Question: Spark plug change

[9340Ruby]

I have a 1993 LT-1 with 55,000 original miles. What do you all think about changing the spark plugs and if so what should I use? What is all involved in changing the plugs on an LT-1? Thanks for the help in advance. BK

 

[Hib Halverson]

Changing plugs on Gen 2 V8s in C4s is a long process because you sometimes have to remove some of the inner fender splash panels to access them.

As for what you should use, if you meant what tools to use--a couple of spark plug sockets, one simple plug socket and one u-joint plug socket, a short extension and a 3/8-drive, flex-head, ratchet is probably all you need.

As for what plugs to use, the OE-style, double-platinums are pretty good, so's the AC Rapid Fire. Best, IMO, are Denso's Iridium Power plugs. Unfortunately, they're not cheap. Regardless of what brand of spark plug you pick, if you run the car hard, consider going one heat-range colder than stock.

Avoid marketing scams such as "Split Fire" and any of Bosch's platinum products, especially the ones with 2 or 4 side electrodes.

 

[9340Ruby]

Thanks. I was really interested in the process. It sounds like a job! BK

 

[crowvet]

Thanks. I was really interested in the process. It sounds like a job! BK

I own a auto repair shop 32years. My advice is to use only ac delco original equipment plugs. I have had a few later model GM products ping ever so slightly after changing plugs. All of these were cured by installing the original plugs. My thought as to why is as follows. These plugs were designed and engineered for your engine. What I think happens is other plug manufactures cross reference the originals and say hey we have a part # here that will work and market it for your application, but they may be slightly different in heat range, gap ect. Todays modern engines are dialed in pretty tight and it doesnt always pay to deviate to far from what was designed for your car. Just my personal opinion, but I have had no tune-up comebacks since adopting this policy. Good luck
Daryle

 

[onedef92]

I'd change the plug wires, also. The O.E.M. Packard wires are rated at a 60,000 service life, so yours are on their way out, too.

Change one at a time so you won't get them cross-wired. Don't forget the anti-sieze compound for the new plugs (aluminum heads).

And I'd order some new wire looms, too, from MAD, Eckler's, etc... since the old ones tend to dry-rot from engine heat and break when you go to pull the wires out.

For plugs? Personally, I really like the NGK TR-55 Double Platinums.

 

[corvetteguy1993]

Iv'e done this on my ruby three years ago - make sure you get some type of plug grease for the plugs since it is a aluminum block and heads - I used a regular spark plug socket with a open end wrench that can be used on it and Yes its a tough one. MAKE SURE it threads correctly - there is nothing worse than a cross threaded spark plug in a aluminum head - I had one playing games but after a little clean up it threaded fine -Good Luck

 

[Edmond]

Make sure to get plenty of as well to ease the pain and

You'll probably be cursing a lot, I find that helps!:L

 

[9340Ruby]

Iv'e done this on my ruby three years ago - make sure you get some type of plug grease for the plugs since it is a aluminum block and heads - I used a regular spark plug socket with a open end wrench that can be used on it and Yes its a tough one. MAKE SURE it threads correctly - there is nothing worse than a cross threaded spark plug in a aluminum head - I had one playing games but after a little clean up it threaded fine -Good Luck

Thanks a lot for the info. Did you have to remove any fender wells when changing out the plugs? Thanks

 

[Toms007]

I've done this twice on my 94. The first time was a real education. I bought the AC Delco replacement plugs (non platinum). I searched and read everything I could on the subject. Here's a couple of hints; It will make things a world easier if you remove the inner fender panels. It's easy to do, just a few bolts, but it gives you a straight shot at several of the front plugs. The front three plugs on both sides are about a 20 minutes total. The first time doing this job the back plug on the passenger side took me about 3 hours and many scraped/bleeding knuckles. Until I figured out if I laid across the top of the engine from the drivers side, that I could get my hand in such a position to unscrew that little B......bugger, without scraping up my knuckles. The back one on the drivers side is a bit easier, but it helps if you are double jointed and have long skinny fingers and hands.

I changed them again this past winter as I was doing some other maintenance and upgrading and had them out anyway. This time, with my previous knowledge, I was able to pull those plugs out in about 30 minutes. When I reinstalled the plugs I went with the NGK TR55 double platinum.

Other thoughts:
As has been previously mentioned, use anti-seize on the threads. I had several different lengths of extensions (from 1"-12"), three different plug sockets, universal joints, and actually, a piece of vacuum hose to stick on the end of that back passenger plug to use as an extension and spin the plug to get it started. I went with OE replacement wires, I wish I had bought the new wire looms as mine disintegrated. Part of the maintenance and upgrading I was doing at that time was installing a new Optispark and water pump, so wires and plugs only seemed natural.

Good luck, it's really not that bad, just take your time and do it right.

 

[corvetteguy1993]

Good Points Toms94 - could not had said it better myself and Yes you will have to remove them - real simple - mark you bolts so the inner fender wells go back the way they came off. I was stupid and had to re adjust the shark fins is what I call them because they were off and may rub the inner part of the hood.

 

[9340Ruby]

Thanks to everyone for your very knowledgable advice! I am going to attempt this.

