Having done a few Monograms in the past (Lola and McLaren) and being very pleased with the way they turned out, I agreed to build one for him.
Unfortunately. I did not take pictures of every step. but, I should be able to describe them well enough.
The first pic. is of the bare chassis......it is in the process of being filed/sanded to clear the inside of the body, and allow some body movement. It is important to file/sand off the raised "cups" on the chassis body mounts, to allow the body posts free movement on the chassis posts....in the pic, you can see where this has been mostly finished....it still needs a final clean up. On the rear axle mounts, you can see where I have temporarily inserted a brass tube (3/16" id.) which will hold some 3/16" od. single flange oilites. By positioning the tube at a slightly higher position in the rear axle uprights, I will raise the position of the rear axle, effectively reducing the ride height, and lowering the cg.
The motor mount locating holes were also filed/sanded a few thou. on their bottom edges, to allow the motor to sit slightly lower in the chassis (the bottom edge of the motor now protrudes just below the bottom surface of the chassis)......not much, but, "everything counts..in small amounts" !!
The second photo, shows the axle tube from a side profile.....I have enlarged the rear axle cups to accept the tube, but, have tried to maintain a "C" shape to the cups, which holds the tube from moving upwards...this really helps hold the tube in place. Try to achieve a very small tolerance between the mating surfaces as most glues are terrible gap fillers..(read weak!!)
I have slightly enlarged the front axle bushing holders to accept a 1/8" od. tube. "U" shaped cutouts are just fine here as the tube will be held with styrene plates glued to the outside of the chassis and the tube. (I used some 30 thou. styrene with a 1/8 hole drilled into it for the side plates).
When securing both the front and rear axle tubes, I used a jig with set up blocks to ensure that both axles will be parallel, and, on the same horizontal plane.......this is critical for a good handling car, and by doing this you eliminate any small variances in the depth of the bushing cups. and negate any minor chassis twists. (You can "bake" the chassis, but, the Monogram chassis is very thick and difficult to straighten, and, most chassis' made of plastic do have a memory, and over time minor twists can reoccur. As well, you are then relying on the bushing cups to be identical in height left to right........this is where the adjustable front ride height systems (slot-its set screw etc.) are worth their weight in gold, as these systems permit minor left to right adjustments to overcome these issues.
A new guide was installed, and a small piece of square styrene tubeing was glued in to route the lead wires through.
The finished rolling chassis........a 7.5mm NSR pinion and an 18mm Slot-it spur fit perfectly, meshed very well, and allowed good clearance for the spur/track.....(the 7.5mm pinion/18mm spur is a very good option for any folks looking to improve these cars......it lets you use a slightly smaller rear tire diameter and still allows reasonable spur/track clearance).
A quick coat of Tamiya flat black spray made it purdy!!, and small urethane washers were glued to the tops of the chassis body mount tabs...these really help eliminate vibration/noise.
A chunk of lead was added to the pocket where the magnet originally lived.
The body mounts were trimmed to square and lower the body, BWA/Dart inserts were painted installed, and she is ready to go.
As it sits it handles very well and is quick, no doubt, as I was asked to install a Piranha motor.....to be honest, I think it would be better with a slightly milder motor. On my track (wood) it is very close to my well sorted Slot-it Chaparral/Alfa's...it is only when overdriven that the very short guide lead of the McLaren rears its ugly head. The McLaren has a guide lead some 3/8 shorter than the Slot-it Alfa (also a very short guide lead car), and this is not the hot ticket on my track, which is fairly fast/flowing.
Anyway, I really had fun with this...it was certainly worth the effort......just hope the new owner feels the same ;)
Cheers
Chris Walker
