COLLOIDAL GRAPHITE.

Manawatu Times, Volume 62, Issue 19, 23 January 1937, Page 13 (Supplement)

COLLOIDAL GRAPHITE.

Although the majority of motorists are familiar with the advantages of Colloidal graphited sump oil in the re- ' duction of cylinder wear, a test recently carried out by the Research Department of the Institution of Automobile Engineers has produced authoritative figures to endorse the use of this substance. During the test, two new engines were taken and were run and left standing during alternative 15-minute ! periods. In addition, during the running | time, each engine was revved at 1000 r.p.in. at light load for five minutes, and at 2000 r.p.m. and a medium load for i the remaining 10 minutes. These alternate running and rcu- I periods were repeated 30 times and the piston rings then measured. It was found that the wear of the engine which was lubricated with plain oil was 50 per cent, greater than that in the engine of the sump oil to which col-. loidal graphite had been added. The tests were continued for a fur-1 ther 150 cycles and measurements again taken. The curves of wear j which plotted as a result of the test showed a clear difference between the | two lubricants, the engine with the colloidally graphited oil showing constantly about one-half the recorded on that lubricated with plain oil. The reason for measuring piston ring wear is that it is simpler and more accurate than the measurement of bore wear. The actual method adopted was to weigh the rings and to check the results by analysis of the metal in the sump oil. Colloidal graphite, naturally, does not replace the properties of a good plain oil. Wnat it does is to take the strain of lubrication when bearing con-) ditions are severe. That it can supplement the properties of an oil in this way, especially during running-in, j seems to be proved by the I.A.E. tests.