New guy 1985 Optima rebuild Thread.

[DennisM]

The thick hex drivewashers are SP-2
The thin hex drivewashers are SP-62
Standard hex drivewashers are OT-19

[BoostCreep]

Okay so in my search for the small parts I have come across the plastic parts kit and springs for the original optima red shocks new from kyosho.
They are under the replacement parts for the 2014 scorpion re-release. Same shocks at least physically in size as the old Optima originals. Cheap too.

That put me on the track of the Scorpion HG shocks. Anybody here have any experience or knowledge about these?
From what I could tell they seem like a nice piece. Expensive from Kyosho but can be had cheaper elsewhere I'm sure.

[BoostCreep]

I managed to get home this afternoon and decided to start assembling the Optima.

I still have some parts on the way and am certain I will be pulling it down again fairly soon but decided I would get it running
sooner rather than later. There are so many tings I still want to change or add or make so this is really going to be a stage 1
build for now. Right now it's mostly a roller but I'm still waiting on shocks.

Here are some pictures from today. It is wearing the original body from 1985 currently.








A progress shot early on.


Hopefully I'll have some more parts show up soon.

This is proving to be a lot of fun so far. Looking forward to the next one. (Mid SE)

[DennisM]

It´s comming along nicely.

2.2´s are too big for a SWB buggy IMO. You really should try a set of 1.9´s

[Coelacanth]

I vote for 2.0" wheels...those look just about perfect on offroad Optimas and SWB Mids.

[BoostCreep]

While I agree on the wheel size issue these were cheap and available and I just wanted to get something
to use in the short term. I will eventually get something in the 1.9-2.0 size for offroad. I probably spent 10
hours looking for a wheel and tire setup in that size that I liked. I found some really nice 1.9 wheels but
tires was proving to be an issue. Everything was for crawlers and trucks and the diameter was too large.

These will get thrown on the rear of my sons car once he wears his out most likely.

On another note it appears my shocks may show up today.

[BoostCreep]

So yes the shocks arrived today along with the steering servo.

I assembled the shocks and here are some of my opinions on the 3Racing shocks for the Tamiya DT-02.

Overall they seem nicely made. Everything fit together well and they included a choice of shock pistons. 2 or 3
hole pistons were included. Assembly was straightforward and bleeding was not a problem once I finally remembered
what I was supposed to do.

The flaws IMO were simple and not deal breakers but definitely some things I'm going to address in the near future.
1. The springs are way to stiff for the Optima. I'll be looking for a better match with the weight of the car. I believe they
are 12 mm in diameter.

2. The included shock oil is too thin. Compression and rebound damping are not in league with the springs on any
level. After building the rear shocks with the 3 hole pistons it was obvious they weren't going to affect the springs much. So
the fronts were built with the 2 hole pistons in an effort to increase the shock resistance. Not much difference really. My feelng
is that the oil is so thin it's bypassing the piston without much effort. Thicker oil will be tested out soon.

3. The extended length of the shocks are a little too tall. The car suspension will accomodate it but combined with the lack of
sag due to the stiff springs it is too high visually.

4. Due to the increased diameter of the upper shock mount the shocks cannot fit in the stock location. A new bracket will have
to be fabricated to accomodate the wider shock.

I also went ahead and did some more assembly on the car. It was during this that I realized how poor some of the hardware looks.
New hardware will be sourced before the next teardown.

Anyhow here are some pictures from tonight.





















Sorry for all the pictures. Got carried away.

I should mention the receiver and steering servo were just placed in the car to help figure out where the reciever needs
to be mounted. I did attach the ESC and am pleased mostly. I may move it back a little further before it's all said and done.

Now if the bearings I'm waiting on and the LiPO's I ordered will get here I may be able to get it out and driving soon.

EDIT. Curiosity got me and I had to try these out.

Street Tires. I think the beadlock wheel makes the rim appear smaller and definitely looks more balanced with the Optima
from a size and style perspective.

[Coelacanth]

There's a couple things you can do to shorten the shocks; you can look for some really short ball-cups and also insert some spacers with 3mm holes underneath the shock pistons, to reduce the distance the shocks will decompress. I think I was able to shorten mine by 8 mm or more.

The 3Racing shocks for the Lazer ZX-5 had oil that was too thick, actually. I went with a lighter oil and opened up the holes in the pistons until they functioned the way I liked. If the springs are 12mm diameter, I think Turbo Optima shock springs (for the Kyosho Gold shocks) would fit. Those come in several levels of stiffness.

EDIT: I wonder if those shock caps are bigger than what was on the Lazer ZX-5 shocks? They look different...anyway, another way you can improve the shock fitment is by using spacers with 3mm holes under the bottom shock ball-studs--maybe 3mm or thicker spacers. This will push the shock bottoms out a bit and if you thread down the adjusting rings a few mm to clear the front shock tower, you will probably have a slightly better angle for the shock tops to sit on the mounting screws.

[DennisM]

wauw, You´ve got the HCG kit for the Optima

Talk to GomachV, he is in the business section. He can help you with some taller towers in G10

We like pictures

[yellowdatsun]

Curious to see how long the chain holds up to brushless power. We always had chain stretch issues even with our crappy motors back then, hence our conversions to a belt drive. Back then the belt was the hot ticket.

