AEM TruTime Adjustable Cam Gear 23851BK User Manual

							
 
TRU-TIME 
CAM 
GEARS  
1993 – 2000 Dodge Neon SOHC 
Part number 23 – 851 
 
 
WARNING: 
,! 
This installation is not for  the mechanically challenged!  If you 
are not mechanically inclin ed or do not understand the 
procedure please do not attempt the installation.  Refer the 
installation to a reputable mech anic. It is highly recommended to 
purchase the factory service manual  to use as a guide along with 
these instruction sheets
. 
Legal in California ONLY for racing vehicles, which may never be used upon a highway. 
ADVANCED ENGINE MANAGEMENT INC. 
15606 South Broadway Center Street, Gardena, CA. 90248  Phone: (310) 258-0030 Fax: (310) 258-0036 
Http://www.a-e-m.com E-Mail: [email protected]  
						

							
 
You have just purchased the BEST adjustable cam sprockets available. These AEM  
adjustable cam sprockets are CNC machined  from billet aluminum and then laser 
etched with cam timing marks for adjustment up to  ±10°  at the cam or  ±20°  at the 
crankshaft. Using the vernier scale on th e sprocket hub helps to perform cam timing 
changes quickly and accurately. The inner  hub is anodized for lasting beauty and 
resistance to corrosion. The out gear sector is hard anodized for resistance to wear. 
We have found that there are significant po wer gains to be made by adjusting the cam 
timing even with stock cams and compression.  Adjustable cam sprockets are usually 
required in applications where an afterma rket or reground performance cams are 
installed or the cylinder head has been milled 0.005” or more. The use of these cam 
sprockets allows the extracti on of maximum power from your  engine. We have recorded 
gains of up to 10~15 horsepower due to  cam timing tuning using adjustable cam 
sprockets. 
When aftermarket or reground cams are instal led, the original manufacturer’s cam 
timing specifications are no l onger accurate. These adjustable cam sprockets allow you 
to make necessary adjustments to cam ti ming to maximize the performance of your 
engine. This is accomplished by “degreeing  in” the optimum cam timing for a particular 
engine set up. 
The adjustable cam sprocket is especially  effective when used with heads that have 
been milled. The adjustability of the sprocket  allows the accommodation of the changes 
in cam timing due to the variation of timing  belt length from the bottom sprocket to the 
top sprocket when the head is  milled. If the head has been mi lled 0.005” or greater the 
relationship between the head and the block is  altered by moving the head closer to the 
crankshaft resulting in  retarded cam timing. 
It must be emphasized that the preceding  descriptions are generalizations and any 
adjustments made must be done with a conservative approach and on a dynamometer 
or on a racetrack. We do not condone any  illegal activity on the street.  
						

							
 
Read and understand these instructions BEFORE attempting to install this 
product
 
Front Cover Removal 
a)  It is important that the  installer familiarize themselves with the procedures before 
starting the installation. This procedure r equires some Chrysler specific tools, 
which cannot be substituted with other or dinary tools. If you do not have access 
to these Chrysler tools please refer  the installation process to a qualified 
mechanic that does.  It is important to  have a factory service manual available for 
reference while undertaking this installati on. This procedure is best accomplished 
using a lift. If a suitable lift is not availa ble, for safety reasons, use appropriately 
rated jackstands. 
b)  Disconnect the negative battery cable. 
c)  Remove all the accessory drive belts. 
i)  Alternator drive belt 
ii)  Air conditioning and power steering pump belt. 
d)  Remove the right front wheel. 
i)  Remove the right inner splash shie ld and the right engine-mount bolt access 
plug. 
e)  Remove crankshaft damper bolt.  Remove damper using Special Tool 1026 and  insert 6827-A or equivalent  pulling tool. (Fig. 1)  
f)  Remove Right Engine Mount (Fig. 2) 
i)  Position a floor jack carefully under  the transmission and engine and use to 
take the load off the right engine mount. 
ii)  Remove purge duty solenoid  from the engine mount bracket. 
iii)  Remove the vertical fasteners and the thru-bolt. 
iv)  Remove the engine mount.  
g)  Remove the power steering pump and set as ide. This will allow you to move the 
power steering hoses from  the front of the engine. Do not disconnect any power 
steering hoses. If you do disconnect any hoses then the o-rings at the banjo 
connections at the top of t he pump will need to be replaced. 
h)  Remove the engine mount bracket. (Fig. 3) 
i)  Remove the front timing belt cover. 
j)  Loosen but do not remove the cam gear retaining bolt. 
k)  Align the camshaft and the cranksha ft timing marks by rotating the engine 
with the crankshaft before loosen ing or removing the timing belt. 
 
Note:  There are two different methods  used for timing belt tensioning, 
mechanical and hydraulic.  Please refe r to the appropriate section based upon 
your model. 
 
