My Nitro touring car is running smoothly with the tyres off the ground but when the tyres hit the ground it refuses to move or rev just idles

[Dogman888]

I think it might be a clutch related issue but i don’t know otherwise, any ideas?

 

[tudordewolf]

Do the wheels stop turning in the air while it's at idle? When you say it won't rev, does the throttle still open, but the engine bogs down instead of moving the car? It's not exactly clear what situation you're describing, a video might help.

It could be tuned too lean so that it's stalling with any resistance, the clutch spring could be broken so that it's always engaged, or something in the diffs could be loose that allows them to freewheel but lock up when power is applied.

 

[gandalfnz]

+1 bad clutch.
Car runs off the ground most likely because wheels spin, once on the ground it shuts off.

 

[cbaker65]

I think it might be a clutch related issue but i don’t know otherwise, any ideas?

Is your throttle servo working an or did you turn the receiver on in the car?..

 

[Dogman888]

Do the wheels stop turning in the air while it's at idle? When you say it won't rev, does the throttle still open, but the engine bogs down instead of moving the car? It's not exactly clear what situation you're describing, a video might help.

It could be tuned too lean so that it's stalling with any resistance, the clutch spring could be broken so that it's always engaged, or something in the diffs could be loose that allows them to freewheel but lock up when power is applied.

Hi, thanks a lot for the help i taught through your ideas and the only one I can see making sense for me is that it might be tuned to lean.
To be honest I had the car not start for a month a while ago and had bought a new piston and sleeve it’s starting now and I went trough the brake In procedure. And haven’t got it tuned at all till now, so I’m not sure
I started it up and got the idle down today here I attached some photos maybe they’ll help I’m not sure how to upload vids so here a link to the vid: https://vm.tiktok.com/ZGJHKrsq4/
Hooe this helps

 

[tudordewolf]

Hi, thanks a lot for the help i taught through your ideas and the only one I can see making sense for me is that it might be tuned to lean.
To be honest I had the car not start for a month a while ago and had bought a new piston and sleeve it’s starting now and I went trough the brake In procedure. And haven’t got it tuned at all till now, so I’m not sure
I started it up and got the idle down today here I attached some photos maybe they’ll help I’m not sure how to upload vids so here a link to the vid: https://vm.tiktok.com/ZGJHKrsq4/
Hooe this helps

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That's a pretty nice, vintage Tamiya TGX!

That engine doesn't sound too happy, kind of struggling. It should be snappier when you hit the throttle. I see the oil spot from the exhaust, that's encouraging, but there should be a little more smoke when you rev it. I'd richen up the high speed needle.

It does look like the clutch is constantly engaged, you might need to replace that o-ring that pulls it inwards.

 

[Dogman888]

That engine doesn't sound too happy, kind of struggling. It should be snappier when you hit the throttle. I see the oil spot from the exhaust, that's encouraging, but there should be a little more smoke when you rev it. I'd richen up the high speed needle.

It does look like the clutch is constantly engaged, you might need to replace that o-ring that pulls it inwards.

yeah you kindoff have a point that the engine idnt as snappy as it used to be check
My tiktok and you should find a couple of vids on how it used to respond.
Abput the o-ring I'm thinking of replacing it with this

 

[tudordewolf]

yeah you kindoff have a point that the engine idnt as snappy as it used to be check
My tiktok and you should find a couple of vids on how it used to respond.
Abput the o-ring I'm thinking of replacing it with this

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Those are pretty good, I use them in my nitros. Might as well get a plain one because the anodizing wears off pretty much immediately, and will only wear away the clutch bell a bit. Here's a cheaper listing for them.

 

[alfredwong2003]

It looks like the problem is in your differentials, I can only see one side of the wheels spin.

The aftermarket clutch may not fit well and you may have to adjust the engine and move it backwards.

 

[Dogman888]

It looks like the problem is in your differentials, I can only see one side of the wheels spin.

The aftermarket clutch may not fit well and you may have to adjust the engine and move it backwards.

