Here you can find information regarding the assembly of the Chevy 3.6L DOHC engine. In this guide we will
start from the inside of the engine including the
crankshaft, connecting rods, and piston ring installation and then move outwards all the way to the pulley belt
system. Along the way correct procedures and torque specs
will be given to aid in the assembly of the engine. Feel free to start from the beggining and work your way
outwards or skip ahead to your current position in the engine for what you may need.
Crankshaft Main Caps Installation
The 3.6L engine block main bearing caps should be inspected for any defects or flaws before installation.
Be sure to lubricate the bearing surfaces prior to installation. Once prepared you can place the caps onto the crankshaft
and begin tightening the bolts down in a multi stage process. On this engine there are 3 different sets of torque specs for the main
cap bolts. These specs are broken down into the inner bolts, outer bolts, and the side bolts. The inner bolts are the ones furthest
to the middle of the engine. The outer bolts are the ones farthest out from the center of the engine and then the side bolts are the
bolts which tighten in from the outside of the engine entirely. The inner main bearing bolts can be torqued down to 15 ft-lbs and
then an 80 degree turn. The outer main bearing bolts can be torqued down to 10 ft-lbs and then a 110 degree turn. Finally the side bolts
can be torqued down to 22 ft-lbs and then a 60 degree turn. Be sure to go through each bolt during each stage of the tightening sequence.
Once finished you should be good to continue with the rest of the engine.
Chevy Impala 3.6L Main Cap Torque Specs (Inner): 15 ft-lbs + 80°
Chevy Impala 3.6L Main Cap Torque Specs (Outer): 10 ft-lbs + 110°
Chevy Impala 3.6L Main Cap Torque Specs (Side): 22 ft-lbs + 60°
Piston and Connecting Rod Installation
To install the pistons and connecting rods you must first install the piston rings into each piston. Be careful
not to stretch the rings or break them during installation. Make sure to put the correct rings in the correct
positions, this can be determined by looking at
the instructions given with the new rings. Each ring manufacturer is different so be sure to check for your
specific rings. Once the rings have been installed you can now fit the connecting rod bearings into the end caps
and lube them up with oil or lithium grease. The piston can now be lowered into the cylinder, make sure the dot
or mark is facing the front of the engine and that you don't scratch the cylinder.
Once installed you can match the connecting rod caps with the correct rods and start to torque the connecting
rod bolts to 18 ft-lbs and then an additional 110 degree turn for each bolt. After all are done rotate the crank
to ensure all pistons move smoothly in and out of their cylinders and nothing binds.
When installing the oil pump be sure to use the proper sealant around the pump base if neccessary to ensure that oil pressure
doesn't drop due to leakage. Both surfaces should be cleaned and preped prior to installing. After preparing the contact surfaces carefully
install the oil pump onto the front end of the engine by aligning the crankshaft through the center of the oil pump hole. There should be
flat ends of the crank that align with the pump. Once in place you can hand tighten down the oil pump mounting bolts. These bolts are the larger
of the pump bolts as shown in the picture. Once hand tightened you can then torque down the 3 hex bolts to 18 ft-lbs. From here you can move onto
installing the timing chain system or the next part of your build.
The first thing you must do when installing cylinder heads is to ensure both the block and head surfaces are
completely clean from dust, oil, and any debris. The next thing you must to is
to set the camshafts to their correct positions to prevent any valves from hitting pistons during installation
and torquing of the head bolts. Much the same you have to set the pistons to their correct
locations, typically this means putting the #1 piston to TDC or Top Dead Center. Once everything is ready you
can install the head gasket onto the engine block by aligning the alignment dowels.
Something I usually do is spray down the head gasket with some engine copper spray from permatex which you can
find here, this ensures that any gaps that could be present between the 2 surfaces gets filled with the
spray. It
also helps to transfer heat between the 2 metals. With the gasket in place you can set the cylinder head onto
the gasket and block, if needed have someone assist with this process as the head can be heavy
and you don't want to scratch anything or drop it! Once the head has been placed you will want to start
installing the head bolts to make sure it doesn't move. Be sure to buy new head bolts as many manufacturers
use TTY or Torque to Yield head bolts meaning they stretch during torqueing and cannot be used twice. Also make
sure to lubricate the bolts in clean engine oil before installing them into the head.
