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Thread: 1992 corvette LT1 spark plugs
04-07-04, 06:26 PM #1josephcookGuest
1992 corvette LT1 spark plugs
Hi Folks, I just had my optispark and water pump replaced to the tune of $1089 bucks. The car runs better but still not great. I want to put in new plugs (and possibly wires) but Im fast running out of money. People have told me that the acdelco plug recommended in the owners manual is not that great. Does anyone have any experience with a mid priced plug that may be better than the one recommended? Any feedback will be greatly appreciated. I love my black rose convertible, its costly but a lot more fun than my ex. Thanks, Joe
04-07-04, 06:44 PM #2drags1998Guest
Hey, another MAINER, Welcome!!! Try Carquest,or one of the others in your area, You should be able find something you can use!!! When you say it dosent run rite, what do you mean? I would have thought whoever did the OPTI would have done plugs & wires if they were needed!! Let me know.
04-08-04, 08:09 AM #3josephcookGuest
1992 corvette spark plugsOriginally Posted by drags1998
04-08-04, 08:25 AM #4
Originally Posted by josephcook
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04-08-04, 10:30 AM #5
- Join Date
- Feb 2002
- Lacey, WA USA
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- 87 Gold Z52 Coupe 02 EB Z51 Supercharged Coupe
I changed the plugs and wires on my 92 last year. Although the car only had 30K miles on it, I was headed out for the 50th Anniversary Caravan to Bowling Green and my round trip would be a little over 6K miles so I thought new plugs and wires would help fuel mileage.
I bought MSD 8.5mm Superconductor wires from Summit Racing for about $60 and, through my shop, a set of NGK Iridium TR55IX plugs. These were pricey at about $4.50 each but from what I had read, they were supposed to be excellent plugs.
One thing I found about changing this stuff, was that there was blood spilled, some very harsh words (my neighbor asked me how many years I had spent in the Navy to be able to come up with the words I yelled out : ) and a good portion of the budget was spent for beer (before, during, and after; especially after!).
The factory AC Delco plugs were supposed to have some platinum "pucks" on the ground electrode. After getting all 8 plugs out, only 1 plug had this little puck left on it! Apparently this is a common occurance with the factory plug.
Here's a few tips and tricks to make the job easier: First, make sure the engine is cold before removing the plugs. You can ruin the threads on the cylinder heads if you attempt to pull the plugs on a hot motor. Have some long 3/8" extensions available along with some universal swivels. A good plug socket with a rubber insert to grab the plug (one with an attached universal is best). Get some anti-sieze compound for the new plugs-you have to put it on the threads of the plugs before installing. You also need some dielectic grease for the boots of the new wires; both ends need to have some grease applied to the inner side of the boot.
On the passenger side, remove the center and rear portions of the lower wheel well. This will make it much easier to access the plugs and where the wires attach to the opti. The #6 and #8 plugs are difficult to do but just bear with it. I had a plug socket with wrench lands and that really helped. Remove the old wires by twisting the boot and pulling back. Do the same with the opti. Because the wires I used were much wider than the factory ones, I had to use my Dremel to open up the little wire looms to be able to hold the wires in place. I didn't use all of them, just enough to keep them from contacting the exhaust manifold.
The driver's side is the toughest because of the accessories hiding the opti. As with the passenger side, pull the center and rear whel well parts. Disconnect the negative battery terminal and then remove the serpentine belt, the alternator, the alternator bracing, and unbolt the A/C compressor and push it out of the way. Remove the belt tensioner and the idler pulley. The P/S pump must be unbolted and moved out of the way. The pump has 4 bolts and they are all accessed through the hole in the pump pulley. There is a small metal shield that hold all 4 plug wires together; that must be removed mostly to get the new wires back in. You can cut the old wires here if you like. The 4 plugs are actually easier to do on the driver's side. The wires are easy to do once you have the accessories out of the way and you can actulaly see the opti. The coil wire is not too difficult but you need to remove the wire from the coil first and then pull it back. Use the wire to twist the boot off the opti connection. Add some dielectric grease to the new wire and thread it down to the opti and press it on.
This whole deal took me over 8 hours to do, but now I think I could do in in around three or so now that I know what to take off to access the opti for a wire change. Persevere, drink some beer when you get frustrated, and keep the garage door closed so the screams and cussing won't scare the neighborhood kids or the family dog!!
The new stuff must have made a difference because I was able to see some increase in fuel mileage on my trip. At one point I saw 31.2MPG average on the digital readout with the cruise set at 81MPH!! Overall average for the 6000 miles was a bit over 27 and in every one of the 16 states we traveled through, our group hit triple digits in every state (personal best: 124 in Oklahoma on I-40)C4cruiser
Corvettes de Olympia
Puget Sound Corvette Club
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02 Vortech supercharged EB Coupe
87 Gold Coupe 4+3 Z52
My Past Vettes: 92 Vert, 78 L82 Coupe, 73 L82 Coupe, 70 LS5 Coupe
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