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-   -   Xray NT1 (https://www.rctech.net/forum/nitro-road/141149-xray-nt1.html)

lil-bump 07-05-2010 04:14 PM


Originally Posted by mikedoo3 (Post 7631371)
I got a used NT1 08 roller from a friend of mine and I'm trying to break in an engine, but the clutch won't engage. Wheels don't move at all with pretty high revs.

Flywheel nut is tight
gap is about .7mm
preload is 10.2 mm (10.2 from end of shaft to top of the preload nut)
clutch nut is about 9.35 mm from end of shaft

Anyone have any ideas. Thanks

Set the gap to .5, Back off the spring nut 1 full turn. When your break-in an engine you want the clutch set very light. When the engine is done; then you can set the clutch to a race tune.



Pass you soon...

mikedoo3 07-05-2010 08:14 PM

Thanks, I'll try that tommorow and see what happens.

rx7ttlm 07-05-2010 08:27 PM


Originally Posted by mikedoo3 (Post 7631371)
I got a used NT1 08 roller from a friend of mine and I'm trying to break in an engine, but the clutch won't engage. Wheels don't move at all with pretty high revs.

Flywheel nut is tight
gap is about .7mm
preload is 10.2 mm (10.2 from end of shaft to top of the preload nut)
clutch nut is about 9.35 mm from end of shaft

Anyone have any ideas. Thanks

holy balls! lol. That is a fair amount of preload. Its dependent on which clutch spring, the clutch disc (yellow or white), and when you really get into it flywheel weight (std or lightened) all play a part in how your clutch performs. So I am going to assume you have the standard xray silver clutch spring (black requires less preload, same with the orion square spring). also assuming which clutch disc (yellow is most popular but is optional)

Assuming your using a silver (stock) clutch spring with yellow clutch shoe your gap should be closer to 0.5-0.6mm. On slick tracks I run as low as 0.4, 0.6 is more for larger layouts and / or high bite. So lets say 0.5 gap to start, and about 0.6mm preload. If that doesn't engage, reduce preload to suit. Next to nitro tuning, clutch tuning is often hard to learn by your self. If your running a stiffer than stock spring like the orion, I start with 0.4 gap, and 0.4-0.6 mm clutch spring preload (preload in this reference is the difference between the clutch nut measurement, and the flywheel nut measurement.) so your 9.35 should be mated with a measurement closer to the 9.75-9.95. On a worn spring sometimes I end up with more. But a reasonably new spring shouldn't be that soft.

mikedoo3 07-06-2010 04:26 PM

I'm still having issues. I loosened the spring nut alot. It is barely compressing the spring. I am having trouble measuring the gap though. I don't have a gap tool and every time I use my calipers I get a different answer. But I think it should be in the ball park. I have to be doing something dumb. Engine is spinning the correct way (wheel on starter box spins towards the front of the car). The clutch is stock, stock weights, spring, shoe (white). I have the clutch weights installed with the flat face up, just checked the manual and although hard to tell from Xray's drawing, it looks flat up. There's really nothing else to it, I don't know what is going on. Drivetrain is free, brakes are not engaged.

rx7ttlm 07-06-2010 04:51 PM


Originally Posted by mikedoo3 (Post 7636444)
I'm still having issues. I loosened the spring nut alot. It is barely compressing the spring. I am having trouble measuring the gap though. I don't have a gap tool and every time I use my calipers I get a different answer. But I think it should be in the ball park. I have to be doing something dumb. Engine is spinning the correct way (wheel on starter box spins towards the front of the car). The clutch is stock, stock weights, spring, shoe (white). I have the clutch weights installed with the flat face up, just checked the manual and although hard to tell from Xray's drawing, it looks flat up. There's really nothing else to it, I don't know what is going on. Drivetrain is free, brakes are not engaged.

try it with the preload nut even with the flywheel nut 0.0 preload and wheels off the ground and see what it does. you may just have a gap that's WAY to big. take shims from the outside (installed in car right side as if you were sitting in the car) and move them to the left side the the 5x10 bearing. Move about 0.3mm and try it again.

mikedoo3 07-06-2010 05:55 PM

I tried it with the preload nut even with the flywheel nut, still nothing. I'll go to the extreme minimum with clutch gap tomorrow. Right now the preload nut is even and the clutch gap is .55mm. The endplay is just about right I think, very very little amount of play.

