| How To Set Timing on a V8 Chevrolet Engine. |
Figure 1
Figure 2
As your engine get older they will wear, and if you have a keeper and want to repair it yourself it is really
not that hard to do if you dont mind getting your hands dirty.
One of the things that will need repair after 75,000 to 100,000 miles is the timing chain.
The cost of the timing chain and gears are usually under $20. It would probably be a good time to
change oil, and coolant when you attempt this job. (you will loose some fluids, make sure levels are
correct before you start the engine when you are done).The most difficult part of changing a timing chain
and gears is "getting to it". The arrow below on "figure 2" shows the location of the timing cover.
Tools Needed:
7/16" socket 7/16" Combination Wrench Flat Head Screw Driver
1/2" socket 1/2" Combination Wrench Phillips Head Screw Driver
9/16" socket 9/16" Combination Wrench Small Hammer
5/8" socket 5/8" Combination Wrench A Gear Puller
Disassembly: To begin you will need to remove radiator and shroud. If you have a 2 piece shroud you
can get by with taking off the upper portion, and the upper water hose.
When taking out the radiator, make sure that the engine is not HOT. You can be severly
burned by the HOT water from a radiator. ( be careful removing transmission cooling lines
on the automatic vehicles (these fitting tend to be softer and the wrench can slip and
damage the nut, if this happens Vise Grips are a good help).
Next The next thing you will remove is the Alternator, Air Conditioning Compressor, and Water
Pump. On some vehicles the Power Steering Pump. Only remove items in the way of the
timing cover.
Next The harmonic balancer will have to be removed before you can remove the timing cover.
First remove the bolts that hold on the belt pulley, and you can then get to the main bolt that
connects to the front of the crankshaft.
There are tools that you can get on loan at your local parts store to both remove and reinstall
the harmonic balancer. You will need to change the front oil seal on the timing cover, It is always
a good idea to change this seal when doing this job.
Next The Timing cover bolts will need to be removed from the front of the cover usually 7/16".
There are 2 bolts usually 1/2" at the bottom of the engine (the area where the timing cover
and oil pan join. It ie better to change the Oil Pan gasket, however sometimes you can
change the timing cover without replacing the Oil pan gasket. Just loosen bolts about 1/2
way and gently pull down on oil pan( just be real careful not to damage the Oil Pan Gasket. If
you do this can cause an oil leak). I have successfully completed this job both ways.
Next When you remove the timing cover you can now see the Timing Chain and Gears. The large
gear on the top is the Cam Shaft Gear and the small gear at the bottom is the Crank Shaft
Gear. To remove the Timing Chain remove the 3 bolts on the Cam Shaft Gear and with a
hammer slightly tap the gear and the upper gear and the chain can be removed ( before you
remove the Timing Chain and gears it would be good to line up the timing gears as shown in
Figure 1 this will make it easier to re-install the new gears). Remove Lower Gear with gear
puller. Replace Oil seal on timing cover. ( with a flat head screw driver place between the
rubber seal and the metal housing from the back side and gently tap with a hammer. Clean
and put oil on the seal and tap back into its home).
Next RE-INSTALL
Replace Items in reverse sequence.(what you took off last, Put on first).
Reinstalling the lower gear can be easily accomplished by using a large deep well socket and
gently tapping it into place (line up with key way).
Install chain on upper gear and bolt back on to Cam Shaft (this will give you the correct
tension required).
The gears must be lined up by the marks or the engine will not run properly.
Reinstall Timing Cover and Oil Pan (be careful not to over tighten bolts (this can cause
damage to the gaskets). Tighten to about 17-20 Pounds.
Next Re-Install all other items taken off. Check Oil and Water Levels.
Figure 2 Provides Firing Order 1-8-4-3-6-5-7-2
Pull off Distributer cap and make sure rotor is pointing to the #1 Spark Plus and follow the
Firing Order Sequence.
NOTE When Cam Shaft Gear and Crank Shaft Gear are Replaced in the Marked position the # 1
Spark Plug is Setting at TDC (Top Dead Center).
We Hope that we have been of help.
Rock Creek Racing & Performance Engines
Guntown, Mississippi
not that hard to do if you dont mind getting your hands dirty.
One of the things that will need repair after 75,000 to 100,000 miles is the timing chain.
The cost of the timing chain and gears are usually under $20. It would probably be a good time to
change oil, and coolant when you attempt this job. (you will loose some fluids, make sure levels are
correct before you start the engine when you are done).The most difficult part of changing a timing chain
and gears is "getting to it". The arrow below on "figure 2" shows the location of the timing cover.
