Restoration Project #8 - Huge Bundle of HPI, Kyosho and HSP.

[tudordewolf]

PS - I've got a hunch that the GS Racing .18 is a re-badged SH. 18 Rear-exhaust, look at the similarities, the "18" is identical. Apart from the head they're an exact match. Now you can have some official specs for your engine!

 

[gandalfnz]

It's funny how parallel some of our projects / solutions run. I just assembled the same clutch shoes and was going to tell you I found a way to make the springs fit, I just put the whole spring in the jaws of a pair of pliers and squeezed it to put more bend in the main "finger" that holds the clutch shoe, now it lies flat.

View attachment 164813 View attachment 164814

Like you, I found them nearly impossible to apply even with a clutch tool. I stuck a screw through the clutch shoe and spring and used the same pliers to move the "leg" a bit further back.

The intended orientation for the clutch nut is with the groove further away from the engine, it looks like you may have done that already. Kyosho's tapered clutch nut is meant to make installation easier, though in my experience it only helps a little.

I think those shoulder bolts from my other Fish build, way back would be the perfect solution to your shaft-end/bearing issue. I'll probably wind up using another couple myself in these builds.

M3 thread, 5mm long, 5mm diameter shoulder x 5mm long.

I've got a dozen, I'll mail you a few if you have trouble finding them locally.

I've thought of dremeling a deeper groove, for the 2-piece clutches too, because I've noticed the outside of that spring starting to wear while the shoes still had plenty of "meat" on them.

I would want to make some sort of jig to get the depth right and also not widen the grooves by mistake, and then also weigh the shoes afterward to within .01g to avoid imbalance.

I wonder if at high-enough RPM's, those "wraparound" style springs might actually lift out of their groove and stretch to the inner diameter of the clutch bell as a result of the centripetal force, potentially snapping them - I had one recently fail and it's encouraging me to try and move away from the "semicircle" style clutches entirely. Kyosho uses 2x shoes from a 3-shoe set on their FW-06, pretty effective in my opinion.


View attachment 164815

Edit: I just worked out that at 35k RPM, there's 13,000 G's of outwards force on the clutch shoes; a 2g shoe experiences 60lbs of pull! (sorry for the metric/imperial mashup) Those wraparound 2-piece clutches are probably fine below 30k RPM, but over that I want the spring & shoe type.

The Kyosho clutch shoes don't have a deeper groove, but the springs are perfectly contoured to them.

Since some of my clutch bells are the last of their stock or otherwise irreplaceable, I might run only teflon/composite shoes in them rather than aluminum to try and maximize their life even if I have to rebuild the clutch more often.

I noticed how your clutch shoe pins on the flywheel are nice and flat with the clutch shoe once installed, mine seem a bit short, if you check my photos.
Damn, I did install the clutch nut the wrong way around, when I had a look at it, it made sense to me to be like that, because otherwise the groove for the spring was a too far away, maybe this is because shoes will also move a bit forward with centrifugal force? I don't feel like removing it all again, lets see how it goes like this.

I was thinking the opposite, even though the spring seems like its not sitting right, once the clutch shoe expands/engages, it could create a much better fit?

Again, interesting, on both of my FW06 (GXR15), clutch shoes are half circle ones, and I fond them to be really good, none have failed on me so far. However there must be a good reason why Kyosho moved away from them with introduction of KE series engines.
HPI RS4's use carbon 2 piece system like the Kyosho drawing you attached, but these cars just don't take off well enough I found, hopefully aluminum will have more grip and being a 3 piece it will be snappier.
I tried using HPI system (2 piece) in the Ffish, and again found it to be quite lazy on take off.

Good idea when it comes to cutting clutch grooves equally, which will be hard, but I will give it a go anyway, just a dremel with a cutting disk with a width approx. the same as the groove.
The thing is, to me it looks like those springs will rub on the bell right away.
I just ordered 8 more sets from JZ.

Regarding the shoulder bolts, did you loosen them a bit, and the applied loctite, because it looks like they will lock up the clutch bell?
Or did you even have to shim them maybe, I guess it all depends individually on the engine and parts involved.

 

[tudordewolf]

Regarding the shoulder bolts, did you loosen them a bit, and the applied loctite, because it looks like they will lock up the clutch bell?
Or did you even have to shim them maybe, I guess it all depends individually on the engine and parts involved.

