VERY NERVOUS! 1st Time Changing Plugs Myself!!

[Donne Trav]

HELP/ASSISTANCE/ADVICE, ETC.!!;help
I've changed plugs in the past -- '65 GTO, '68 Firebird, '72 & '74 Lincoln
Mk III & Mk IV. This is my first attempt at changing the spark plugs in this
1994 LT1. I've read a lot of posts suggesting the difficulties in taking on
this task, but the costs at the local dealerships have made me want to give
it a try. Would a few of you tell me exactly what I will encounter? TOOLS?
Is this done ABOVE the engine or UNDERNEATH (on jack stands)? And
what's up with the # 8 plug? I've heard a lot about # 8.

 

[John Robinson]

Suggestion

I have never done the plugs on my 93. I have researched this and hear is what I think you will have to do to change the plugs. Jack the car up and put it on jack stands. Remove the front tires and the inner fenders. This will give you access to the plugs. You will probably need a 5/8 plug socket with a 3/4's socket on the end a long 3/8 extension a swivel for the socket or better yet a second 5/8 socket with the swivel on it. As for the number eight plug this is were the plug socket with the 3/4 end comes into play. The idea is to put a wrench on the socket from the top and turn the socket out that way. Something I have been looking at but have not done is at Harbor Freight they have a set of ratcheting wrenches that are offset for about $12.00 in the set is a 3/4 wrench. Finally patience and anything else you have in your tool box may come into play.

 

[Toms007]

Donne, it's really not that bad. #6 and #8 (back two on passenger side) are a little difficult to get to, not so much in getting them out as to get the new ones started. The plugs angle slightly toward the rear and you must get them started straight, or else you'll cross thread them (not good). I used a little piece of 3/8" (I think) fuel line to stick on the end of the plug and help me get #8 started. The reason #8 is so difficult is that there is so little room between the exhaust manifold and the heater housing. Oh, I did all of mine from the top side.

I had to lay across the top of the engine, from the drivers side and use my left hand to finally get to that #8 plug. I just couldn't get the correct angle any other way.

On the rest of the plugs, I removed the inner fender panel on each side, the ASR box, and had a multitude of different extensions, u-joints and wrenches to do the job (most I didn't use). With the inner fender panels out 4 of the plugs were straight shots.

Make sure that the engine is COLD when you do this, it lessens the chance of a pulled thread in the aluminum head. I also used a very slight amount of "anti-sieze" on the threads of the new plugs (don't get any of that stuff on the electrode, it'll ruin the plug). That's about all I can think of right now, let us know how it went.

Oh and welcome to CAC.

 

[2VettesMike]

I guess I'll give it a try. I have changed them three times on my 93 (150K miles). The first time was with the inner fender panels in place working from the top of the motor. Big mistake. Access from the bottom appears limited but maybe someone has given it a try and can comment on that approach.
It was the easiest for me to take the inner fenders off to get access through and around the front suspension.
Be sure to put anti-seize compound on the new plugs since the heads are aluminum. I would recommend plug wires too if this is the first change. The plug wires are harder than the plugs in my opinion. This is a good Saturday morning job.

 

[gmjunkie]

It was the easiest for me to take the inner fenders off to get access through and around the front suspension.

Thats the easiest way there is!!Pull both rear Splash Shields,Long Wobble extension and Getter Done!!!

PS Tom's rubber hose trick is the best way to start them back in without cross threading!!

 

[DaleD]

I just did it on my L98. That's supposed to be easier. The passenger side was brutal, the driver's side was ridiculously easy. I got a lot of good advice here and elsewhere. Here's my summary:

- Make sure the engine is cold.
- Start with the passenger side so you are fresh.
- Jack it up, put it on a jack stand, and remove the passenger side wheel, and passenger side fender skirts. It's the only way.
- Get a 3/8" drive with an articulated head.
- Get a spark plug socket that will accept a wrench on the end. On #2 I used the articulated 3/8" drive and a short 3/4" socket to drive the 5/8" spark plug socket.
- Don't use a knuckle adapter, you'll just break plugs if you're like me.
- Using hose to put the new plugs in... that advice is gold.
- Get a friend to help. Sometimes you get tired, or have trouble threading something, another person to give it a shot is very nice.
- If you're doing wires, do them one at a time. I got bit hard by not following this advice!!!
- Be patient, take your time.

