Small Block Chevy Rebuild
so actually this is classified as a re-freshening (if this is a word) but
the actual procedure is exactly the same for a rebuild minus some machine
work. This is the block after a complete dis-assembly, hot tank and oil
journal brushing, honing, and re-washing sitting here waiting for the
assembly. Upon dis-assembly we found a worn cam, and cracked heads (the
reason for the failure and subsequent rebuild). I miked the cylinders upon
disassembly and found only 3 thousands taper on the worst cylinder, thus the
cheap rebuild, ie... we will re-use the pistons installing new rings, and
use the old crank since nothing was worn, and the journals are still in
excellent shape. All other parts (except for the normal reused stuff is
Once the honing is done and oil journals cleaned, we cleaned the pistons
removing the carbon especially from the ring lands. Once all re-used pieces
are clean and covered, assembly will start. Don't scrimp on clean. A dirty
engine will fail fast, chewing up the bearings and puting severe scratches
in the freshly machined cylinders. A dirty engine is the same as pouring
dirt down the carbuetor of a running engine.
To follow is a step by step assembly, and with a good engine assembly
manual, and a few specialty tools, there is no reason why you can't do this
yourself. I have built engines easilly in a day, but since there is no rush
on completion, I am going to string the actual work out to about a week or
longer (hey, it takes time to clean my hands and take pictures between
The steps don't show the cleaning or dis-assembly process, and it is just as
important as the assembly.
Mark each Main and Rod cap prior to disassembly with a good set a number
punches. Number each main cap according to it's relation to the engine, in
other words the cap at the front is Number 1 and sequential to the back.
Same goes for the Connecting Rods: On a chevy, the left (or drivers side) of
the engine starts with the front cylinder being number one, followed by odd
numbers 3, 5, and 7, while the right (or passenger side) of the engine is
even numbered 2, 4, 6, and 8. Get a good repair manual and look at engine
configuration to see how your particuliar cylinders are numbered.
Get a set of engine brushes, and clean, clean, clean, until no dirt is
present anywhere on any parts used in re-assembly. If your not going to
reuse something, throw it away, and don't let it dirty up, and clutter up
your work area.
a view of the bottom with all gasket surfaces cleaned and brass freeze plugs
installed. With the cleaning process on going the engine will be wrapped in
plastic until we are ready to install the crankshaft which will ultimately
be the first step.
out of the solvent tank. This crankshaft shows no signs of wear other than a
couple of small scratches that we will buff out prior to assembly.
One important note: When storing a crank, always support it standing up, and
never lay it down. If layed down, the crank will become bent in a short
amount of time with no support on the journals. Same goes for camshafts. If
left in the packing box, they are fine laying down, but if you don't have
the box, it must hang from a wire or stand perfectly straight and supported
from falling. If you accidentally drop the cam, you will most likely buy a
new one, as it will shatter when it hits the ground.
Crankshafts may also break or crack if allowed to fall over.
mentioned earlier, a cracked head was one of the main reasons this engine
Here is the two freshly rebuilt 68cc 1.94 intake 1.60 exhaust heads we chose
to install on this engine. This will be one step to increase compression
(over the cracked 74cc heads) thus generating a touch more horsepower. Other
torque and horsepower mods will be mentioned later.
step the machine shop did that we can't show is the installation of the cam
Allot of people make the mistake during the rebuild to re-use the cam
bearings with a new cam. These bearings are as critical as the crankshaft
main and rod bearings.
Worn cam bearings can throw off cam timing, and cause a loose fit of the
timing chain which will change timing, and eventually cause the chain to
fail, the cam to fail or both.
next step is to install the crankshaft.
Here is a view of the 5 sets of main bearings and the plastigauge that is
used to check clearance between the journal and bearing surface.
of the main bearings is a simple procedure but utmost care and attention
should be given.
First, make sure the journal under where the bearing will sit is clean and
particle free. Any dirt will cause the bearing to warp upon torqueing the
caps and may cause the bearing to come in direct load contact with the
crankshaft which is very bad.
