R/C Tech Forums

Go Back   R/C Tech Forums > General Forums > Electric On-Road

Reply
 
Thread Tools Search this Thread
Old 09-09-2014, 10:41 PM   #736
Tech Elite
 
CraigMBA's Avatar
 
Join Date: Mar 2003
Location: Valley of the Dirt, CA
Posts: 2,832
Trader Rating: 22 (100%+)
Default

I built another transmission tonight, in an effort to come up with why I haven't been having the problems other users have. I think I came up with something, I got one to bind. Let's talk about what isn't the problem first.

The case halfs were slightly warped (bowed in the middle) by 0.15mm per side, but so were all the other cases I put together and all the other one I had handy by to measure (a had five or six). IMO that's not the problem.

My bearing surfaces cast into the cases were round and true. The bearings do press fit into the case, but you want that because the last thing you want with a gear drive train is stuff lashing around. IMO that's not the problem.

Usually I tap all the holes before I assemble the parts, especially on the carbon rein stuff. I didn't do that on these, and had to hand drive the case half screws in.

And then I had the problem. We are over torquing the cases. I had to do it to get the screws in.

After I disassembled the trans, tapped the holes, and re tightened at a reasonable torque (the spec for this screw in like 9 inch pounds) the problem went away. The friction from the plastic is supposed to hold these case halfs together anyway.

Also, I have continued to measure pinion lash and it's always 0.3mm too loose. Add a 0.3mm shim on the input shaft, followed by the rest of the parts per the manual build. If your tolerances are off, you won't be able to put the roll pin in, so you may need to reduce to 0.2 or so.

So, lesson #1, use one of these:



lesson #2, don't over torque those case halfs. Snug is enough.

Lesson #3, add extra shims to the shaft before you put bearings on. If you can easily get the roll pin in, add more! If you can't get it in, take some out. So far, mine have taken an extra 0.3mm to get right.

Questions? Comments?
__________________
* Cee Lo Dizzle, the Secizzle * Red Bull * Team Homies * Pintura de Negro Mate * USVTA #152

Last edited by CraigMBA; 09-09-2014 at 10:43 PM. Reason: Lose isn't loose
CraigMBA is offline   Reply With Quote
Old 09-09-2014, 11:04 PM   #737
Tech Elite
 
metalnut's Avatar
R/C Tech Elite Subscriber
 
Join Date: Feb 2013
Location: Seattle
Posts: 2,726
Trader Rating: 36 (100%+)
Default

Thank you for the write-up. Not to toss a stick into your spokes, but I tapped every single thread on my cases to begin with. I don't like forcing a screw into plastic, so I always tap. I have the screws holding the cases very loose, we're talking two finger tips on a hex driver, and it still binds noticeably. But on my cases you can see them unwarping as I tighten then, even lightly.

I'm going to take them apart and re-shim per your instructions, but they won't be smooth. I'll recheck them after the first race night.
__________________
Team Nervous | Team Scruffy | Team Orange

"If you ain't first, you're last!"
- Ricky Bobby
metalnut is offline   Reply With Quote
Old 09-09-2014, 11:05 PM   #738
Tech Elite
 
metalnut's Avatar
R/C Tech Elite Subscriber
 
Join Date: Feb 2013
Location: Seattle
Posts: 2,726
Trader Rating: 36 (100%+)
Default

Oh, another but separate question. I got the TRF belt tensioner mentioned a page or two back to keep the battery from sliding forward. That's a no go, Houston. Even with a screw coming out of it, it doesn't really stop the battery movement much. Plus, the battery can still slide to the rear.

Are you guys using any type of thin rubber feet/pads under the battery, the anti-slip kind?
__________________
Team Nervous | Team Scruffy | Team Orange

"If you ain't first, you're last!"
- Ricky Bobby
metalnut is offline   Reply With Quote
Old 09-09-2014, 11:14 PM   #739
Tech Master
 
EDWARD2003's Avatar
 
Join Date: Jan 2003
Location: Kagoshima, Japan
Posts: 1,919
Trader Rating: 6 (100%+)
Default

I had similar problems with the gears mashing/binding against each other. I couldn't figure out what to do. I ended up placing two gaskets on top of each other and the problem has gone away.

The extra gasket has given that tiny little bit of room for the gears to mesh up correctly.
EDWARD2003 is offline   Reply With Quote
Old 09-09-2014, 11:45 PM   #740
Tech Elite
 
Johnny Wishbone's Avatar
 
Join Date: Feb 2006
Posts: 3,285
Trader Rating: 6 (100%+)
Default

Quote:
Originally Posted by metalnut View Post
Oh, another but separate question. I got the TRF belt tensioner mentioned a page or two back to keep the battery from sliding forward. That's a no go, Houston. Even with a screw coming out of it, it doesn't really stop the battery movement much. Plus, the battery can still slide to the rear.

