thats the one i bought and it will be installed in a few weeks. my oem one is fine screw hole wise and they are excellent oem dizzy with one flaw. the vent screens an because clogged with debris and start damaging the inside of caps corrosion wise. i have burnt out 3 caps to misfiring in the last 14 months. all things over time wear as is my dizzy gear so a replacement is needed. i was going to put an oem back in there but since everything in my ignition system is msd besides the plugs, it just seemed fitting to to the dizzy too. and share the experience with others.
btw delphi has since redesigned ed the oem a while back.
---------- Post added at 08:43 AM ---------- Previous post was at 08:43 AM ----------
sorry could net get the pictures on.
PATTERN FAILURES
Plagued with Problems by Design
O presence of a white or tan residue on the inner walls of
the cap and rotor, and the terminals will be encrusted
(see illustration 1). The contaminants are conductive and
can promote a misfire condition, resulting in misfire
codes being stored in the diagnostic memory.
Inspect the base of the distributor and the distributor
shaft for the presence of rust. While the distributor
housing is made of plastic, you are looking for an
accumulation of debris from other internal metal components.
Components that are affected by corrosion
should be replaced. The accumulation of debris in the
distributor housing can restrict the ventilation screens.
Most technicians are not aware that this style distributor
is fitted with vent screens, as the distributors on these
applications seldom have to be pulled for service, with
the exception of replacing the intake manifold gaskets.
The vents are positioned at the base of the distributor and
are almost impossible to see with the distributor mounted
in the engine (see illustration 2). In fact, the screens are
easily missed while viewing the distributor on a work
bench. The two vent screens are approximately the
diameter of a pencil eraser and they are easily plugged
when debris is present. The frequency in which they plug
increases with vehicle mileage. Naturally, as the engine
wears, the blow-by gases increase, thus an increase in
the gases collected in the distributor housing. A malfuncccasionally
you will encounter a system or component
that develops a history of pattern failures
that can elude your best efforts. Problems or premature
failures can result from a manufacturing defect with a
component, a problem due to the design of the system,
or a secondary system malfunction may lead to a premature
component failure. When the industry encounters
the same failures or circumstances, then most likely you
are dealing with a design issue. It is unlikely that multiple
manufacturers of the same part would make the same
manufacturing mistakes. Identifying and acknowledging
these issues early on are imperative in making an
accurate diagnosis in a timely manner, and in maintaining
good customer relations.
GM trucks and SUVs equipped with the Vortec engine
are good examples of an ignition system that has developed
some common failures that would be considered
a normal characteristic. Distributor cap and rotor contamination,
resulting in a misfire condition and stored
misfire codes, has become a common occurrence. The
codes may be cylinder-specific or random misfire codes.
It is not uncommon to remove the distributor cap on one
of these engines and observe heavy deposits of a white
or tan powdery residue. The distributor caps used on
these applications are susceptible to more than just
contamination problems. Read on for a thorough description
of some of the problems and possible solutions.
POOR DISTRIBUTOR VENTILATION
The aforementioned ignition system has encountered
excessive levels of distributor cap corrosion, resulting in
internal arcing and misfiring. Many technicians are of
the opinion that the type of metal used in the construction
of the terminals is the reason for the heavy concentrations
of deposits and misfire conditions. This is not the
case. GM has acknowledged what we have suspected all
along, that the corrosion condition and the heavy deposit
formation is the result of inadequate ventilation in
the distributor housing. The gases collect in the distributor
cap and housing, and in the presence of heat and high
voltage, form corrosive deposits, resulting in internal
arcing and misfire conditions. When these conditions
are present, the cap and rotor will usually reflect the presence of a white or tan residue on the inner walls of
the cap and rotor, and the terminals will be encrusted
(see illustration 1). The contaminants are conductive and
can promote a misfire condition, resulting in misfire
codes being stored in the diagnostic memory.
Inspect the base of the distributor and the distributor
shaft for the presence of rust. While the distributor
housing is made of plastic, you are looking for an
accumulation of debris from other internal metal components.
Components that are affected by corrosion
should be replaced. The accumulation of debris in the
distributor housing can restrict the ventilation screens.
Most technicians are not aware that this style distributor
is fitted with vent screens, as the distributors on these
applications seldom have to be pulled for service, with
the exception of replacing the intake manifold gaskets.
The vents are positioned at the base of the distributor and
are almost impossible to see with the distributor mounted
in the engine (see illustration 2). In fact, the screens are
easily missed while viewing the distributor on a work
bench. The two vent screens are approximately the
diameter of a pencil eraser and they are easily plugged
when debris is present. The frequency in which they plug
increases with vehicle mileage. Naturally, as the engine
wears, the blow-by gases increase, thus an increase in
the gases collected in the distributor housing. A malfuncccasionally
you will encounter a system or component
that develops a history of pattern failures
that can elude your best efforts. Problems or premature
failures can result from a manufacturing defect with a
component, a problem due to the design of the system,
or a secondary system malfunction may lead to a premature
component failure. When the industry encounters
the same failures or circumstances, then most likely you
are dealing with a design issue. It is unlikely that multiple
manufacturers of the same part would make the same
manufacturing mistakes. Identifying and acknowledging
these issues early on are imperative in making an
accurate diagnosis in a timely manner, and in maintaining
good customer relations.