Second, make sure your installing the bearing with the lock or index tab in
the correct position (see arrow), and Third, make sure the block side
bearing has the oil hole and the hole lines up with the hole in the block as
both halves are not alike.
is a view of the block with all bearings installed and double checked to see
that the tabs are in the correct position and the bearings flush with the
Install the bearings in the caps at this time and also look for and clean
any dirt or particles from the caps. Remember: A dirty engine is a ruined
Don't lube the bearings yet!
carefully install the crankshaft making sure not to rotate the assembly
while dropping the shaft into place. The crank should slide into place
easilly and no tapping, pounding, or rotating is needed. If the crank don't
go in easilly, a problem may be evident like a bent crankshaft. If in doubt,
take the crank to a machine shop and have it checked. If the crank still
don't fit, have the block checked for block shift. The block may need line
boring, or in worst cases, the block will need replaced.
the tedious job of installing the plastiguage. These little thin pieces of
plastic can be tough to get in the right location on the journal but with a
little patience, they will stick in the middle of the journal and stay there
long enough to put the main cap on. Sit the cap on and just finger start the
bolts until all plastiguage is on every journal and every cap is in place,
then screw the bolts on snug but not tight, infact a general rule is finger
tight to start.
Extreme care is needed to make sure the crank doesn't rotate. If it does,
pull the cap and re-plastiguage the journals.
the caps need to be torqued.
Again, don't rotate the crank during this step.
In the case of our small block with 4 bolt main caps, the torque specs
called for torqueing the inner bolts to 80 lb.ft. and the outer bolts to 70
Start with half the specified torque. I used 35 as a standard to torque the
caps starting from the inside bolts and working to the outside bolts. Once
the 35 lb.ft. was set on all caps, I reset the Torque Wrench to 80 and did
the inner bolts on all caps, reset to 70 and did the outer bolts.
Again, work from the inside, outward.
Once all bolts are torqued to specs, loosen and remove all the main caps,
again makings sure the crank doesn't rotate at all.
small paper container the plasitaguage came in is also the guage for
checking the crush on the plastic. I cut each section the length I need with
scissors when I install the guage, then use one cut section to measure each
Here the guage shows .002 on this particuliar journal. The specs show a
clearance of .001 to .003 as a safe journal to bearing clearance, so we are
fine on this journal for assembly. If your plastiguage doesn't fall within
.003 or doesn't crush at all, it's time to mike the crank and find out what
oversize bearings or possibly a new crank is in order. If you skip the
plasiguage step, as some amateur mechanics tend to do due to it being time
consuming, you take a big gamble as to whether or not clearance is correct.
To tight will cause the bearings to seize and spin and fail, while too loose
will cause the engine to knock, have low oil pressure, and the quick failure
of the newly installed bearing.
all the journals checked, remove the crank and install the rear main seals
found in the gasket set.
Very Important: Make sure the lip of the seal points inward and NOT toward
the back of the engine.
If you get this backward, an almost instant rear main seal leak will happen
when you start the engine the first time.
The last thing you want to do is remove the pan from underneath the vehicle,
pull the oil pump, rear main cap, and replace the seal, this time in the
a good engine assembly lube, put a good puddle in each journal, and cap and
sit the crank in place for final installation. Some engine mechanics
opinions differ on whether to remove the plastiguage once the clearance is
checked. My belief is the plastic is non-abrasive so I don't worry about
removing it. The first time the crankshaft rotates after assembly, most
traces of the plastiguage are gone.
important is to dip each bolt in oil upon final assembly. This aids in
proper even torque load on the bolts which will prevent the bolts from
possibly coming loose or breaking due to binding during the final assembly
and torque each cap same as done when plastiguageing.
Each cap has to go back, in the same place as it was when dis-assembled for
rebuilding. Get a set of number punches and mark each journal on the same
side of each cap. Also note that most blocks including chevrolets have
arrows that must be pointed toward the front of the block.
Once all caps are in place, torque and recheck (Yes I go over my assemblies
twice and sometimes three times) to insure you didn't miss a bolt, rotate
the crankshaft to make sure it moves freely.
No severe drag should be encountered. Check for any binding, or dragging
during any part of the rotation.
next step on our assembly is to clean pistons and rods (since we are reusing
ours) and remove any carbon and build-up from the ring lands. For those that
went to the machine shop and had the old pistons pressed off, and new
pistons pressed on, nows the time to inspect the pistons for crackes around
the piston pin, and make sure rods are installed in the right direction (yes
even machine shops make mistakes).