[BoostCreep]

Speaking of the chain, have people in the past used a dry lube on say the chain and final pinion gears? Thinking about the different
reasons why chains stretch and one is heat. In this case it's probably just mechanical overload but can't hurt to talk about it.

After further research it is clear that the springs from the turbo Optima shocks will fit on my new shocks. So that opens up a large
variety of different springs. I'm going to order some different weight silicone oils and springs and do some testing in the near future.

And for ride height here is what I'm trying to accomplish. I want the shock damping and spring rates to allow the car at least 1/2" or more
of sag when it's resting on it's own weight. This can be tough to determine as side friction from the tires can keep some of the sag from
happening.
My reasons for not wanting to shorten the shocks or limit travel are:

1. Even at full shock extension the suspension is not experiencing any mechanical binding in either the suspension itself or the halfshafts. With that being
the case I'd like to have all the travel available so when the car does get airborne the suspension extends down and it has more travel to soak up the landing.
This will rely on compression damping in the shock initially upon impact as the springs will be soft enough in the first bit of travel as to not really affect the
shock movement.

2. At the limit of compression the suspension is still in the safe range mechanically and the car is not bottomed out. I know it sounds a little off but I do not think I want to raise the
shock upper mounting position to make the car lower. Finding the right springs may prove difficult to provide initial compliance but still be still enough to minimize bottoming out.

Also tonight I did a proof of concept on my steering servo mount.

Pictures:
The bracket is a little cobbled together. It will have to be re-made properly before it's installed permanently.




Also the footprint of it is too large. Need to trim off the extra material.






Here it is in place. I need to order or make some 5mm standoffs to go between the bracket and the top plate. I really
need my lathe parts that were ordered last week to show up.




I'm also going to get different srews and countersink them so nothing is protruding from the face of the mount.

So that's it for todays update.

[BoostCreep]

Well I'm out of town again for work so no real new updates coming in the next week except for this.

I got my machined steering servo mounts back today. I was unhappy with my hand made version
and since the resources are available I had these made.



Just need to spend a little time countersinking the servo mount holes and polish it up some.

I also ordered some taps size M2.5 x .45 to finish off the bracket mounting holes. With a 5mm standoff
a M2.5 x 10 screw will be the correct length for mounting. These will be anodized along with the rest of the
aluminum parts when I get to that point.

[terry.sc]

The Turbo Optima shock mounts don't raise the shocks up much. Here they are on one of my runner Optimas



If you want to stick with the current setup look at a dual spring setup. You can get double spring mounts so you can use a harder spring for normal use and a soft spring to extend when at full droop. Touring car springs go down to 20mm long so you should be able to put something together that should fit. Something like this:

[BoostCreep]

Thanks Terry for the dual spring idea. It had crossed my mind but seeing it makes it a little more of a solid idea.

So updates.

First the 3Racing shocks. After having been gone for 6 days I got home and noticed the oil has been leaking out of the shock
bottom seals while I was away. I honestly think the shock oil provided in the kit is so thin that it contributes to this problem. I
plan to go ahead and get some heavier oil, different /lighter springs and redo the shocks again. On another note. The one thing
that struck me as odd during the assembly of the 3 Racing shocks was the lack of a diaphragm at the top of the shocks. Does anyone
sell different size diaphragms for shocks? Thinking I could find a set that fit these and that it would help with the overall performance
of them.

Next up. Last Friday just before I left for the airport my charger and Lipo battery showed up. So today while I was at work I set them up
and charged the battery. That sparked a chain of events that culminated in me actually DRIVING IT TONIGHT. I just went ahead and
mounted the steering servo the traditional way as now that I have a battery in place i need to modify the steering bracket that I had made
to clear the battery. Shouldn't be too much work just couldn't happen today. Plus the micro taps I ordered are not in yet.

I am very pleased with how well it handles. I had removed the 3Racing shocks earlier and bolted on a set of Golds from an Ultima I had picked up.
I was easy on the throttle as the ESC is still on the default parameters and I didn't want to munch anything in the gearbox but going easy
into the throttle and making some tight turns at speed I was very impressed. It didn't handle this well before I'm sure.

After about a 10 minute run (It's dark and late) neither the motor, ESC nor battery was even warm. It had plenty of speed available and I'm
interested to really figure out what the new limits are. Really fun.

So next I need to mount the GoPro to it and go run in the woods.

Also once I get to tuning the ESC I'll post up on the procedure and settings just in case anyone else is thinking of going this route. And if I've
botched a setting maybe someone here will catch it.

Thanks again all for your help, good advice, and inspiration. This is already way better than it would have been if I hadn't found this forum and
I've gottem some ideas for how to really get it to where I want from looking at some of your builds on here.

I'm looking forward to starting the next phase of this build but I expect that will be a few months down the road.

[BoostCreep]

Me again. Posting for posterity here.

So I've run a couple of charges on it now and WOW Brushless and Lipo is awesome.
I think I need a wheelie bar! This thing is stupid fast compared to 30 years ago.

With the knowledge that the old gearbox wasn't designed for this much power I have really been gentle from a
stop when accelerating. It wheelies easily from a roll. I'll be switching back to a brushed system once the re-re
is in hand and swapping this into that car. It's fun but I can already see the writing on the wall.

On another note. Running the gold shocks has very much improved the handling and suspension control.
All of these things are old news I know but it's all new to me. Having fun with it to say the least.

Out of town with work again but I'll be postong some more pictures once I get home now that it's a runner.