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4G63 ADJUSTING MAIN CLEARANCE

Practical Engine Building

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Hi guys,

Having some trouble deciding the best way to achieve my target clearance for the mains. I know playing with different sized bearing shells is the best way to get your target clearance but in my case, with Std size bearings my clearance is loose by about 1.5 thou. Next oversize bearing (.025mm) still won't get me to the oil clearance I want. So I ended up ordering 0.25mm oversize bearings.

Should I grind the crank undersize to get my clearances with the .25mm bearings or is it a better idea to machine the mating surface of the crank girdle and bore/hone the main tunnel and stick with the Standard size bearings?

Thank you

Best thing is to use 1, and 2, thou' undersize bearing shells mixed to the desired clearance - -0.001 should be easy to find, not sure about - 0.002". The smaller one will normally be placed in the load bearing part - cap for mains, rod for big ends.

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