I have been informed I need new spark plug wires to stop my engine from missing. Will it do any harm to drive the car until I can get it into a mechanic next week? I was also told it was very difficult to do and I wouldn't be able to do it myself. My car is a 95 LT1 coupe.

 

Probably not, but possibly yes. A miss will cause the unburned fuel to pollute 1 or more o2 sensors and cat.

 

 

Try running your engine at night, in pitch black. If you see sparks, like from a bad wire to your block, you really don't want to drive it like that. Open flames in the engine compartment are not a good thing.

And from what I've heard, it is a pain to change the wires, expect 30-45 mins to do 1-7, and 90 minutes to do wire #8.

How much is your time worth?

 

Electrical shorts like that can also wreak havoc on your car's other electrical components.

Corvettes are weak enough in this area due to the unique grounding system (fiberglass body panels) so there's no sense in aggravating the problem.

 

Spark plugs are worse. I got bloody knuckles on #8

 

Changing plug wires on an LT1/LT4 Corvette is no walk in the park. If you're planning to try to tackle the job yourself, let me know and I'll pass along a list of tech tips I wrote up a while ago.

Driving the car with a miss is not a great idea. In addition to potentially jeopardizing the O2 sensors and cats, unburned fuel tends to dry-wash the cylinder walls, and to work its way down past piston rings into the crankcase, where it dilutes the oil. Driving a car a few miles with a dead miss won't kill the car, but I'd keep it to a minimum.

Be well,

SJW

 

Hey SJW, could you PM me with your tips? I just got my C4, so I have no idea what condition the plugs/wires are in, but I will want to change them at some point. I might be willing to attempt it myself.

Any experience with changing plugs/wires on an old G20 Van? I gave up getting the rear 4 plugs out of that machine after about 2 hours of trying. I wonder if the vette is harder?

 

Rather than PM them to you, I'll just post them here, as the OP may also be interested:

Changing the plug wires on an LT1/LT4 Corvette is not a lot of fun, but it can be done. Here are a few tips:

1. Raise the front end of the vehicle to a more comfortable working height.

2. Remove the inner fenderwell center panel on the driver's side. This will allow you to both see and do the job much more easily on the driver's side. You may also find it helpful to remove the wheel.

3. Unbolt the ASR bracketry from the frame, so that you can slide the ASR unit around to get it out of your way.

4. Unbolt the power steering pump so that you can move it forward around a half inch. This will make it much easier to sneak the plug wires in/out behind the pump.

5. Remove the serpentine belt and tensioner.

6. Use dielectric grease in the boots at both ends of the wires. Be sure to "burp" the air out of the boots after you get each of them pushed firmly into place, so that the trapped air doesn't try to push the wires off later.

Some guys report that they've had decent success accessing the Opti-end of the plug wires from underneath of the car, and that this saved them the trouble of removing the belt and tensioner. I haven't tried this, so I can't comment.

Take your time, work with care, and pay attention to what you're doing. The OEM replacement plug wires from your Chevy dealer are high quality parts, and will route (and fit into the wire looms) correctly. Run the new wires properly, and make sure they stay away from anything that moves, is sharp, or gets hot.

The passenger's side is not such a bad job. The driver's side is a Queen Royal Beyotch (mostly because all of the belt-driven accessories are hanging on the driver’s side of the front of LT1/LT4 engines, and they leave little room for you to work or see what you’re doing). With plenty of patience, beer and Band-Aids, you'll get it done.

The spark plugs on the driver's side aren't so bad, when you've got things apart to do the wires. The passenger's side, however, is not so easy. The number 8 plug in particular can be a real headache, but with good tools and enough patience, you can get it done. Because there isn’t room for a ratchet on top of the spark plug socket, I use a plug socket that has a hex head on it so that it can be turned with an open end or box end wrench. It's useful to have more than one plug socket to choose from, as some will work better than others due to differences in length, wall thickness, etc.

Be sure to apply a small amount of anti-sieze compound to the threads of the new plugs before you install them so that they won’t seize in the cylinder heads in the future (this is especially important with aluminum heads). Just make sure none of the compound gets onto the electrodes or insulators of the plugs. I apply a very thin stripe of compound across the threads in one spot, and it spreads itself around the threads as I screw the plug into the hole. Also be careful that you don’t pick up any of the grunge that may have accumulated over the years around the spark plug hole in the cylinder head on the new plugs’ electrodes/insulators/threads while you’re installing them – try your best to get the tip of the plug straight into the hole on the first shot.

For OEM parts at great prices, contact Chris May at Superior Chevrolet (1-800-728-8267), and tell him you're a Corvette Forum member.

Regarding the G20: What model year and what engine are we talking about here?

Be well,

SJW