New guy 1985 Optima rebuild Thread.

[BoostCreep]

Good afternoon. First post.

Where to Start? Okay in the mid 80's (1985 I believe) I bought a Kyosho Optima RC Car kit. Some history. My first RC car was a Tamiya Audi Quattro. It was a 2 wheel drive kit with an Audi body. I was always disappointed it wasn't 4 wheel drive. Well when I saw the 4 wheel drive Optima I had to have it. So after saving my coins I bought one and a 2 channel Futaba radio. Since I already had a charger and compatible batteries it was an easy transition.

So as it worked out I didn't drive it regularly for very long as 6 months later I was driving a real car and well my passions changed at that point. So it mostly sat around and once my original NiCads had died I didn't drive it at all. Periodically I would think I was going to use it again and through those times of "let me fix this or remove and check that" I managed to lose the motor and pinion gear, the gear cover, and the right front shock. Don't ask me how as at this point I'm not even able to recall the details of the when and where. Before 2 days ago I hadn't done anything at all with it in at least 15 years.

Here we are 30+ years later and my son, who's 9, just got his first legitimate remote controlled car for Christmas. Now the reality is that after the wife and I split up I didn't even know I still had this car. I didn't find it in my shop when moving. I just assumed it was gone. Then the other day my son and I were out in the woods behind my place and he was driving his car. He made the comment that he wished I had a car to drive as well and I mentioned that I did but I never found it when I moved from the farm. At that moment his eyes lit up and he said he knew where it was. Today (01/08/2016)he brought it to me when I picked him up and so now it's time to get this thing back on the road.

First step was doing an assessment of what's here, what's broken or missing and how do I want to proceed in acquiring the parts to restore it. I found an Optima specific website with links to manuals, other peoples projects and parts suppliers for various things. So with some fresh ideas in mind and a good look at the assembly manual I started my search for the things needed to get this car back to operational status. It should be noted that I am sure to make some poor decisions and parts blunders along the way. I've been out of it so long I don't know up from down in the RC world.

With that in mind here is the basic breakdown of my plans.
• Since a new motor is required I am going to go to a brushless motor and electronic speed control. I ended up getting a Speed Passion Reventon S Controller and SV Competition Motor 3500KV and t11R specs and programming box on Ebay. 540 frame size for $49.90 and $14.00 shipping. I realize there have been many of these that fried almost immediately. Others have run them without issue. I'm hoping I get lucky. Also it appears I would be better off with a 17.5R rather than the 11R I've got on order. Learning curve at work here. Oh well these things will all get worked out eventually.
• I went on Ebay and found a bearing set for the Optima. I ordered it at a cost of $13.99 and $2.50 shipping.
• I found a 15 tooth pinion gear for $12.95 and $3.95 shipping and purchased that as well. (that was a mistake. Any standard 32P would have worked. Lesson Learned.)
• I got a various collection of parts on Ebay. It has the gearbox cover and some shocks as well as a chain, spare motors and another pinon gear. Won the Auction for $34 and $7.00 for shipping.

On 01/09/2016, I disassembled the car completely and cleaned/polished all the aluminum bits. I'm considering getting them anodized as I know a guy who owns such a company locally. Everything has cleaned up well so far and I was happy to see that everything was in great shape as far as wear is concerned. Once my bearings show up from Fast Eddy I'll start reassembly unless of course I decide to anodize. Here are some pictures;

As I got it 2 days ago before any claeaning with my sons car.


Prior to disassembly.


Missing shock.


Body removed.


Gearbox.


Bottom Side.


A little dirty.


Partially disassembled.


Fully disassembled and boxed up into sections RF, LF, RR, and LR.


I'll post more pictures in the near future.

Last night I found out that the Kyosho Tomahawk from the 80's had been re-released in 2015. Looking at the car it appears the body will fit the optima (not the same but close) and the shocks look identical. Hmm. This looks promising. So FYI the front shock set for the Tomahawk which matches the red of the original Gen 1 Optima is part # SC222R. $26.99 from Kyosho (Link http://www.kyoshoamerica.com/Front-Shock-Set-RedTomahawk_p_23948.html) Rear set is #SC223R. $27.99.

