Just Built a Frog - Need Help!

[CraigF]

My first post, and my first and only RC car (I do helis and just starting in subs, the usual stuff).

A bit of the story: I bought the Frog in late '85. Shortly after, I got a new job in a different city. The company paid to pack up and sell the house while I worked at the new place. So I wasn't there during packing...and I completely forgot about the Frog in all the upheaval. Discovered the Frog box (rather large) totally mint etc. in the bottom of a large box packed with curtains from the old house. Since the curtains were totally useless for the new place I never unpacked that box...until last week. Yes, I'm a packrat.

I thought cool, I'll build this up and run it in the house, scare the pets etc. Such an old model, it would be an embarassment to run in public what with all the hot stuff available now... Yesterday I had to get some surface RC gear anyway, so thought that mechanical speed control sounded kinda cheesy, I'm used to ESC/BEC, so kinda randomly (the specs seemed OK) picked out an ESC, the Novak XRS. Will that be OK, anybody know, electrically and for fit? Also, it would be really convenient to me if I could run with 7-cell packs, they're my standard for other stuff. It sounds like (from the Mabuchi site) the motor should take it. Comments? Thanks!

Anyway, today I thought I should maybe see what other people use with RS540 motors, re ESC and batt voltage. And I started to read that the Frog is a bit of a collectible. I had no idea. And maybe I shouldn't have built it...it's not finished by any means, the chassis is complete and rolling, no radio gear installed, never been powered up, body/wing only roughly cut out and still need to be trimmed to shape. Too late I guess, might as well run it. I see it's recommended I replace the wheel bearings with ball bearings right away, will do that tomorrow if available at LHS (they specialize in cars, so I'm hopeful). I won't paint the body/wing or use the decals. Anything else I should "preserve"? I'm planning to use the stock rear tires, I doubt they'll wear much indoors.

Thanks for any suggestions re the motor circuit stuff. Apologies for rambling, just a little "excited" to find out that I don't have to be too embarassed about asking re the Frog after all (why I didn't ask around re the XRS before ordering...).

[Neil_S2000]

Frogs are very collectable. Yes it would have been more collectable if you hadn't built it, but that doesn't mean it was wrong to do it. If it were me I would keep it on the shelf, and buy a used Frog as a runner. A new built Frog is still pretty rare!

[bholio]

You should be able to fit the ESC in there somewhere. Maybe you could figure out how to mount it where the MSC servo goes. Another good spot is where the unneeded 4 cell radio battery pack would go inside the frame.

Be careful with an upgraded motor & 7 cell battery packs. The frog transmission and rear driveshafts are somewhat fragile. They will not take large amounts of power for very long without starting to slip and grind.

Bearings are even more important in the transmission than the wheels, if they are not in there already. You might want to consider opening it up and putting some in there.

If you want to know what an unbuilt frog would have been worth, check ebay 'completed items' to see if any sold recently.

If you are concerned about value, keep the original body, decals & in their current unused state. Wheels and tires too. Of course, that sucks alot of the fun out of it.

In its current partial-built, unused state, especially if you haven't damaged the body and decals, you could probably get enough money for it on ebay (or tamiyaclub) to buy a new current-model RC car. Once you drive it, forget it. It will just be another used Frog. No shortage of those.

[CraigF]

Thanks, makes sense re batt voltage, I've since read the rear diff can be a source of problems. I forgot that with the ESC I'd be a servo short, so yeah, should be plenty of room for the ESC...especially since I likely won't even bother to put the clear body shell on now, still thinking about it. Decals look mint to me, aged much better than waterslide ones typically do. I have tons of 8.4V packs, guess I could wire in one or two 50A diodes in series to drop the batt voltage. I would think the ESC should handily limit the voltage to the motor, being a DC motor and "voltage controlled" (sorry, I'm used to brushless). OTOH, might be time to start collecting 6-cell packs as I do have other uses for them, but can't otherwise use 5-cell packs.

