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Calcimator

Cam Sizing Calculator

Find the right cam size for a given crack width. Enter the crack measurement and get recommended cam sizes with expansion range and placement quality rating.

Inputs

mm

Results

Best Cam Size

#1

Expansion Percentage

79%

Placement QualityAcceptable
Matching Cam Sizes2
All Matching Cams#1, #2
Cam Min Width24 mm
Cam Max Width38 mm
How to Use This Calculator
  1. Measure the crack width at its narrowest point in millimeters, using calipers or a nut tool for accuracy.
  2. Enter the crack width — the calculator checks it against the expansion range of ten standard cam sizes (#00 Micro through #6).
  3. Read Best Cam Size for the size whose expansion range best centers on your measurement, with its Cam Min Width and Cam Max Width shown alongside.
  4. Check Expansion Percentage to see how far into that cam's range the crack width falls — 25-75% is ideal; below 25% it may walk, above 75% it may be over-retracted.
  5. Review Placement Quality — Optimal (25-75% expansion), Acceptable (10-90%), or Marginal (outside that range).
  6. Check Matching Cam Sizes and All Matching Cams to see how many, and which, cam sizes could also cover this crack width for building your rack.

What each input means

Crack Width
Measured width of the crack in millimeters. Use calipers or a nut tool for accuracy. Measure at the narrowest constriction point.

What each result means

Best Cam Size
The cam size with the most optimal expansion percentage for this crack width.
Expansion Percentage
How far the best cam is expanded. Ideal range is 25-75%. Below 25% the cam may walk out; above 75% it may be over-retracted.
Placement Quality
Rating based on expansion percentage: Optimal (25-75%), Acceptable (10-90%), or Marginal (outside ideal range).
Matching Cam Sizes
Number of cam sizes that can fit this crack width.
All Matching Cams
Complete list of cam sizes whose range covers this crack width.
Cam Min Width
Minimum crack width for the recommended cam size.
Cam Max Width
Maximum crack width for the recommended cam size.

How this is calculated

Worked example, using the default values

  1. Identify Input Parameters
    Crack Width = 35 = 1 input(s) provided
  2. Calculate Best Cam Size
    Best Cam Size
    #1 = #1
  3. Calculate Expansion Percentage
    Expansion Percentage
    79 = 79
  4. Calculate Placement Quality
    Acceptable = Acceptable
  5. Calculate Matching Cam Sizes
    Matching Cam Sizes
    2 = 2

Engine last updated . Checked against 2 independently-derived tests — how we verify calculators.

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