock on your set screw that holds the cvd onto the pinion gear shaft. from inside the bulkhead push on the pinion gear as hard as you can. while doing this put on the cvd and lock down the set screw with the cvd as close to the bearing and bulkhead as possible. make sure there is absolutely no play in the pinion gear to move inward or outward. now put the rear diff back in and try the engagement. notice it any quieter? this should do the trick almost every time. does this make sense? let us know if you have questions.

I'm glad to hear the 2200kv on 4s works good. That's what I have, I plan to run the 2200kv with MMM, 4s 5000mah 30C, 14/48 gear. I hate to have to buy something when I already have something.

I appreciate your time for the write up but I'm not clear as to what you said about fixing the rear diff, may a video would help, but im not going to mess with it until I run it for a while, may be the sound will be gone once the gears are worn a bit.