Fit and measure a wrist-pin to determine the wear involved.
On the main bearings... I would just add the recommended oil clearance to the initial machined journal dimension for determining the shell dimension.
dieselgman
It's kinda weird that with all the information available on these engines, the technical stuff is thin on the ground... but I suppose that's why we have this forum.
If no-one has the info we'll figure it out!
Time to drag the thick green book closer. (This thing knows more than google
)
Machinery's Handbook, twenty-first edition of 1980
Summary of relevant information on page 1540:
RC (Running Clearance), Categorized from 1-9
RC1 - Close sliding fits. Accurate location without perceptible play
RC2 - Sliding fits. Accurate location. Fit, move and turn easily. Not intended to run freely. May seize with small temperature changes.
RC3 - Precision running. Closest fit which can be expected to run freely. Slow speed, light journal pressure. Not suitable for where appreciable temperature changes are likely to be encountered.
RC4 – Close running fit. Accurate machinery with moderate surface speeds and journal pressure where accurate location and minimum play is required.
RC5 & RC6 – Medium running fits. Higher running speeds and/or heavy journal pressures.
RC7 – Free running fit. Accuracy is not essential and/or large temperature variations.
RC8 & RC9 – Loose running fits. For wide commercial tolerances together with an allowance on the external member.
If I look at this RC5/RC6 looks about right?
For RC5, in the 2” range, the clearance must be between 2.5 thou (0.064mm) and 5.5 thou (0.14mm).
Lets say the crank measures 1.998”, then the bush must measure
Minimum: 1.998” + 0.0025” = 2.0005” (50.81mm)
Maximum: 1.998” + 0.0055 = 2.0035” (50.89mm)
Machinery's Handbook, twenty-first edition of 1980. Page 1543
Machinery's Handbook, twenty-first edition of 1980. Page 1544
Regards,
DS