One thing I just noticed is that when I give it a little throttle, the pinions turn a little bit in the wrong direction. The engine can't be spinning backwards though can it.

keavze 07-06-2010 08:15 PM


Originally Posted by mikedoo3 (Post 7636823)
I tried it with the preload nut even with the flywheel nut, still nothing. I'll go to the extreme minimum with clutch gap tomorrow. Right now the preload nut is even and the clutch gap is .55mm. The endplay is just about right I think, very very little amount of play.

One thing I just noticed is that when I give it a little throttle, the pinions turn a little bit in the wrong direction. The engine can't be spinning backwards though can it.

looking at the pinions, it should be spinning counter-clockwise...
are the flyweights 'loose' in the pins?

Team-RTR 07-07-2010 06:10 AM

hey guys, just wondering if anyone could post a link to instructions to mod an 08 topdeck to 2010 specs? i know its floating around the net somewhere but im having a hard time finding it.. any help would be appreciated.

mikedoo3 07-07-2010 04:22 PM

The flyweights don't seem loose in the pins, but one of them is cracked around the hole. It doesn't seem bad enough to where that would affect anything though. I set the clutch gap very small but the clutch still won't engage. I didn't bother measuring it because it was so small of a gap. Spring has least amount of preload possible without the spring nut binding on the bell. I asked the person I got the car from about the clutch and he said it was all stock. The spring is kinda worn out silverish and feels hard as crap. I can't compress it with my fingers. I don't really have any trouble starting the spring nut though.

Will the stock clutch engage at low RPM (for engine break in) when set up properly? At this point I am going to try to get local help, there is nothing else I can do.

CraigX 07-07-2010 06:32 PM


Originally Posted by mikedoo3 (Post 7640944)
The flyweights don't seem loose in the pins, but one of them is cracked around the hole. It doesn't seem bad enough to where that would affect anything though. I set the clutch gap very small but the clutch still won't engage. I didn't bother measuring it because it was so small of a gap. Spring has least amount of preload possible without the spring nut binding on the bell. I asked the person I got the car from about the clutch and he said it was all stock. The spring is kinda worn out silverish and feels hard as crap. I can't compress it with my fingers. I don't really have any trouble starting the spring nut though.

Will the stock clutch engage at low RPM (for engine break in) when set up properly? At this point I am going to try to get local help, there is nothing else I can do.

Just to make sure, the flyweights come all together and you have to trim them apart when you install them in the clutch. Are there three separate flyweights?

rx7ttlm 07-07-2010 06:57 PM


Originally Posted by CraigX (Post 7641518)
Just to make sure, the flyweights come all together and you have to trim them apart when you install them in the clutch. Are there three separate flyweights?

The flyweights come separated into three pieces and they are black. Your clutch shoe material is usually white or yellow, sometimes red for alternate brands.

LiL_JaSoN 07-08-2010 05:09 AM

which piston in the shocks are u guys using?

rx7ttlm 07-08-2010 09:39 AM


Originally Posted by LiL_JaSoN (Post 7643147)
which piston in the shocks are u guys using?

I have been pretty happy with 2 hole front (1mm holes) and 3 hole rear (1mm holes) and I change oil weight anywhere from 500 - 600. I usually start with 600cst

mikedoo3 07-08-2010 02:54 PM

Craig, yes, there are 3 flyweights. I actually got the car moving today but I don't think its right. There is very little clutch gap and the spring is on the lowest possible preload. The person I got the car from said the clutch spring is the stock kit spring.

I have to go like 1/4 throttle and hold it there for about 2 seconds before the car starts moving, then it starts building momentum. I really want easy engagement for engine break in. Does that seem right?

LiL_JaSoN 07-08-2010 05:31 PM


Originally Posted by rx7ttlm (Post 7644004)
I have been pretty happy with 2 hole front (1mm holes) and 3 hole rear (1mm holes) and I change oil weight anywhere from 500 - 600. I usually start with 600cst

cool, so i installed it.. filled it up with oil. the shocks feels nice and smooth (100% rebound).

then when i follow the instructions to get 50% rebound (pull in/out shockrod 15x).

the rebound doesnt look/feel smooth.. its jerky.. the first 50% jerks out (feels like there is no oil), and the last 50% is smooth


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