Ref - L-OS71641600 -
Now we are in the realm of specialist I.C Car racing. For mainly T-type head (Turbo head) .12~.15 class racing engines and 21VZ. Use when atmospheric temperature is low
A cold weather plug
Glow plugs are considered to be consumables - But by using a low voltage to start ( under 1.5 volts) and not burning the plug dry, you prolong the life of your glow plug. It is also worth washing out a new engine after running in to prevent small particles shorting the plug and destroying it. Blowing plugs on new engines is less common now a days, but is still something that can happen.