The factory plastic barbell is approximately .020” to loose so particles as big as 500 Microns can leak passed the factory Barbell. When oil leaks pass the Barbell it goes unfiltered directly to the Cam Bearing, Lifters, Crank and Rod Bearings. Your oil filter will filter out approximately 25 Microns depending on the brand of filter. Our Aluminum Precision Billet Barbell fits with approximately .001” clearance which will let only about 20-25 Microns pass by, that is the same as the filter.
Another important part is the shaft of the Barbell. The oil has to flow around it to get through to the oil port. Our Billet Barbell has a 30% smaller shaft for much less flow restriction.