Line for a JRM Shortblock
Oil System Installation
a new oil pump shaft with a "steel" sleeve on the
oil pump. Place oil pump in place and torque the oil pump stud
to specifications. Always use an oil pump stud, a stock oil
pump stud is not adequate. (figure 1 and 2) Carefully
install the pick up tube making sure not to damage the tube
while pressing it into the pump. Check the pickup tube to pan
clearance. Measure from the oil pan flange on the block with
the pan gasket in place, to the bottom of the pick up tube.
(figure 3) Next place a straight edge across the oil pan
rails where the oil pump will be located. Measure from the
bottom of the straight edge to the bottom on the pan (figure
4). This measurement must be greater by 3/8" or .37
of an inch. Adjust the pick up tube until you have the proper
3/8" or .37 inch of clearance. Improper oil pump to
pan clearance can cause oil pressure loss, which will cause
failure. Before you can install the oil pan you must install
the timing cover.
Cam button clearance with the timing must be .005 to .010.
Check this by using modeling clay. Adjust the clearance by
carefully bending the timing
cover. Install both the timing cover and oil pan using a quality gasket
sealer. Building a leak-free engine is important, but too much gasket
sealer will quickly be washed to the bottom of the oil pan where it can
plug the pickup tube (figure 5 and 6). This will cause oil starvation resulting
in bearing failure. The oil filer adapter will need to be tapped
and plugged with a 1/4 inch pipe plug. This should be done before installing
the adaptor on the engine (figure 7).
Harmonic Balance Installation
you are using a bonded balancer we recommend marking the
inner and out ring with a center punch. These marks give
you a reference
to see if the outer ring has spun (figure 8). If the outer
ring does spin, your timing cannot be set correctly. When
installing the balancer, it is very important to use a proper
installation tool (figure 9). Do not use the crank center
bolt; you can pull the threads out of the crankshaft. NEVER
hammer on the balancer. Attach the pointer tab. After
you have the balancer installed rotate the crankshaft, setting
the #1 cylinder on visually as close to top dead center (TDC)
as possible. Move the piston down in the bore and attach a
TDC stop tool over #1 bore (figure 10) and tighten the bolt
stop. Slowly turn the crank clockwise until the piston contacts
the stop; note the reading on the balancer. Turn the crank
counter clock wise until the piston stops again, and note this
reading on the balancer. True
TDC lays is exactly half way between these marks you've made
on the balancer (use a ruler to find this point). Paint or
scribe a new TDC line or move the pointer if needed; adjust
the pointer and/or line on the balancer until the mark on
the balancer lines up with zero (0) on the timing pointer
Cylinder Head Installation
starting head installation make sure lifters fit the lifer
bores properly, lifters should fall under their own weight
and spin freely. If you are using heads that have been excessively
milled, using a valve bigger than 2.055, or using a valve
lift more than .580 lift, use modeling clay to check piston
clearance. 060" on intake and .100" on exhaust valve
is acceptable (figure 12 and 13). Once you have established
that you have the proper valve clearance you're ready to install
heads. Make sure both surfaces are clean and dry. Install studs
now if you are using studs. Use a Teflon sealant or RTV silicone
on studs or bolts. This is necessary to seal head bolts and
any other fastener that protrudes into the water jacket. Using
a good thread sealer will also lubricate the threads for a
uniform torque. Use lube between the cylinder heads, head bold
washers also. Make sure you have the right length head bolts;
you need at least .500" of thread in the block. Run
head bolts or stud nuts down with a speed wrench (figure
use an impact wrench to run bolts of nuts down. Install gaskets
making sure gaskets are installed with the proper side up.
Torque bolts in three steps using the proper sequence; starting
in the center of the head on Chevy small block (figure 15
and 16). Use 30 Ft./Lbs. on the first step, followed with
and on the final step use 70 Ft./Lbs., going over bolts twice
in the last step.
Valve Train Installation
the lifter bores with 50 wt. oil. Generously lubricate the
cam contact surface (bottom of the lifter) with break-in lube.
This applies to either solid or hydraulic. Before installing
the lifters, put oil on push rod cup in the lifters. If you
are using roller lifters you must soak lifters in clean mineral
solvent to remove assembly grease from the roller bearings.
Then soak the lifters in oil for at least ten minutes before
installation. Now that the lifters are installed you need to
determine proper the push rod length. If your head has +.100" longer
valve you should start with a +.100" push rod. Mark the
rips of the valve on the #1 cylinder with a black mark or a
bulling compound. Install push rods and rockers on that cylinder;
make sure that #1 cylinder is at top dead center (TDC). Run
rocker nuts down until there is no valve lash. Be sure that
the push rod is seated in the push rod seat and not hitting
the head or guide plate. Rotate the engine for two revolutions.
