Don't rev the engine in neutral. I want it to last a long time, you see.
Literal
Engine [obj-を] idle-revving do [must-not-ちゃいかん]. Long-lasting make-want [because-からね].
空回り 'idling / spinning in vain' (空 'empty' + 回り 'spinning'). ~ちゃいかん is a dialectal/rough contraction of ~てはいけない 'must not.' 長持ちさせたい uses the causative of 長持ちする 'to last long' + たい — 'I want to make it last.' からね provides the explanation with a softening ね.