| AGK Racing Cams are stock cams that have
been re-ground. First, the lobes of a stock cam are ground down.
Then hard face welding is used to add material and create an oversized
lobe. Each cam is now ready to be ground to its specific profile.
Due to this process, the lobes of an AGK cam are taller and wider than
the stock cam. As a result, you will need to do some grinding on
the block to add clearance for the larger cam lobes. We basically
take the engine completely apart to install one of our cams so we can
thoroughly clean all of the debris from the block and assemble a
spotless engine. This would be a great time to upgrade any
additional parts you have in mind for your engine.
Follow the steps below to see how we install our cams. Keep in
mind, there may be a different way of performing this engine
modification. We put this information together to help guide
people who may have questions about the cam installation process.
We also provide pictures and information below which will help racers
with other engine modifications too. |
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Start by removing the fuel tank, muffler, carburetor,
recoil, fan shroud and valve cover. When you are finished, your
engine should look similar to the one pictured on the left. |
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Remove the flywheel. Use an impact and a 19mm
socket to remove the flywheel nut. |
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Remove the starter cup and thread the flywheel nut back
on, just until the nut is flush with the end of the crank. You
don't want any of the crank threads exposed. |
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Whack the nut with a hammer while gently prying against
the flywheel with a screwdriver. This will break the flywheel
loose from its taper. The first time we did this, we had to hit
the crank several times before the flywheel broke loose because we were
uncomfortable with hitting the crank. Now, we hit the crank with
two decent blows and the flywheel comes loose on the second hit.
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We are going to replace the flywheel key with a new
filed key. To remove the old key, we use a punch to push the key
down on one end. This will cause the key to rotate up on the other
end.
Flywheel key (p/n HON13331). |
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Remove the cylinder head. Rotate the crank until
both valves are closed (springs are not compressed). There are
four 12mm bolts holding the head in place. Two are located under
the valve cover. This particular engine has been upgraded with
head studs.
Stud kit (p/n AGKBST). |
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With the cylinder head removed, you can see the
factory dished piston in place. This motor will be upgraded with a
flat top piston. Note: the arrow on the piston is positioned
closest to the pushrod hole. We also removed
the head gasket and push rods after pulling the cylinder head off.
Flat top piston (p/n HON13101). |
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Remove the side cover. There are six 12mm bolts
holding the side cover in place. This engine has been upgraded
with grade 8 side cover bolts which come with the stud kit mentioned
above. |
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With the side cover removed, you can see the govenor and
low oil sensor have already been pulled from this engine. This
engine also has a billet rod. |
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Remove the cam and lifters. Simply slide the cam
straight out and remove the two lifters. |
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Remove the end cap from the connecting rod. To
remove the bolts from the end cap on this ARC billet rod, a 12pt. 1/4"
socket is needed. |
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Remove the connecting rod and piston. Just push
the rod up the bore and pull the piston and rod out together from the
top.
ARC Billet Rod (p/n ARC6270). |
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Remove the crank. Now you can simply pull the
crankshaft out of the block. |
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Now the engine is disassembled. The only part
remaining is the coil and we are going to leave it in place for now. |
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The AGK .276" lift cam is on the left and the stock cam
is on the right. Although it's difficult to see in this picture,
the lift and longer duration on the AGK cam is very noticeable.
AGK
Racing Cam .276" lift (p/n AGKCAM276). |
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Put the engine block on its side and drop in the AGK
cam. |
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Here you will see where the exhaust lobe will hit the
block at the bottom of the cylinder. This is where you will need
to grind the block so the lobe will clear. |
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This where the intake lobe comes into contact with the
block at the bottom of the cylinder. . |
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We used a felt tip pen to mark the two areas that need
grinding. |
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We used this bit on the end of a Dremel to grind the
block. Although we are going to clean the block afterwards, we
cover the bearing and the area the cam rides in to prevent metal debris
from entering. |
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We finished our first pass at grinding and we are ready
for a test fit. |
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With a little more grinding and another test fit, we now
have sufficient clearance for the exhaust lobe. |
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You can use a feeler gauge between the block and cam
lobe to make sure you have at least .030" of clearance. It's
difficult to see in this picture, but we added a little extra clearance
so we can install a bigger cam in the future. |
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It's time to thoroughly wash the engine block. You
should remove the coil now so you don't get it soaked. We wash the
block with soap and water and blow it out with compressed air. |
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Install the crank. With the engine block all
cleaned up, you can slide the crank into place. |
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Install the connecting rod and piston. |
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If you don't have a ring compressor, you can use a
popsicle stick to push the rings into the bore while you use your other
hand to to gently put pressure on the top of the piston. Make sure
the connecting rod is lined up with the crank journal, otherwise, you
will be pulling the rod and piston back out so you can rotate the crank
in place. |
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Install the rod end cap. We applied some 30w oil
to the bearing prior to assembly. Make sure you use the proper
torque for the rod bolts. We crank these ARC billet rod bolts to
170 in.-lbs. If you had a stock rod and you are installing a
billet rod at this point, be sure to follow the manufacturers
installation instructions. |
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Install the lifters. We put some oil on the shiny
surfaces of the lifters and push them into place. The oil should
keep the lifters from falling back into the block. |
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Install the AGK cam. We applied oil to each cam
surface that contacts metal. Make sure you line up the timing
marks on the cam gear and the crank gear. You will notice each
gear has a dimple punched into it. These dimples need to line up
where the two gears mesh together. |
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You will need to rotate the cam and check for clearance
where the lobes pass the connecting rod. The AGK cam lobes are
wider than the stock lobes. |
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We grind the inside of each lobe if necessary to clear
the connecting rod. Do not grind on the top of the lobe where the
lifter rides. Just grind a small amount off of the inside of the
lobe to ensure it will not come into contact with the connecting rod.
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Install the side cover. Make sure the two dowel
pins are in place and slide the side cover on. Tighten the side
cover bolts in a criss- cross pattern and torque them to 17 ft-lbs.
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Install the cylinder head. With the timing marks
on the crank and cam lined up, your piston should be at top dead center
(TDC). With a new head gasket and the two dowel pins in place,
bolt down the cylinder head. Torque the bolts to 17 ft-lbs using a
criss-cross pattern. |
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Install the push rods and set the valve lash.
Loosen the rocker arm locking nuts and turn the rocker arms to the side.
Drop in the push rods and put the rocker arms back into place. We
set the valve lash at .002" intake and .003" exhaust. |
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Lap the flywheel to the crank. Apply the lapping
compound to the crank. Slide the flywheel on and spin the flywheel
over the lapping compound. Start with the coarse compound and move
to the fine compound. When you are finished, thoroughly clean all
of the compound off of the flywheel and crank. |
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Install the flywheel timing key. We filed a stock
key and tapped it into place with a hammer. |
