If you want to finish first, you first have to finish.
Below are some tips to keep you engine running at its highest
performance. These are some things you can do to get yourself
in the winner's circle. We recommend doing these things after
the car is washed and dried early in the week to give yourself
time to fix if a problem has developed.
Carburetor Floats:
The carburetor floats are adjusted using the nut/screw combination
located on the top of the carburetor bowls. In most cases you
will need a large flat head screwdriver and a 5/8" box
wrench to perform this operation. Also, keep a clean rag handy
to wipe-up any gas or alcohol. The level is either located using
the screw hole or sight glass located on the side of the bowl.
We will assume we are using a carburetor with a screw hole.
The level we are going to maintain is just below the screw hole.
When you softly shake the car from side to side, fuel should
dribble from the bottom of the hole. You should not have to
shake the car violently to get fuel, nor should it run out.
With the engine running at idle; and the car sitting at ride
height, remove the front (primary) bowl side screw. (If the
floats are too high. fuel will run out of them, shut the engine
off and follow the instructions below to lower the level.) To
adjust the level, place the box wrench over the nut. You then
loosen the center screw just enough that the nut will turn using
the wrench. A small amount of fuel may appear, wipe-up as necessary.
The nut is what adjusts your float, not the screw. You have
to loosen or tighten the screw in conjunction with the nut (have
the screw tight enough that fuel is not pouring out of the screw/nut).
To raise the float level, turn the nut counter-clockwise. as
if you were removing the nut. Watch the level closely, if you
get to high, turn it back a little. To lower the level turn
the nut clockwise. Think about it as if you are turning the
nut down, the level is going down. Once you have the level as
defined above, tighten the screw and recheck. If it looks good
install the screw and go to the rear (secondary) bowls and do
the same.
Timing:
To adjust the timing have the engine running at idle. Our adjustment
will be using a GM engine. Using you engine builders recommendation
for timing, use a timing light to check where your engine timing
mark to balancer timing mark align. If the timing is not correct,
loosen the distributor or magneto hold down bolt enough that
distributor/magneto can be turned using some pressure. You do
not want it to spin freely. Turn the distributor/magneto clockwise
to take timing out, and counter-clockwise to increase timing.
Once you have the desired timing, increase engine speed using
the carburetor to approximately 4,000 rpm's and recheck. Adjust
timing accordingly if it is not correct. Once timing is correct,
tighten the distributor/magneto hold down bolt and recheck.
Repeat steps above if the timing is not correct.
Valves:
The first thing to do is clean the entire top of the engine
off with compressed air to make sure nothing can get in the
engine. Get all the tools needed for the job and assemble them
on the car. Use quality feeler gauges. To help accidentally
using the wrong size gauges, bend the one or two on a 45-degree
angle. Take the plugs out and lay them in order so they can
be return to the same cylinders when the opperation is complete.
Next, take off the valve covers. Put all the nuts and bolts
far enough from the motor so you don't have to worry about them
falling into the engine. Take a flashlight and look over the
springs and any other mechanical parts very closely for any
cracked or missing parts. Take the time and check everything
thoroughly! After looking over the heads, bump the engine over
and look at all the belts. (Make sure the car is out of gear
before you do this, and fingers are clear of the belts). Look
very closely for any tears or holes from rocks. It is also a
good time to check if the belt is running in the middle of the
pulley. Intake and exhaust valve lash settings should be written
in a book, as well as on the intake. These are the cold settings.
Along with the lash settings, also have spark plug gap and timing
settings written on the intake. This is all good information
to have nearby when things get hectic at the track.
The valve lash is always measured between the tip of the valve
stem and the bottom surface of the rocker that pushes the valve.
Start at the number one cylinder, which is the left side (driver's
side) front of a GM engine. (On Fords number one is the front
cylinder on the passenger side.) Adjust the exhaust first. Don't
try to get the intake and exhaust at the top together, but rather
do them one at a time. Bump the engine over until the exhaust
valve (the header pipe is below this valve) is at the top of
its stroke. At the same time the intake valve should be down
and just starting to come up. You will be able to wiggle the
exhaust rocker, unless the setting is way too tight. You might
have to turn the engine over several times until you hit it
just right. Place the correct thickness feeler gauge between
the rocker and tip of the valve. The feeler gauge should go
in with a little bit of pressure applied. Not to easy and not
too hard! The shaft mounted rockers have the adjustment screw
on the push rod end. Stud mounted rockers are adjusted at the
stud in the middle of the rocker. After adjusting each rocker,
tighten the lock nut and check it again. If the adjustment still
feels right with the adjuster locked down, you can move on to
the intake valve. To get the intake valve in the right position
bump the engine until the exhaust valve just begins. With many
cams, the setting for the intake and exhaust valves are different
so be sure you use the right feeler gauge! Continue through
al1 the valves using the same procedures. You can also make
it practice to check the valve spring pressure with a valve
spring gauge. This is a good way to see if your springs are
getting soft, or if you have a broken or cracked spring. When
you complete setting all the valves, check all the adjusters
one more time. Now is a good time to check the header bolts
since they are often more accessible with the valve covers off
and spark plug wires out of the way. Next, reinstall the spark
plugs. If you have aluminum heads put a small amount of never-seize
on the threads to make them easier to remove next time. Attach
the plug wires making sure they are on the right plugs (a very
common mistake, especially when in a hurry) and hear them snap.
Then check the top of the heads once more for anything that
is not supposed to be in there. Put the valve covers on. If
you do not already know the correct torque settings for everything,
including header bolts, rocker studs etc., get a list from your
engine builder.