Remove the rockers, check the pattern and adjust push rod length
until the pattern is in the center of the valve. If the pattern
is in the intake manifold side. of the valve use a longer push
rod. If the pattern is on the exhaust side of the valve use
a shorter push rod. Make sure at this point the rocker arm
is not contacting the valve spring retainer or valve spring.
Apply assembly lube to the push rod and guide slots in the
head; along with the push rod cups and valve tip contact points.
Lube the rocker arm surfaces that contact the valve and push
rods. Install the rocker arm applying lubricant to the rocker
pivot sockets and the pivot balls (stock Chevy rocker arm)
and then set the valve lash.
final installation, set the intake on the engine and check
the port and intake bolt alignment. Bolt the intake to one
head. Check the other head to see if it's parallel with the
intake manifold. Use a feeler gauge to check this. If the heads
have been milled excessively you may be required to mill the
intake manifold flanges or they will be mismatched and not
seal properly. Check the space between the manifold and the
block rail; you should have clearance of 0.060" to 0.120".
If this is correct, glue the gaskets to the heads using and
RTV bond adhesive. A bead of 1/8" is sufficient. When
bolting on the intake manifold make sure to use the proper
length bolts. If the bolts are too long they contact with the
push rod or if they are too short they may pull the threads
out of the head. Torque intake bolts following the diagram
listed on the last page of this manual.
installing the distributor you must prime the oil pump. Make
sure the oil filter is installed, and oil pan drain plug is
tight. With the engine upright pour about 4 qt's of oil into
the pan through the distributor hole. this will minimize washing
the breaking lube off the camshaft. Next install a special
oil pump-priming tool. Connect an oil pressure gauge to the
oil galley take off either end of block. Make sure the opposite
oil galley take off is plugged with an 1/8" pipe plug.
Prime the oil pump using an electric drill turning clockwise
for 1-2 minutes. During priming oil may not reach the rocker
arms. This might not occur until the distributor is in place
and the engine is running. Carefully inspect the distributor
gear for excessive wear. If you are using a roller cam you
must use a bronze distributor gear. #1 cylinder will need to
be at top dead center. Mark the distributor base in line with
the #1 post on the distributor cap. With a long screwdriver
rotate the oil pump shaft until it's line up with the distributor
drive. Lubricate distributor with camshaft lube. Install the
distributor. When the distributor engages the helical gear
on the camshaft it will turn about 45 degree clockwise. You'll
want to start with the distributor about 45 degree counter
clock wise from its desired location. Place the distributor
in the distributor hole. Wiggle it in place. If the distributor
housing doesn't fall in place and sits up about 3/8" you
might need to reposition the oil pump shaft until it does.
Make sure the distributor doesn't bottom out on the oil pump
shaft before settling on the intake manifold by installing
the distributor first without a gasket. The distributor should
rest on the intake manifold. It's very important to get the
distributor installed correctly so the engine will fire and
run without excessive cranking time. The distributor should
point to the #1 mark on the distributor and the #1 cylinder
should be at TDC. (Excessive cranking time can lead to camshaft
failure and oil/fuel contamination.)
Valve Cover Installation
you are using steel valve covers be sure to use load spreaders.
JRM suggests you use a double cork gasket. Make sure the valve
cover clears rocker nuts and stud girdle.
Water Pump and Pulley Installation
installing the water pump and pulleys make sure the water pump
does not hit the timing cover. If you're using a cam stop on
your water pump be sure that it "just touches" the
cover. Too much pressure on the front cover will cause the
cam button to wear through the front cover or cause the cam
gear to wear on the block. You may check this by putting a
piece of paper between the cover and the cam stop; if you can
barely pull the paper out without tearing it, the pressure
is set correctly. Make sure the pulleys are all aligned properly
and the belts are not too tight.
engine installation make sure the bell housing dowel pins are
the correct length. If your race car requires a mid- plate
stock dowel pins will need to be replaced with longer ones.
This is also the good time to check the fuel filter and replace
if it's needed. If you've had over heating problems, or if
your radiator has been
used more than one season, it should be replaced. Also make sure your fan
shroud fits correctly around the fan blade. Half the fan blade should sit
outside the shroud with no more than 1 " of clearance around the blade.
This will allow the fan to draw the maximum air through the radiator. Fill
the radiator with water. Remove the thermostat housing to let any air locked
in the system out. Before bolting on the carburetor, check the power valves,
jets, airs bleeds, and replace gas- kits as needed. Make sure the throttle
opens completely and closes properly.