I did shim them, on both ends - I didn't need all 5mm of the shoulder, just a little extra. Once installed, it's the same as if you had a longer pilot shaft with the usual retaining screw in the end. I shimmed mine so that when the bolt was screwed in completely, the clutch bell still had a tiny bit of play forwards and backwards, which seems to be the suggested setup.

The head of the shoulder bolt is small enough to fulfill the role of the screw that goes in the end of the pilot shaft normally; it'll retain the bearing but not rub on the clutch bell.

It really is a perfect solution to the problem. I've got half a mind to start selling them as "SG Shaft extensions" for $10 a pop, along with sets of drilled engine mounts for putting pilot-shaft engines in HSP vehicles. Thanks again for verifying that spacing, it's coming together very nicely. I also cut down my engine mounts so a bump box will reach the flywheel, and cut them at the "flange" so they've got an extra-wide base. I even sanded the bases to the same plane of flatness after installing them.

Something I like doing with the 2-piece clutches is mounting them "backwards", because that means they're "grabbed" by the rotation of the clutch bell; it gives very sharp / snappy, all-or-nothing engagement. You could do the same with your 3-piece clutch shoes, so the spring fits into the groove the way you've place them.

 

[gandalfnz]

PS - I've got a hunch that the GS Racing .18 is a re-badged SH. 18 Rear-exhaust, look at the similarities, the "18" is identical. Apart from the head they're an exact match. Now you can have some official specs for your engine!

View attachment 164817

Interesting, so much power, thank you for letting me know.
Just confirms again that its the Kyosho carb that is making the engine sing in my case.
My 11K is posted already, that didn't take long actually.

I did shim them, on both ends - I didn't need all 5mm of the shoulder, just a little extra. Once installed, it's the same as if you had a longer pilot shaft with the usual retaining screw in the end. I shimmed mine so that when the bolt was screwed in completely, the clutch bell still had a tiny bit of play forwards and backwards, which seems to be the suggested setup.

The head of the shoulder bolt is small enough to fulfill the role of the screw that goes in the end of the pilot shaft normally; it'll retain the bearing but not rub on the clutch bell.

View attachment 164818
It really is a perfect solution to the problem. I've got half a mind to start selling them as "SG Shaft extensions" for $10 a pop, along with sets of drilled engine mounts for putting pilot-shaft engines in HSP vehicles. Thanks again for verifying that spacing, it's coming together very nicely. I also cut down my engine mounts so a bump box will reach the flywheel, and cut them at the "flange" so they've got an extra-wide base. I even sanded the bases to the same plane of flatness after installing them.

View attachment 164819

Something I like doing with the 2-piece clutches is mounting them "backwards", because that means they're "grabbed" by the rotation of the clutch bell; it gives very sharp / snappy, all-or-nothing engagement. You could do the same with your 3-piece clutch shoes, so the spring fits into the groove the way you've place them.

I am a little confused, as to how you shimmed those shoulder bolts on both ends, but if I had seen one in person, it would become much more clear.
Unable to find them locally, and amazon is out of stock.
It does look really professional/factory from that photo!

I thought clutch shoes can only be installed in one direction, in order to have the most grip, with flywheel spinning counterclockwise...
To me they would have less grip by if installed the other way around.

Good idea with trimming those mounts. Pull start kind of grew on me lately, don't have to worry about batteries for the rotostart being charged + also maintenance on the starter box.

 

[tudordewolf]

I am a little confused, as to how you shimmed those shoulder bolts on both ends, but if I had seen one in person, it would become much more clear.

I meant that I shimmed it both forwards from the clutch nut and back from the end of the shoulder bolt.

Bear with my messy, on-the-fly cross section, but here's a 30-second sketch with the clutch bell omitted. Imagine you sliced an engine in half down the centerline, here's my approximation, zoomed in on the tip of the crankshaft:

What I'm referring to with backwards clutch shoes is the self-servo effect, as observed in drum brakes, which are nearly identical in construction to our clutches:

It's kind of like the difference between trying to push a rake in front of you and dragging it behind you, one way will have much more friction than the other because the direction of motion will increase the opposing force between the surfaces.

