18-09-2019, 08:02 PM
(This post was last modified: 18-09-2019, 08:29 PM by Zetomagneto.
Edit Reason: Missed word
)
Hi Colin, this discussion relates to splash fed big ends, modern engines are pressure lubricated, the oil pressure ensures the oil passes through the bearing so no need for a hole in the rod.
You will find some modern rods have a cutout in the sides.
Side clearance on modern engines is calculated by the manufacturer based on bearing area and bearing clearance , the side clearance is such that once the oil has passed through the bearing it can quickly escape.
Oil pressure is generated by bearing running clearance, not by having small side clearance.
You will know modern engines have very tight tolerances which is why they use such thin oil.
It is well known that big end bearings are highly loaded on the exhaust stroke, there is no resistance for the piston , the only thing stopping the piston hitting the head is the big end bearing.
You will find some modern rods have a cutout in the sides.
Side clearance on modern engines is calculated by the manufacturer based on bearing area and bearing clearance , the side clearance is such that once the oil has passed through the bearing it can quickly escape.
Oil pressure is generated by bearing running clearance, not by having small side clearance.
You will know modern engines have very tight tolerances which is why they use such thin oil.
It is well known that big end bearings are highly loaded on the exhaust stroke, there is no resistance for the piston , the only thing stopping the piston hitting the head is the big end bearing.