in late 1970's & early 1980's i was doing Machine work + rebuilding + assembling Chevy SBC350 BBC454 and International Harvester 345cid Engines
for 2 Oil Field Companies for their Fleet Hot Shot Trucks these Hot Shot Trucks routinely get 200,000+ miles on their Engines
started using a new Machine Shop to rebuild my Connecting Rods ,
he would grind + open up Rod pair side clearance to +0.025" and Chamfer big end diameters on each side at same time .
Before "open up Rod pair side clearance to +0.025" results ---> no real oil consumption problems
After "open up Rod pair side clearance to +0.025" results --->
definetly real oil consumption problems
now for these "before/after tests" on these various Fleet Engines ...
at that time i was using either [1]= Perfect Circle / Dana Piston Ring sets or [2]= TRW/Ramsco Piston Ring sets
when i saw these results , i quit using that Guy to recondition my Rods !
but it got me to start looking at Oil Ring designs
the TRW/Ramsco and the Perfect Circle/Dana oil ring designs effectively were "BLOCKING" oil flow thru the
oil ring groove back to the crankcase .
those Oil Ring designs would either BLOCK or prevent enough oil flow off the Cylinder walls
at the outside of the oil ring , or inside of the oil ring ( 2 different designs ... but same effects )
so i started looking at Hastings and Sealed Power Oil Rings :
the Sealed Power version was mostly exactly like GM was using ... its design was able to effectively move oil off the walls
and funnel it back to crankcase
the Hastings oil ring design was also very effective in moving oil off the walls and funnel it back to crankcase
the Hastings oil ring design is a Vertical type ...its the "forerunner" of the current Total Seal Racing Oil Ring design
... it has the ability to effectively moves oil off the Cylinder Walls ... but at a lower Oil Ring tension , frees a little TQ and HP up
the SpeedPro / Sealed Power Ol Ring design ... effectively move oil off the Cylinder Walls
... but at a little higher Oil Ring tension , so you don't quite free up a little TQ and HP , like the Total Seal / Hastings / Pedwrick Oil Ring design
so here's my Theory ,
if you are comparing whether or not excessive Rod Pair Side-Clearances increase oil consumption or not ??
...you should real-world test various Engines that would have :
TRW/Ramsco and the Perfect Circle/Dana oil ring designs
-VS-
Total Seal / Hastings / Pedwrick Oil Ring design
so that if you have a bad oil ring design with excessive Rod Pair side-clearance
it will then show up oil consumption with TRW/Ramsco and the Perfect Circle/Dana oil ring designs
and NOT so much or no oil consumption if you are testing that with :
Total Seal / Hastings / Pedwrick Oil Ring design or Sealed Power / Speed Pro or GM/Chevy designs
test this out with 200,000 + mile Fleet Hot Shot Trucks