Once all the head bolts have been installed and finger tightened you can start the torqueing process, almost all
head bolts have a multi-step process for torqueing. On this 3.6L engine there are 2 different size head bolts being the M11's
and the M8's the M8's are the smaller of the 2. Make sure you use all new head bolts as they are TTY bolts and can only be used
once as they stretch during installation. The M11 cylinder head bolts get tightened down to 22 ft-lbs and then a 150 degree turn.
The smaller M8 cylinder head bolts get tightened down to 11 ft-lbs and then a 75 degree turn. Be sure to go through each bolt
during each step before moving onto the next value. Once complete you can move onto installing the camshafts and timing chain system.
On the Chevy 3.6 DOHC engine the timing system is ran by the use of 3 different timing chains. 2 of the chains run from idler sprockets up to
each cylinder head in order to run the VVT camshaft sprockets. The third timing chain from the oil pump or crankshaft sprocket to the 2 idle sprockets.
This timing chain system is rather complex so be sure to study the image provided and if you are not familiar with engine timing do additional research.
Before installing the timing system be sure to install the cylinder heads and torque them down properly by following the steps above. Once the heads have
been installed you can install the camshafts into the proper locations. Each cylinder head has an intake and exhaust camshaft which are labeled using an
I and E. The intake camshafts will go on the inward most side of the engine with the sprocket side facing the front of the engine or where the timing chain
and oil pump go. The exhaust camshafts go on the outward side in the same fashion. Make sure that each rocker arm and hydraulic valve is in place and
remains in place as you install the camshafts and tighten them down. The camshafts get fastened down using bearing caps which should be installed
with lubrication and torqued down to 8 ft-lbs. Once all 4 camshafts have been installed and torqued down you can install the camshaft sprockets or VVT
actuators and torque them down to 43 ft-lbs. Be sure to hold the camshafts down with a large wrench on the flat ends while torqueing down on
these as otherwise they will just spin. Once tightened you can then move to install the idle sprockets and tighten them down to 43 ft-lbs.
The crankshaft sprocket simply slides onto the crankshaft after the oil pump has been installed and aligns using a woodruff key. From here we can
install the timing chain on the right side of the engine and align the yellow link with the dot on the sprockets. On the idler gear the painted
link should be visible through the hole. Now install the timing chain tensioner guide and timing chain guide and hand tighten down the bolts.
The tensioner can then be installed, they are different for each side so be sure to use the right one by aligning the oil hole with the tensioner oil hole.
Hand tighten down the chain tensioner and then torque down the tensioner and guide bolts to 18 ft-lbs. Moving downwards we can install the middle timing chain
that ranges from the crank to the idler sprockets. This chain aligns using small arrow marks with the painted marks on the chain. The right side
guide for this chain comes preinstalled on the oil pump but if removed can be reinstalled once the chain is in place and torqued down to 18 ft-lbs.
The tensioner side of the middle chain system and the other guide can also be torque down to 18 ft-lbs. Finally the last timing chain can be installed
by following the same steps as the right side chain by aligning the painted marks and dots and then installing the tensioner and guides. Once installed be
sure to double check each painted mark on every chain and then release the tensioners slack and ensure that each chain is tight on its sprockets teeth.
From here we can move onto the timing cover and the valve covers.
Chevy Impala 3.6L Crankshaft Position Sensor Torque Spec: 8 ft-lbs
Timing Cover Installation
The timing cover on the 3.6L is used to cover up the internals of the engine and hold in massive amounts of oil. For this reason I recommend using
some silicon sealant along with a new gasket during installation. Be sure to clean all of the metal surfaces prior to installation and placing the silicon onto the metal.
With everything ready to install be sure to double check your timing and engine internals before placing the cover in place. Another tip is to lube up the
crankshaft seal with some oil so it seats better. If everything is good to go then place the cover
onto the engine block and begin to tighten down the bolts hand tight. Once all of the bolts have been hand tightened and you wait the recommended
time your sealants manufacturer says to you can tighten down the timing cover bolts to 18 ft-lbs. Be sure to tighten them in a cross pattern going from
one side of the cover to the other instead of tightening them all down in a row as this can cause a leak to occur.
Much like the timing cover on the 3.6L the oil pan plays an important role in keeping the engine oil inside the
engine. For this reason I recommend using a new gasket as well as some silicone sealant
during installation. Using the same technique as before with the cover you clean the surfaces of both the oil
pan and the engine block and then install the new gasket onto the block and then follow
it up with some silicone sealant. Be sure to follow your sealants instructions to ensure you get the best seal
from your application. The oil pan bolts torque to 18 ft-lbs in a cross pattern design. The oil pan side bolts get
tightened down to 37 ft-lbs.
