NTC3 new engine /tranny trouble

[jetmechG550]

I just put an OS CV-R .12 in my NTC3 and after running through the break in with it, the two speed will not shift. If I run it hard on the throttle it gets to the point where it is supposed to shift and it does nothing but rev. It's defintely not hitting second gear. If I come to a complete stop after that and try to move it just revs with no movement. If you let the rpm's come down you can hear a click like something is engaging. I've tried adjusting the tranny both in and out and starting over from scratch at 3 1/2 turns and it still does the same thing. I'm starting to wonder if it is a clutch problem more than a tranny problem. The original engine was an AE .12, is it possible that I need to shorten up the crank shaft a little more to get the clutch not tighter? Wanted to ask questions before I go cutting. Sorry for the long post and thanks in advance.

 

[NCNitro]

Well I'm not familiar with the TC3, if the crank requires you cut it prior to installing the collet, flywheel, and clutchnut on the engine, and you leave it too long, it is possible your shaft is spinning inside the flywheel which could cause that problem. Check your clutch and spring as well. If it is the tranny, is it possible you may have loosened the set screw that holds it to the shaft instead of the shift point adjustment screw?

 

[jetmechG550]

The clutch springs and shoes are new, and I went with the stiffer spring. I adjusted on the right screws (the two black that are at and angle). When the car "misses" the shift and the first gear doesn't seem to engage the tranny just spins freely until the rpm's come down and then you here the click and I'm back in 1st. I think I may look at the springs inside the tranny and see if they could be shot. Thanks NCNitro

 

[Diver6127]

If you had your threaded shaft cut, then your shaft might still be a little too long by 1 or 2 threads.

I went through this same problem a few months ago. I had the shaft cut on an OS 15CV-R and it wound up being too long. You can either grind it down or do what I did ... I got the HPI collet assembly (p/n A804). It came with a .5mm spacer in it. Install the spacer in back of the collet before replacing the flywheel and clutch nut. Replace clutch shoes, springs, shims, bearing, clutchbell, flanged bearing, spacers and lock screw (in this order). This should cure the problem. If it still slips you may want to look for a package of shims with random thicknesses to suit your needs. I beleive serpent has a package of shims. I will see what the part number is IF necessary. For starters, go with the HPI Collet set. I think the .5 thickness should be fine.

When the shaft was too long I had the same symptoms as you. High revs, no movement. RPM's drop and it engages. Another tip, if this has been happening for a while, check your bearings in your diff. They might have been damaged as well. That engagement or clicking can be harsh on those bearings. Mine needed replacement.

 

[jetmechG550]

Thanks Diver, I'll look for that collet from HPI. I think OFNA has a shim kit for about $5 that I've seen at the hobby shop. I appreciate the help. I've also been looking for an excuse t upgrade bearings.

 

[RatzoRC]

Also might be the one way bearing on the 2 speed.
I had a similar problem and that fixed it.
It's the one just behind the 2 speed spur gears.

 

[jetmechG550]

I tried shimming the collet/flyweel and it seemed to work a little better than it went back to doing the same thing. I think it is in the tranny so I'll be headed to the LHS to get some springs and a new bearing. I'm thinking that something got screwed up when the connecting rod broke on the old motor. Thanks for all your help, I'll post the solution if I ever get it.

 

[jetmechG550]

It was the one-way bearing. I think it got hosed when the AE motor blew. Thanks for all your help.

 

[Krunknshot]

I had the same problem after I got my 2speed installed, I could run it and it would not shift. If I held it in my hands it would goto shift and boag out. When I let off it would click (pretty loud), I played with the settings of that tranny for a while then I tried motor adjustments. I found it was the low setting on my engine not the high speed I fideled with that and wow it worked, not I have to adjusted it so that it wont shift that fast.

I have Venoms Speedometer installed and so far can get the car to 58mph I currently have the 50/54 spur 22/26 pinion (Blue and Black) Does anyone have any input on what gearing would be faster.

Nitro TC3
2-speed
Dynamite .12spd

 

[jetmechG550]

I think the 48/52 with the Purple and Red pinions. I think that final ratio would be lower which will give you more top end. AE has a gear ratio chart somewhere on their website. If you can't find it let me know and I can e-mail it to you. I thought that set-up was on one of the team drivers cars. I'm going to work on a little tuning, I'm still not real happy with the shift point, it seems to be later than I want and it doesn't seem to change with adjusting the screws out.

 

[Diver6127]

I run a little bit of a harder gear set up (the shift is hard and quite noticable). 21/27 pinions and 54/48. It's a 6 tooth drop but as I said, it shifts very hard and is perfect for where I race. It's also hooked up to a Novarossi NS12S3A1 engine, so there is enough "umph" to get this setup moving.

Be careful of the gear setup. Not all engines have the powerband to move the NTC3 with anything less than the 22/26 tooth pinion combo. They will get the car moving but you won't get the results you want.

BTW, with any gear change, there will be a variance in the shift points. I would suggest bringing the 2 speed back to factory settings and start making some passes till you get the shift where you want it.