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-   -   Locking the revo in 2nd gear to use motor braking/reverse (https://www.rc-monster.com/forum/showthread.php?t=7441)

jnev 09.13.2007 01:37 AM

Should the screws lock into place...? Because mine kind of just falls in, and hits the gear beneath the clutch...

BrianG 09.13.2007 02:06 AM

Well, the screws actually thread into the holes in the gear. If they don't, I wonder if you actually got 3mm screws?

jnev 09.13.2007 02:31 AM

Wow, you must be right. I'll have to go back to the store and buy some new ones. 3mm would translate to M3 screws, correct?

BrianG 09.13.2007 02:39 AM

Yeah. Don't you have a little box with all your RC screws? There is a substantial difference between 4mm (M4) and 3mm (M3), lol. And, if you got the wrong diameter, you might have gotten the wrong length as well, which would explain why they don't sit flush against the clutch. When you go to your LHS, get someone to get the correct part who is sober! :mdr:

jnev 09.13.2007 03:00 AM

I actually just found the screws. I thought they were in my rc screws box, but they ended up in another box :lol:. But I am unsure how the screws should fit. They are even longer than the previous ones, and don't even fit in the whole. They only fit through the gear that covers the clutch...

BrianG 09.13.2007 10:38 AM

Well, all I know is that 4mm (M4) screws that are 10mm long will work perfectly. The screws actually thread into the gear holes, so you'll have to do a little bit of work. :wink:

Cajun 09.13.2007 12:51 PM

Quote:

Originally Posted by BrianG (Post 118143)
Well, all I know is that 4mm (M4) screws that are 10mm long will work perfectly. The screws actually thread into the gear holes, so you'll have to do a little bit of work. :wink:

Yep, that's what I used in mine and they fit perfectly.

jnev 09.15.2007 02:43 AM

Its a miracle!!!
 
Again, the screws I though were right, were wrong. :diablo: So I was finally able to go buy the right ones... and they fit!! Hurray!! :lol:

Just thought I would let everyone know that If I can do this mod, anyone can.

Bad news though, is that the bits I have for the drill are not sharp/hard/strong enough to drill through the shaft. So as of right now, I still have the stock pins in. Any recommendations on really hard drill bits?

jnev 09.15.2007 11:53 PM

Quote:

Originally Posted by jnev (Post 118453)
Bad news though, is that the bits I have for the drill are not sharp/hard/strong enough to drill through the shaft. So as of right now, I still have the stock pins in. Any recommendations on really hard drill bits?

Anyone?? :cry:

david lamontagn 09.23.2007 09:48 AM

Just a little question about the mod jato pin to secure the gear in the revo tranny.
Somes guys here talk about the Jato outdrive pin, but can i use the revo drive shaft pin? (the one who secure the drive shaft to the diff output)

Thank's

David

jacobsjo87 10.07.2007 07:58 PM

If I have the robinson racing is the process the same to lock the tranny in second gear?

BrianG 10.07.2007 08:52 PM

Hmm, I guess I missed some of these questions. If it's not too late:

@jnev: I had some Ti coated bits I used. Even so, I wore a bit out doing this. So, get a couple and use cutting oil to help wear and cooling.

@David: The Revo outdrive is substantially larger than stock or even the Jato outdrive pins. If you use the Revo pin, the hole in the shaft will be too big and there won't be much metal left in the shaft and the shaft might break instead. The Jato pins are slightly larger and seem to be made of a different type of metal and have held up where the stockers didn't.

jacobsjo87: You mean the RR internal metal gears? If so, the process is about the same, you might have to drill the necessary holes. Even if the holes are present, you'll have to tap some 4mm holes as well. The stock 2nd plastic/nylon gear has holes arrayed evenly across it so it's easy to self-tap some 4mm screws into it.

retiredtech 10.21.2007 10:59 PM

Which CB and 2nd gears are you guys using to start off with ?? And can you give me a link to the r/c monster revo motor mount ? Thanks for any help

BrianG 10.21.2007 11:07 PM

Most, if not all, aren't using clutchbells - we're using Mod1 pinions (scroll down) . Second gear depends on the user. Standard ratio works fine, but I use the wide ratio set for a taller transmission gearing. This allows a better range for spur/pinions.

This is the motor mount: http://www.rc-monster.com/proddetail...d=RCMrevomount

BrianG 11.02.2007 07:31 PM

Nitro Revo Transmission Pin Mod
 
A buddy and I were at the track today playing with the Revo and Jato and I blew my spare Revo tranny. This was the one I had not done the "pin mod" on, so I thought I'd snap a few pics as a sort-of "how to"...

The broken pin:

http://scriptasylum.com/forumpics/pinmod4.jpg

The Revo FOC tranny screw pin is a different color than the stock chrome-like tranny screw pin. I wonder if they are hardened and stronger? Well, I called Traxxas and they said "they might be". Huh? Oh well, no real help there. They did say I should loosen the slipper to help control the torque, but then I'd lose much of the BL snap. Might as well drive a nitro! :smile:

Assortment of pins to choose from:

http://scriptasylum.com/forumpics/pinmod3.jpg

The Jato pin is too short to use anywhere in the tranny, but is included in the pic just for reference.

I noticed that whenever a pin broke, it was right where the threads meet the shaft, so that must mean that that spot is the most stressed. So, I modified two of the stock pins so they are about 7mm long each and then threaded both screws on each side of the gear hubs so the shaft tips meet inside the shaft. Below is a pic of the modified screw pin:

http://scriptasylum.com/forumpics/pinmod5.jpg

When cutting the black FOC pins and the original chrome pins (same size, diff color), the black ones seemed to take longer to cut with the dremel, so I think they are harder. This method has an added benefit: Since both sides are now captured, if a pin does break, the broken end won't fall out and mess up the other gears.

Picture showing the relative shaft diameters and gear hub thicknesses:

http://scriptasylum.com/forumpics/pinmod1.jpg

As you can see, each of the three shafts are different in diameter, so there is easy no "one fix for all" solution. The output shaft seems to be made of a softer metal so it is pretty easy to enlarge the hole. The input and idler shafts seem to be hardened so it is a PITA to drill. And the smaller shafts aren't big enough in diameter to hold up when drilled out.

Steps for each shaft:


Input (top) shaft: Since 2 modified pins will be used: in the plastic gear hub, enlarge the hole on the other side of the gear hub (opposite the threaded side) using a 7/64" drill bit to allow for the threads of the second pin. Modify two of the stock chrome pins like in the picture above and screw them in. The chrome ones are OK to use here because the pins have less force being exerted on them due to the gearing.


Idler/middle shaft: Basically do the same thing as the previous step, but use two of the black FOC pins instead. The pins here need the extra strength.


Output shaft: Since the output shaft is a softer metal, and has enough diameter, drill out a 2.5mm hole in the output shaft and the gear hub. There is no suitable "standard" size that properly equates to 2.5mm. Then drill a 1/8" (or 3mm) hole in one half of the hub to allow for the larger pin threads.


Another alternative I haven't tried is to use either a cut allen wrench or drill bit shaft instead of the 2mm pins for the input or idler shafts. A 2mm wrench may be strong enough without needing to enlarge the shaft holes. You'd just need to file off the "points" of the allen wrench so it will fit. If done right, you could just use a bit of muscle to press-fit the pin in place. If it's too loose, you could epoxy or JBWeld the ends of the pin to keep them from falling out.

I torture tested this setup and it seems to be holding up very well.


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