Are you guys using any type of thin rubber feet/pads under the battery, the anti-slip kind?
Just use the poster tack like I mentioned before, all grip no slip.
__________________
Gary Lanzer
Team VBC HK
Team R1WURKS
Johnny Wishbone is offline   Reply With Quote
Old 09-10-2014, 12:19 AM   #741
Tech Elite
 
metalnut's Avatar
R/C Tech Elite Subscriber
 
Join Date: Feb 2013
Location: Seattle
Posts: 2,726
Trader Rating: 36 (100%+)
Default

Quote:
Originally Posted by Johnny Wishbone View Post
Just use the poster tack like I mentioned before, all grip no slip.
Right, I looked into your suggestion before and all I could find is stuff that's 1/8" thick or more. Do you use something much thinner?
__________________
Team Nervous | Team Scruffy | Team Orange

"If you ain't first, you're last!"
- Ricky Bobby
metalnut is offline   Reply With Quote
Old 09-10-2014, 08:50 AM   #742
Tech Elite
 
Johnny Wishbone's Avatar
 
Join Date: Feb 2006
Posts: 3,285
Trader Rating: 6 (100%+)
Default

Quote:
Originally Posted by metalnut View Post
Right, I looked into your suggestion before and all I could find is stuff that's 1/8" thick or more. Do you use something much thinner?
You just take a small piece and flatten it out like playing with playdoo you can make it as thick or as thin as you want it. I usually take a small ball of it about 1/4 inch in diameter, and roll it into a long piece about 1/2 inch long and put it on each end of the battery. Then push it flat on the battery. Install the pack into the car and push it down at both ends so your pack doesnt feel like it has any rock to it (could be a slightly buldged pack) and tape it down. You can reuse the tack several times before it has too much lint in it, then just redo the process with new tack. I should mention that I will peel the tack off the pack each time and redo the process just to make sure it stays fresh and sticky side down.
__________________
Gary Lanzer
Team VBC HK
Team R1WURKS
Johnny Wishbone is offline   Reply With Quote
Old 09-10-2014, 09:14 AM   #743
Tech Elite
 
CraigMBA's Avatar
 
Join Date: Mar 2003
Location: Valley of the Dirt, CA
Posts: 2,832
Trader Rating: 22 (100%+)
Default

Quote:
Originally Posted by EDWARD2003 View Post
I had similar problems with the gears mashing/binding against each other. I couldn't figure out what to do. I ended up placing two gaskets on top of each other and the problem has gone away.

The extra gasket has given that tiny little bit of room for the gears to mesh up correctly.
The gear diff should be slightly rough when you put it together. After you run it once or twice, the gears bed in and the diff smooths out. If it's too free, the extra lash will destroy the gear set.
__________________
* Cee Lo Dizzle, the Secizzle * Red Bull * Team Homies * Pintura de Negro Mate * USVTA #152
CraigMBA is offline   Reply With Quote
Old 09-10-2014, 09:30 AM   #744
Tech Elite
 
metalnut's Avatar
R/C Tech Elite Subscriber
 
Join Date: Feb 2013
Location: Seattle
Posts: 2,726
Trader Rating: 36 (100%+)
Default

Quote:
Originally Posted by CraigMBA View Post
The gear diff should be slightly rough when you put it together. After you run it once or twice, the gears bed in and the diff smooths out. If it's too free, the extra lash will destroy the gear set.
I noticed something about my rear gear diff (with 2K AE diff fluid in it). I built it with metal gears and gear shafts right away and used a single 0.3mm shim on each side (per instructions), but I used red TRF o-rings and bearings instead of bushings. The diff came out butter smooth. However, 3 weeks later, sitting on a shelf, the gear diff is now grindy as if I used too thick shims. My guess is that the orange o-rings swelled up and pushed the shims up, thus forcing the gears together more.

Any thoughts on this issue? Re-shim with thinner shims, different o-rings?
__________________
Team Nervous | Team Scruffy | Team Orange

"If you ain't first, you're last!"
- Ricky Bobby
metalnut is offline   Reply With Quote
Old 09-10-2014, 09:58 AM   #745
Tech Elite
 
CraigMBA's Avatar
 
Join Date: Mar 2003
Location: Valley of the Dirt, CA
Posts: 2,832
Trader Rating: 22 (100%+)
Default

Quote:
Originally Posted by metalnut View Post
Thank you for the write-up. Not to toss a stick into your spokes, but I tapped every single thread on my cases to begin with. I don't like forcing a screw into plastic, so I always tap. I have the screws holding the cases very loose, we're talking two finger tips on a hex driver, and it still binds noticeably. But on my cases you can see them unwarping as I tighten then, even lightly.

I'm going to take them apart and re-shim per your instructions, but they won't be smooth. I'll recheck them after the first race night.
In that extreme case, I would do what Juan suggested, and add a 0.1mm shim to each of the six case screws.