This was supposed to be just for fooling around in the house. Thus part of the reason for the ESC, I thought the Frog would be all but uncontrollable inside with just the 3 speeds. Does running in the house count the same as running outside? I will try not to ruin anything that's stock. I doubt this car will ever see eBay, I'm a "keeper" rather than a collector, but I will respect the thoughts of collectors and maintain the car in fine condition now that I know. For outside I will get something else. Thanks.

[Twmaster]

I would not run (read that as ruin) the stock tires. Buy a set of cheap aftermarket tires/wheels off somebody here or on the 'Bay and save those original tires. You'll be glad you did up the road.

[]

[Dingo_aus]

I had a similar experience with a FAV. Found my brother's old one. Needed spares went back to the original shop like 15 years after buying the first one. The bloke there sold me a NIB FAV minus speed controller and front tyres for AUD$50. This was about 6 years ago. Got bored one day started building the second FAV. Didn't realise the value of NIB.

Oh well soon I hope to use the brand new parts to create reproduction spares. Hope is to have a spare one of everything. And yes if they turn out ok I'll offer them of sale too.

[CraigF]

OK, get the message re the tires, will see what I can find. Glad I didn't glue them on as per instructions, seemed unnecessary for slower indoor use. I should have mentioned, I can take measurements/pics etc. of original "new" parts if anybody needs them. Probably not since this kit is so common, but anyway... From what I've read here, this is likely the original kit version as there were no motor connectors included or mentioned.

I've read that molybdenum grease seems to be popular for that pesky diff. I have that handy, as well as lithium, graphite, silicone, and a few types of grease with Teflon in them. What is good to prevent wrecking the diff gears? Anybody try that Finish Line Teflon grease, meant for bicycles? Or even the SuperLube Teflon grease (I don't know how that is for wear, I usually use it for its high temp properties). I just used the Tamiya grease that came in that tiny tube, and probably not enough of it either, have to redo. Thanks.

Regards,

Craig

[HunterZero]

I used molybdenum grease for the diff and hex drive shafts in my Frog, and they have lasted well, even with a Technigold motor.

As long as you keep the hex dogbones clear of grit using the boots provided, and keep them packed with molybdenum grease, they'll last well.

The main problem with the diff is that the gearbox halves flex and allow the diff to seperate, which can cause damage to the gears. Shouldn't be too much of a problem with the stock or mildly hot motor. If the gearbox sounds crunchy when you're turning, then this is the likely cause. Solutions include...

1. Remove the small metal rod that goes through the diff, drill out one of the gearbox joints, thread the other and tap a screw through the diff.

2. Shim the diff with metal washers.

3. Just squeeze the gearbox plates back together (temporary fix).

If you want to part with the original 3-step MSC, I'm interested in it []

- James

[oldfrogshot]

Hi Craig, and welcome to TC -

I've put up some pictures of a 'screw mod' for the frog diff here:

http://www.tamiyaclub.com/showroom_model.a...=24674&sid=3142

I've also made up some drive shafts and hex adapters for the frog. Please refer here:

http://www.tamiyaclub.com/xforum/topic.asp?TOPIC_ID=8104

Wish I had a spare box of Frog stuffed somewhere safe like you did!!!

[WillyChang]

Stick the XRS to the side of the steering servo, hopefully the motor wires will be long enough to reach.

XRS is a great unit.

quote:Originally posted by CraigF

I have tons of 8.4V packs, guess I could wire in one or two 50A diodes in series to drop the batt voltage. I would think the ESC should handily limit the voltage to the motor, being a DC motor and "voltage controlled" (sorry, I'm used to brushless). OTOH, might be time to start collecting 6-cell packs as I do have other uses for them, but can't otherwise use 5-cell packs.

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id="quote">id="quote">

ESCs use Pulse Width Modulation, so technically the motor gets time-modulated pulses of the full voltage anyway.

