Edelbrock 7893, 7892 user manual

©2003 Edelbrock Corporation
Brochure No. 63-0079

Page 1 of 2

Rev. 1/03

ACCU-DRIVE CAM GEAR DRIVE SYSTEM

Catalog #7892 - Small-block Ford V8s, 289/302/351-W

Catalog #7893 - 1985 -1995 5.0L Ford V8s with Hydraulic Roller Lifter Cams

INSTALLATION INSTRUCTIONS

(4º retarded at the crank, 2º at the cam) and install on keyway onto
crankshaft. Use the “0º” standard keyway hole as a baseline for
camshaft timing.

(d) Install the one-piece Ford fuel pump drive #C3AZ-6287-B and

retaining capscrew. Finger tighten only at this time to hold parts in
place. Make sure pin is in pump drive.

5. Align the cam gear and crank gear timing marks as shown in Figure 1.

6. Install the idler gear sub-assembly as follows:
(a) The large idler gear must be installed on the passenger side (right

side) of the engine.

(b) With large idler cranked tightly into mesh, make certain the small

idler (left side of engine) has free vertical movement (clearance) of
no less that .005" or no more than .070". NOTE: The gears will be
severely damaged from friction if they do not have the proper
running clearance as noted.

7. With the idler sub-assembly fully installed in mesh with crank and cam

gears and the large idler gear axle all the way back against the block,
check the clearance between end of idler axles and front cover as
follows:

Please study these instructions carefully before installing your new Accu-Drive Cam Drive System. If you have any questions or problems, do not
hesitate to contact our Technical Hotline at: [phone] from 7:00 am to 5:00 pm, Monday through Friday, Pacific Standard Time or e-mail us
at: [e-mail]. Please fill out and mail your warranty card.

• EMISSION CONTROL SYSTEMS: Check local laws for requirements. Not legal in California on pollution-controlled motor vehicles.

• POWER PACKAGE: Edelbrock Accu-Drive gear drives are part of a Total Power Package parts system that can be completed with the use of dyno-matched
Performer, Performer RPM,or Torker II cams, intake manifolds,and carburetors. For competition applications, use Edelbrock Victor intake manifolds. Please
refer to the Power Package Guide in the Edelbrock catalog to select all the components you need. To order a catalog, please call 1-800-FUN-TEAM.

• ACCU-DRIVE OPERATING PRINCIPLE

The Accu-Drive system utilizes a free floating idler gear that is self-aligning and connects the crankshaft and camshaft gears into proper mesh. The large
floating idler gear is positioned on the right side of the engine (passenger side). During normal operation, the drive power is
transmitted from the crankshaft through the large floating idler to the camshaft gear. During the running operation, there is no backlash between these
gears.
The small idler gear (located opposite the large idler gear driver side) is also free floating. This small gear does not carry any operating gear loading. The
small idler must be allowed to float vertically as noted in Figure 1. The small idler prevents the large idler gear from being
disengaged from mesh in the event the engine is rotated backwards.

• GEAR ASSEMBLY CAUTION NOTES:

❑ Never hammer directly on gears. You will damage the gear teeth and cause early failure.
❑ Lubricate all gears and bearings with engine oil before installing front cover.
❑ The small idler gear must be free to float vertically with the large idler gear in tight gear mesh with the crankshaft and camshaft gears. See Figure

1 for proper clearance. CAUTION: If gears do not have proper clearance, the gear teeth will become overheated and discolored and will fail due to
excessive friction between the mating gears.

❑ Large idler gear shaft length may require material removal to obtain the correct clearance between the cylinder block and front cover. See Figure 3.
❑ If a non-stock front cover is used, be sure idler gear axles do not have more than .030" front end clearance. Install allen head capscrews inside cover

(if necessary) to obtain proper clearance.

❑ Do not use aluminum hub harmonic balancer with your Accu-Drive. Use only stock or aftermarket steel harmonic balancers.

INSTALLATION INSTRUCTIONS

NOTE: THE FOLLOWING STEPS ARE CRITICAL FOR THE PROPER OPERATION OF YOUR ACCU-DRIVE!

1. Remove stock timing cover. Rotate engine to Top Dead Center of cylinder
#1 so that the timing marks on the original crank and cam sprockets are
directly lined up with each other, i.e. the mark on the crank sprocket will
be straight up and the mark on the cam sprocket will be straight down.
Using suitable gear puller, remove stock crank and camshaft sprockets
and timing chain. Refer to repair manual if necessary for individual steps.

2. Assemble Accu-Drive as shown in Figure 1.

3. Install crank gear with the large inside chamfer toward rear of engine and
timing mark toward front of engine. Make certain crankshaft drive key is
aligned with keyway of the crank gear before assembling.

4. See Figure 2 “Camshaft Gear Assembly” for correct assembly.

(a) Place well-lubricated thrust washer on the rear (block) side

of cam gear.

(b) The Edelbrock Accu-Drive system is furnished with an 0.032" thick

thrust ring that installs between the back side of the cam gear and
the front side of the camshaft thrust plate. Torque the thrust plate
retaining capscrews to 9-12 ft./lbs. NOTE: No thrust button is used
on Ford engines.

(c) Select the desired keyway in the crank gear “0”

(standard), “A” (4º advanced at the crank, 2º at the cam), or “R”

©2003 Edelbrock Corporation
Brochure No. 63-0079

Page 2 of 2

Rev. 1/03

(a) Place a small amount of clay on the front end of both axles as

shown in Figure 3.
NOTE: It will be necessary to cut material off rib inside front cover

to hold idler gears in place.
(b) Install front cover with gasket in place.
(c) Remove cover and measure the thickness of the compressed clay.

It should be .005"-.030". Do not tighten cover down until proper

clearance has been obtained. Without sufficient clearance, there is

risk of cracking the cover when tightened down.
(d) If clearance is less than .005, you will need to grind off idler axle as

shown to obtain proper clearance. If clearance is greater than .090,

replace left side (larger idler side) stud with tapered end axle

provided in the kit. Re-install idler assembly and recheck for

minimum clearance between block and front cover.

8. With all gears correctly in mesh and timed, tighten the camshaft
capscrew to 35 ft./lbs. It would also be a good idea to use Locktite™ or
equivalent on the bolt threads prior to final assembly.

9. Lubricate all gears and bearings with engine oil.

10. Re-install the front cover.

11. Re-install all components removed in preparation for step 1.

Figure 1

Accu-Drive for Ford 289/302/351-W V8s

Power idler (22 teeth)

Timing Mark

Reverse idle (20 Teeth) should have
between .005-.070 free vertical travel with
power idler in hard mesh with cam and
crank gears

Camshaft timing can be advanced or retarded by
4° (crankshaft degrees) from stock timing by using
the appropriate alternate timing keyways in crank
gear.

1

2

Timing Mark

3

View looking at front of engine

Legend
1-Crank gear
2-Large Idler gear
3-Cam gear
4-Small Idler gear

4

ÌÌ



0

R

A

Must use Brass

Thrust Ring

(0.032" thick)

Camshaft

retaining

plate

Figure 2

289/302/351-W Ford

Cam Gear Assembly

Figure 3

Idler Axle Clearance Stock Ford

Front Cover

Remove material on this end of
axle to obtain correct clearance
(.005"-.030")

Place clay in this area
to check shaft end
clearance

Cut off rib as necessary to hold
idler gears in place

Block

Crankshaft

Edelbrock Corporation

2700 California Street

Torrance, CA 90503

Toll-Free Tech Line: 1-800-416-8628

Tech E-mail: [e-mail]