Valve Train Technology
For Kart & Jr. Dragster Racing
If you have
any questions concerning installation or proper use of your new
Go-Parts products, call us toll-free at 1-800-976-9376.
Cam cards and
application sheets are also available by calling Go-Parts'
tech line toll-free at 1-800-976-9376.
Take the time to make sure that your camshaft is
installed and clearanced
instructions are designed to help you properly adjust your valve
lash. It is a necessity for you to properly and accurately install
your camshaft in the engine to insure proper performance. All measurements
taken can be verified against Go-Parts cam card and application
Complete Valve Lash Adjustment Instructions For Modified Class Briggs
& Stratton 5 HP Engines
Lash" describes the clearance (space) between the bottom of
the valve stem and the top of the lifter stem. If you do not adjust
the valve lash, your valves will not close completely when the engine
reaches operating temperature due to the expansion of metals. You
will remove material from either the valve stem or the lifter stem
to create this clearance.
Remember that your goal is a hi-performance racing engine, it is
in your best interest to follow these instructions. By not following
these simple steps, you may reduce horsepower, efficiency, and the
performance of your engine.
You can not adjust valve lash accurately without a valve guaging
tool and a feeler guage.
the crankshaft until the piston is at TDC (top dead center)
so that both valves are fully closed.
a feeler guage, select the correct thickness according to your
camshaft's application sheet and insert it between the intake
valve stem and lifter stem. If the valve moves up, you need
to remove material from it until there is no movment.
the valve, place it in a valve guaging
tool, and remove only a slight amount of material. (A valve guaging tool ensures that the stem will sit squarly
on the lifter when finished)
the valve back in the valve guide, and use the feeler guage
to re-check the lash.
the valve moves up, remove it and repeat these steps until there
is no vertical movment. Remove only very slight amounts of material
from the valve stem at a time, excessive valve lash will restrict
air-flow and reduce engine performance.
repeat the procedure for the exhaust valve.
finished, you will be ready to check the "Off The Seat"
valve openings and closings given on the camshaft's spec sheet.
there is too much valve lash when you begin or if you introduce
too much valve lash you will have to start over with a new valve,
start with a new lifter, or remove material from the valve seat
so that the valve sits lower. The easiest remedy is to start
with a new valve.
Using a new lifter requires removing, re-installing, and re-degreeing
the camshaft in addition to replacing the lifter.
Removing material from the valve seat accurately requires special
equipment usually found only in engine shops.
you can't get the correct results, call us toll-free at 1-800-976-9376