SCX10-III: Things to know before you build yours (Tips)

[R2j]

Here are some pictures.......

[Ambis]

Originally Posted by Ambis

I'm going to today. It's driving me nuts. Need to debug the exact place where this happens and see how to fix it.

One thing might be just to loosen all the transmission cover screws a bit, since I used a powertool with them (such very long screws omg).

Okay. Open heart surgery performed.

I tore everything apart starting from the spur inwards, but not the dig-side.

Everything looked A-OK. There is no ticking sound when there is no load on the system. Even when all the axels are connected. Only when I touch one tire (doesn't matter which) on the table, running them slowly (=system gets some load), then the ticking sound starts. I'm beginning to think it's just some backlash from all the 2-speed engagement things etc.

I could find nothing wrong with anything in the trans.

Maybe I should just slab that trans completey full of grease, to dampen the sound if nothing else

[Texas30cal]

I’ll try to get into it tonight, I don’t really like how sloppy the top shaft is so I’ll prob make one from 4140 like I did for my Capra. there’s got to be something it’s so constant and steady while under load , maybe the engines got a bad rod bearing

[2mtech]

Originally Posted by Texas30cal

...maybe the engines got a bad rod bearing

I'd check your mains first, pretty sure this isn't a 4-bolt.

[Texas30cal]

I know this is long but I’m not a great teacher and am trying to explain so you can make sense of my ramblings. I disassembled the whole trans , looking at the top (spur gear) shaft, there is a funny wear pattern in the shafts black coating from the gear being loose on the shaft and also wear from spinning inside the bearings. I say wear, it’s only the coating not into the steel, but enough to let me know that things are too loose seeing as this thing has less than 10 minutes on it. No time to make a shaft so I did some improvised knurling with my automatic center punch, drove a old bearing on over the punch marks and drove it back off. Near zero slop in the shaft and gear now but admittedly the gear/shaft prob aren’t running perfectly true. The other issue I found is all the bearing pockets are loose. I wasn’t sure how loctite gel would do in this case so I used a thin plastic bag cut into 3/4” squares. Put a square on top of the pocket and shoved the bearings in, nice and tight! Trim the excess with the hobby knife and the center where necessary. I reassembled per the instructions with grease same as before. When I installed the motor and ran it the gear mesh was noisy, better with the clamping screws loose. So I set the mesh on 15 for 14t gear and it was better with the screws tight. Next, we all know there are good/better pinions, I swapped to a diff brand 13t pinion gear set to 14 and it’s a lot better. Will run it tomorrow and see how she sounds but on the bench it’s a huge improvement so far. Any suggestions, comments, ridicule are all welcome !!!!

[AK KRAWLER]

Nothing wrong with this improvising, seems to be the nature of the beast... I’m sure there will be revisions and aftermarket cases available at some point.

[mikemcE]

Well I did figure out what was causing the awful noises...... was not anything in the transmission, acmes , or powertrain. It was the stupid hard front body clip pulls, rubbing on the tires when turning!! I adjusted the position, and will replace with some soft pulls from proline that I have.
I adjusted the dig servo... zeros at 1:00 for disengaged rear, perfect 70/30 EP for 3 positions of dig.


Hang up and Drive

[Texas30cal]

I got mine reassembled but haven’t driven it yet, will see as soon as possible

[drzjohn]

Originally Posted by mikemcE

Noticed an area of confusion...... when mounting the transmission ears, make sure the passenger side is installed before all others, the screw is blind after the lower plate is installed.

I also recommend chamfering the dig and shift threaded attachments and prethreading them.....


Hang up and Drive

"chamfering" the dig and shift threaded attachments can you explain please and why was it needed ?
My lever seems a little bit too tight even with the pivot screw backed out a bit

[Texas30cal]

Well the clicking was still there after installing it and putting tires on the ground. I’ve been thinking about it, it’s approx 3 clicks per rev of the driveshaft.
There is clicking with dig/rear output removed (fwd only)
There is clicking with transfer case gears removed (rwd only)
There is clicking in both high and low
There is clicking with motor/pinion removed and a load on trans

What does that leave?
Only the 2 27t gears up front

The bore of the gear (both) is not parallel to the OD of the gears, as they rotate the pressure being at a angle now is making the gears slide on their shafts clicking as they hit the bearings.

