CVR’s C4 Corvette Starter Motor Mega Boosts VIN 8 and VIN J Starting Power

The first thing to let go on my 1990 Corvette Z51 after buying it used with 69,000-plus miles on the clock was the starter, but it didn’t happen all at once. That would have made it too easy to diagnose the fault. It was a sneaky, intermittent problem that at first seemed like ensuring the clutch pedal was fully depressed was all it took to start, but then the problem grew worse.

Having never owned a Corvette newer than a 1959 model I imagined the ’90’s problem was due to some modern-age DOT safety requirement like having a clutch pedal safety switch, so I located it and wired a bypass. This seemed to solve the problem for a few days. Then one early Sunday morning at the Balboa car show it reared its ugly head again. The beauty of a stick shift is they’re easy to start with a bum starter or a dead battery.

A friend and I pushed it to a fast roll then I hopped in and popped the clutch. A few blocks later the ’90 Z51 stalled so I had to crowd source a couple of obliging tourist lads from the crosswalk to help me push-start it away from a green light on Balboa Blvd. From there, I drove straight home and put the ’90 up on jack stands.

The RPO Z51 (VIN code J) with a German-made ZF six-speed manual transmission utilizes a Delco-Remy gear reduction starter (PN 10455702) whereas automatic transmission equipped cars (VIN code 8) use a conventional Delco-Remy starter. The Delco-Remy reduction drive starter is smaller in size, weighs less and offers more cranking power than the conventional Delco-Remy starter.

When my Delco-Remy starter motor worked it cranked briskly, as it should, so the starter solenoid was suspect. Similar to the disc in a conventional starter, the copper plunger contacts in the reduction starter’s solenoid tend to wear out prematurely.

I learned solenoid rebuild kits are not readily available anymore. In the search for Delco-Remy model number 10455702 replacement parts I ran across CVR High-Performance Racing Products (Arnprior, Ontario, Canada) and its Protorque Ultra starter. It was the impressive specifications of the CVR starter (PN 9323) versus sourcing a rebuilt Delco-Remy that inspired the upgrade. Vette