Tamiya Dyna Blaster

I recently acquired a vintage Tamiya Dyna Blaster kit (58123).  The Dyna Blaster, released in 1993, was an attempt by Tamiya to create a racing truck version of the Dyna Storm buggy (58116).  You don't see them come up for sale very often and even when they do the prices are never very high.  I do not think this kit was very popular here in the USA.  I love the box art body styling, colors and decals.  This kit will stay NIB for the foreseeable future.

The truck uses a unique clutch system called "MDC" (Multi-Disc Clutch).  The spring tension in the clutch is adjusted through a nut accessible on the spur gear shaft.

Here are the side panel shots:

Since this was designed to be a racing truck, Tamiya did not include any speed control or motor with the kit.  The front and rear tires are the same as the Stadium Blitzer (58106 & 58482) and Stadium Thunder (58181 & 58524).

Tamiya still used blister packaging in 1993

Tamiya Saint Dragon Restoration (part 2)

After almost a year and a half I finally finished restoring the Saint Dragon (58083).  The first installment of the restoration included evaluating the chassis, purchasing replacement parts where necessary and selecting some vintage hop-ups to use in the rebuild.

Because I subsequently purchased a runner Madcap chassis and just recently finished its restoration, I decided to keep the original red friction shocks on the Saint Dragon and make this rebuild more of a shelf queen.  The condition of this chassis is much nicer than the Madcap and I want to keep it that way.  The black C.V.A. shocks intended for this car went to the Madcap, however the other hop-ups, including the motor plate (53060), Thorp 48P gear set and Astute universal joints were used as I had planned. 

I followed the manual to ensure a proper rebuild, substituting hop-up parts where required.  Ball bearings replaced the plastic bushings, of course.

Here is the almost-finished chassis before the shocks and radio system were installed:

During the rebuild, the thin chassis front screw posts started to groan and slightly split, so I added some springs on the outside of the posts for reinforcement.  It helped prevent the posts from breaking further.  As I have mentioned before, these posts are one of the weakest parts of this otherwise excellent chassis.

Springs helped reinforce the weak screw posts

I used a Tamiya TEU-104BK electronic speed control with Novak 3 Amp BEC circuit (5460), Futaba R113ip receiver and Futaba S148 servo for radio gear.  The motor is an Epic Paradox 27T stock motor with 19T 48P pinion meshed to the vintage Thorp 48P gear and ball diff set. 

I have to admit I was a little bit nervous to trim the original vintage body.  I wasn't sure how brittle the plastic had become and did not want to cause an unwanted crack in the body during the trimming process.  There were already signs of stress fracturing in some parts of the body where some tight bends were located and the worst thing that could happen is for the plastic to split in those locations.

Before I started trimming the body, I decided to wash it completely using soapy water both inside and out.  Then I soaked the body in very hot water for approximately 15 minutes.  My hope was that the plastic would absorb some of the water and become slightly less brittle.  I know nylon parts can be boiled to restore their flexibility, so why not try a similar approach with polycarbonate?  I did not boil the body for fear of warping, but the water was hotter than I could handle with my hands.  I have no idea if the hot water soak helped at all, but the body did not split, crack or break during the trimming process.

Tamiya had already pre-drilled the body mount holes and the antenna hole, plus the rear vents and the inside part of the front shock cutouts were pre-cut which made trimming much easier and faster.  I used an X-Acto knife with a fresh #11 blade to do most of the trimming because it seemed to stress the body less than using lexan scissors.  Also, the body has some very deep and intricate inside corners which are extremely difficult to do with scissors.  I carefully scored a continuous line all the way around the body by following the molded-in cutout lines, then, using lexan scissors, cut the excess lexan at strategic corner points.  The scissor cuts were made in such a way that the lexan pieces could be bent along the score line and separated from the main body.  The resulting edges were amazingly smooth and as straight as the score line itself, so precision is more important than speed when scoring.  In all, it probably took about 3 hours to completely trim and sand the body.

Once trimming was finished I masked the cockpit window on the inside of the body and painted it using Tamiya PS-1 white polycarbonate spray paint (86001).  Finally, I applied a set of original Tamiya decals using the soapy water technique.

