Which is better Heli coil or Larger Bolt

[Jack Klarich]

There are also time serts avaiable they work like heli coils but are made of steel and last forever, unlike heli coils the threads do not stretch

 

[NEWHD74FAN]

Time serts spec. and look like a viable alternative, but cost, availablility and need for ornamental or non-critical covers application hard to justify...sparkplug holes and other critical areas I would say yes...JMO.