The EPA has taken the lead out of our
gasoline and caused big problems for every pre-Evo Harley-Davidson owner, including
overheating and detonation.
After much time and testing of various
combinations of valves, guides, and seats, we are happy to announce our
No Lead Conversion Process, a combination of parts and cylinder head
work that makes your pre-Evo Harley engine run just fine on no-lead gas.
Let’s start with the valve seats, the
area of your combustion chamber most prone to overheating due to no-lead
Our replacement valve seats are
.060"oversize and composed of an exotic alloy of expensive
minerals: 42.1% nickel, 34.12% iron, 12.3% chrome, 6. 7% molybdenum,
2.02% carbon, 1.63% silicon, and 1.13% manganese. The high nickel
content allows the valve seat to expand and contract with the aluminum
Now to the process: After glass beading
the old valve seats are removed. Your heads will be machined to a
.005"interference fit at .450 degrees before installation of the
new valve seats.
The seats are then matched by hand to the
ports and combustion chamber. Mild porting is included at no extra
charge. The seats are ground to specified height and narrowed to
.060" on the exhaust and .045" on the intake, then radiused
and polished into the port.
Now to the valve guides: Our cast-iron
valve guide is porous and retains more lubricant. It also resists
dimension changes at high temperature thus maintaining proper clearance.
Here’s the process: The old guides are
removed and measured. The holes are cleaned and checked for size. The
heads are again heated to 450 degrees and .002" larger guides are
installed with our special sealer and solid copper gaskets.
The valve stem to guide clearance is then
machined to .001" on the intake and .002" on the exhaust. The
valve guides are then machined for the stem seals.
Our valve stem seals are all Teflon with
dual springs. One is used to hold the seal to the guide and the other is
used to maintain proper tension on the valve stem. This positively stops
oil consumption, increases vacuum in the intake port, and stops blow-by
in the exhaust port.
Our new High Flow valves are the highest
quality. The intake is made of solid tool steel tested at “68 ”
Rockwell, with polished head and nitrided stem. The exhaust valve is
made of stainless tool steel with polished head and nitrided stem, to
resist distortion and wear at temperatures in excess of 2200 degrees.
These valves are guaranteed for the life of your engine.
Knuckle and Panheads are uprated to
accommodate 1.937" Intake valves. Ironhead Sportsters are uprated
to 1.750"Exhaust valves. The valves are hand lapped to the seat for
a positive seal.
Your valve springs will be tested and
replaced as needed for the camshaft of your choice. So, we need to know
the valve lift of your cam before final assembly to be sure adequate
clearance is provided.
Stripped threads will be repaired and
charged to you accordingly unless otherwise requested.
The No Lead Conversion can be done in two
weeks turn-around time. Shipping time can vary according to your
schedule. Please specify your preference.
Our work and products are guaranteed for
one year. For an estimate on your particular application contact us
directly by telephone at 805-481-6300. Or you can
Shovelhead with No Lead