Turn the idle screw up and fill the carburetor with fuel before installing
on the engine. It is best to start anew engine with a carburetor you are
familiar with; one you know is in good condition. Make sure you connect
the return spring to the throttle.
Starting the Engine and Breaking in the Camshaft
review the procedure list making sure you have not left out
any steps. Re-check to make sure the engine oil pump has been
primed. Have your timing light hooked up and have water ready
to fill the radiator. Engine should fire within five seconds,
or refer to our trouble shooting guide as needed.
As soon as the engine fires make sure you have oil pressure. Set the idle so
the engine idles at 2000 RPM. Set your timing correctly and finish filling the
radiator with water. Let the engine idle at 2000 RPM for 20 minutes. It's very
important not to let the engine idle below 2000 RPM during this break in period.
If it does it could cause camshaft problems. Check the fuel pressure and the
carburetor float levels. After the 20-minute break in allow the engine to cool
completely. Re-torque the cylinder heads, reset the valves, and change the oil
and oil filter.
Your new JRM engine is ready for the track. Your first night at the track you
should allow the engine to warm up before going on the
track for hot laps. Oil temperature should be 180 degrees. During the first session
of hot laps increase the engine RPM slowly for the first few laps. Keep a close
eye on your
gauges, oil pressure, water temperature, and fuel pressure. After this hot lap
engine is ready to race! Good Luck.
|Camshaft Degreeing Instructions
|The purpose of degreeing a camshaft is to ensure that it is
phased correctly with the crankshaft. Some factors that may cause
improper positioning are:
1. Cam or crank gear marked incorrectly.
2. Incorrectly machined cam or crank gear keyways.
3. Misindexed cam keyway or dowel pin.
4. Improper machining of camshaft or crankshaft.
5. Accumulation of machine tolerances
The important factor to remember is that
camshaft position or phasing to the engine is extremely
important for the engine
to operate at maximum efficiency. Equipment needed to properly “degree” in
a camshaft is available at COMP Cams® and is as follows:
1. Degree Wheel
2. A rigid pointer that can be attached to the block.
3. A dial indicator to accurately measure cam lift.
Note: Refer to your spec card for maximum lift and check your
dial indicator to be sure it has sufficient range to measure
the full cam lift.
4. Either a magnetic or attachable base to affix the dial
5. A Top Dead Center piston stop.
6. A solid lifter to fit your engine. Engines that have
non-adjustable rocker arms will also require an adjustable
pushrod length checker to accommodate
7. A means to attach the degree wheel to the crankshaft.
There are several accepted ways to degree a camshaft. At COMP
Cams®, we feel the Intake Centerline
Method is the easiest and most accurate. This method of cam degreeing
is very practical and indifferent to design characteristics.
It simply involves positioning the center, or point of maximum
lift, of the #1intake lobe with top Dead Center of the #1 piston.
The Intake Centerline Method still requires accuracy to be correct,
but it is somewhat more forgiving. Once you have degreed a camshaft
using this method, you will be surprised at its ease. We also
recommend positioning the dial indicator on the #1 intake retainer
because lift measurements will include any deflection that may
occur in the pushrod and rocker arm. This makes the degreeing
process as accurate as possible in relation to what actually
goes on inside the engine.
A "Cam Degreeing Kit" is available, COMP Cams (part# 4796)
|Time to Go to Work
1: The camshaft and timing set have been installed. Make
sure that the timing marks on both the cam gear and crank gear
aligned properly per the cam installation instructions. Use
chalk or similar marker to better define the marks.
2: For example, we have our cam card and it suggests
weinstall the cam on 106 degree intake centerline. Install
all the rock-er arm s and pushrods in the engine as normal.
intake lobe, install the solid lifter in place of the hydraulic
lifter. If a solid lifter or roller cam is being checked, use
that respective lifter. Adjust the #1 intake lash to exactly
zero. Do not pre-load the lifter. Next, adjust the #1 exhaust
lash to zero. You should be able to turn both pushrods with
your fingers easily.
3: Attach your COMP Cams® pointer (part # 4794) to
the block. Many people will make a pointer out of somesort
of rigid, yet manageable wire.
A stiffcoat hanger wire works well (fig. B).
4: Attach the degree wheel to the balancer and install
the assembly on the crankshaft. There are several ways to
attach the degree wheel to the crankshaft. In our example,
the degree wheel is mounted to the balancer. The crank may
be rotated from either the front or from the flywheel end.
Obviously, if the engine is in the car, you must rotate from
the front. Remember, the greater the leverage, the smoother
the crank rotation, thus more accuracy. NEVER use the starter
to turn the engine while degreeing the cam.