 

[gandalfnz]

I meant that I shimmed it both forwards from the clutch nut and back from the end of the shoulder bolt.

Bear with my messy, on-the-fly cross section, but here's a 30-second sketch with the clutch bell omitted. Imagine you sliced an engine in half down the centerline, here's my approximation, zoomed in on the tip of the crankshaft:

View attachment 164822

What I'm referring to with backwards clutch shoes is the self-servo effect, as observed in drum brakes, which are nearly identical in construction to our clutches:

View attachment 164821

It's kind of like the difference between trying to push a rake in front of you and dragging it behind you, one way will have much more friction than the other because the direction of motion will increase the opposing force between the surfaces.

Understood about the shimming, thank you for the drawing, yes I had to do the same, in fact I need to order some M5 shims, as I only had M6.
There is maybe 1mm or less of a gap between the bell and the flywheel, you can clearly see the clutch shoe, I am hoping the shoe moves a bit forward once engine is running, otherwise the shoes will not engage along their entire surface.
I think having a small gap there is good, so the dust from the shoes wear can escape.

Sorry, about the clutch shoes in reverse, are you talking about the half circle ones, because they have no orientation, but the 3 piece one should only be installed one way.
I cannot see, how they will engage if engine spins to the left, and they are mounted to the left as well, or the opposite than we have them now?
Am I understanding this correctly?

Very useful conversation.

Thanks

 

[tudordewolf]

Sorry, about the clutch shoes in reverse, are you talking about the half circle ones, because they have no orientation, but the 3 piece one should only be installed one way.

I'm talking about the the half-circle ones, it was kind of a tangent, I believe orientation does matter. Now that I think about it I realize the 3pc clutches risk "catching" their spring on the clutch bell if mounted backwards and would have generally bad outcomes.

I'm partially basing my understanding on previous forum conversations I've seen on the subject, here, here, and here, apparently a Hudy tuning guide published this at some point. There's a PDF here from hudy.net that I'm downloading right now that should have that piece of info in it.

They'll engage in either direction, the difference is between whether they're facing "forward" to the rotation or backwards. The shift point won't change, they'll experience the same forces and pivot out at the same RPM, but what happens at the moment of contact will be different; "normal" orientation will be gradual increase in friction, backwards will lock up much faster but wear the clutch shoes more. The latter is counter intuitive to me, because I would imagine that less sliding motion = less wear, and reverse orientation would theoretically slip less.

 

[gandalfnz]

I'm talking about the the half-circle ones, it was kind of a tangent, I believe orientation does matter. Now that I think about it I realize the 3pc clutches risk "catching" their spring on the clutch bell if mounted backwards and would have generally bad outcomes.

I'm partially basing my understanding on previous forum conversations I've seen on the subject, here, here, and here, apparently a Hudy tuning guide published this at some point. There's a PDF here from hudy.net that I'm downloading right now that should have that piece of info in it.

They'll engage in either direction, the difference is between whether they're facing "forward" to the rotation or backwards. The shift point won't change, they'll experience the same forces and pivot out at the same RPM, but what happens at the moment of contact will be different; "normal" orientation will be gradual increase in friction, backwards will lock up much faster but wear the clutch shoes more. The latter is counter intuitive to me, because I would imagine that less sliding motion = less wear, and reverse orientation would theoretically slip less.

Interesting.
I reversed the pilot nut, and tried the car, it works good, but I shouldn't have weakened those springs a bit, as now it really needs a low idle for them to stop turning while in the air. Maybe once the clutch shoes wear, it will be ok.

I was wondering, do clutch shoes need break in as well? Thought about it after I gave it a few good throttle blips...

Installed a new brake disk, no rubbing this time, so thank you for recommending this flywheel.
Now, the only issues I see is weak braking, and if I tighten the brake more, it applies even when in neutral.

Will send some photos soon, the build looks nice now, but this is anything but its far away from a stock Ffish.

 

[tudordewolf]

Interesting.
I reversed the pilot nut, and tried the car, it works good, but I shouldn't have weakened those springs a bit, as now it really needs a low idle for them to stop turning while in the air. Maybe once the clutch shoes wear, it will be ok.

I was wondering, do clutch shoes need break in as well? Thought about it after I gave it a few good throttle blips...

