Camshaft Gear Installation

by Steven St-Cyr

Determining TDC for a Camshaft Gear

This actually happened to me in the process of a rebuild af an F-134 coming from a M38A-CDN1 Jeep. The camshaft did not have a reference mark. Thanks to the help of Don Norris I figured out a way of determining how to install the camshaft gear in the right position. Good luck.

These following steps are not critical for now. Directions are given with crankshaft up.

  1. Draw a perpendicular outward from the keyway.
  2. Mark that tooth as 14; see Figure 1.
  3. Count down clockwise 14, 13, 12 ... 3, 2 ,1, 0.
  4. Mark that tooth as 0, small line in Figure 1. This is your aproximate TDC mark for now.
  5. Install both gears as below on TDC.

Figure 1

Alternate Method

  1. Cut a sheet of paper as in Figure 2 below, keeping the original corner square.
  2. Determine TDC using steps above.
  3. Place the corner right in middle of camshaft bolt hole.
  4. Place one side of the sheet right in middle of keyway and in middle of 14th tooth. If your gears are correctly installed the other edge of sheet should pass right in middle of TDC mark of crankshaft gear.

Figure 2

Thanks to Don Norris and Steven St-Cyr for putting this together. -- Derek Redmond

See also Rebuilding an F-head Engine, Page 3: Installing the Valves and Camshaft.

Return to the CJ-3B Tech Tips page.

FacebookVisit CJ3B.info on Facebook.

CJ3B Home | Contents | Search | Links | 3A and 3B Community

Last updated 19 August 2012 by Derek Redmond redmond@cj3b.info
All content not credited and previously copyright, is copyright Derek Redmond