RX-7 Reliability Modifications
By Rob Robinette
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Want to keep your RX-7 alive and healthy? These are some well known tips for
keeping your car happy. Excess heat in the engine compartment is a common
problem with the 3rd gen RX and anything you can do to keep it down will help. I
usually pop my hood open when I can after a hard drive to help dissipate engine heat. The RX-7 also
has a low coolant warning buzzer. If it comes on for any reason, pull over and
shut down the engine as soon as possible to prevent engine damage. Don't try to
make it to the nearest gas station to add water. You'll regret it later when
your mechanic quotes the cost of an engine rebuild. If you are researching the
purchase of a used 3rd gen RX-7 see the Buying a Used
RX-7 How To.
Replace Transmission and Differential Fluid - Put synthetic fluids by
Red Line or Neo in them.
Replace the Oil and Filter at 2,000 Mile Intervals - The oil in the
oil cooler lines doesn't get flushed during a change so change your oil more often. This is especially
important for modified cars running high boost because of more blow-by into the
Flush the Coolant System - Use distilled water and high quality
anti-freeze. See Coolant
System Flush How To.
Replace the Fuel Filter - Every 15,000 miles. If it clogs it can
cause lean running at high power which leads to detonation and engine damage.
See the Fuel Filter Replace How To.
Minimize Wheel Hop - Wheel hop can occur in the RX-7 when you spin
the rear tires. It puts a tremendous strain on the entire drive train,
especially the differential's output shafts. If you encounter wheel hop get out
of the gas. You can minimize it by lowering the air pressure in the rear tires,
down to around 18 psi for full up drag race launches. There are also
"launch kits" available that modify the rear suspension to reduce or
eliminate wheel hop.
Reliability Mods For All Cars
Replace Pre-Catalytic Converter (pre-cat) With Down Pipe - The
pre-catalytic converter is attached to the turbos. It tends to clog up and hold
excess heat in the turbos and engine compartment. It can also break up and
clog/destroy the main catalytic converter leading to failed emission tests and
Install a Boost Gauge - You need one to monitor the health of the
turbo control system. The RX-7 has a tendency to blow vacuum hoses lose and
cause the control system to malfunction. With a boost gauge you can verify a
normal boost pattern.
Replace/Eliminate the Air Separation Tank (AST) - It's made of
plastic and has a tendency to
crack and dump all your coolant causing overheating and engine damage. There are
several after-market metal tanks available for around $150. You can also just eliminate the
tank for around $50, see the AST Elimination How To.
Replace Vacuum Hoses - They bake in the hot engine compartment,
become brittle, crack or come loose and cause boost control problems. See Vacuum
Hose Replacement How To.
Modify the Stock Air Box - Prevents the
intake from pulling hot air backwards through the intercooler which can lead to
detonation and engine damage.
Upgrade the Front Anti-Roll Bar Mount - The stock mount tends to
crack. Several after-market mount reinforcers are available. This is especially
important if you upgrade the stock anti-roll bar, race or Autocross.
Replace Rubber Intake Hose Couplers - The rubber couplers between the
Y-pipe and the crossover intake tube crack and leak. Replace it with silicone
hose couplers, or better yet replace the Y-pipe and
crossover tube with the upgraded Japanese RX-7 part.
Clean and Lube the Antenna - The antenna retraction mechanism in the 3rd gen RX-7 fails
at a pretty high rate. You can delay its failure by cleaning and lubing it while its
extended. I used WD-40 to clean it and then wiped it down with some light 3M oil
hasn't failed yet).
Reliability Mods For Modified Cars
Install an Air/Fuel Gauge - As you modify your engine it will run
leaner. If it gets too lean, detonation can occur which damages the rotor's apex
seals. A complete engine rebuild is required to replace the apex seals. Install
an A/F gauge so you can monitor how lean/rich your engine is running. AutoMeter
has a nice 20 LED gauge for $50.
Install a Water Temperature Gauge - The stock water temp gauge does not work
well enough to monitor the engine's temperature. The gauge will show normal temperature until
it is too late. Overheating the RX-7 can be fatal for the engine because the
side seals can be damaged by excessive heat. The damaged seals allow coolant to
pass into the combustion chambers. A total engine rebuild is necessary to repair
Install an After-Market Knock Sensor - If detonation begins to occur, an
upgraded knock sensor can retard your timing and prevent apex seal damage. See http://www.safeguard.bizland.com
for J&S's knock sensor.
Upgrade the Radiator - A modified car puts heavier demands on the cooling
system. If your after-market water temperature gauge shows high temperatures,
upgrade the radiator. See the Install Racing Radiator How
Upgrade the Intercooler - The stock intercooler is woefully
inadequate. If you want to increase boost above stock levels you need to improve
air charge cooling. Inadequate cooling can lead to detonation and apex seal