Hi, well it might seem that way but that is because the tyres are un-even
I want to buy new tyres, to rule this variable out buy when i go out and get them i will rip apart thw chassis and service and free up the whole drive train. Il probably post pics when i do

Those are pretty good, I use them in my nitros. Might as well get a plain one because the anodizing wears off pretty much immediately, and will only wear away the clutch bell a bit. Here's a cheaper listing for them.

Thanks for thw clutch option, il probably order one for that cheap and il just have to paint for it from china.
Buy if you have seen the vids it doesn't really make senxe to me that underload it doesn't rev so it may not be the clutch

That's a pretty nice, vintage Tamiya TGX!

That engine doesn't sound too happy, kind of struggling. It should be snappier when you hit the throttle. I see the oil spot from the exhaust, that's encouraging, but there should be a little more smoke when you rev it. I'd richen up the high speed needle.

It does look like the clutch is constantly engaged, you might need to replace that o-ring that pulls it inwards.

Thanks for admiring my TGX
Well to be honest I just put in a new piston and sleeve and I barely got 2 tanks of idle now but i think it’s enough for break in.
I might go back to the original settings on my needle an play around from there.

 

[tudordewolf]

Buy if you have seen the vids it doesn't really make senxe to me that underload it doesn't rev so it may not be the clutch

It could be several things at once. The wheels should stop entirely when it's at idle, and they never stop turning. That suggests the clutch is rubbing. These engines don't produce much torque at idle, so it's struggling to pick up speed when you open the throttle. Normally they can rev up a bit, the clutch engages, and then they start moving, but if the clutch is rubbing, it'll already have resistance on it when you open the throttle.

If you pull the brake, does the engine stall?

 

[Dogman888]

It could be several things at once. The wheels should stop entirely when it's at idle, and they never stop turning. That suggests the clutch is rubbing. These engines don't produce much torque at idle, so it's struggling to pick up speed when you open the throttle. Normally they can rev up a bit, the clutch engages, and then they start moving, but if the clutch is rubbing, it'll already have resistance on it when you open the throttle.

If you pull the brake, does the engine stall?

It used to stall but I had fixed that should tune it and try again

 

[Lukedavis]

It used to stall but I had fixed that should tune it and try again

Have you checked your idle needle? My NR (Nitro Rustler) used to non-stop spin the tires even on the ground. I just had to close it a bit and then make sure that when you have full brakes the carb slide or whatever it's called doesn't move. That will at least rule out 1 issue. From what I have seen, you want the gap to be about the width of a credit card.

 

[Dogman888]

I think it might be a clutch related issue but i don’t know otherwise, any ideas?

It could be several things at once. The wheels should stop entirely when it's at idle, and they never stop turning. That suggests the clutch is rubbing. These engines don't produce much torque at idle, so it's struggling to pick up speed when you open the throttle. Normally they can rev up a bit, the clutch engages, and then they start moving, but if the clutch is rubbing, it'll already have resistance on it when you open the throttle.

If you pull the brake, does the engine stall?

Hey well I took your thaught on the matter into account and I striped the motor of the chassis and inspected the drivetrain.
Well that I found is that 2 of my rims where tightening against the wheel blocks and seizing them. I installed longer wheel hex’s and started her up again and to my surprise
I put it on the floor and it began to move, slowly! I’m pretty sure it’s a clutch issue as basically the little torque passing through the clutch was being seized my those 2 tyres, and now that everything was slacked and freed up it began to move. I also know this is a torque issue as when I begin to rev it then grab both tyres it dies down.

It could be several things at once. The wheels should stop entirely when it's at idle, and they never stop turning. That suggests the clutch is rubbing. These engines don't produce much torque at idle, so it's struggling to pick up speed when you open the throttle. Normally they can rev up a bit, the clutch engages, and then they start moving, but if the clutch is rubbing, it'll already have resistance on it when you open the throttle.

If you pull the brake, does the engine stall?

Hey thanks for all the help, well basically rlly good news, I freed up the drivetrain and tuned the car so when I brake it doesn’t stall and got that down perfect and now that I have other wheels on it not seizing the drivetrain anymore therefore it buyer smooth.
In turn this made the little torque passing through the clutch move the car at a slow speed, I think this is a big step and should be ordering a clutch soon.
This is a link to a vid on the progress: https://vm.tiktok.com/ZGJ9dj6ef/