MSD or optispark
Last edited by betyelou; Apr 17, 2009 at 03:04 PM.


The Best of Corvette for Corvette Enthusiasts
1). Drain the cooling system, by opening the petcock on the radiator, and then by removing the knock sensors on each side of the engine block
2). Disconnect the battery negative cable
3). Remove the air cleaner bellows and serpentine belt, disconnect electrical connections to MAF and water level sensor
4). Disconnect radiator and heater hoses, and remove the water pump (you may also want to remove the radiator hoses to get them out of the way)
5). Remove the harmonic balancer pulley (3 bolts) - you may want to spray some PB blaster where it mates to the hub, and also mark the pulley's position. Note that the pulley bolts must be roughly at 10, 2 and 6 o'clock in order for the opti to clear the hub. The pulley may be difficult to remove (hence the PB Blaster) - one method is to loosen the three bolts slightly, then fire up the engine briefly to see if that breaks it loose. If that fails, you can tap on it with a 2x2 from underneath and behind, rotating the engine every few taps.
6). Mark the spark plug wires and vacuum hoses, and disconnect from the opti
7). Remove the cap from the opti and mark the location of the rotor
8). Remove the opti
9). Check the seals around the opti and water pump drives, replace if necessary, and clean the water pump mounting surface.
10). Install new opti, noting rotor location - make sure it mates easily with the front cover without force
11). After plug wires, etc. are attached to new opti, install the balancer pulley (coat the mating surface with anti-seize first), connect battery and start the car briefly to make sure opti is functioning properly
12). Reinstall everything in reverse order - note - check the o-ring on the engine shaft for the water pump to see if it needs replacing. A new water pump will come with only one o-ring for the pump, so you may need to buy another. Also make sure to use thread sealant on the water pump bolts.
13). Make sure to bleed air from cooling system when refilling.
You may find that removing the belt tensioner and the coil gives you a little more room to work. Also, this is the optimal time to replace the plug wires and hoses. If replacing the plug wires, you will find that loosening the power steering pump to allow you to pull it forward a bit is helpful.
Wait until you need new plug wires!!! Almost just as bad!!! 

Let me know if you have troubles with the opti, I can make a trip to Columbia and pass some tools if needed. It really isn't that bad.
bill
. These cars a so much more advanced than a C3, but I do love a challenge!


Also, while the opti is out it's a good time to check the water pump and replace it as well if it shows any signs of wear. You can change an opti without removing the wp, but you can't change the wp without removing the opti.
Finally, whether you replace the wp or not, it's a good idea to fit a drain tube to the weep hole to allow coolant to bypass the opti in case the waterpump does fail.
Last edited by jrzvette; Apr 19, 2009 at 11:25 PM.
I had it towed to the local dealer (I'm often on the road and I dont have time to work on it at all), and they told me that the water pump had a seepage issue which caused corrosion in both the distributer and (once they got it apart) the wiring harness. They recommended replacing the water pump as well as the damaged parts. They showed me the parts - and they were really frammissed.
FWIW
Tom
