Installed a new brake disk, no rubbing this time, so thank you for recommending this flywheel.
Now, the only issues I see is weak braking, and if I tighten the brake more, it applies even when in neutral.

Will send some photos soon, the build looks nice now, but this is anything but its far away from a stock Ffish.

I wound up removing and re-building mine, I have to retract what I said earlier about the tapered kyosho clutch nut - it helps a lot. You only have to get the spring started, then you can press the shoe down onto the pin and it'll snap into place.

I think clutch shoes may wear in in the sense that they contour the the inside of the clutch bell. Here's a set of mine very clearly displaying the contact patch:

Also, this was the exact amazon listing I got my bolts from, dunno if it's available for you. I'd be happy to pass some along, it's not like I need all 10.

I realize now that anodized shoes are pointless or even counterproductive, since the anodization immediately wears off into a fine abrasive...

My solution to that braking issue was to shorten the fuel-line "bumper" on the brake linkage, so it has a sharper transition from engaged/disengaged. I think it is because slide carbs less travel than rotary carbs, the brakes have to make do with a shorter stroke from the servo.

There's a beauty to the FFish's flexibility; it's simplicity and roomy layout lends itself to modding, and the cheapness / variety of parts all in constant stock make it a very project-friendly platform.

I tried mounting up an engine and discovered the "center-drilled" engine mounts are about 3-5mm too far back for both the single and 2-speed transmissions. The gears engage but only halfway along their width, I'll redo them with just a bit more forward offset.

 

[gandalfnz]

I wound up removing and re-building mine, I have to retract what I said earlier about the tapered kyosho clutch nut - it helps a lot. You only have to get the spring started, then you can press the shoe down onto the pin and it'll snap into place.

I think clutch shoes may wear in in the sense that they contour the the inside of the clutch bell. Here's a set of mine very clearly displaying the contact patch:

View attachment 164881

Also, this was the exact amazon listing I got my bolts from, dunno if it's available for you. I'd be happy to pass some along, it's not like I need all 10.

I realize now that anodized shoes are pointless or even counterproductive, since the anodization immediately wears off into a fine abrasive...

My solution to that braking issue was to shorten the fuel-line "bumper" on the brake linkage, so it has a sharper transition from engaged/disengaged. I think it is because slide carbs less travel than rotary carbs, the brakes have to make do with a shorter stroke from the servo.

There's a beauty to the FFish's flexibility; it's simplicity and roomy layout lends itself to modding, and the cheapness / variety of parts all in constant stock make it a very project-friendly platform.

I tried mounting up an engine and discovered the "center-drilled" engine mounts are about 3-5mm too far back for both the single and 2-speed transmissions. The gears engage but only halfway along their width, I'll redo them with just a bit more forward offset.

You always praised the Kyosho clutch nut? Not sure what you mean.
Yep anodized wears off, which is why I got mine in plain metal.
I will have to play around with the brakes.....
Which engine is that in the photo, I like how HSP VX18 clutch uses a pilot nut that has a circlip on it. Is that the VX18 nut or a different one?
Hmmm, weird, for me since I used the flywheel you recommended, everything slotted and aligned absolutely perfect!
The spurs and clutch bell aligned really well, (see photo).
I had the same issue as you when I used the traxxas flywheel, they engaged only half way.
Waiting for nice weather to give it a good run, raining for the next 10 days here....
Winter is coming...!

 

[tudordewolf]

You always praised the Kyosho clutch nut? Not sure what you mean.
Yep anodized wears off, which is why I got mine in plain metal.
I will have to play around with the brakes.....
Which engine is that in the photo, I like how HSP VX18 clutch uses a pilot nut that has a circlip on it. Is that the VX18 nut or a different one?
Hmmm, weird, for me since I used the flywheel you recommended, everything slotted and aligned absolutely perfect!
The spurs and clutch bell aligned really well, (see photo).
I had the same issue as you when I used the traxxas flywheel, they engaged only half way.
Waiting for nice weather to give it a good run, raining for the next 10 days here....
Winter is coming...!

View attachment 164882

View attachment 164883

View attachment 164884

View attachment 164885

View attachment 164886

That gear mesh looks perfect, it must be my choice of flywheels.

