ADDENDUM TO 1984 IMMEDIATE REPORT
GRIZZLY DELUXE MOTOR TOBOGGAN
The Grizzly motor toboggan used by K5 during the 1983-84 field season has been extensively reported on by Pyne (1984). However, after speaking to various Antarctic Division staff over the past year, we feel it is necessary to add a few points:
1. Variator belts:
As reported in Pyne (1984), the variator belt was changed twice (at 788 km and 1600 km) whilst towing moderate loads. We do not consider this excessive and are not surprised that one field party using Grizzlys this season did not experience this problem as their total mileage was only approximately 450 km, and another party changed their belts at approximately 500 km (J. McConchie, pers. comm.).
2. Overheating:
In Pyne (1984), it was considered that the cause of damage to the left piston of the Grizzly engine was a result of overheating.
After talking to Rod Vardy (1984 Base Engineer and a qualified motorcycle mechanic) who stripped the engine at Scott Base, it became obvious that the damage was caused by the wrong grade of spark plug and not the wrong fuel mixture. We would like to point out that the total spares issued to an event which was to travel 1800 km was one variator belt and one pair of Champion spark plugs, and that considerable pressure had to be used to have these allocated. R. Vardy considered the spare spark plugs were "several grades too hot and that the damage to the left-hand piston was a direct result of this" (pers. comm., 1984).
We hope these notes help clear up some misunderstanding of K5's use of the Grizzly motor toboggans in 1983.
T. Macpherson
A.R. Pyne
Reference
Pyne, A.R. 1984. Immediate Report of Victoria University of Wellington Antarctic Expedition 28, 1983-84.