Editing Timing tabs and damper TDC lines SBC
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==The three most common locations for the timing mark on the damper== | ==The three most common locations for the timing mark on the damper== | ||
The exact years of the type of damper timing marks overlap one another, depending on the exact application. | The exact years of the type of damper timing marks overlap one another, depending on the exact application. | ||
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− | #The pre-1969 damper has the TDC line on the outer ring at the 2:30 o’clock position- or 2º before the keyway centerline- i.e. the line is to the LEFT of the keyway, looking at the front of the damper or engine. The keyway is seen in the ID of the damper nose. | + | #The pre-1969 damper has the TDC line on the outer ring at the 2:30 o’clock position- or 2º before the keyway centerline- i.e. the line is to the LEFT of the keyway, looking at the front of the damper or engine. The keyway is seen in the ID of the damper nose. |
− | #The damper used from 1969 to about | + | #The damper used from 1969 to about 1984 has the TDC line at the 2 o’clock position- or 10º before the keyway. You'll find that aftermarket dampers are the 10º type, as are the bolt-on tabs sold by the aftermarket, unless they're adjustable. <br>{{Note1}}This includes the SBC 400, although the 400 damper is counterweighted because the engine is externally balanced. Do not mix and match internal and external balanced dampers! |
− | #A third timing mark was used from 1978 to about | + | #A third timing mark was used from (some) 1978 to about 1995, and nearly all 1984-1995. It is at the 12 o’clock position- or 40º before the keyway. This damper uses a timing cover that has the tab welded on at about the 12 o'clock position. Professional Products lists the years for this type damper line as being 1984-1995 and is a 6-3/4” diameter damper. |
==Relocating the damper line== | ==Relocating the damper line== | ||
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===Checking the outer damper ring for movement=== | ===Checking the outer damper ring for movement=== | ||
− | [[File:Damper line.jpg|left|400px]]Draw a sharpie line as shown in the image below. When the timing light is pointed at the TDC line, the sharpie line will also be seen. By revving the engine and running it at different speeds, if the outer ring is loose, the line on the outer ring will be seen to move independently of the line on the inner hub. | + | [[File:Damper line.jpg|left|400px]]Draw a sharpie line as shown in the image below. When the timing light is pointed at the TDC line, the sharpie line will also be seen. By revving the engine and running it at different speeds, if the outer ring is loose, the line on the outer ring will be seen to move independently of the line on the inner hub. |
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===Part numbers=== | ===Part numbers=== | ||
*The p/n for plastic cover '''with''' sensor hole is: p/n10244600 | *The p/n for plastic cover '''with''' sensor hole is: p/n10244600 | ||
− | *The p/n for plastic '''without''' sensor hole is: p/n12552557 | + | *The p/n for plastic '''without''' sensor hole is: p/n12552557 |
==Resources== | ==Resources== |