Sand Scorcher Desert Racer MK1 - more progress - part 2

Right, I started cracking on with my SS project shown here http://www.tamiyaclub.com/forum/index.php?showtopic=45205, and here Part One. I started on the second wing (fender) on the other side of the Beetle (Bug) body, and finished drilling the holes and attaching it.

Pic's! ;-

Using Sand Scorcher (1979 edition) input gear in gearbox / gearcase. Ballraces for more durability (wear resistance) than the standard Phosphor Bronze "Oil-less" bearing bushes that SS1979 uses as standard. Not going for rubber shielded ball races because the rubber shield ain't gonna keep the salt (sea) water out when I run on a beach near the water... The gear is Brass. 

Buggy Champ 2009 / Sand Scorcher 2010 / "SRB MK3" gearbox being used since I didn't want to subject an original SS1979 gearcase to salt water corrosion when running on the beach and through the water near the shore! The surface of the casting is more shiny than the original SS1979 gearcases, which were "satin". The MK3 gearcase has a slightly "dirty" appearance though when seen in the flesh, even when new like this one here, because of a mottled appearance of the surface. There were some "bad" casting marks on it as well which were a tad dissappointing. The mould is very crisp compared to the MK2 and MK1 and I think it's been computer (CAD) designed. They must have "lost" the original moulds...

I am using a Team CRP Idler gear in brass to replace the original one which looks to be Nylon-66 and the original is known to deform with heat under prolonged use with powerful motors so I am told.

I decided to replace the stock kit plastic solid main final drive gear (which is not a differential) with a limited slip differential (a Thorp brand Ball diff' in this case) so that if one wheel slips in the sand, the other should provided at least some grip. The diff' tightness is adjustable via an allen head bolt through the hole you see in the half shaft which is sticking up in this picture. Unfortunately my old Thorp was bought second hand and is fairly "shagged out" and is noticeably rough in it's action (much more so than my "Jakes" ball diff' that is also very difficult to get) and maybe I'll end up using a Tamiya ball diff' that they made especially for the SS2010 edition.

These are the "Tin Snips" for cutting the 0.7mm thick Aluminium alloy sheet that the home made wings are made from.

Holes drilled for clip assembly so that the body can be mounted onto the roll bar. The SS1979 and SS2010 bodies have these holes, the Blitzer Beetle (BB) shell used here has only the "stubs" of the holes on the underside of the shell showing, where the holes used to be in the SS1979 body when they modified the mould for the BB. So I drilled them out with a 1.5mm drill bit held in a Swivel Head Pin Vice, and then opened the holes out with a 2mm drill bit. I had to recenter the left 1.5mm hole (when seen from the inside of the shell) slightly with a needle / rat tail file, before making it 2mm, as it has to be in the right place and I seem to have a knack for letting my drills wander...  also note that the screws are going to point inwards (so that they get closer to each other towards the end of the screws) since the top of the body is rounded on the roof and it forces the screws inwards, whereas the bodyclip wants parallel screws. This creates stress on the screw holes and leads to cracks in the shells. To avoid this I made one screw a looser fit in it's hole than the other. Also I think I will be reinforcing the area around these holes with 1 or 1.5 or 2mm PolyStyrene sheet to prevent further stress fractures when the body is clipped and unclipped from the chassis roll bar and when the car is jumped and the body shakes around (or when you land on the roof!). Which reminds me, I plan to be adding a functional roll bar internally to protect the body from severe cracks if it rolls.

Thorp ball diff. Worn! But works! Or so the seller told me when I bought it several years ago! Well I can tell it works when rotating each half, but it's got a sort of rough action. This is because the Thrust Washer and 1/16 balls are worn. The thrust washer has already been turned over once and is actually starting to disintegrate. I could use a new one. But then again the SS2010 optional ball diff. is cheap at 18 GBP on Ebay...

Cheers,

Alistair G.