Need advice on changing 90 SC spark plugs. It looks like a nightmare job...
- Thread starter flowerse123
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S_Mazza
Registered User
Very reasonable. I'd pay it.
So would I!
1FSTBRD
Registered User
I figured that the $150 price may have changed once the mechanics got into the job and realized--"holy crap, we're working on a spaceship here" and weren't accustomed to the car and it's complicated nature. Although, when i'd got my Compustar alarm installed, heh heh, the guy said it would be done by noon, and it was about 5 pm before he'd got it finished. Likely with some 
involved.
I decided to change out the spark plugs, myself. Got some NGK G-Power platinum plugs that were for the SC's (1 heat range colder) and some NGK wires. In the end, it took me 6 hours.....doing this again would be much easier, though, because the bulk of the time is just about the learning curve. Then again, I also had a spark plug boot that was seized onto the plug, and trying to route some of the plug wires down through the crevices (ie: between the lower IC tube and the valve covers) was a pain. At least 4 of the plugs weren't loosening up that well, and when you only get one click on the ratchet in those confined spaces, I was only turning the plugs maybe 1/4 to 1/5th of a turn, so it took an incredibly long time, because hand loosening the plugs was not working until they were almost completely out of the threads. I'd done anti-seize on all the plugs, plus put some dielectric grease on all of the plugs/ terminals. Compounding problems a bit was that as the evening went on, my natural light source was waning. At one point, I was going to call it a day, when the sun was going down, but my stubbornness--and elation from slowly getting yet one more plug changed--made me want to finish this on this night, as opposed to taking the frustration into another day.
I can't imagine an overweight person doing this very well.....i'm an average sized guy and squeezing in my arms and hands through and around wires, hoses, manifolds, dipsticks, etc was difficult enough. My hands and arms are scraped up with some cuts and red, irritated skin. Doing this involves being a contortionist, too--bring your hand over, bring it under, etc. I found that I was ultra cautious to hold onto the plug when I was trying to re-locate the actual spark plug hole......there's no way that there's a visible way to find it (other than a couple of plugs), you have to feel around in there. That's a prime opportunity for dropping a plug and smashing an insulator and making it more costly and frustrating.
If the brake fluid reservoir/ master cylinder was a bit smaller (I have a '91), it would have made the driver's side just a little easier.
The passenger side wasn't too bad.....i'd taken off the intake tube and though it was still a hassle, it was much easier, overall, than the driver's side. Some people say to take off the A/C compressor and coolant overflow tank--I didn't need to do that and still had enough (relatively speaking) clearance. Others say to go from underneath on the passenger side, but i'd found that the clearance between the fender and the manifold was too tight. I suppose if you took off the throttle body, that there would be a slight bit more room, too, but a stubby or smaller ratchet will do. If a plug is really stuck, though (in my case fairly stuck), the middle plug is more difficult to do, because you need enough ratchet leverage to loosen it and a stubby won't really do. I lucked out that the plug wasn't ridiculously stuck, but it was difficult to do because the end of the ratchet was hitting on the TB and I had to strain to even get the ratchet to have one click on the turn and i'd settled for the very laborious process of loosening it very slowly, but with lots of leverage.
The driver's side, i'd tried to access it by taking off the upper and lower IC tubes, but the lower tube it seemed, couldn't really be taken out of there--at least not without having to remove other things to get at it. There's a nut holding the lower IC tube on, that's right past the power steering pump/ pulley, but removing that even didn't allow the lower IC tube to be taken out of there. The upper IC tube being removed had allowed better access at routing the plug wires down, but that's about it--maybe it had allowed me to get at the middle plug on the driver's side a bit better.
The plug by the firewall, i'd done that from below. By far, that's the easiest of the whole 6. the middle plug, i'd done from up top, but, by far, the most difficult plug was the one closest to the front of the car (#4, I think). Anyone that gets this one from the top is MacGuyver--I found that I couldn't contort my hands and arms to get at it, even with the lower IC tube loosened up. I found that what worked best for me (and this was at night, with a flashlight under the car), was to go in between the steering linkage arm and the lower IC and come from around the exhaust manifold and there was a small but visible 2-3 inch area where I could see the plug, and could properly seat the ratchet and plug socket by supporting the back of the ratchet while I loosened it.
