Issue running my HPI RS4 Evo3 Mustang Nitro RC 1/10 scale

[HueyC]

Hello friends,
I'.ve recently ran into an issue with my nitro RC and can't make out what is causing it. Initially, I thought it was tuning issue, running too lean but spitting oil out and plenty of smoke. I've attach a video in hope that some can point me in the right direction... almost sound like it "flat-line" from time to time... or burp like something was engaged and then free-wheeling... I know throwing out these two examples trying to describe the sound but hopefully the video will help. If you listen, you'll hear it come in and out... maybe air leak but I've ruled out the fuel tank; already did submerge test under water and fine.

One thing I have discovered is that the flywheel will turn CW for 1/4" and then lockup. On my other Nitro vehicles that are not "Star T3.0" engine, I recall that it will not turn CW, only CCW. Not sure if this is an issue but this is my second engine replacement. I've checked the original T3.0 and it does the same thing... able to turn the shaft CW for at least 1/4 - 1/2" turn

 

[olds97_lss]

I don't see a video.

The pullstart will limit how far the flywheel will rotate in one direction because as you turn the flywheel, it's locking the one way bearing in teh starter and tightening up the slack inside on the pull start rope spool.

 

[Certified Mike]

I'm wondering if the one way bearing is fried? That could account for the weird noises as well. I also see no video so it's no more than a guess based on what info you've provided.

 

[HueyC]

How do I post a video? I am new to forum and haven't found a way.

How do I post a video? I am new to forum and haven't found a way.

I got it. Have to post on u tube or Facebook.... I'll get that uploaded and cc you link. Thank you for responding to my post. Very much appreciated.....

 

[HueyC]

All,

Here's my link to my video. Please let me know what you think intermittent sound might be... you can hear pitch drops off and then comes back.

when I reply individually, does it get posted to everyone that responded to post?
Well here's uploaded vid. Thanks

 

[cbaker65]

Have you ever had the clutch apart since you've had the car?

Your clutch shoes could be worn out an riding on the clutch springs ,the engine sounds good!...

 

[WVNed]

I hear an engine that is idling to fast and you blipping the throttle. What else am I supposed to notice?

 

[cbaker65]

I hear an engine that is idling to fast and you blipping the throttle. What else am I supposed to notice?

Exactly ,the engine running with that high rev ,should be already taking off with good clutch!

 

[HueyC]

Have you ever had the clutch apart since you've had the car?

Your clutch shoes could be worn out an riding on the clutch springs ,the engine sounds good!...

I had the engine taken off and removed the clutchbell... single screw in front. It was two piece clutch shoe and it felt pretty tight when I pulled on it outward.... wasn't loose. With that said I am not sure if that's the way to test. See attach picture with clutchbell off.

I had the engine taken off and removed the clutchbell... single screw in front. It was two piece clutch shoe and it felt pretty tight when I pulled on it outward.... wasn't loose. With that said I am not sure if that's the way to test. See attach picture with clutchbell off.

Exactly ,the engine running with that high rev ,should be already taking off with good clutch!

You all agree that what you hear is clutch issue? See the photos, what does worn clutch look like because I can't tell... looks new to me and when I pull on shoe it is tight on the spring assy clip.

Let me understand what you saying, it's not spring tension but wear on the shoe on outskirt of the surface, is that what you're trying to convey? I keep thinking that as long as spring tension is ok, clutch is fine....

I hear an engine that is idling to fast and you blipping the throttle. What else am I supposed to notice?

Can you hear inconsistency in engine pitch... sudden flatline or higher pitch noise as if something was loose or not engaging...

 

[cbaker65]

I had the engine taken off and removed the clutchbell... single screw in front. It was two piece clutch shoe and it felt pretty tight when I pulled on it outward.... wasn't loose. With that said I am not sure if that's the way to test. See attach picture with clutchbell off.



Let me understand what you saying, it's not spring tension but wear on the shoe on outskirt of the surface, is that what you're trying to convey? I keep thinking that as long as spring tension is ok, clutch is fine....

Looking at the shoes & the spring ,it looks like the spring sticks past the shoe ,if it does ,then the shoe
is worn out causing the spring to ride in the shoes space! That's not good!

Is there a flat spot worn on the bottom of the spring?
Also ,if the shoes is worn bad ,it will take higher revs to get the car moving!

I would get a new set up ,a 3 shoe flywheel with 3 shoes ,it will have better contact with clutch bell!...