8.4V won't hurt it, they'll handle 12V and beyond. (Most 12VDC power tools and car gadgets are 540 powered...)

But... being a valuable new-built Frog and all... you might wanna replace the kit motor (plastic endbell?) with a modern 540 with metal endbell. They're dirt cheap and metal endbells don't melt.

[NYDriver]

The Frog is my favorite car, I have seven of them, not couting some rolling chassis I have a three frog projects I am about to start. I would certainly not run your car, complete and make it a Shelf Queen. You can easily purchase a good condition RTR Frog runner here or on Ebay for the $50 to $100 range depending on condition. The great thing about Frogs is that they is a large abundance of spare parts availible, both used and NIP, so your dont have to fear wreaking it. There are also a ton on vintage mods for them on the market, which I like to do to my Frogs.

Have Fun

Tom

[CraigF]

Thanks again guys.

Yes, the motor has a black plastic endbell. I didn't know the ESC used PWM, and now that you mention it, I don't know how else it might have worked...this'll be my first for a DC motor. It makes sense to put in a current 540 motor, save the original for "stock" after I make sure it still works.

FWIW, the MSC has some black oxidization on the large contact pads of the switch unit. This almost looks like silver oxide to me...these weren't silver-plated were they? Brass and copper sure don't turn that blackish color normally just from air.

I've already bought too much stuff to put the Frog on the shelf. If I hadn't decided to run it, I wouldn't have even found this place. I'm going to run it a bit at least. I don't know, I have this idea that these were built to be used. I want to see it run. So I'll use it gently, without the original electrics. I have lots of things here that look and work perfectly that are much older than the Frog, so I can take care of stuff. It's a good thing that I found this site to find out that the Frog is worth preserving though. I just figured it was an old really technically out of date model that I could "abuse" without having to worry... You know, I found the receipt for the Frog, and they weren't particularly cheap at the time, at least in Canada, but neither was any RC gear in those days.

Anybody know if the "1150" bearings in the Tamiya TLT-1 set are OK for the Frog? They're sure a lot cheaper in that set than buying 1150 bearings in 1/2/4's. Don't want to spend a lot, just for light running and to preserve the stock plastic "bearings".

I guess under the running circumstances I've mentioned it's best to use the lowest ratio gear set? I put the normal set in. But I can't figure out if I should maybe use the high ratio set so the motor can be run slower for the same wheel speed. Mechanical stuff confounds me, I'm electrically oriented... Thanks.

[NYDriver]

You can get a complete set of bearings on Ebay for under $10.

Also, a trick I use if you have troble with the ESC or reciever fitting under the body is to flip the recievver tray over, doing this give you about another 1/8 of an inch of clearance if you mount somthing on it.

Tom

[CraigF]

This is pretty OT, but not irrelevant to Frog replacement parts. And you probably all know it anyway. I just don't trust eBay. I stopped using it in '97, when it started to become a haven for scam artists, it was great before then and I was a big regular. For some of my interests, the eBay items are at least 95% fake, it's easy to tell by those involved in the hobbies. And sometimes we know a for sale item really isn't, because it's a swiped photo of an item one of us owns and has in our possession. And eBay does nothing to stop it, in fact it might be held against *you* if you complain...people have been banned from eBay for complaining about somebody selling stuff that *they* own. So it's caveat emptor as usual, just a lot more caveat for eBay. Most people are honest.

Anyway, I can tell for sure that some eBay items purported to be for the Frog are not original/genuine/whatever you want to call it, and the sellers very carefully don't actually say that they are, they just hint at it. And in some cases I'm sure the sellers don't even know, they got the items from somebody else. But I can tell, I just opened the kit and know exactly what came in it...

Anyway, I'm not looking for original parts, just replacements, but it annoyed me a bit to see that people might not be buying what they think.