Since we will re-use the pistons for this project, we soaked the pistons in
the solvent tank for a couple of days, removed any excess carbon, inspected
each piston for burning or defects and got ready for re-assembly.
The picture above shows Ida doing the dirty work.
Ida finished cleaning, I opened the box that contained the Piston
rings. Depending on manufacturer, rings can come in a box (as the picture
shows) or in individual packets, or envelopes but all should be marked
bottom, middle, and top. Pay close attention during disassembly to see where
each ring sit in their respective grooves.
the first piston cleaned, the job of installing the rings begin. Start with
the bottom oil rings and install the grabber (or little serrated looking
non-spring ring) and then install the two wiper rings to lock the grabber
ring in position.
Rings can be broke if put under the slightest load bind so extreme care is
needed. The procedure is hard to explain, but you want to carefully slip
one end of the ring over the edge of the piston while keeping the other end
sitting on top of the piston then carefully screw the ring around the
circumference until the ring is in it's groove. You should practice with an
old ring to perfect this installation process before you try it with a new
one. If you can't understand what I am getting at, go down to your local
autoparts store and purchase a ring installer. The installer grips the ends
of the ring and spreads them for direct install. While this works fine, I
prefer the twist or screw method since it's doesn't stretch the ring out of
Once the oil grabber and two lock rings are installed, the middle
compression and top compression rings is next. Most ring manufacturers
place a dot on one side of the ring. This signifies the top or this side up
of the rings. Always look for this dot, and make sure it's facing up.
Also make sure not to get the second or middle ring and the top ring mixed
up when installing. Most middle rings are alloyed different and will burn
up if placed on the top groove directly against the heat of combustion.
another purchase item you must have or borrow to do the job since there is
absolutely no other way of doing this. This Ring Compressor is a compress
type spring steel collar that compresses the rings by clamping down around
the piston with the use of a locking clamp built in to the compressor. While
many styles are available (including some cheaper versions with regular hose
clamps) this style is the one (and in fact the same compressor) I have used
for the last 20 years and have never once broke or chipped a ring. Make
sure the compressor is tight all the way around with no gaps between the
piston and compressor. A slight tap with a hammer around the compressor
will insure the rings are seated in their grooves and ready to install.
is the assembly with ring compressor, rod bearing and bolt protectors
installed and ready to be slid into it's respective cylinder. Make sure the
rod bearing is installed correctly since it's hard to change or install once
the piston is in the bore. The protectors on the bolts keep the rod studs
from scratching the crankshaft throw during assembly and should be included
in the kit. If the protectors are not in the kit, get two 3 inch lengths of
3/8 fuel line and put over the studs.
the cylinder with assembly lube. Be generous here since this is the
lubrication the cylinders will use until motor oil gets sloshed up there
during start up.
is a view of the installation of the piston into the cylinder.
Notice I am using the rubber handle end of a ball peen hammer to tap the
piston through the compressor and into the bore. Also note the direction of
the piston as the index mark or notch in the top of the piston needs to be
facing toward the front of the engine. Make sure the compressor is tight
against the cylinder so the transistion between the compressor and bore is
The last thing you want to happen here is for the ring to slip out at the
bottom of the compressor and snap off as you give the piston a firm tap to
send it into the bore.
Also notice we are building this engine outside. We could have moved into
the shop in a nice sterile environment for this, but since we wanted to suit
the build for everyone, we chose to do this out under mother nature. If
extreme care to cleanliness is observed and with a good concrete floor under
your feet, you can build an engine anywhere as long as high winds and dust
aren't around while you have the engine uncovered. Afterall, the outdoors
is allot cleaner than allot of shops I have worked in, all kidding aside.
extreme care once the piston is in the cylinder, and keep tapping the piston
until the rod journal seats with the crank throw.
