Burning smell?

[Pricey98]

Recently I've noticed an odd smell from my 172. If I accelerate past around 4.5k I get a slight whiff of burning. It smells like clutch, however there is no noticeable slipping at any revs, no smoke, etc. I'm potentially looking to sell the car soon, so would like to get this sorted if I can.

 

[Coops Mk1]

If it smells vaguely hot burning oily its likely to be a leak from the vvt solenoid seal which can work it's way onto exhaust manifold area

 

[obcuz]

If it's like a burning plastic smellie from engine bay, suspect alternator...