How do you calculate bearing clearance?
Measuring the inside diameter of a main or rod bearing will require a dial bore gauge. The best ones to use are accurate down to 0.0001-inch. With these two tools you can quickly determine the clearances in any engine. Measuring bearing clearance is only valuable if the numbers are accurate so use quality tools.
How do you fix insufficient connecting rod bearing clearance?
Engine Bearing Clearance, Corrective Action:
- Rework the bearing housing of the engine block, if it has been filed down.
- Also, replace the connecting rod, if its bearing cap has been filed down.
- Check journal surfaces and regrind if necessary.
- Above all, Install the new bearing and follow proper installation procedures.
How big is the oil film clearance on a cylinder?
A loaded connecting rod at peak cylinder pressure will reduce that oil film clearance to as small as 0.0002-inch. With a static bearing clearance of 0.002-inch that means the upper half of the rod bearing has 0.0198-inch worth of clearance.
What should side clearance be between connecting rods?
Per our recommendation, the vertical bearing clearance (oil clearance) for our connecting rods should be 0.0030”-0.0035”. The side clearance between connecting rods sharing a rod journal should be a minimum of 0.0150” and no more than 0.0200”.
How does bearing clearance affect the flow of oil?
So as bearing clearance increases, the load carrying capacity is reduced because the load is concentrated in a smaller area. Common sense dictates that bearing clearance directly affects oil flow with predicable results. Reducing the clearance will increase the restriction to flow and reduce the volume of oil past the bearing.
What do you need to know about torque wrench?
• Run the nut down to near contact with the washer or bearing surface and check the friction drag torque required to turn the nut. • Add the friction drag torque to the desired torque. This is referred to as “final torque,” which should register on the indicator or setting for a snap-over type torque wrench.
A loaded connecting rod at peak cylinder pressure will reduce that oil film clearance to as small as 0.0002-inch. With a static bearing clearance of 0.002-inch that means the upper half of the rod bearing has 0.0198-inch worth of clearance.
So as bearing clearance increases, the load carrying capacity is reduced because the load is concentrated in a smaller area. Common sense dictates that bearing clearance directly affects oil flow with predicable results. Reducing the clearance will increase the restriction to flow and reduce the volume of oil past the bearing.
Per our recommendation, the vertical bearing clearance (oil clearance) for our connecting rods should be 0.0030”-0.0035”. The side clearance between connecting rods sharing a rod journal should be a minimum of 0.0150” and no more than 0.0200”.
Why is oil clearance important in vertical plane?
It’s important to always measure oil clearance in the true vertical plane as all bearings are designed with an eccentricity to produce additional clearance at the bearing parting line. This is done to compensate for load because the sides of the bearing housing will pinch inward at the parting line under high load.