Make sure the piston is not twisted and goes in straight as a crooked or
turned rod can nick the crank journal and cause you to do some deburring of
the crank which is not a fun job.
the rod is seated insert the other half of the bearing shell in the rod cap,
plastiguage each bearing as you install each piston and torque the cap (on
this engine we torqued the caps to 45 lb.ft.). Check the plastiguage and if
within limits, coat liberally with assembly oil and install and retorque the
Repeat this for each cylinder as you do each cylinder so as to not forget a
step or accidentally forget to torque a cap. Again, I double and triple
check my work to make sure I didn't forget something.
the person that origionally dis-assembled the motor used a punch on the cap
to mark each cylinder, we took the time to correctly number stamp each rod
so that the next person (in the far future) that dis-assembles this engine
already has cylinder orientation to the pistons.
Stamping each rod before dis-assembly takes allot of headache out of trying
to figure out where each piston and rod goes for re-assembly. Remember,
utmost care is critical in the successful rebuild of an engine.
as we end this session, make sure (no matter how clean your environment) to
bag the engine in a couple of large garbage bags.
Seal the open ends with coated wire or wire ties or anything that will seal.
This will ensure your engine will be as clean as you left it the next time
your ready for more assembly work.
all the plastiguaging behind us things speed up now as we strive to finish
this project with about 4 more hours of labor on top of the 3 hours we
already have invested.
Here the Victor Head Gasket is fitted and readied for the head.
little touch-up with the die-grinder was in order. We used a gasket cleaning
pad that is non-abrasive and it's only enemy is gasket material. Don't use
sand paper as it could create a fisher or scratch large enough to cause a
the head in place, dip the head bolts in clean oil and install each one for
a total of 17 (that is on a small block chevy). There are 3 lengths of
bolts but it will be easy to figure out which ones go where. Tighten the
bolts just finger tight for now.
is a good time to clean out a small pan or in this case cut the bottom out
of an old antifreeze jug and clean it out and I mean clean. Put your
lifters in this container and completely cover with oil (in an antifreeze
jug it takes just under a quart) since this step will be next after the
heads, and this moment of preparation gives plenty of time for each lifter
to soak up oil for assembly. Pictured is the Cam, Lifters already soaking,
and the Cam Lube which prevents the cam from abnormal wear on startup.
this engine the correct torque for each bolt is 65 lb.ft. in sequence which
will be shown in any good shop manual. Remember to use half torque for the
first sequence and then retorque to the correct value. Allot of engine
builders will come back once the engine has been run for an hour or so and
retorque the heads but that is not necessary in my opinion, but I will give
the initial torque of 65 about 15 minutes to set in, then come back and
retorque the bolts again in sequence to 65 again. I find I get another
nudge out of each bolt by doing this and although it slightly increases the
bolt stress it will not cause any problems since the bolt torque specs on
these grade 8 bolts is allot higher than the stress we are putting on
them. Repeat this step for the other head.
we install the Camshaft a generous supply of Cam Lube is poured onto each
lobe and main surface as we slide it in, being extra careful not to slam the
lobes against the bearing surface and using gentle pressure to guide the cam
in, and if at any time the cam has to be forced, into the bore, something is
wrong and the cam should be removed and surfaces checked. Don't worry about
this stuff dripping off since it's as thick as grease and sticks to
everything including your hands and is tough to wipe off.
the cam in place, pump each lifter with a pushrod a couple of times while
still in the oil to dislodge any air bubbles that may be present and then
put a lifter in each lifter hole and make sure each one will seat easily
without having to force them.
we install the Timing chain and gear set. We chose the Cloyes double roller
set with advance/retard crank gear which allows you to advance or retard the
cam 4 degrees. Advancing the cam increases torque and cuts horsepower while
retarding the cam increases horsepower and cuts torque.
We chose a 0 degree or straight up setting since we had chose a RV2 high
torque cam and no advance or retard was recommended. Install the crank gear
first, align the marks straight up and then install the cam sprocket and
chain, making sure the marks line up. Install the 3 bolts in the cam and
tighten to specs.