Tools Needed:
7/16" socket 7/16" Combination Wrench Flat Head Screw Driver
1/2" socket 1/2" Combination Wrench Phillips Head Screw Driver
9/16" socket 9/16" Combination Wrench Small Hammer
5/8" socket 5/8" Combination Wrench A Gear Puller
Disassembly: To begin you will need to remove radiator and shroud. If you have a 2 piece shroud you
can get by with taking off the upper portion, and the upper water hose.
When taking out the radiator, make sure that the engine is not HOT. You can be severly
burned by the HOT water from a radiator. ( be careful removing transmission cooling lines
on the automatic vehicles (these fitting tend to be softer and the wrench can slip and
damage the nut, if this happens Vise Grips are a good help).
Next The next thing you will remove is the Alternator, Air Conditioning Compressor, and Water
Pump. On some vehicles the Power Steering Pump. Only remove items in the way of the
timing cover.
Next The harmonic balancer will have to be removed before you can remove the timing cover.
First remove the bolts that hold on the belt pulley, and you can then get to the main bolt that
connects to the front of the crankshaft.
There are tools that you can get on loan at your local parts store to both remove and reinstall
the harmonic balancer. You will need to change the front oil seal on the timing cover, It is always
a good idea to change this seal when doing this job.
Next The Timing cover bolts will need to be removed from the front of the cover usually 7/16".
There are 2 bolts usually 1/2" at the bottom of the engine (the area where the timing cover
and oil pan join. It ie better to change the Oil Pan gasket, however sometimes you can
change the timing cover without replacing the Oil pan gasket. Just loosen bolts about 1/2
way and gently pull down on oil pan( just be real careful not to damage the Oil Pan Gasket. If
you do this can cause an oil leak). I have successfully completed this job both ways.
Next When you remove the timing cover you can now see the Timing Chain and Gears. The large
gear on the top is the Cam Shaft Gear and the small gear at the bottom is the Crank Shaft
Gear. To remove the Timing Chain remove the 3 bolts on the Cam Shaft Gear and with a
hammer slightly tap the gear and the upper gear and the chain can be removed ( before you
remove the Timing Chain and gears it would be good to line up the timing gears as shown in
Figure 1 this will make it easier to re-install the new gears). Remove Lower Gear with gear
puller. Replace Oil seal on timing cover. ( with a flat head screw driver place between the
rubber seal and the metal housing from the back side and gently tap with a hammer. Clean
and put oil on the seal and tap back into its home).
Next RE-INSTALL
Replace Items in reverse sequence.(what you took off last, Put on first).
Reinstalling the lower gear can be easily accomplished by using a large deep well socket and
gently tapping it into place (line up with key way).
Install chain on upper gear and bolt back on to Cam Shaft (this will give you the correct
tension required).
The gears must be lined up by the marks or the engine will not run properly.
Reinstall Timing Cover and Oil Pan (be careful not to over tighten bolts (this can cause
damage to the gaskets). Tighten to about 17-20 Pounds.
Next Re-Install all other items taken off. Check Oil and Water Levels.
Figure 2 Provides Firing Order 1-8-4-3-6-5-7-2
Pull off Distributer cap and make sure rotor is pointing to the #1 Spark Plus and follow the
Firing Order Sequence.
NOTE When Cam Shaft Gear and Crank Shaft Gear are Replaced in the Marked position the # 1
Spark Plug is Setting at TDC (Top Dead Center).
We Hope that we have been of help.
Rock Creek Racing & Performance Engines
Guntown, Mississippi
After the engine has been thoroughly warmed up the valves may be adjusted with the engine shut off as follows: With engine in position to fire (i.e. Compression up on #1 cylinder) Adjust as follows Exhaust 1-3-4-8 Intake 1-2-5-7. Then turn the crank 1 complete revolution which brings # 6 Up to firing position at this time adjust as follows Exhaust 2-5-6-7, Intake 3-4-6-8 Adjust to zero lash. Valves can be adjusted when the engine is running with caution. After engine is warmed up to operating temperature remove valve cover and attach gasket to head to keep the oil from dripping everywhere. At idle speed loosen rocker nut until you hear it clatter turn nut down slowly until noise stops. This is zero lash position. Turn nut an additional 1/4 turn wait 10 seconds if still no clatter tighten nut. Repeat on all 16 rockers. |