 

[Greg Gore]

I thought the two toughest ones on my 96 were numbers 6 and 8 due to the limited room available beside the AC evaporator housing. In addition the plug wire boots can get stuck in place on the plug porcelains and you have to be careful about pulling on them. Gently twist to break the bond and pull firmly on the boot, not the wire. Try to avoid prying them off with a screwdriver too; if you accidentally puncture the boot you will then have a place for the spark to jump through as it looks for a good nearby ground such as a close convenient bolt.

 

[Hib Halverson]

Let's talk a bit about antiseize.

If you change your plugs when the engine is cold, the plug threads and the threads in the head are kept clean and you don't overtighten the plugs, you really don't need antiseize with modern engines.

That said, it can't hurt to use it...well, actually it can if you do not apply antiseize correctly.

A lot of the antiseize sold retail is has a metallic component...often or moly. You want to be very careful when using metallic antiseize to not get even the slightest amount anywhere near the tip of the plug. Get some on either of the electrodes and you'll have a misfire you can't get rid of until you replace that plug.

I don't usually use antiseize, but I do take great care to keep threads clean and install plug properly when the engine is cold.

The comment above, from the shop owner saying whenever he installs anything but ACD plugs, the engines exhibit light ping....I've NEVER observed that but, admittedly, the plugs I've used are either stock or really good aftermarket stuff like Densos. I agree that there are some plug maker's application data that is inaccurate, but it's not all that way. If you're not going to run stock plugs, you can't go wrong with Denso, NGK or AC Rapidfire aftermarket products if they are appropriate for the application. Now some of the other stuff...well...they can cause trouble.

 

[John Robinson]

Tools Needed

I have not changed the plugs in my 93 yet with 90K. I have a question for those who have done the job. It seems to me that on the back plugs a socket with a 3/4 hex on the end would work with a wrench on the socket. I have been looking at Harbor Freight and they have a set of ratcheting offset wrenches that would fit the hex on the plug socket. Would this work?:crazy

 

[Toms007]

I have not changed the plugs in my 93 yet with 90K. I have a question for those who have done the job. It seems to me that on the back plugs a socket with a 3/4 hex on the end would work with a wrench on the socket. I have been looking at Harbor Freight and they have a set of ratcheting offset wrenches that would fit the hex on the plug socket. Would this work?:crazy

John, this might help with that #8 plug. As I think back, I believe that I tried a short socket and ratchet on the end of the plug socket. I also think that I night have tried an end wrench as well. I will say, anything that you have at your disposal will give you more options on attacking the situation. What works for one person, might not work as well for some one else. I don't have the offset ratcheting wrenches, but I have bought quite a few of the HF tools and for the money they would be worth having around.

 

[muddywaters]

Hey guys, with the death of Leaded gasoline the sparkplug business died also, hence the aftermarket flood of useless plugs. It's OEM for me on the Vette's. On my ATV, which is a single cylinder, I got rid of the NGK(Honda) for Autolite Platinum, it idle's smoother, runs better, seems to be more responsive. This could all be a Placebo thing, but when you have a single clyinder any changes are noticable, that is, If you actually use( not abuse) the machine.................Just my .02.......

 

[pkincy]

I support the AC 41-906 although my last set fouled pretty badly.

I only pull the drivers side inner fender panel; only 5 10mm bolts

#s 1 and 3 I get with a 10 inch extension and a u joint through the panel opening and under the AC compressor.

#s 5 and 7 require the EGR hose and the ASR to be undone and pulled out of the way.

#s 2 and 4 are conventional and ez to get to.

#s 6 and 8 Wow, I hope you have small hands.

I would never attempt this without a reasonable tool set.

Enjoy,

Perry

 

[Rowdy1]

A Thought.........

Snap On tools makes a socket for the tough to get to plug. It's advertised as a "Muscle Car" plug socket made for cars with headers. It's a short socket with the center drilled out so the tip protrudes and it has a 5/8 6 point on the end for an open ratchet or a wrench. It's well worth the $27 and Snap On is the only one I've ever seen that makes it. I have two of them, one for the tool box and one for the trailer tool box.

 

[Toms007]

I support the AC 41-906 although my last set fouled pretty badly.

I only pull the drivers side inner fender panel; only 5 10mm bolts

#s 1 and 3 I get with a 10 inch extension and a u joint through the panel opening and under the AC compressor.

#s 5 and 7 require the EGR hose and the ASR to be undone and pulled out of the way.

#s 2 and 4 are conventional and ez to get to.

#s 6 and 8 I get from under the car.

I would never attempt this without a reasonable tool set.

Enjoy,

Perry

Snap On tools makes a socket for the tough to get to plug. It's advertised as a "Muscle Car" plug socket made for cars with headers. It's a short socket with the center drilled out so the tip protrudes and it has a 5/8 6 point on the end for an open ratchet or a wrench. It's well worth the $27 and Snap On is the only one I've ever seen that makes it. I have two of them, one for the tool box and one for the trailer tool box.

Good points guys. Rowdy, I believe that your comment goes hand in hand with one I made earlier, the more various tools you have at your disposal the more options it gives you when you are trying to get at some of these things. I guess I need to run down my Snap-On guy and take a look.