Note: Incase your not famaliar with oil galleys, check to make sure they are
all plugged before this step as you don't want a cam sprocket in the way of
driving the half inch plugs into the lifter galleys, infact this might be a
good time to check to see that all the galley plugs are installed, which you
should find in that good shop manual you purchased to show you the things I
can't on this webpage.
the timing cover, find the gasket in your kit, add a light coat of gasket
sealant and install the timing cover. This is the first piece of sheet
metal which indicates we are getting closer to completion.
is a view with the timing cover in place. Be sure to double check the timing
chain and gears for proper alignment and the cam bolts are tight to
the timing cover in place it's now time to install the Harmonic
Balancer. Do not soak this part in solvent or immerse it in anything other
than soap and water to clean off the grime.
Solvents and oils will soften the rubber that insulates the balancer and
allows it to do it's job and the balancer will slip or worse, fall
completely off causing allot of damage.
The balancer is shown here being pressed on and set to 0 degrees putting
number 1 cylinder at Top Dead Center (TDC).
adjustments can be one of the toughest things to get right on any engine and
careful attention to the shop manual should exercised.
On our small block, the specs show a 0 lash against the hydralic lifters, so
with each lifter at 0 lift we tighten each rocker till tension is felt in
the pushrod and then give the rocker nuts and additional 1/2 turn, which
gives some preload to the lifter but doesn't bottom it out in the lifter
is a view of the back of the motor showing the shiny cam plug.
Also note the two block holes that don't have freeze plugs installed
yet. If you wait until the engine comes off the engine stand like I do to
install the last two plugs, just don't forget to do it, infact I have seen
some mechanics that tape the plugs to the flywheel just to remind them that
it needs to be done.
we make the engine too top heavy on the stand, it's time to roll the block
over and install the oil pump. With a new pump out of the bag, we installed
the oil pick-up, aligned the screen parallel to the pan bottom, then tack
welded the pick-up to the pump to guarantee that the pickup don't end up
twisting up out of the oil due to vibration, or just Murphy's Law inflicting
a suprise on our assembly.
the oil pump installed and the bolt torqued to spec, it's now time to clean
up and install some more sheetmetal.
the pan cleaned and gaskets installed the pan was on and bolted in place in
Care should be taken when cleaning the inside of the pan to clean all the
grime out of the windage tray which is the area under the flat peice of
sheetmetal that covers part of the bottom of the pan.
the engine upright the mating surface for the intake manifold was checked
and wiped of oil as needed and the intake gaskets placed and ready for the
intake manifold is carefully set in position as to not to disturb the
gaskets and 12 bolts installed and torqued to 30 lb.ft.
Make sure the end gaskets don't slip out during the installation and gasket
sealer should only be used around the water jackets and at the corners where
the front and rear seal mate with the intake gaskets.
assembly is finished with the installation of the Valve Covers.
Plenty is left to do with a coat of fresh Chevy Orange Paint, the
installation of the Carburetor, Exhaust Manifolds, Water Pump, Fuel Pump, as
well as Distributor, and all the other final prep for installation into the
While this series is just the basics, it should point the basic "shadetree
mechanic" in the right direction to building the engine and saving a few
bucks on labor.
Nothing is more pleasing than to hear the fruits of your labor start up and
purr like a kitten, and give you many miles of trouble free service.
Just remember to follow the manual, get the right tools for the job, and if
you get stuck, seek help from a reputable mechanic. Remember, he started
out doing what your wanting to do, and should have no problem with giving
you advise on your project.
Good luck on your mechanical endeavors.
finally we masked off all gasket surfaces still waiting for something to be
bolted to them and gave it a fresh coat of Chevrolet Orange Paint. We then
added the Fuel Pump, Chrome Valve Covers, and Exhaust Manifolds as well as
the Harmonic Balancer Pulley.
Before we stick it in the truck we will add the Water Pump, Carburetor, and
have the Distributor all rebuilt and ready once the engine is bolted in,
then comes the task of finding where all the brakets go, misc. wires and
About another 2 to 3 hours of work and the truck will be running.
One more overlooked item to do prior to installing in the vehicle, is to
prime the oil pump and run oil through the oiling system. Hook an oil
pressure guage to the pressure tap at the back of the engine and monitor oil
pressure while priming, and make sure it's good and steady.
Check around for a primer, since most mechanics have a busted or converted
distributer for hooking to a drill and doing this job, which makes the whole
task allot easier, but nonetheless do prime it, and give your engine the
extra lubrication it needs on start-up to prevent premature wear.
Back to the toolbox!