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Planning doing 4 oil grooves/side in H-rod big end thrust face to extract used oil and lubricate cylinder walls and piston pin.

Any thoughts about that kinda idea?

OIt should not effect oil pressure compared to using narrow rod big ends with piston steered rods?

Subject is B20 with 85mm stroke grinded crank and wide B230 H-rods and ofcourse B230 rod bearings.

In my mind theres no downsides doing this because in many cases B230 narrow rods are used with piston steering in stroked B20?

Just a few thoughts about this idea

There is no surplus "used oil" to be extracted from the rod bearings. If you make it easier for the oil to escape from the bearings it will have a negative impact on oil pressure in the bearings. Which you probably will not be able to see on the gauge since the pressure in the rod bearings is a consequence of the centrifugal forces inside the holes drilled through the crank.

Why would you want to get more oil on the cylinder walls? An excess of oil on the walls will make the oil scrapers less effective which in turn will make the compression rings less effective.

quattro skrev: ↑ons dec 13, 2023 10:32 am Just a few thoughts about this idea

There is no surplus "used oil" to be extracted from the rod bearings. If you make it easier for the oil to escape from the bearings it will have a negative impact on oil pressure in the bearings. Which you probably will not be able to see on the gauge since the pressure in the rod bearings is a consequence of the centrifugal forces inside the holes drilled through the crank.

Why would you want to get more oil on the cylinder walls? An excess of oil on the walls will make the oil scrapers less effective which in turn will make the compression rings less effective.

Good points,thanks for your answer.

Main point was to get hot oil out trapped between empty space between rod and crankpin sides and lubricate piston pin but ofcourse oil gets all around cylinder walls because hard to aim where it splatters.



But how it lowers oil pressure compared to std B230 rod with 25mm wide big end versus 29.6mm wide big end with few grooves and using same B230 bearings in both cases?
With narrower rods there is over 2mm clearance in both sides and theres no problems in oil pressure with std narrow B230 rods in grinded B20 cranks with rods steering from piston.

Maybe i just leave rods way they are.