| Regrinding
camshafts to alter lift and duration is a time-honored
“hot rodding” technique that’s been with
us since the 1920’s. However, not all regrinds are
created equal, and it’s important to understand the
distinction between the two types when selecting performance
cams. A standard regrind
is where material is removed from the tip of the cam lobe
to increase duration, and material is removed from the
heel of the lobe, reducing the base circle of the cam
and thereby increasing lift. This practice originated
with the pushrod engines of yore, and is acceptable due
to the wide range of adjustability the pushrod valvetrain
offers in order to obtain correct valve clearance, This
however is not the case with the overhead cam engine of
an Alfa Romeo, where valve clearance is adjusted by means
of shims. As the thickness range of shims is limited,
very little material may be removed from the heel of a
cam lobe before losing the ability to adjust clearances. |
 |
This is where the welded-up regrind comes
in. A welded up regrind
is created by welding material onto the tip of the cam
lobe, then reshaping as desired. No material is removed
from the heel of the lobe, thus stock adjustability
is retained. As an added benefit, the welded lobe is
harder than that of the stock cam, with improved wear
characteristics. Centerline’s 11mm and higher lift
cams are welded-up regrinds.
- back to Tips and
Techniques -
|
