Ive done loads of searching on here bout doing the cambelt on the 172. why can t it be done without the timing tool.i use a universal twin cam locking tool which locks the sprockets. Ive done plenty of twin cam belts and cant see how it can be different from others. is it a must to release both cam gear nuts. Cant i just lock the cam with a pin, slide my locking tool in the cam gears, remove tentioner then remove belt.