I thought had initially said the Kyosho clutch nut wasn't that much better than the HSP one.

That's the Sh.12 destined my next Fish, with an 18/23:

1.48HP / 41,000 RPM manufacturer spec. If I hit that with that gearing I'll do 62mph.

That clutch nut with the circlip slot is "stolen" from one of my Thunder Tiger engines, it was included with the Evo-12P. I got an extra engine so I nabbed it from the box. Might upgrade one to 2-shoe clutch setup with a groove-style clutch nut.

I managed to find the part number, AA0199B:

Edit: I thought I'd found some in stock, but no.

 

[tudordewolf]

Found another, this one has both a groove and a slot: HPI 101062, and it looks available.

 

[gandalfnz]

Found another, this one has both a groove and a slot: HPI 101062, and it looks available.
View attachment 164890

Thanks a lot for linking these.
I am not super happy about my Cbell, I mean it spins freely, but not like when you give it a spin it remains spinning for close to 10s or so....
I like if I move the car back by hand, Cbell just keeps on rolling on some of my cars.
For me, its showing out of stock on those shoulder bolts, if you don't mind send me a couple, It would be much appreciated.
Not sure how it works, but if you can send me a request for payment on paypal, I will be more than happy to pay for them and shipping?
When are we going to see that TRX running with 11k?
Thank you!

 

[tudordewolf]

Thanks a lot for linking these.
I am not super happy about my Cbell, I mean it spins freely, but not like when you give it a spin it remains spinning for close to 10s or so....
I like if I move the car back by hand, Cbell just keeps on rolling on some of my cars.
For me, its showing out of stock on those shoulder bolts, if you don't mind send me a couple, It would be much appreciated.
Not sure how it works, but if you can send me a request for payment on paypal, I will be more than happy to pay for them and shipping?
When are we going to see that TRX running with 11k?
Thank you!

I know what you mean about the clutch bell spinning freely, it's also a useful indicator of good mesh with the transmission. On most of my builds the driveline doesn't "freewheel" for very long until I've run it up to speed at least once. I think the various brand new bearings, shields and shims need to tolerance in just a bit.

I must confess, I've accidentally let the TRX fall into development hell. Other projects are more exciting and less work. I'll probably wind up buying another pivot-ball truck roller and just transplant it in instead of trying to finish the Frankenstein'd monster that it became. These 2 builds I've been talking about will probably get finished & run first, then that one, then the other engine swaps.

I'm beveling another flywheel for the Sh.12 to try and use the mounts I already made, here's my improvised lathe setup- I sand it with a dremel while turning it.

And the redone mounts on the other engine, ultimately I'm glad I redid them in purple to match:

 

[gandalfnz]

I know what you mean about the clutch bell spinning freely, it's also a useful indicator of good mesh with the transmission. On most of my builds the driveline doesn't "freewheel" for very long until I've run it up to speed at least once. I think the various brand new bearings, shields and shims need to tolerance in just a bit.

I must confess, I've accidentally let the TRX fall into development hell. Other projects are more exciting and less work. I'll probably wind up buying another pivot-ball truck roller and just transplant it in instead of trying to finish the Frankenstein'd monster that it became. These 2 builds I've been talking about will probably get finished & run first, then that one, then the other engine swaps.

I'm beveling another flywheel for the Sh.12 to try and use the mounts I already made, here's my improvised lathe setup- I sand it with a dremel while turning it.

View attachment 164927

And the redone mounts on the other engine, ultimately I'm glad I redid them in purple to match:

View attachment 164928

True that about cbell spinning freely for a while with a perfect mesh and other variables that play a part in it, but even you spin it by hand while the engine is not mounted, some of them will spin much longer than others.

That's a shame, I really wanted to see how 11k can make 3.3 run, mine should be here soon, so I will post results.

Do you just hold the drill with your hand and sand paper in the other, of you locking the other end of the crank shaft into some sort of centering tool?
I shimmed my flywheel with a 1mm washer, so there is 0.2 mm of a gap between it and the carb body, almost touching, so no need to machine the flywheel. Maybe that's why the spur/bell mesh is so good.

 

[tudordewolf]

True that about cbell spinning freely for a while with a perfect mesh and other variables that play a part in it, but even you spin it by hand while the engine is not mounted, some of them will spin much longer than others.