A couple decals (the gray/silver ones above the cockpit window) want to wrinkle even after completely drying and undergoing extensive heat treatment with a hair dryer and toothpick.  Not sure what can be done about that, but overall it still looks pretty good.

I remember seeing pictures of the Saint Dragon years ago and thinking how ugly the body styling looked.  As such, it was never on my list of vintage cars to buy.  But because this car was in such great condition, including the original, uncut body, I had to respect its history and properly make it into a complete Saint Dragon box art restoration.  After finishing the work, I have to say that I am glad I did.

Tamiya Toyota Hi-lux Monster Racer Restoration (part 1)

The Tamiya Toyota Hi-lux Monster Racer (58086) is a vintage radio control stadium truck from 1990.  I found this example on a "for sale" section of a forum that I visit.  Please note that all of the pictures shown here depict the truck exactly as I received it from the seller.  I had not touched or cleaned anything at this point.

Not to be confused with the all-metal Toyota Hi-lux 4x4 Pickup (58028), the Hi-lux Monster Racer uses the same plastic tub chassis as the Nissan King Cab (58081) released in 1989.  Besides the obvious expected body differences between the Toyota Monster Racer and Nissan King Cab, the wheels of the Toyota are red in color and it has ribbed front balloon tires while the Nissan has white wheels and spiked tires all around.  Other than those differences, however, I believe both trucks are exactly the same.

This truck is in very good condition which you'll see in these pictures.  It was run, but was most certainly not abused.  It is definitely all-original, including the radio system and manual speed control (MSC).  I don't know if the motor is original - it could be.  I should note that at the time of this writing, Tamiya has not yet re-released either the King Cab or Monster Racer, so there are no re-release parts in this truck.

I can't say I am a fan of the body color or design, but it was done fairly well and the body is still in good condition with only a few minor scuffs and scratches.  The decals are in good shape, too.

Front ribbed balloon tires are in excellent condition.

The paint scheme is an original design, not box art.

The rear spiked tires are also in great condition.

With the body removed, the condition of the chassis is revealed.  The tub is clean with no obvious signs of damage or repair.

I don't even know if it was ever jumped since there are almost no scratches on the bottom of the chassis.

Very clean chassis underside indicates this wasn't jumped much, if at all.

The receiver's rubber bag is no longer rubber - it has petrified into a hard cocoon.  I hope this isn't too hard to remove.  Maybe it will flake off like a hard shell coating.

Age has deteriorated the rubber bag containing the receiver.

A couple of custom aluminum spacers were installed to widen the battery compartment, presumably to allow for a longer battery pack.

Aluminum spacers allow for a longer battery pack.

The front end and steering assembly looks good.

The front and rear wheels look brand new.  There are none of the usual cuts, scrapes, dings or other damage you normally see on a used truck like this, especially where the rubber meets the outer rim.

Where is the curb rash?

No wheel damage at all?! Outstanding!

And the front and rear tires look almost brand new as well.  Maybe these wheels and tires weren't used when the truck was driven.

Ribs are in perfect condition.

Spikes have some wear.

The next step will be to be totally disassemble the truck and clean all parts.  Then the parts will be inspected for any damage (I don't predict to see any) and replacement parts will be sourced.

One idea I have is to turn this into a King Cab, however finding a body is going to be next to impossible.  NIB bodies go for big bucks and I have not found any reproduction bodies for sale.  King Cab wheels and tires are also quite expensive.  I'll have to take a wait and see attitude for this restoration, so I won't be doing any more work on this for a while.

Tamiya Vajra Built and Finished

I actually built the Vajra in early 2012 but didn't finish the body until early 2013.  The build was a good one and quite interesting, but not without some frustration at the design in some places.  I understand why Tamiya made the choices they did, I think, but I still feel like a better design for these parts I am about to mention could have been thought of for the Avante chassis (on which the Vajra is based).  I realize the basic design of the chassis is over 25 years old and fault can be found in almost all chassis designs, but for some reason some of the design "issues" I found during the build of the Vajra jumped out at me as very obvious and annoying from an engineering perspective.  Maybe I was in a hyper-critical mood during the build or something.

For the first one, in step 10 of the manual, a piece of tape is used to hold a gear shaft on the front end before a front suspension arm is mounted that blocks the shaft from coming out.  

