Wednesday June 09, 2004
Custom Vanquish MG Differential
by Mark Thomas
Well I am sure most all of us would agree that VMG has some of the finest detailed RTR and kit cars available. And there have been many topics both plus and minus about these pieces. I myself have been bit hard recently by the VMG bug.
As of this time I have 8 of these beauties with 1 more on the way. Now after doing all the recommended differential upgrades and tips to add extra life to the diff (which in all honesty works just as it should) even after all this it still seemed to me that something was still holding these cars back. Now this may not apply to some of you but if you have 1 or more long straights in your track, you might know what I mean. Ok with that said, let me show you what I have done to 4 of my models and soon to the rest to improve the over-all performance. Let me also add that I ran 20 laps on this car before and after on an 82 lane. Before the modification the car ran in the mid 10s, After the modification it was in the mid to low 9s. You can do this for less than $3.00.
I will start with removing the diff., just take a small screwdriver and fit it just between the diff. tube and the chassis. Give it a light pry upward and it should pop out of chassis. Do this on both sides of the diff..
Next I will remove the wheels/tires/brake rotors To do this I use a small pail of needle nose pliers, grab the axle with the pliers being careful not to crimp the axle tubes, and give the wheel a twist as you pull it off the axle. Do this on both wheels.
Now that the diff is stripped, we can measure our axle length. To do this I used a piece of flat steel and laid a ruler and the diff. flat against it. Now all four cars that I have done all measured 2 5/16. I chose to make them 2 1/4 so it would give the needed clearance inside the rear body.
Now the parts list you will need to compete the conversion. All of the brass and steel wire can be bought at most hobby shops in 1 to 3 pieces.
1. Axle- I use 3/32 piano wire cut to 2 1/4. Be sure to camphor the ends so it will insert easily into the wheels.
2. Gears- I chose to use the Artin 27tooth crown with a 10tooth brass pinion. 2.700
3. Axle tubes - For these we need a piece of 7/32 brass tubing. This will be used to fill the large holes where the diff. was held in place, and will also hold the axle bushings. 2 pieces will be cut from this.1 will be 1/4 and the other is 7/32 long.
4. 1 pair of oilites 3/32 x 3/16 flanged Parma #624
5. Axle spacers- 1 piece of 1/8 brass tubing. We will need 2 spacers cut to 3/32 in length.
Now we are ready to get our axle tubes set in place to be glued. First slide the oilites into the axle tubes. Now place the longer tube into the wide side of the chassis and the short tube in the narrow side. Push the tubes in where they are flush with the inside of the chassis. Now take the axle and slide it threw the oilites, this will center the oilites with each other. Next apply your favorite type of glue to each side of both axle tubes and each of the oilites and let dry. I like to use epoxy because it can be removed without damage to the plastic chassis.
Now that the glue has had time to set, pull the axle back out of 1 side of your axle tube. Then you can slide your gear of choice on the axle and center the whole unit. I find it best not to glue the crown gear yet. Now take your axle spacers and slip 1 on each side of the axle, repeat the same with the brake rotors.
Ok now we're ready to put the wheels/tires on. After putting both on the axle, adjust your fit to get the axle to spin as free as possible with the least amount of slop. Now your ready to adjust the crown gear to the mesh you prefer. Now add a drop of glue to both sides of the crown gear.
Well that's it. I added a bit of flat black paint to blend the brass with the chassis so it doesnt stick out so bad. Again, this may not be for everyone and some of you may have already done this, either way it is a cheap and successful performance boost to a wonderful car that otherwise may have not seen the track since the first time you bought it.