2)  Timing Belt Removal 
a) Hydraulic Tensioning 
i)  Loosen the timing belt tensioner fa steners and remove timing belt and 
tensioner.   Do 
NOT loosen, tighten, or remove the tensioner pivot bolt.  
(Fig. 4) 
 
 
  
						

							
 
b) Mechanical Tensioning 
i)  Insert a 8mm Allen wrench into the belt tensioner.  Before rotating the 
tensioner insert the long end of a 1/8”  or 3mm Allen wrench into the pin hole 
on the front of the tensioner.  Rotate  the tensioner counterclockwise with the 
Allen wrench, while pushing in lightly on  the 1/8” or 3mm Allen wrench, until it 
slides into the locking hole. (Fig. 5) 
ii)  Remove timing belt. 
Note:  Do not rotate the camshaft once  the timing belt has been removed or 
damage to the valve components may occur. 
 
3)  Cam Gear Removal 
a)  Remove the cam gear retaining bol t, and slide the stock cam gear off the 
camshaft. 
b)  Install the AEM Adjustable Cam Gear  in the reverse process of removing the 
stock cam gear. 
c)  Finger tighten the cam gear retaining bolt.  Do not torque the cam gear  retaining bolt until the timing belt is installed.   If you tighten the cam gear 
retaining bolt before the timing belt is installed then damage to the valve 
components may occur. 
4)  Timing Belt Installation (refer to step a or step b depending on the 
model of your vehicle.)   
a) Hydraulic Tensioner 
i)  Place the hydraulic tensioner into a  vise that is equipped with soft jaws.  
Slowly compress the plunger until the  hole in the plunger lines up with the 
hole in the tensioner body.  Insert the  metal rod that is supplied in the kit 
through the tensioner body and plunger to  retain the plunger in place until 
tensioner is installed. (Fig. 6) 
ii)  Set the crankshaft sprocket to TDC by aligning the sprocket with the arrow on 
the oil pump housing, then back off  3 notches before TDC. (Fig. 7) 
iii)  Set the camshaft to TDC by aligning  the mark on the cam gear with the mark 
on the rear timing belt cover. 
iv)  Move crankshaft to ½ mark before  TDC for belt installation. (Fig. 8) 
v)  Install timing belt.  Starting at the crankshaft, go around the water pump 
sprocket and then around the cam gear. 
vi)  Move the crankshaft sprocket to TDC to  take up belt slack.  Install tensioner 
to engine block but do not tighten fasteners. 
vii) Use a torque wrench to apply 250 in.-lbs.  of torque to the tensioner pulley.   
viii)With torque being applied to the tensioner pulley move the tensioner up 
against the tensioner pulley bracket and tighten fasteners to 275 in.-lbs. 
ix)  Pull tensioner plunger pin.  Preten sion is correct when pin can be removed 
and installed. 
x)  Rotate crankshaft through two revolu tions and check the alignment of the 
timing marks. 
b) Mechanical Tensioner 
i)  Set the crankshaft sprocket to TDC by aligning the sprocket with the arrow on  the oil pump housing, then back off  3 notches before TDC. (Fig. 7) 
ii)  Set the camshaft to TDC by aligning  the mark on the cam gear with the mark 
on the rear timing belt cover.  
						

							
 
iii)  Move crankshaft to ½ mark before TDC for belt installation. (Fig. 8) 
iv)  Install timing belt.  Starting at the crankshaft, go around the water pump 
sprocket and then around the cam gear. 
v)  Move the crankshaft sprocket  to TDC to take up belt slack. 
vi)  Remove the 1/8” or 3mm Allen wrench from belt tensioner. 
vii) Rotate crankshaft through two revo lutions and check the alignment of the 
timing marks. 
5)  Reassembly 
a)  Torque the cam gear reta ining bolt to 85 ft.-lbs. 
b)  Reinstall the timing belt cover. 
c)  Install engine mount bracket.   Torque bolts to 30 ft.-lbs. 
d)  Install power steering pump assembly. 
e)  Install right engine mount. 
f)  Remove jack from under engine. 
g)  Reinstall crankshaft damper using M12x 1.75x150mm bolt, washer, thrust bearing 
and nut from Special Tool  6792.  Install crankshaft damper bolt and torque to 105 
ft.-lbs. 
h)  Install accessory drive belts.  Replace  if they show any signs of deterioration. 
i)  Reinstall the right inner splash shield. 
j)  Perform relearn camshaft and cranksha ft alignment procedure in the Engine 
Miscellaneous Section of  the DRB Scan Tool. 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
  
						

							
 
Reference Diagrams: 
 
 
 Fig 1: Crankshaft Damper Removal Fig 2: Right Engine Mount Removal 
 Fig 3: Engine Mount Removal Fig 4: Hydraulic Tensioner  
						

							
 
 
Fig 5: Mechanical Tensioner Fig 6: Compressing Hydraulic Tensioner 
Fig. 7:  Aligning Crank to 3 Notches from TDC Fig. 8: Aligning Crank to the ½ Mark 
 
 
 
 
 
 
 
 
 
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