 

[DaleD]

I also used a very slight amount of "anti-sieze" on the threads of the new plugs (don't get any of that stuff on the electrode, it'll ruin the plug).

I don't want to hijack the thread, but this seems pertinent. I didn't get anti-sieze on the electrode, but I was a bit liberal with it. I didn't realize the stuff was a problem. Anyway, when I finally got the car started, it seemed to run ok, but made some smoke. I thought it was running rich. Now that you mention this, I think it may be that I got the anti-sieze far enough down the threads that it's burning. I don't think it's a big problem, what do you think?

 

[gmjunkie]

I just did it on my L98. That's supposed to be easier. The passenger side was brutal, the driver's side was ridiculously easy. I got a lot of good advice here and elsewhere. Here's my summary:

- Make sure the engine is cold.
- Start with the passenger side so you are fresh.
- Jack it up, put it on a jack stand, and remove the passenger side wheel, and passenger side fender skirts. It's the only way.
- Get a 3/8" drive with an articulated head.
- Get a spark plug socket that will accept a wrench on the end. On #2 I used the articulated 3/8" drive and a short 3/4" socket to drive the 5/8" spark plug socket.
- Don't use a knuckle adapter, you'll just break plugs if you're like me.
- Using hose to put the new plugs in... that advice is gold.
- Get a friend to help. Sometimes you get tired, or have trouble threading something, another person to give it a shot is very nice.
- If you're doing wires, do them one at a time. I got bit hard by not following this advice!!!
- Be patient, take your time.

No need for all that!! Just the right tools for the Job!!No Broken Plugs!!! I can change the plugs in a C4 in about a hour and 15 min!(HOT!!) Just remove the Rear Splash Shields and leave it on the ground!! I use a 15" and a 1" Snap-On Wobble extension,see photos below!! (Notice the male ends of the extensions!)

 

[DaleD]

No need for all that!! Just the right tools for the Job!!No Broken Plugs!!! I can change the plugs in a C4 in about a hour and 15 min!(HOT!!)

You're way better at this then I'll ever be, but we knew that!

I spent 3 hours on #2 alone. From the perspective of a non mechanic, what I posted is how I'd attack it if I had to do it again.

 

[rascal_rascal_99]

Don't let it scare you, it's really not a bad job to change the plugs. Changing the plug wires is definitely more of a challenge unless someone out there has a secret tip I haven't heard about for running the wires and plugging them into the opti. When I did mine, I do remember having about three feet of extentions with one swivel joint in the middle to get to the back plug on the drivers side...put it this way, the ratchet was about six inches outside the edge of the car. I held it steady in the middle where the swivel joint was and this plug turned out to be a piece of cake. I did all mine from above, I do think I remember pulling the drivers side tire off to get to the front two plugs, but not the passenger side...I also did not remove any of the fender wells on mine, but if the Corvette Doctor Junkie says it's easier to do it that way, I'd definitely atleast consider it!

 

[Toms007]

I didn't have those "wobble" extensions when I did mine, but I do now and they are a god-send.

 

[jrogensk]

I just changed the plugs and wires, along with the water pump, this past weekend. The wires were definately the hardest part. I don't know how they can be changed without removing the water pump. Even with the water pump out I couldn't get my hands in there. Luckily my friend has smaller hands, so between us we were able to get it done.

The plugs didn't seem that difficult, but my friend was doing those while I was putting the water pump back on. He only had a few problems with the two rear passenger plugs. Pulling the splash guards does help. I didn't jack it up or pull the tires.

I should have replaced the opti while I was in there, but I just didn't have the money. I still have a slight miss. :ugh