 

[Certified Mike]

I would tend to agree with @cbaker65. About the clutch. It seems a likely good place to look. The video sounded to me as if something may have been rattling but I am listening and watching on a phone so I am limited. You may be out of adjustment but if the spring is beyond the clutch material, you're shoes need replacing. If that is happening, you'll likely have a shiny ring inside the clutchbell where there was metal to metal contact.

 

[HueyC]

I would tend to agree with @cbaker65. About the clutch. It seems a likely good place to look. The video sounded to me as if something may have been rattling but I am listening and watching on a phone so I am limited. You may be out of adjustment but if the spring is beyond the clutch material, you're shoes need replacing. If that is happening, you'll likely have a shiny ring inside the clutchbell where there was metal to metal contact.

Thank you so much for fast response. I will check tonight when I get home. You don't know how much I appreciate your comments... I am newbie in this hobby and this knowledge goes along way. I tried calling HPI support but it's terrible. I've found Redcat support much much better... seems like HPI support plane hobby more than Rc from their phone prompt. I'll post my findings.... again thank you guys

I would tend to agree with @cbaker65. About the clutch. It seems a likely good place to look. The video sounded to me as if something may have been rattling but I am listening and watching on a phone so I am limited. You may be out of adjustment but if the spring is beyond the clutch material, you're shoes need replacing. If that is happening, you'll likely have a shiny ring inside the clutchbell where there was metal to metal contact.

If shinny rings exist on the inside clutch bell, should I replace that along with shoe?

 

[Certified Mike]

This forum is all about helping each other out. Its a great place to learn. You should spend some time poking around and reading. I have no opinion about the support numbers. I've never called one.

If there is no wear from the spring, in other words, no damage to the bell, no need to replace. You may want to lightly scuff the inside of the bell...very light abrasive to give a clean surface area for the new shoes to break in on. It is more likely that you will find the springs have been slightly cut into by the bell as an obvious damage but you may need to be looking for a slight flat spot or shiny spot on the spring outer surface (the surface that would contact the bell) I would replace the spring with the shoes no matter what.

The clutch bell isn't usually a whole lot of money anyways... IMO, better to have and not need... Saves on shipping in many cases too.

While you are there, make sure the bearings spin smooth and the flywheel is tight too. Keep in mind that diagnosis on line even with a video isn't an exact science in this case especially. Where you are new and because of your 'noise' I would spend some time going over all the metal screw to metal parts using BLUE locktite (use blue only and only on metal to metal). Make sure all the gears are meshed properly etc. This is a great way for you to learn about your car. Do them one at a time and don't over torque anything. The vibrations caused by a nitro with tend to loosen hardware over time... Sometimes very quickly.

 

[HueyC]

Will do. Again thanks and have a great weekend!

 

[Certified Mike]

Def let us know what you find and how you make out! Enjoy the weekend!

 

[HueyC]

Finally home for weekend, took it apart again and looks like you were right on target. See better picture this time... there's s ring inside clutch bell... don't think that's normal. Plus, tried zooming on the shoe spring... definitely see spring wear shiny shaved down ends

 

[Certified Mike]

Glad to see it was an easy fix! (@cbaker65 is good! ) I would check pricing and if it is cheap enough, just go ahead and replace the shoes, spring(s) and the bell at once to start fresh. Good luck!

 

[olds97_lss]

Make sure to clean the new shoes and the inside of the bell with DA (alcohol) to remove any oil. New bells tend to have oil on them... as do used bells. Any oil will cause excess slip and premature wear.

Probably a good idea to replace the CB bearings as well. Usually a 5x10 bearing. I usually buy them 10 at a time to have spares, but I also have 4 nitro's I have to keep up with. At $1 a bearing, it's cheap to have extra. Vs spending $13 on a pair of the HPI replacement B021...

 

[HueyC]

I have ordered bell, 18T, 22T pinion orange gear, 5x10 bearings for inner and outer bell housing and shoes. It wasn't too bad, all said and done $34.00. Hopefully, that's all it is but I suspect so....

 

[HueyC]

Make sure to clean the new shoes and the inside of the bell with DA (alcohol) to remove any oil. New bells tend to have oil on them... as do used bells. Any oil will cause excess slip and premature wear.

Probably a good idea to replace the CB bearings as well. Usually a 5x10 bearing. I usually buy them 10 at a time to have spares, but I also have 4 nitro's I have to keep up with. At $1 a bearing, it's cheap to have extra. Vs spending $13 on a pair of the HPI replacement B021...

I am thinking about buying 5x10x4mm CB bearings by roll of 10 on eBay. I have several 1:10 scale nitro Rc as well. Haven't had to replace bearings yet but are they typical same size and dimension? Just curious... since you stock up.