Edelbrock 7800 Serie Instructions D'installation page 2

• TIMING MARK ALIGNMENT
NOTE: Alignment of the timing marks as shown below does not always indicate Top
Dead Center (TDC) of the number 1 cylinder on the compression stroke. Many engine
families (Chevrolet, Pontiac, etc.) will be at TDC of number 1 on the exhaust stroke and the
crankshaft will have to be rotated one full turn before the distributor can be installed and timed.
If you are installing a new camshaft, the crankshaft will have to be rotated anyway to adjust the
lifter pre-load for all cylinders. TDC of number 1 (compression) can be determined by observing
that both intake and exhaust valves are closed, or, with the spark plugs removed, by feeling
compression buildup with your finger as you rotate the crankshaft towards TDC. TDC will be
indicated by the timing marks on the harmonic balancer.
1. Keyway marked with "o"(zero) is for standard "straight-up" timing.
2. Keyway marked with 4A is to advance cam timing 4°.
3. Keyway marked with 4R is to retard cam timing 4°.
• NOTE: It is advisable to use a ruler or other straight-edge to help determine that the timing marks
are properly lined up on the centerline between the crank and the cam. "Eyeballing it" can lead
to timing errors.
Timing
Mark
Crankshaft
keyway
Timing
Mark
Crankshaft
keyway
©2016 Edelbrock LLC
Rev. 11/10/16 NP
Crankshaft
Figure 3
Standard
Figures 3-4-5 are typical of Ford V8 chain alignment.
Figure 6
Standard
Figures 6-7-8 are typical of Chevrolet, Chrysler and AMC V8 chain alignment.
Edelbrock, LLC • 2700 California Street • Torrance, CA 90503
Toll-Free Tech Line: 1-800-416-8628
keyway
Figure 4
4° Advance
Crankshaft
keyway
Figure 7
4° Advance
Page 2 of 6
This line indicates proper timing mark alignment
(see arrows)
Crankshaft
keyway
4R
Figure 5
4° Retard
Crankshaft
keyway
Figure 8
4° Retard
Catalog # 7800 Series Timing Chains
Brochure #63-0128
Timing
Marks
Crankshaft
keyway
Crankshaft
keyway