Tape?  Really?

All Tamiya had to do was put a flat-headed screw right next to the shaft to hold it in place, similar to how suspension arm hinge pins are held in place on some modern buggies.  The shaft diameter is very thin at 2mm, too, compared to the normal 5mm Tamiya normally uses.  This, to me, seems like a design failure because compromises were made that undermine the reliability of the vehicle or at least raise serious questions about it.  Again, I think I know why they designed it that way: First, they had to allow the bevel gear (H2) to be removed quickly because it prevents the removal of the diff and they didn't want you to have to take the gearbox halves apart to do it.  Second, the 2mm shaft diameter was chosen due to the limited amount of space and bevel gear design inside the front gearbox.  Anything larger would not have fit.  But take a look at the TA-01 design, which has similar driveshaft-to-front-diff mechanics but doesn't have tape holding a 2mm shaft in place.  Sure, it has one more gear in between the bevel and diff, but seems to be a stronger design.  In my opinion, too many compromises were made in order to eliminate one gear "for improved efficiency".

Another frustration is that the front and rear outer diff joints are only held in place by the pressure of the swing shaft dogbones and the foam/springs inside their cups pushing against them.  There is no screw holding them in place, so when a dogbone is removed, the diff joint falls out.

BA25 and BA26 are only held in place by the dogbones inserted into them

No big deal, right?  I mean, other Tamiya kits have diff joints that aren't held in place either.  That's true, but at least those diff joints have a much longer shaft profile that sticks inside the differential unit itself like the ones that come with the stock Avante 2011 re-release shown here:

PB10 and PB11 fit deep inside the differential and don't fall out easily

The Vajra outer diff joints have very short interlocking protrusions that mate with the differential inner joints and they wobble as they spin under load making the whole system seem unreliable.  I am also concerned that the outer diff joints are going to wear out quickly.  Yet it's almost impossible to buy them separately.  TamiyaUSA's store is perpetually out-of-stock, not to mention how expensive they are.  After all of this complaining, I should note that I have not had the diff joints pop out at any time during many battery packs of driving.  As for wear, the jury is still out.

The wheels and tires.  Taken from the brushless powered Tamiya Super Levant (57796), I think the wheels and tires are simply too heavy for this chassis.  They make the Vajra seem clumsy.  The chassis, which is nothing more than a lengthened Avante chassis reminiscent of the Egress, wasn't designed for large truck tires.  Installing regular buggy wheels and tires, however, transforms the Vajra into a pretty nice truck.  

The adjustable turnbuckles, while having tiny hex nuts built into them which make adjustments somewhat tedious, are handy for making the necessary camber and toe-in modifications.

I know many people do not like the styling of the body, but I actually don't mind it so I won't count it as another negative talking point.  What I did do, however, was cut the front wheel wells narrower than marked in the manual since I knew from the start that I'd be using smaller wheels and tires.  The black lines in the below picture approximate the curves I followed.  Check out the pictures below of the finished body on the chassis to see the front wheel well cut outs in more detail.

Black lines show approximate front wheel cut outs I made

I highly recommend replacing the stock servo saver with the hi-torque one from Tamiya (51000).  It eliminates some slop associated with the stock servo saver making the truck more responsive.

Here are some pictures of the finished chassis with a few different types of wheels and tires mounted.

Stock wheels and tires:

Duratrax wheels and Duratrax Bandito tires:

Seben Racing BRF3 wheels and tires:

The truck uses a Futaba R113ip receiver, Futaba MC330CR electronic speed control and Hitec HS-645MG servo for steering.  The motor is an unknown brand unlabeled 19 turn double wind. 

The body was simple to paint because it was all one color: black.  I used Tamiya PS-5 Black (86005) after masking the windows.  The manual calls for Tamiya PS-31 Smoke (86031) to tint the windows but I left them clear.


Here are more pictures showing the wheel and tire combinations with the body.  If you look closely at the side decals in the pictures and compare them with the decal sheet, you'll notice that the "Vajra" text has been removed.  I strategically removed the text from the decals because I am not very fond of the name.  Due to the decal's busy lightning bolt style design, it's hard to tell the text is missing unless you know where to look.