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The car is a '67 L79 with factory A/C. I have ordered some Denso W14-U plugs and before they arrive I wanted to ask for "how to" from those who have done this on an A/C car. To change the driver's side plugs is a no brainer. The passenger side...not so much. I plan on doing this from underneath (using a qwik lift) and removing the right front tire for best access. Though I have changed hundreds of spark plugs in my life, I have never done a Corvette with A/C. Looking for helpful hints as to the best way to access the passenger side plugs, as well as, any special tools needed i.e. flexible joints, etc. Again, any and all hints from those who have done this will be appreciated. Thanks in advance.
Last edited by leif.anderson93; Jan 25, 2019 at 10:58 AM.
Passenger side rear two plugs you get from underneath. You may have to remove the bottom splash shield on this side for better access.
Passenger side front two plugs, I get from on top. Remove spark plug shielding, loosen AC compressor and roll side to side as needed for access (compressor still mounted but bolts loose), remove retainer that holds heater hoses together at front of engine passenger side to allow AC compressor to move more free. I have been successful in also being able to get my torque wrench into the front plug area to torque these plugs. If you do not want to do this, the compressor may not need to be moved/rotated as much. I have not been able to get the front spark plug shield reinstalled, and have left it off. It can be done, but I just don't want to take the time to do it. The attachment connections for this shielding are not centered correctly on my car and require adjustment: this is the difficulty for me. So just easier to leave this final shield on the shelf.
Thank you Larry. I know this is going to be a joyful experience and that's my reason for gathering info from those that have been there, done that. Thank you, again.
UPDATE...Received the new Denso W14-U plugs this week and had some time today to install. Car up on the Qwik Lift, right front tire removed. Removed the dust/debris shield from the passenger side and easily accessed both #6 & #8 from underneath. Was able to reach #2 & #4 thru the wheel well...tight fit with universal joint and 10" extension but relatively easy...no cuts or abrasions. While under the car, decided to change #5 & #7. Back on the ground, installed #1 & #3 from top side. About 1 1/2 hours start to finish, taking my time. Not nearly as bad as I thought it was going to be with the A/C.
Plugs hadn't been changed in 10 years and approximately 30000 miles. I was somewhat surprised to see what was in there. Car was running very smooth with plenty of power. Drove her around the block to be sure all was good...rain was threatening, so no extended drive. Runs just fine.
I would not put Denso plugs in my Corvette for the same simple reason I wouldn't use Kumho tires- it just doesn't feel right. AC R45S's in my L79 fo rthe last twenty years with no problem.
Plugs looking that good after 30000 miles should be replaced with the same ones. The consensus on CF seems to be that AC heat range 43 plugs are too cold for the street, but yours show that for your motor and your driving style its just about perfect.
Don't forget Band-Aids or larger gauze bandages for the hands and wrists.
Larry
Also stop your blood thinners for 3 days prior. This is an awful job. I have had my '64 since 1970 and know the job well. I have taken the compressor off the brackets and lifted it up for access. Driver side-20 minutes Passenger side-1 hour at least
On my '66 coupe with factory A/C I've always removed the plugs from underneath the car. I never wanted to move the compressor. #2 and #4 are all done by feel, the plugs, even the shielding, you can't see a thing. Every time I've done it (just twice so far thankfully!) I've told my self, next time I should leave the shielding off, but I still re-install it. I'll definitely check out going through the wheel well next time. Thanks for that tip.
For those of you who don't know the joy we're talking about...
...somewhere beneath this morass are spark plugs and ignition shielding, oh and a fuel pump too!
Plugs looking that good after 30000 miles should be replaced with the same ones. The consensus on CF seems to be that AC heat range 43 plugs are too cold for the street, but yours show that for your motor and your driving style its just about perfect.
I thought they looked pretty good myself. The last four years, I drive her about 5000 per year. 70% highway, 30% back roads. I'll see how these new, hotter plugs work and how long they last.
So what is your update on your ignition/ no start trouble
Started just fine yesterday after plug change. Going for a ride shortly. The "crank-no start" issue hasn't reared it's ugly head since I last reported in my other thread. If and when it does again, I'll certainly keep all informed. Thanks for asking.
Plugs looking that good after 30000 miles should be replaced with the same ones. The consensus on CF seems to be that AC heat range 43 plugs are too cold for the street, but yours show that for your motor and your driving style its just about perfect.
I'll do you one better than that: those plugs didn't need changing in the first place. They can be re-installed and run for another 15,000-30,000 miles.
I'll do you one better than that: those plugs didn't need changing in the first place. They can be re-installed and run for another 15,000-30,000 miles.
You're most likely correct...but, I'm not going there. Probably won't toss them either.
You're most likely correct...but, I'm not going there. Probably won't toss them either.
Don't toss them! Plugs need to be replaced when their electrode surfaces become rounded off and worn....or if they are severely fouled/carboned up and cannot be cleaned. Your plugs are not fouled, and the electrode tips are as sharp as new plugs (which they are, with only 3k miles on them!!)
Don't toss them! Plugs need to be replaced when their electrode surfaces become rounded off and worn....or if they are severely fouled/carboned up and cannot be cleaned. Your plugs are not fouled, and the electrode tips are as sharp as new plugs (which they are, with only 3k miles on them!!)
The rationale behind the plug change was this. The AC plugs had 30,000 miles on them, not 3,000. The car was running absolutely fine but I thought I would pull #1 and see how it looked. Looked fine but when I saw they were R43, everything I've read says they are too cold for today's driving. So, ordered up the Denso plugs and changed them. If nothing else, it was a good exercise in "how to". Just got back from a 40 mile drive. Car started right up, idles smoothly, accelerates sharply, and pulls from 30MPH in fourth with no lugging. I'm sure it's just my imagination but she seems to accelerate a bit more briskly. Like I said, I'll keep the old AC plugs and I'm happy that I changed them...sure hasn't hurt anything. Truly appreciate everyone's comments.
The rationale behind the plug change was this. The AC plugs had 30,000 miles on them, not 3,000. The car was running absolutely fine but I thought I would pull #1 and see how it looked. Looked fine but when I saw they were R43, everything I've read says they are too cold for today's driving. So, ordered up the Denso plugs and changed them. If nothing else, it was a good exercise in "how to". Just got back from a 40 mile drive. Car started right up, idles smoothly, accelerates sharply, and pulls from 30MPH in fourth with no lugging. I'm sure it's just my imagination but she seems to accelerate a bit more briskly. Like I said, I'll keep the old AC plugs and I'm happy that I changed them...sure hasn't hurt anything. Truly appreciate everyone's comments.
I lost a zero somewhere! Those plugs, for 30k miles in a carbureted car are about as good as it gets. I generally change mine out in my carbureted cars at 15-30k, depending on wear. Good call on your part, although it looks like the heat range you were running was doing just fine, looking at the plugs. You won't have any issues with your new plugs, either.
Spark Plug change