At this point I'm waiting on parts and refurbishing the ones being re-used in the meantime.

Looking for any advice on this one. Parts are definitely more difficult to find than expected.

Thinking about picking up a set of RC10 shocks and retrofitting to get a little more travel out of the suspension. Thoughts?

[Coelacanth]

Looks like a great project there, and your back-story is generally similar to mine...Optima forgotten in a dusty box for a couple decades, gets found, and undergoes a restoration & modernization. I went through all that several years ago, too...happened upon a few Kyosho and Optima-themed websites, joined, but found them to be mostly ghost-towns...I'd make a post and all I'd get in response was the sound of crickets chirping. You're in the right forum now. Although this site is AE-centric, the guys here have a wealth of knowledge on ALL vintage RC brands.

The Optima series--especially the original car--has several weaknesses. The red shocks, although pretty, were a pain to rebuild and frequently leaked. I imagine the re-re red shocks for the Tomahawk addressed this but I don't know their exact lengths. If you upgrade your original Optima with taller Turbo Optima shock towers, you have the option of upgrading to Kyosho Gold shocks (they're still as good as anything out there, vintage or modern); however, that can be pricey. 3Racing made a shock set for the Kyosho Lazer ZX-5 that will bolt onto a Turbo Optima with minor mods, and is affordable at under $30 for a full set...however, those are getting hard to find too. 3Racing makes similar shock sets for various cars, I imagine some might be a pretty close match...just measure your desired uncompressed shock length, from center of the eye-holes top/bottom, and search eBay for "3racing damper".

It looks like your front end is straight, which is a rarity among Optimas...usually that front skidplate is all bent to hell up front and usually the U-shaped bumper brace is bent or broken accordingly.

If you're going to drive the car a lot, you'll need a spare final pinion or two (OT-41, the one that goes inside the rear gearbox). The OEM gear is soft aluminum and wears out fast. You can buy repro gears and alloy bumper brace from www.pargustore.com, but the gears are also soft aluminum...but also much cheaper than trying to source the "hard final pinion", a much harder upgraded pinion gear either made from hardened aluminum (Kyosho) or steel (Thorp). They're out there but they typically sell for $40+. Ridiculous price for a single gear, IMO.

If your original tires still have good rubber, without cracks or weather-checking, I'd consider putting those wheels & tires in a Ziploc bag for safe-keeping. You can buy repros but those OEM tires are worth a pretty penny; you should keep them for when you retire the Optima as a shelf-queen and use something else in the meantime. Wheel & tire options is a whole topic unto itself, you'll need to do some searches on here and you'll find lots of info. My own build threads showcase a pile of mod ideas, upgrading, bulletproofing, etc. for the Optima series.

Good luck with the resto, I'm looking forward to updates!

[BoostCreep]

Thanks Coelacanth (Prehistoric non-extinct fish??) for the reply and helpful info. edit: I just went through your Barney thread and that is definitely the direction I'm headed. That is an amazing Optima. I already have the front belt drive diff from a mid. What else is needed to do a belt drive conversion?

You pretty much hit the nail on the head. Although 1 of my rear shocks still seems to have decent compression and rebound damping. Only 1 however.

And on the Gold shocks great suggestion but again parts availability is tough. I'll keep looking.

I checked out 3r Racings website but it seems like they are either in between production runs or they are getting rid of some of their product line. Not much was available sadly.

Sadly my tires are not all in good shape. I'm storing them anyway.

For tires so far I've got a street setup in mind with Duratrax Bandito tires. Diameter of 85mm. Rim size needs to 2.2 but I've not decided on which rims yet. Open to ideas.

Looking at a dirt setup as well but not liking what I've found so far. Everything is either too tall a diameter, think trucks, or I just don't like the design.

As it sits I'm waiting on parts. Everything is boxed up and safe for now. I'll keep you guys posted as to what happens next. Should have some parts rolling in within the next week.