5: Before installing the piston stop, rotate the crankshaft
to get the #1 piston in approximate T.D.C. position with
both the intake and exhaust valves closed. This can be a
rough guess, but it can save you from making a mistake
later. Adjust your pointer to zero or T.D.C. on the degree
6: Turn the crankshaft opposite the engine rotation
approximately 15-20 degrees. This will lower the position
enough to allow the T.D.C. stop to be installed in the spark
plug hole. Screw in the piston stop until it touches the
piston. (fig. C). Continue to turn the engine in the same
direction until the piston comes back up and touches the
piston stop. Mark the degree wheel with a pen or pencil on
the number the pointer is on (fig. D). turn the engine in
the other direction, same as engine rotation, until the piston
comes back up and touches the piston stop. Make a mark on
the number the pointer is on (fig. E).
7: Remove the piston stop after marking the two points
on your degree wheel. Rotate the crankshaft to the midpoint of
the two marks. This point is T.D.C. for cylin-der #1. Without
rotating the crankshaft, adjust the degree wheel to read 0 degrees
at the pointer (fig. F). You are now ready to locate the intake
lobe centerline relative to T.D.C. If you are not absolutely
sure that your 0 degree mark is set at T.D.C., repeat this procedure.
This step is critical to proper cam align-ment.
Step 8: Attach the dial indicator to the dial indicator mount.
Position the dial indicator mount so the tip will contact
the retainer of the #1 intake valve (fig. G). It is important that the indicator
plunger be parallel to the valve stem. Any variance in the angle of the indicator
introduce geometric errors into the lift readings.
Rotate the engine in the normal direction of crankshaft
rotation until you reach maximum lift. The dial indicator
will change direction at the point of maximum lift. At
this point, set the dial to zero (fig. H).
Step 10: Back the engine up (opposite normal
rotation) until the indicator reads .100”. Turn the engine back in the
normal direction of rotation until the dial indicator reads
.050” before maximum lift. Record the degree wheel
Step 11: Continue to rotate the engine over
in its normal direction of rotation until the indicator
goes past zero
to .050” on the closing side of maximum lift. Again,
record the degree wheel reading.
12: Add the 2 numbers together and divide by 2. That number
will be the location of maximum lift of the intake lobe in rela-tion
to the crank and piston. This is the intake centerline. For example:
The first degree wheel reading was 96 degrees. The second reading
was 116 degrees. These 2 numbers (96 +116) added together will
be 212. 212 divided by 2 will equal 106. Your actual intake centerline
is 106 degrees. Reference back to your cam spec card and we see
that the recommended intake centerline for your camshaft is 106
degrees. Everything is where it should be.
In the event that your camshaft did not degree in as per
specs, it will be necessary to either advance (move ahead)
or retard (move back) the cam to meet suggested intake centerline.
Depending on the engine application, there are several different
for advancing or retarding the camshaft.
One common method
is by use of a crank gear with multiple keyways-each one
being at a slightly different relationship
to the gear teeth. A 2nd method is to use offset bushings
that fit on the cam pin and in the cam gear. The offset will
or retard the cam depending on how the bushing is placed
on the cam pin. Another method is by offset keys that fit
the crank gear keyway. A more elaborate system uses an adjustable
timing gear. Contact COMP Cams® or your local COMP Cams® dealer
for the method best suited to your application.
|NOTE: When degreeing a cam, remember to look
at the degree wheel as a full 360 degrees no matter how the
degree wheel you’re
using is marked. Many degree wheels are marked in 90 degree or
180 degree increments. On wheels that are marked in 90 degree
keep in mind that
you must continue to count the number of degrees past 90
degrees. Be sure all readings are taken from
Top Dead Center. Keep in mind that to advance the cam, you
must lower the intake centerline. For example, if our cam
has a lobe separation of 110 degrees, the cam is “straight
up” when the intake centerline is 110 degrees. Moving
the centerline to 106 degrees advances the can 4 degrees.
If we change the centerline to 112 degrees, thiswould be
2 degrees retarded.
We at COMP Cams® hope that these instructions will be
helpful in making your camshaft installation and degreeing
a successful experience. COMP Cams® produced a video entitled “The
Proper Procedure to Install and Degree a Camshaft” (fig.
I). This video covers all of the points
discussed here and illustrates many other helpful tips to
achieve the maximum performance from your engine. If you
wish to order
this video, or if you have any other questions concerning
your cam change, please call our CAM HELP® technical
line at 1-800-999-0853. Our technical special-ists are here
you 7:00 AM to 8:00 PM (CST) Monday through Friday.