The screws that caused the most trouble on mine were the two that are on the end of the case opposing the pinion. I could cinch down the other four (the two around the pinion and the two in the middle of the case) and everything was fine.
__________________
* Cee Lo Dizzle, the Secizzle * Red Bull * Team Homies * Pintura de Negro Mate * USVTA #152
CraigMBA is offline   Reply With Quote
Old 09-10-2014, 09:59 AM   #746
Tech Elite
 
CraigMBA's Avatar
 
Join Date: Mar 2003
Location: Valley of the Dirt, CA
Posts: 2,832
Trader Rating: 22 (100%+)
Default

Quote:
Originally Posted by metalnut View Post
I noticed something about my rear gear diff (with 2K AE diff fluid in it). I built it with metal gears and gear shafts right away and used a single 0.3mm shim on each side (per instructions), but I used red TRF o-rings and bearings instead of bushings. The diff came out butter smooth. However, 3 weeks later, sitting on a shelf, the gear diff is now grindy as if I used too thick shims. My guess is that the orange o-rings swelled up and pushed the shims up, thus forcing the gears together more.

Any thoughts on this issue? Re-shim with thinner shims, different o-rings?
Run it and seat the gears.

If you run less shims, the outdrive moves side to side. No bueno.
__________________
* Cee Lo Dizzle, the Secizzle * Red Bull * Team Homies * Pintura de Negro Mate * USVTA #152
CraigMBA is offline   Reply With Quote
Old 09-10-2014, 10:06 AM   #747
Tech Elite
 
metalnut's Avatar
R/C Tech Elite Subscriber
 
Join Date: Feb 2013
Location: Seattle
Posts: 2,726
Trader Rating: 36 (100%+)
Default

Quote:
Originally Posted by CraigMBA View Post
In that extreme case, I would do what Juan suggested, and add a 0.1mm shim to each of the six case screws.

The screws that caused the most trouble on mine were the two that are on the end of the case opposing the pinion. I could cinch down the other four (the two around the pinion and the two in the middle of the case) and everything was fine.
Right, that's exactly what I had, a 0.1mm shim on each of the "rear" screw posts. That seems to work well, I think I'll play with that a little more.

Quote:
Originally Posted by CraigMBA View Post
Run it and seat the gears.

If you run less shims, the outdrive moves side to side. No bueno.
Metal gears seat?
__________________
Team Nervous | Team Scruffy | Team Orange

"If you ain't first, you're last!"
- Ricky Bobby
metalnut is offline   Reply With Quote
Old 09-10-2014, 11:42 AM   #748
Tech Elite
 
CraigMBA's Avatar
 
Join Date: Mar 2003
Location: Valley of the Dirt, CA
Posts: 2,832
Trader Rating: 22 (100%+)
Default

All gears seat.

http://www.ringpinion.com/technicalh...r_Break-In.inc
__________________
* Cee Lo Dizzle, the Secizzle * Red Bull * Team Homies * Pintura de Negro Mate * USVTA #152
CraigMBA is offline   Reply With Quote
Old 09-11-2014, 04:00 AM   #749
Tech Elite
 
Racing4Evo's Avatar
 
Join Date: Sep 2002
Location: SoCal
Posts: 2,118
Trader Rating: 2 (100%+)
Send a message via AIM to Racing4Evo
Default

Quote:
Originally Posted by metalnut View Post
I noticed something about my rear gear diff (with 2K AE diff fluid in it). I built it with metal gears and gear shafts right away and used a single 0.3mm shim on each side (per instructions), but I used red TRF o-rings and bearings instead of bushings. The diff came out butter smooth. However, 3 weeks later, sitting on a shelf, the gear diff is now grindy as if I used too thick shims. My guess is that the orange o-rings swelled up and pushed the shims up, thus forcing the gears together more.

Any thoughts on this issue? Re-shim with thinner shims, different o-rings?
Yes, you're right, the orings have swelled and you will need to replace the shims and orings. I see this problem a lot now with the orange orings...
Racing4Evo is offline   Reply With Quote
Old 09-11-2014, 08:24 AM   #750
Tech Elite
 
CraigMBA's Avatar
 
Join Date: Mar 2003
Location: Valley of the Dirt, CA
Posts: 2,832
Trader Rating: 22 (100%+)
Default

I stand corrected!
__________________
* Cee Lo Dizzle, the Secizzle * Red Bull * Team Homies * Pintura de Negro Mate * USVTA #152
CraigMBA is offline   Reply With Quote
Reply



Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are Off



All times are GMT -7. It is currently 11:28 AM.


Powered By: vBulletin v3.9.2.1
Privacy Policy | Terms of Use | Advertise Content © 2001-2011 RCTech.net

SEO by vBSEO 3.5.0