And if anyone has experience with a brushless in one of these, what rating, in your opinion would be fun/safe for the driveline. Certainly setting the accel ramp and max output to softer settings would help I'm just looking for advice as well I'm a little green in this area.

Thanks again.

Greg.

[Coelacanth]

Thanks Coelacanth (Prehistoric non-extinct fish??) for the reply and helpful info. edit: I just went through your Barney thread and that is definitely the direction I'm headed. That is an amazing Optima. I already have the front belt drive diff from a mid. What else is needed to do a belt drive conversion?

If you have a Mid front diff, you'll also need the Mid rear diff and belt (SWB Mid belt). The rear diff is typically quite expensive; usually in the $50 range, just for the rear diff. The cost almost makes it not worth the effort. I had a few rear diffs already as I found one cheap on eBay and another came out of a Mid parts car. It's probably cheaper to buy a Mid parts lot than it is to buy just the parts you need for a conversion.

I attached 3 images showing how the regular Optima gearbox is modded for a belt drive. I've heard that it's possible to do the mod WITHOUT drilling the 2mm holes and installing the Mid belt pulley, but I did it exactly as illustrated. Perhaps someone who has done the belt conversion without the pulley in the gearbox can chime in.

You could actually stick with the chain drive, the Optima did quite well with it, the only down-side being the maintenance (removing links when the chain stretched and having to adjust the chain tension often). If it's for a casual driver, spare yourself the cost of the belt conversion and leave it as a chain drive.

I checked out 3r Racings website but it seems like they are either in between production runs or they are getting rid of some of their product line. Not much was available sadly.

I know that you can find many 3Racing damper sets on eBay, I bet the ones for the Tamiya DT-02 might work (70mm/90mm), P/N #DT02-01/V2/LB, but let me measure my stock Kyosho Gold shocks tonight if I have time. As long as they're within +/- 5 or 6mm, there's things you can do to mod the length; installing shorter or longer ball-cups or putting spacers on the piston shafts beneath the piston rings to limit the shock travel are some of the things I did.

For tires so far I've got a street setup in mind with Duratrax Bandito tires. Diameter of 85mm. Rim size needs to 2.2 but I've not decided on which rims yet. Open to ideas.

For a street setup, Custom Works Street Trac rear tires are a perfect fit for 2" wheels, such as the Turbo Optima wheels, or other vintage 2" wheels like HPI 5-Stars, Pro-Line, etc.; you'd have to track down some vintage 2" wheels on eBay, or find Turbo Optima wheels, which aren't really that rare. As for wheels to fit the Bandito tires, I'm also interested to see what 2.2" options might work. 35mm wide fronts/45mm wide rears on 2.2" wheels seems too wide to me.

http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXNTK7&P=M

The easier route is to go with a set of HPI Vintage Series wheels, tires & foams. They're a bit smaller diameter than original tires, but look and work great on asphalt...just upsize your pinion gear by a few teeth to compensate. I'm running that wheel & tire combo with my CYANide car.

Looking at a dirt setup as well but not liking what I've found so far. Everything is either too tall a diameter, think trucks, or I just don't like the design.

Here again, 2" wheels are the way to go, just like the Turbo Optima had. If you take some time searching eBay, you'll eventually find vintage 2" wheels with 12mm hex hubs.

And if anyone has experience with a brushless in one of these, what rating, in your opinion would be fun/safe for the driveline. Certainly setting the accel ramp and max output to softer settings would help I'm just looking for advice as well I'm a little green in this area.

For brushless, I'd stick with 13T or higher. Anything lower would be too much, without doing some drivetrain bulletproofing...adding hard final pinion gear, the Turbo Optima's limiter gear instead of the Optima's solid gear, belt conversion. There's lots of affordable motor & ESC combos in the 13T - 17.5T range that would be suitable for the Optima.

[Coelacanth]

I just noticed these wheels & tires pop up in today's ad email from AsiaTees.com, they look quite promising...but unfortunately, the product webpage doesn't list any specs other than it being for 1/10 buggy. I emailed them to request some specs: wheel diameter, tire outside diameter and width. Can't go wrong at that price, and they also have similar options with offroad tires.

