R/C Tech Forums - NTC3 2 speed rebuild.. not shifting correctly

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mrcammy187

07-22-2010 09:23 AM

NTC3 2 speed rebuild.. not shifting correctly

Hey guys (and gals).. I love my ntc3.. I've had it for 7 years now. It was a single speed originally but over the years i have upgraded to 2 speed and other things. recently i have got back into the hobby with a few friends. My car sat for a bout 4 yrs and after dusting it off, it started with no problem and ran great for several nights until one of the outdrive bearings decided to depart. ;)

So.. I decided on a full rebuild with new parts.. 120.00 later the car is back together and it's initial run went like a dream. there were a few things like forgetting to tighten the carb bolt so the carb decided to depart on the 2nd run.. reconnected & tightened and no problems.. The car ran beautifully. Made me remember the day i bought it the 1st time 7 years ago... I was drag racing my buddies 4-Tec and holding with him until about 3/4 ways down the lot. It ran great... Went home and slept

The next day went out again. I made NO CHANGES to the car at all. I get out there and put the spurs to her... 1st gear went fine... then it shifted into 2nd and the RPMs skyrocketed and it did not grab second. I had to wait for idle to come down to where it would "pop" back into 1st. So this is what i did to try fixing it.

I assumed it was the 2speed clutch. I thought it may be the clutch spinning on the main shaft "in-drive". I tightened both set screws until i could see the clutch just start to separate. (manual instructions). I went back out and ran it up n down, the car started to shift properly but after a few left and right sweepers, the same thing would happen... shifts into 2nd and it doesn't grab the gear. I continued to make minor adjustments and i got it to start grabbing the gear but i can tell there is something not right... I can hear a distinct "clunk" as it drops back into 1st gear.

Has anyone had this issue before? Can you give me some hints to try?
Thanks, Mike

nitrodude

07-22-2010 09:43 AM

Quote:

Originally Posted by mrcammy187 (Post 7704294)

Its you 2spd oneway, its acting up. You can try some oneway oil, or just replace it.

mrcammy187

07-22-2010 09:49 AM

Hmm.. Thats what my buddy said too... Weird it's brand new. What grease is the correct to use? I have some Associated Black Grease or the "clear" grease. Will these work?

nitrodude

07-22-2010 10:10 AM

Quote:

Originally Posted by mrcammy187 (Post 7704380)

Hmm.. Thats what my buddy said too... Weird it's brand new. What grease is the correct to use? I have some Associated Black Grease or the "clear" grease. Will these work?

DONT USE ANY GREASE!! You need Serpent one way Lube, its Xceed now.

http://www.kamikazercracing.com/prod...p?prod=SER1680

Get a bottle of that, it will last you a lifetime, you only need a little bit. Also, dont try to clean the bearing, it just gets worse.

Turbo9000

07-22-2010 10:13 AM

Quote:

Originally Posted by mrcammy187 (Post 7704380)

Hmm.. Thats what my buddy said too... Weird it's brand new. What grease is the correct to use? I have some Associated Black Grease or the "clear" grease. Will these work?

also, make sure the shaft that the one way bearing rides on looks good. A new bearing is pretty cheap. I would just replace it, and buy a couple spares. If you spin it by hand you can feel the difference between an old worn out one-way and a new one. make sure there is a very positive feeling lock up, if the one-way feels like it is slipping at all, if there is a weak lock-up, or if you can put a side load on the gear and slip the bearing, then toss it.

I have a bottle of serpent one-way oil that i use. dont put toooo much lube on the one-way, i wouldnt use grease.

mrcammy187

07-22-2010 10:30 AM

You guys are awesome... I am just surprised cause it is literally a brand new part. Only had 1 evening of use and it worked perfectly. It is a brand new 2 speed kit to replace the 7yo 2speed i had in there originally. Just so I get it right, the one-way is located between the 1st & 2nd main gears right? The 2nd gear screws into it with 3 screws?

nitrodude

07-22-2010 10:44 AM

Quote:

Originally Posted by mrcammy187 (Post 7704514)

Thats right. Did you get a new shaft too? The shafts wear out too, if the shaft is worn out, it will do the same thing. If you didnt replace the shaft, get a new shaft first and see. I would still get the oil, its the only lube that will work.

mrcammy187

07-22-2010 11:54 AM

Yes i purchased an entire 2 speed kit. In the kit there was a new shaft also. The only thing i did from 1st night of driving to the next night was that i used alcohol to clean the car, liberally spraying it all over.. Do you think that would've caused that?

nitrodude

07-22-2010 12:00 PM

Quote:

Originally Posted by mrcammy187 (Post 7704827)

Thats your problem, oneway bearings dont need to be cleaned, just oiled. Get that Xceed oil and lube the bearing. You can put a drop in the bearing, or put some on the shaft and spread it with your finger. I use the finger method.

I use alcohol to clean my car sometimes too, but I try to stay away from the 2spd, so far I've never had a problem.

gfilos

07-22-2010 12:09 PM

Quote:

Originally Posted by nitrodude (Post 7704847)

one way bearing need to be cleaned time to time. most of the time i use some break cleaner, i then blow it with compressed air and relube with serpent one-way lube. Never had a oneway failure:nod:

mrcammy187

07-22-2010 01:02 PM

Yeah i literally just used a spray bottle and tried to just knock off all the blow by oil from the exhaust (why wouldn't they put a nipple on the pipe?). so i did not take apart the 2speed, i just sprayed the car with alcohol.

Geezatec

07-22-2010 02:34 PM

2 shoe clutch may not be adjust the same distance. Recheck assembly. Or just startover. It has been sitting. Bothshoes may not be engaging the same time. causing the clunk when shifting.

mrcammy187

07-22-2010 03:30 PM

thanks geezatec,
Yeah thats what I thought too. I'll try to describe what happened.. so the 1st drive after full rebuild with all new parts... it drove great but last night (2nd evening running) when it shifted, it was going into "no gear".

I did this a few times seeing if it will work itself in but nothing, kept doing the same thing. at 1 point I kept the rpm up and let the car roll to a stop, leaving the car in "2nd gear" (not letting it downshift to 1st). I picked the car up (keeping rpm up) and I can see that the 2nd gear clutch was not engaged, it was just sitting there..

What i thought it might be was the clutch set-screw with the ball bearing (center of the clutch shoe) wasn't screwed in far enough to let the ball rest against the flat spot on the shaft. So i gave those a little adjustment, tightening.

It seemed to help but it would still spin free in 2nd after going through some lefts and rights under power.

since it was still doing it i decided to fieldstrip the 2speed trans and rebuild it. I did this but still no real improvement. The only thing i have not checked is the one-way.

Geezatec

07-22-2010 04:50 PM

Allen Grup screw, acts as distance between shoe and flywheel. The air gap should be .50mm. The outer screw on shoes andjust the engagement of 2nd gear. Looser they are, the earlier it engages. Both shoes should engage the same time. Put some white out on one screw, not to mix them up. remember you want to engage equally.

Good luck.

One-way Bearing should be clean & lubed every other race just for maintenance. You'll know when it should be done.

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