[WillyChang]

quote:Originally posted by CraigF

FWIW, the MSC has some black oxidization on the large contact pads of the switch unit. This almost looks like silver oxide to me...these weren't silver-plated were they? Brass and copper sure don't turn that blackish color normally just from air.

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Now that you mention it, you're probably right.

The black stuff usually comes off with a light rub anyway.

Or if you've put your fingers on it, your prints come up in black.

quote:Anybody know if the "1150" bearings in the Tamiya TLT-1 set are OK for the Frog? They're sure a lot cheaper in that set than buying 1150 bearings in 1/2/4's. Don't want to spend a lot, just for light running and to preserve the stock plastic "bearings".

id="quote">id="quote">

Yep, toss the plastic bushings as far away as you can.

If you're after lots of 1150s and only 1150s, buy a set

for a TL01 touring car. You'll get two dozen!

Frog goes pretty quickly even in stock configuration, so

the lowest gearing ratio (smallest pinion on motor) is good.

[CraigF]

I cleaned off the MSC pads with some Caig stuff, and I'm pretty sure it *is* silver, kind of a fancy touch considering what it's on. FWIW, I also do silver plating for odds and ends when I want higher conductivity, oxidization is the downside, but easy enough to clean.

Ordered some bearings (Duratrax) and a motor (Trinity P2k2), so will just pull out the whole wired drive electrics unused, maybe for model display one day. It is awfully hard to find a stock RS540 around here at a store because they say nobody wants them, and ordering a Tamiya one is a bit pricey for what it is. And the P2k2 doesn't cost much more locally than a RS540 online, after you add in the costs of importing/shipping to here. The P2k2 is more useful to me for other projects if I "retire" the Frog.

I am thinking of buying some decals to stick on the clear Frog body, just so it's not so bare. I'm not confident I can paint the "proper" Frog color scheme as I've never done multiple colors on the inside of a shell...in fact I can't quite figure out how to do it when your first applied color "counts", no correcting as such.

I would not mind finding out about some cheap common tires that would fit the stock wheels. I see what you mean, the rubber on the stock ones is very soft and would wear quickly. Thanks.

[HunterZero]

You're right about that - the rubber on the old tyres is very soft, and will wear out real quick. The rear spikes are usually gone after a few runs.

The front wheels are easy - just replace them with any 2WD buggy fronts that use 1150 bearings, eg Wild One fronts.

The rear is a bit more complicated, since you'll need other wheel adapters, either the Tamiya 4-pin adapter (the right adapters for the Frog comes with sets of older 2WD rear wheels, or someone here might be able to help you out) so you can use Wild One/Fox/Falcon rears. The other option is hexagonal adapters. Oldfrogshot makes alu hex adapters so you can just use modern buggy wheels.

- James

[CraigF]

Thought I'd just let you know what I decided. After getting deeper and deeper into trying to run the Frog without wrecking any of the hard-to-get parts, I decided to finally follow the logical route and not run the Frog after all.

So I bought a Gravel Hound. Man, it sure doesn't *look* nearly as strong as the Frog, actually pretty wimpy looking in comparison, but from what I've read it's surprisingly durable, but not very fast stock. That should suit me for now, I think I can use the stuff I've bought with it. It comes with an ESC though not a great one, and a Johnson 540 motor. I guess this isn't the right forum to ask, but you can redirect me: do you think the Novak XRS ESC and Trinity P2k2 motors are worthwhile in such a car, or should I stick to the stock motor/ESC and then maybe get something more "powerful" if I want it? I don't have these items yet, still on backorder. I guess what I mean is, is the XRS/P2k2 a worthwhile upgrade, rather than just an upgrade for $$ sake, should I skip them? Thanks!

[mr_pushrod]

Try it standard to start off with, may take you a while to get the hang of it fully. Then try the XRS and P2k2 setup, it may be as fast as you'll ever want to go. At the end of the day, the XRS is a much better esc so is worth getting while the motor will give you a good boost of power without cutting runtimes too short.