Here you can find information regarding the assembly of the Ford 3.8L 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 beginning 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 3.8L V6 engine block has 4 main crankshaft caps that hold the crankshaft into place. During assembly be sure to use new bearings
and apply the proper assembly lube to the bearings before installing. You can start by cleaning all bearing surfaces with a clean cloth and then
installing the bearings in to their proper places being the engine block and the main caps. Once installed you can apply lube and place the caps into there locations
on the crank and begin to hand tighten the oiled bolts. Once all caps and bolts are in place you can start from the middle and work outwards and torque the bolts to
30 ft-lbs and then an additional 90 degree turn. Once the vertical bolts have been tightened you will notice there are some horizontal cross bolts that fasten into the caps
from the side of the engine. These bolts will need to be tightened to 22 ft-lbs and then an additional 90 degree turn. With both the vertical and cross bolts in and tightened
you will want to turn the crankshaft over and ensure there are no binding and spots where it doesn't turn smoothly.
Ford Mustang Crankshaft Main Caps Torque Spec : 30 ft-lbs + 90°
Ford Mustang Crankshaft Cap Cross Bolts Torque Spec : 22 ft-lbs + 90°
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 33 ft-lbs and then an additional 90 degrees. After all are done rotate the crank
to ensure all pistons move smoothly in and out of their cylinders.
Ford Mustang Connecting Rod Torque Specs : 33 ft-lbs + 90°
Oil Pump Installation
The oil pump on this engine goes onto the timing cover by the use of 2 different sized bolts. The small of the bolts being M6 sized need to be torqued to 8 ft-lbs.
While the larger of the two being M8 bolts will need to be torqued to 20 ft-lbs. When installing the oil pump be sure to have clean surfaces on both parts and to prime the pump itself with
oil so that it does not start off dry.
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. The 3.8L has two different sets of bolts, one set being shorter than the other
which I will refer to as shorter and the others as longer. To start off you will need to tighten all bolts to 15 ft-lbs in a cross
pattern, then to 29 ft-lbs and finally to 36 ft-lbs. Once all bolts are at 36 ft-lbs you will then loosen the longer bolts 3 full turns
and then retighten them to 33 ft-lbs doing one bolt at a time. The reason for loosening the bolts is to set them in the threads as they are TTY. Next we will do the
same for the shorter bolts by loosening them 3 turns and then torqueing them to 19 ft-lbs. Finally we can tighten all the bolts a total of 180
degrees doing them 90 degrees at a time. After torquing the heads are completely installed and you can now move to intalling the timing.
Ford Mustang Cylinder Head Torque Spec Step 1 (All) : 15 ft-lbs
Ford Mustang Cylinder Head Torque Spec Step 2 (All) : 29 ft-lbs
Ford Mustang Cylinder Head Torque Spec Step 3 (All) : 36 ft-lbs
Ford Mustang Cylinder Head Torque Spec Step 4 (Longer) : loosen 3 turns | 33 ft-lbs
Ford Mustang Cylinder Head Torque Spec Step 5 (Shorter) : loosen 3 turns | 19 ft-lbs
Ford Mustang Cylinder Head Torque Spec Step 6 (All) : 90° + 90°
Timing Chain and Guides Installation
The timing system on the Ford 3.8 OHV is rather simple as it just includes one chain that goes from the crankshaft sprocket
up to the camshaft sprocket. The camshaft in this engine is located in the middle of the engine block and has a single sprocket that
includes a gear drive for the oil pump on it. There is a thrust plate which holds the camshaft into place. The thrust plate bolts should be torqued
down to 8 ft-lbs. The sprocket gets fastened on by a single bolt which should be torqued to 33 ft-lbs. With the sprocket installed we can move the timing chain
onto the two sprockets and line them up as shown in the picture with the marks facing each other. Once timing correctly we will install the chain guides and torque them to 12 ft-lbs.
with the guides in place we can move to the upper portion of the engine and install the pushrods and rocker arms onto the valves. The rockers arms are torqued down to 26 ft-lbs.
Ford Mustang Camshaft Sprocket Bolt Torque : 33 ft-lbs
Ford Mustang Camshaft Thrust Bolts Torque Spec : 8 ft-lbs
Ford Mustang Timing Chain Guide Torque Spec : 12 ft-lbs
Ford Mustang Rocker Arm Torque Spec : 26 ft-lbs
Timing Cover Installation
The timing cover on the 3.8L primarily covers just the single timing chain on the engine but also encompasses the oil pump. Since this part deals with most
of the engines oil containment you should be sure to use a good new gasket along with some quality silicon sealant to ensure the oil does not end up leaking out down the road.