P/N: BRKT645004W-R

http://www.asiatees.com/display?Miscellaneous-All-Parts-Hop-Ups-Upgrades&brand=Miscellaneous&model=All&id=102360&pid=1

[BoostCreep]

Wow thank you very much for the detailed and informative posts. I'll keep the belt drive conversion as a down the road swap. Just collecting pieces at the moment. I had heard about making the rear belt drive out of a Mid front and a chain driven rear by swapping that portion of the differential over. If/when I get it all togethre I'll do the swap. I'll be driving long before then. We'll call that phase 2.

Also finally ordered some wheels for my street tires.
Axial Wraith Aluminum 8 spoke beadlock wheels. 2.2 inch. A little spendy I suppose but I like them.


And again thanks for the heads up on the tires. I went ahead and got a set of the 6 spoke rims and off road tires as the price was right.
Eventually I'll get I nicer set for offroad once these are worn out.

[Coelacanth]

I know some guys claim you can simply swap the diff halves, but I've tried it and they don't fit well together. The bolt holes line up well enough, but the half of one diff has an inner lip that fits snugly inside the other half, but this is lacking on the other kind of diff. So while yes, they WILL technically screw together, they won't mate securely. The inner lip that's supposed to slip inside the outer lip on opposing diff halves just ends up resting on top, which would likely allow dirt to contaminate the inside.

[Coelacanth]

I just noticed these wheels & tires pop up in today's ad email from AsiaTees.com, they look quite promising...but unfortunately, the product webpage doesn't list any specs other than it being for 1/10 buggy. I emailed them to request some specs: wheel diameter, tire outside diameter and width. Can't go wrong at that price, and they also have similar options with offroad tires.

P/N: BRKT645004W-R

I got a reply to my email requesting specs on these tire/wheel sets:

http://www.asiatees.com/display?Miscellaneous-All-Parts-Hop-Ups-Upgrades&brand=Miscellaneous&model=All&id=102360&pid=1

2.2" wheels, 80mm tire outside diameter and 38mm tire width...so those would be a good option for some cheap road tires that, except for the 2.2" wheel size, are similar to Turbo Optima tire dimensions.

[tamiyadan]

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[BoostCreep]

Coelacanth those would be a good size. 85mm is a little tall but just a couple mm's over the stock size from my measurements.

TamiyaDan, could you elaborate a little. I'm curious as I would think the belt would be more robust. But if the chain is really that stout than that would be good news.

Thanks again for the replies and information.

[tamiyadan]

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[BoostCreep]

Thanks Dan. That all makes sense. I suppose I could see a chain having a higher breaking point but I figured friction would be the detriment.

I am surprised that the belts stretch so much. Perhaps there have been improvements in belt contstruction since these were made. I had a motorcycle with a belt. It was definitely more reliable than a chain drive and sprockets. My current bike has a chain drive. Definitely requires more maintenance and wears out faster than the belt did.

On another note the Axial wheels and AsiaTees off road tire/wheel setups showed up today. Here is a picture of them side by side.


The wheels are really nice. If it ever becomes a shelfer these will be perfect. In the meantime I'll be running them on the street and the white 6 spoke set in the dirt.

Question about radios. My original setup is a Futaba FP-2L 2 Channel stick with reversing. It is digital and I'm guessing it still works. I need to power it up to verify.
In any event it appears I'll need a Futaba G to J adapter (cable with connectors). When it comes to the ESC will that adapter work and plug in directly to them ESC or will there need to be another cable involved?
Would I just be better off upgrading to a 2.4ghz system. It is even legal to run the old Futaba anymore?

[tamiyadan]

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[Coelacanth]

As long as weight isn't an issue, I like the 2.2" narrow crawler beadlock wheels, because they have a nice negative offset that both looks good, and keeps the tires from rubbing against the shocks...plus, you don't have to futz around with CA cement. The only issue is the larger hole in the wheels; you need to use some washers with a 5mm hole or the wheels will wobble. I previously bought HPI cone washers that were perfect for this, but I'll need to track down the part number...

[DennisM]

I think You mean 4mm washers Marc?