That's a shame, I really wanted to see how 11k can make 3.3 run, mine should be here soon, so I will post results.

Do you just hold the drill with your hand and sand paper in the other, of you locking the other end of the crank shaft into some sort of centering tool?
I shimmed my flywheel with a 1mm washer, so there is 0.2 mm of a gap between it and the carb body, almost touching, so no need to machine the flywheel. Maybe that's why the spur/bell mesh is so good.

I will get to it, sorry to have talked it up so much when I got mine and then never posted about it again.

I used a dremel with a sanding drum, and then a cutting disk, both seemed equally effective and were equally prone to developing a frustrating "bounce" instead of smoothly riding the surface.

 

[gandalfnz]

Gave the Fish a test today, I am having issues tuning, and I think its the poopy SH carb. I am tempted to move a carb from one of my gxr15 engines to this one, just to see how it will behave, but not a big fan of robbing parts from one car to put on another.

It really flies with the new cbell and this Force engine.

It idles fine for a few runs, then starts idling really low and shuts off (see video end), then I up the idle, then after a few passes idle is too high....?

But, its a ROCKET!

 

[tudordewolf]

It idles fine for a few runs, then starts idling really low and shuts off (see video end), then I up the idle, then after a few passes idle is too high....?

That looks like its running nice!

Same tuning issue I haven't solved yet on my FW-06. I think it could be the LSN delivering inconsistent fuel, perhaps from gelled fuel slightly clogging the valve, in my case? It was my first time taking it out in ~6 months. I also wound up with an idle gap smaller than seemed usual, so maybe an air leak, but I don't know how / where it would have developed one just sitting, unless one of the needle o-rings cracked.

The GRX-15 carb also arrived, I may just upgrade it to that.

 

[gandalfnz]

That looks like its running nice!

Same tuning issue I haven't solved yet on my FW-06. I think it could be the LSN delivering inconsistent fuel, perhaps from gelled fuel slightly clogging the valve, in my case? It was my first time taking it out in ~6 months. I also wound up with an idle gap smaller than seemed usual, so maybe an air leak, but I don't know how / where it would have developed one just sitting, unless one of the needle o-rings cracked.

The GRX-15 carb also arrived, I may just upgrade it to that.

Which carb are you using with your FW-06, sorry I keep forgetting, is that a KE15 or Tiger 12, paired with which carb?

From what I could see online, stock V2 (KE15) FW06 can idle super low, and sounds really nice.
6 months storage if ARO was applied should not make it gum up, I mean I have cars sitting for over a year and they fire up fine.

I can tell you one thing, which I discovered on my nitro Slash, after sitting for a while, the O rings in the carb (LSN and HSN) got stiff and leaked air, and same, my Slash tune was lost from last time, and I was wondering what the heck is going on, only to find out its the O rings.

I don't understand why everyone uses rubber o rings in the carb, instead of silicone, because I believe silicone is more resistant to fuel and oil, it does not harden?
But, I am finding difficulties finding small enough silicone rings, I know I had a look on ALI and could not find them, maybe you will be more lucky?

You got the GXR15 carb after all? How much for? Please let me know what you think, keep in mind that carb is sensitive, do only smaller 1-2 hr increments when tuning. Good luck!

Cheers

 

[tudordewolf]

Which carb are you using with your FW-06, sorry I keep forgetting, is that a KE15 or Tiger 12, paired with which carb?

KE15 w/stock carb, which I'm pretty sure is a rebadge of a Force .15 engine. I wound up swapping it back from the TT engine, it seemed redundant with the TT-Fish. The other cars I'd sat for a season fired up and had no issues.

Plastic carb body which is ok I guess, but I do generally admire the metal ones more. Appreciate the tip about the GX carb, I snagged it for ~$45 which seemed extremely reasonable.

It was very reliable before, so it does seem like it's one specific issue and not a general malaise of the engine. Definitely true about the low idle, though too low seemed prone to stalling after WOT runs.

The smallest silicone o-rings I can find still have a 4mm OD, slightly too much for carb needles which I believe need 2mm or 3mm OD rings, which that store has in NBR rubber. Might be worth picking up to do replacements with anyway, and its dirt cheap.