I added a .2mm shim to each shaft, and on the bench installed, under enough load to wrinkle the sidewalls and overload the HW1080 there is no more clicking.

If it’s not raining here tomorrow I’ll get out and run it a couple packs, if raining I’ll beat on the drivetrain indoors on the carpet and see how it does!!!

[JatoTheRipper]

Originally Posted by R2j

Has anyone else had an issue with clearance between the servo horn and chassis? I'm using a Spektum S6280 servo, and had to file on the chassis, lower edge of shock tower and horn itself a bit to make it move more freely. I don't think it will be an issue now that I filed it down, but may file down the mounting tabs on the chassis brace servo mounts to gain some more clearance.

Odd since I'm sure it was designed for a Spektrum servo. I'm not having the same issue as you, but I'm using the Holmes v3. My servo horn does hit the cutout in the Panhard mount just before or at the same time as the knuckle hits the steering stop.

[mikemcE]

Originally Posted by drzjohn

"chamfering" the dig and shift threaded attachments can you explain please and why was it needed ?
My lever seems a little bit too tight even with the pivot screw backed out a bit

Chamfering is a simple process of tapering the end of the hole. As the part isn’t threaded, starting without tapping can be a pain. A simple spin of your #11 blade in the hole make it easier


Hang up and Drive

[antonio_cadiz]

Originally Posted by Texas30cal

Well the clicking was still there after installing it and putting tires on the ground. I’ve been thinking about it, it’s approx 3 clicks per rev of the driveshaft.
There is clicking with dig/rear output removed (fwd only)
There is clicking with transfer case gears removed (rwd only)
There is clicking in both high and low
There is clicking with motor/pinion removed and a load on trans

What does that leave?
Only the 2 27t gears up front

The bore of the gear (both) is not parallel to the OD of the gears, as they rotate the pressure being at a angle now is making the gears slide on their shafts clicking as they hit the bearings.

I added a .2mm shim to each shaft, and on the bench installed, under enough load to wrinkle the sidewalls and overload the HW1080 there is no more clicking.

If it’s not raining here tomorrow I’ll get out and run it a couple packs, if raining I’ll beat on the drivetrain indoors on the carpet and see how it does!!!

please pic

[NABeast]

I hope you will be able to buy a gear for single speed conversion and help take the slack out of the trans.

[Alexander_0_1]

Um, are any of the chassis parts compatible with the SCX10.II? It would be nice to have that trans+skid plate, servo bracket for my Jeep, as well as my 6x6.

[Texas30cal]

Originally Posted by antonio_cadiz

please pic

I drove it a lot today and it’s still doing great, I plan to pull it back out in the next couple of days to inspect. When I do I will take pics.

[drzjohn]

Originally Posted by Texas30cal

I drove it a lot today and it’s still doing great, I plan to pull it back out in the next couple of days to inspect. When I do I will take pics.

Can you show us where you put the shims using the picture in the build manual please ?

[Texas30cal]

I’m not allowed to post attachments.

I added them on the two shafts with the identical 27tooth gears, between the gear and bearing on the side opposite the drive pins to be sure there wouldn’t be any interference. I tried .3mm shims to start with but it was too much and put the trans in a bind. I switched to .2mm shims and it added a very slight amount of drag but nothing to worry about. I use tamiya shims from kit number OP-587.

[soze]

Got up to finishing Step F yesterday.

I did not have a m3 tap to use for the shock towers to mount the shocks, so I did something different.

I took the supplied black grease and squirted a little bit into the hole. After that the screws seemed to go in just fine without fear of breaking them while still being very snug and tight.

I did thread the hole with just the black grease and screw first before mounting the shocks though.

[rbspeed]

Originally Posted by soze

Got up to finishing Step F yesterday.

I did not have a m3 tap to use for the shock towers to mount the shocks, so I did something different.

I took the supplied black grease and squirted a little bit into the hole. After that the screws seemed to go in just fine without fear of breaking them while still being very snug and tight.

I did thread the hole with just the black grease and screw first before mounting the shocks though.

This is a much better way to tap the holes. I did it the same way.

The M3 tap will produce overlarged holes, so the screws will wobble.