Also before putting on the timing cover and tightening it down be sure you have the oil pump installed correctly and tightened down properly. If everything is cleaned and preped for the
installation of the cover then go ahead and put it in place and torque down the cover bolts to 18 ft-lbs.
Ford Mustang Timing Cover Torque Specs : 18 ft-lbs
Oil Pan Installation
Much like the timing cover on the 3.8L 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 8 ft-lbs in a cross
pattern design.
Along with the pan is the oil pan drain plug, this gets removed and reinstalled quite frequently and can be
torqued down to 11 ft-lbs.
Ford Mustang Oil Pan Torque Specs : 8 ft-lbs
Ford Mustang Oil Drain Plug to Head Torque Specs : 11 ft-lbs
Valve Covers Installation
The valve cover installation is rather simple, there are rubber seals for each bolt hole and a silicon 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 silicone gasket to ensure it does not leak.
The valve cover bolts torque down to 106 in-lbs or about 9 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.
Ford Mustang Valve Cover Torque Specs : 9 ft-lbs
Intake Manifold and Fuel Rail Installation
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 torque to 8 ft-lbs
and can be tightened starting from the inside and going outwards. The coil pack
for the spark plugs can be torqued down to 60 in-lbs or about 5 ft-lbs and the spark plugs themselves can be
torqued down to 10 ft-lbs, be careful not to overtorque these as they can snap and cause big problems.
When installing the fuel rail make sure that all the fuel injectors are in good condition and that all the
o-rings are in place and
are in good condition. If everything is good you can place the fuel rail into position and push the injectors
into their holes and start to torque the rail bolts to 90 in-lbs or about 8 ft-lbs.
Ford Mustang Intake Manifold Torque Specs : 8 ft-lbs
Ford Mustang Ignition Coil Torque Specs : 5 ft-lbs
Ford Mustang Spark Plug Torque Specs : 10 ft-lbs
Ford Mustang Fuel Rail 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
location you can put the manifold onto the heads and begin to torque the bolts to 25 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 is 30 ft-lbs.
Ford Mustang Exhaust Manifold Torque Specs : 25 ft-lbs
Ford Mustang Exhaust Pipe Torque Specs : 30 ft-lbs
Water Pump and Thermostat Installation
The water pump on this engine gets installed onto the timing cover and has bolts that go into both the cover as well as the engine. Since
the pump will have bolts going all the way through its important to use a good gasket and sealant when applying the part otherwise you could have coolant
and oil leak outside of the engine and mix internally. If applying sealant be sure to get around all the bolt holes. The bolts that go through the cover and
straight into the engine should be torqued down to 19 ft-lbs. The nuts that come out of the engine block and stick through the cover should be tightened to 6 ft-lbs.
The bolts that don't go all the way through to the block but instead just go into the cover should be tightened to 18 ft-lbs. Once the pump has been tightened
down onto the timing cover you can install the pulley onto the pump. The pulley bolts get tightened down to 19 ft-lbs.
Ford Mustang Water Pump to Engine Torque Specs : 19 ft-lbs
Ford Mustang Water Pump to Cover Torque Specs : 18 ft-lbs
Ford Mustang Water Pump Pulley Bolts Torque Specs : 19 ft-lbs
Front Dress and Pulley belt Installation
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 crank shaft pulley gets torqued to the crankshaft dampner which it itself gets tightened down to the crankshaft.
The dampner torque specs are 110 ft-lbs and then the pulley to the dampner torques is 24 ft-lbs. The belt
tensioner and idler pulley can both be torqued down to 20 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 30 ft-lbs and then when installing the mount to the vehicle it can be torqued anywhere
from 95-125 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.
Ford Mustang Crankshaft Damper Torque Specs : 110 ft-lbs
Ford Mustang Pulley to Damper Torque Specs : 24 ft-lbs
Ford Mustang Idler Pulley Torque Specs : 20 ft-lbs
Ford Mustang Belt Tensioner Torque Specs : 20 ft-lbs
Ford Mustang Engine Mount to Block Torque Specs : 30 ft-lbs
Ford Mustang Engine Mount to Frame Torque Specs : 120 ft-lbs