Along with the pan is the oil pan drain plug, this gets removed and reinstalled quite frequently and can be
torqued down to 18 ft-lbs.
Chevy Impala 3.6L Oil Pan Torque Specs : 18 ft-lbs
Chevy Impala 3.6L Oil Pan Side Bolts Torque Specs : 37 ft-lbs
The valve cover installation is rather simple, there are rubber seals for each bolt hole and a silicone gasket
that prevents oil from leaking out of the engine. It is recommended to replace both the seals
and the gaskets although if they are in good condition you can reuse them. If you do choose to reuse them I
would use some silicone sealant along with the silicon gasket to ensure it does not leak.
The valve cover bolts torque down to 106 in-lbs or about 8 ft-lbs in a criss cross order. Be sure not to miss
any bolts to avoid having oil leak out onto the exhaust pipes and cause a lot of smoking.
When installing the intake manifold you want to make sure you have all the surfaces as well as intake holes
cleaned out before placing the manifold into position. Once cleaned you can then place
the intake manifold gaskets onto the alignment pins. If you want you can also use a little bit of sealant on the
gaskets to help ensure there are no leaks. With the gaskets in place you can now put
the manifold down onto the gaskets and begin to install the bolts. The intake manifold bolts should
be torqued down to 18 ft-lbs. The ignition coils can be tighten down to 8 ft-lbs and the spark plugs themselves can be
torqued down to 13 ft-lbs, be careful not to overtorque these as they can snap and cause big problems.
When installing the throttle body make sure that all of the gaskets are in good condition and will hold a seal as you do not
want to be leaking gas fumes around the engine. If everything looks good you can tighten the throttle body bolts down to 8 ft-lbs.
Chevy Impala 3.6L Throttle Body Torque Specs : 8 ft-lbs
Exhaust Manifold Installation
The exhaust manifold can be installed by cleaning the surface areas on both the head an the manifold itself and
then by using the exhaust manifold gasket and putting it in place. Once the gasket is in its
location you can put the manifold onto the heads and begin to torque it down to 15 ft-lbs. I always use some
copper spray from permatex on the exhaust manifold gaskets to ensure I do not end up with
any exhaust leaks once done. When you go to install the engine into the vehicle or if it is already in the
vehicle the torque specs for the exhaust manifold to the exhaust pipes or catalytic converter is 18 ft-lbs.
The EGR system consists of a series of pipes that range from the manifold to the head. The EGR pipes on this engine can be
tightened down to 15 ft-lbs.
The water pump on the Chevy 3.6L engine should be installed by using
a new gasket and if desired some silicone sealant to help prevent leaks. Be sure to clean both metal surfaces prior to installing the pump. Once
prepared the pump can be moved into placed and then tightened down. On this engine the water pump tightens down to the engine block using 8 ft-lbs
of torque. Be sure to tighten down the bolts in a cross pattern to ensure no leaks develop. The old
water pump bolts are TTY and should not be reused more than once. The water pump pulley can then be tightened down onto the pump
itself using 8 ft-lbs of torque.
Chevy Impala 3.6L Water Pump Torque Specs : 8 ft-lbs
Most of what is left on the engine is just place and tighten objects such as the belt pulleys, belt tensioner,
throttle body, oil filter neck, crankshaft pulley, and motor mounts. If the items have a gasket and hold either
oil or coolant inside the engine then feel free to add some sealant along with the gasket. Always be sure to
inspect your gaskets and replace them if there is any deteriation or flaws with them. For the
belt system the crankshaft pulley gets torqued to 74 ft-lbs and then an additional 150 degree turn. This is extremely tight so I recommend holding the
crankshaft somehow during the tightening procedure. The drive belt
tensioner bolt can be tightened to 43 ft-lbs and the idler pulley bolt can be torqued down to 43 ft-lbs. When installing be sure they
both turn smoothly and if they do not then replace them with new ones as the bearings can go bad. The engine
motor mount can be installed onto the engine block if it hasn't been already, the torques for
the mount to the block is 59 ft-lbs and then when installing the mount to the vehicle or frame it can be torqued to
35 ft-lbs. Finally the throttle body can be installed on top of the intake manifold
with a good gasket and some added sealant using 7 ft-lbs in a criss cross pattern. For installing the belt you
can use a tool to move the tensioner into its springed state and install the belt as shown in the
picture. The power steering pump should be tightened down to 25 ft-lbs. The alternator can be tightened down to
37 ft-lbs.
