28-11-2018, 10:00 AM
(This post was last modified: 28-11-2018, 10:01 AM by Zetomagneto.
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(28-11-2018, 01:36 AM)Terrytuned Wrote: Zeto you can increase side clearance to improve flow but you need to get some heat into the oil before driving,you get a better flow through by drilling.The oil is cooling the bearing as well as lubricating, it's centrifugal force that is providing the pressure, as long as sufficient oil is entering the crank flow through removes heat. Terry.Terry, I agree that centrifugal force gives pressure to the oil at the point where it is exiting the crankpin hole, however it is hydrodynamic pressure between the two surfaces which prevents metal to metal contact.The oil is heated in the bearing by shearing, and as you say if there is insufficient flow the oil ,and therefore the bearing will overheat.
Your experience shows that drilling the holes appears to have no detrimental effect, but I am not convinced it is necessary.
Colin, I meant to say if your rods are currently undersize, and the white metal is sound no need to remetal, get them bored and narrowed to suit the new crank.prior to dealing with the big ends,Check small ends for wear, as Bob Foreman says there is so little material it makes it difficult, or perhaps inadvisable to bush them