The gears in {HEAD ~ the planetary gear trains} are sized to provide {TAIL ~ a desired speed reduction} from the crank shaft to the cam shafts 
The gears in { HEAD ~ the planetary gear trains } are sized to provide { TAIL ~ a desired speed reduction } from the crank shaft to the cam shafts
OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH