MSD 8.5mm Spark Plug Wire Replacement
Thread Starter
Instructor
Joined: Sep 2013
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MSD 8.5mm Spark Plug Wire Replacement
Just replaced the plug wires on my 71 Stingray along with the plugs. (Accel Header Plugs) Car will not start. Found (2) wiring diagrams for 350 small block & tried both ways. Car ran before changing plugs & wires. How can something that simple be so nerve racking? The engine ID # shows that this is a 1980 motor. I should also mention the distributor is an MSD. HELP!!!
Race Director
Joined: May 2006
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1. did you test if you are getting a spark at the plug end of the wires?
2. What gap did you use on the plugs?
3. Did you do one wire at a time or all of them at the same time to cause you to question the wire sequence?
4. Remove the distributor cap and turn the engine over till the groove on the harmonic damper lines up with the zero on the timing tab. At this point the rotor in the distributor should be pointing at the #1 or #6 wire, is that what you see?
2. What gap did you use on the plugs?
3. Did you do one wire at a time or all of them at the same time to cause you to question the wire sequence?
4. Remove the distributor cap and turn the engine over till the groove on the harmonic damper lines up with the zero on the timing tab. At this point the rotor in the distributor should be pointing at the #1 or #6 wire, is that what you see?
Thread Starter
Instructor
Joined: Sep 2013
Posts: 118
Likes: 1
1. did you test if you are getting a spark at the plug end of the wires?
2. What gap did you use on the plugs?
3. Did you do one wire at a time or all of them at the same time to cause you to question the wire sequence?
4. Remove the distributor cap and turn the engine over till the groove on the harmonic damper lines up with the zero on the timing tab. At this point the rotor in the distributor should be pointing at the #1 or #6 wire, is that what you see?
2. What gap did you use on the plugs?
3. Did you do one wire at a time or all of them at the same time to cause you to question the wire sequence?
4. Remove the distributor cap and turn the engine over till the groove on the harmonic damper lines up with the zero on the timing tab. At this point the rotor in the distributor should be pointing at the #1 or #6 wire, is that what you see?
Team Owner
Joined: Jun 2001
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From: Virginia USA
Just replaced the plug wires on my 71 Stingray along with the plugs. (Accel Header Plugs) Car will not start. Found (2) wiring diagrams for 350 small block & tried both ways. Car ran before changing plugs & wires. How can something that simple be so nerve racking? The engine ID # shows that this is a 1980 motor. I should also mention the distributor is an MSD. HELP!!!
Is it trying to start and spitting sputtering backfiring? If that's the case then you are getting spark just your firing order is off.
Did you have to crimp then ends (either end)? If so then maybe you didn't get a good crimp.
Also make sure you are using the proper wire for your application:
Types of Spark Plug Wires:
Carbon Core “OEM” Wires
OEM wires work well with bone stock factory cars. For your typical grocery getter and ghetto cruiser, the OEM wires will work well getting spark to the spark plugs and won’t push the engine beyond factory specs. They require frequent replacement as the carbon core breaks down or cracks. Keep in mind that the factory treats plug wires as consumables and placed on a routine replacement cycle. Using a high powered ignition system will shorten the life of these plug wires.
Solid Core Wires
Solid core wires are usually made with a stainless steel or copper core, both of which conduct high electrical current very well. They also have no RFI suppression ability and that makes them a poor choice for electronic ignition systems. The frequencies broadcast into the atmosphere interfere with the electronic modules in the area. These should only be used on high performance cars that use magnetos or a points and condenser type ignition system. As with any rule, there are exceptions. The Granatelli Motor Sports solid core wires have proven to be very effective at suppressing the EMI and RFI emissions and still maintain the superior low resistance conductivity of solid core wires.
Low Resistance “Spiral” type Wires
The most popular plug wires for high performance street vehicles and race cars is the Spiral type wires. The construction of these wires is done by winding a very fine wire around the core. This wire is typically an alloy of copper, nickel or tin and usually a combination of the three metals. This winding serves to lower the RFI and EMI and still have a lower resistance in the wire. Spiral type wires should be considered when using any high performance ignition system or have upgrades to the engine that raises the cylinder pressure or add more fuel to the combustion. Our experts from MSD and Accel also agree that the higher the cylinder pressure and the more fuel there is, the higher the voltage needs to be to start a spark in the combustion chamber.
LINK
Carbon Core “OEM” Wires
OEM wires work well with bone stock factory cars. For your typical grocery getter and ghetto cruiser, the OEM wires will work well getting spark to the spark plugs and won’t push the engine beyond factory specs. They require frequent replacement as the carbon core breaks down or cracks. Keep in mind that the factory treats plug wires as consumables and placed on a routine replacement cycle. Using a high powered ignition system will shorten the life of these plug wires.
Solid Core Wires
Solid core wires are usually made with a stainless steel or copper core, both of which conduct high electrical current very well. They also have no RFI suppression ability and that makes them a poor choice for electronic ignition systems. The frequencies broadcast into the atmosphere interfere with the electronic modules in the area. These should only be used on high performance cars that use magnetos or a points and condenser type ignition system. As with any rule, there are exceptions. The Granatelli Motor Sports solid core wires have proven to be very effective at suppressing the EMI and RFI emissions and still maintain the superior low resistance conductivity of solid core wires.
Low Resistance “Spiral” type Wires
The most popular plug wires for high performance street vehicles and race cars is the Spiral type wires. The construction of these wires is done by winding a very fine wire around the core. This wire is typically an alloy of copper, nickel or tin and usually a combination of the three metals. This winding serves to lower the RFI and EMI and still have a lower resistance in the wire. Spiral type wires should be considered when using any high performance ignition system or have upgrades to the engine that raises the cylinder pressure or add more fuel to the combustion. Our experts from MSD and Accel also agree that the higher the cylinder pressure and the more fuel there is, the higher the voltage needs to be to start a spark in the combustion chamber.
LINK
Race Director
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Plug wire sequence
http://www.corvette-restoration.com/...stallation.pdf
Le Mans Master
Joined: Mar 2001
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From: Watkinsville, GA and Glen Cove, NY
Pull off driver side valve cover and put a socket on the bolt in front of the crank pulley, or use key to bump the engine. Rotate the engine until the timing mark lines up somewhere around the 0 on the balancer. Make sure both #1 cylinder valves (driver side farthest forward) are closed (rocker arms both up). If not rotate again to 0 mark. At this point, the rotor will point to or just past your #1 cylinder. Follow the pre described firing order.
Last edited by 69ttop502; Mar 10, 2017 at 07:21 AM.
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