The issue with ratchets, for me, was that sometimes I needed more leverage to loosen some plugs with a bigger ratchet, but the bigger ratchet wouldn't always fit in that particular area. So, with the smaller one, I really had to struggle to loosen some. The tough thing is also having to one hand it--not being able to support the ratchet with another hand.
The condition of the plugs were good--nice and golden. No idea how long they've been in there, but they're probably good for some more mileage. One thing that i'd also noticed was that one plug was fairly loose, and that I think I may have been losing a little bit of compression/ boost from it.
involved. I decided to change out the spark plugs, myself. Got some NGK G-Power platinum plugs that were for the SC's (1 heat range colder) and some NGK wires. In the end, it took me 6 hours.....doing this again would be much easier, though, because the bulk of the time is just about the learning curve. Then again, I also had a spark plug boot that was seized onto the plug, and trying to route some of the plug wires down through the crevices (ie: between the lower IC tube and the valve covers) was a pain. At least 4 of the plugs weren't loosening up that well, and when you only get one click on the ratchet in those confined spaces, I was only turning the plugs maybe 1/4 to 1/5th of a turn, so it took an incredibly long time, because hand loosening the plugs was not working until they were almost completely out of the threads. I'd done anti-seize on all the plugs, plus put some dielectric grease on all of the plugs/ terminals. Compounding problems a bit was that as the evening went on, my natural light source was waning. At one point, I was going to call it a day, when the sun was going down, but my stubbornness--and elation from slowly getting yet one more plug changed--made me want to finish this on this night, as opposed to taking the frustration into another day.
I can't imagine an overweight person doing this very well.....i'm an average sized guy and squeezing in my arms and hands through and around wires, hoses, manifolds, dipsticks, etc was difficult enough. My hands and arms are scraped up with some cuts and red, irritated skin. Doing this involves being a contortionist, too--bring your hand over, bring it under, etc. I found that I was ultra cautious to hold onto the plug when I was trying to re-locate the actual spark plug hole......there's no way that there's a visible way to find it (other than a couple of plugs), you have to feel around in there. That's a prime opportunity for dropping a plug and smashing an insulator and making it more costly and frustrating.
If the brake fluid reservoir/ master cylinder was a bit smaller (I have a '91), it would have made the driver's side just a little easier.
The passenger side wasn't too bad.....i'd taken off the intake tube and though it was still a hassle, it was much easier, overall, than the driver's side. Some people say to take off the A/C compressor and coolant overflow tank--I didn't need to do that and still had enough (relatively speaking) clearance. Others say to go from underneath on the passenger side, but i'd found that the clearance between the fender and the manifold was too tight. I suppose if you took off the throttle body, that there would be a slight bit more room, too, but a stubby or smaller ratchet will do. If a plug is really stuck, though (in my case fairly stuck), the middle plug is more difficult to do, because you need enough ratchet leverage to loosen it and a stubby won't really do. I lucked out that the plug wasn't ridiculously stuck, but it was difficult to do because the end of the ratchet was hitting on the TB and I had to strain to even get the ratchet to have one click on the turn and i'd settled for the very laborious process of loosening it very slowly, but with lots of leverage.
The driver's side, i'd tried to access it by taking off the upper and lower IC tubes, but the lower tube it seemed, couldn't really be taken out of there--at least not without having to remove other things to get at it. There's a nut holding the lower IC tube on, that's right past the power steering pump/ pulley, but removing that even didn't allow the lower IC tube to be taken out of there. The upper IC tube being removed had allowed better access at routing the plug wires down, but that's about it--maybe it had allowed me to get at the middle plug on the driver's side a bit better.
The plug by the firewall, i'd done that from below. By far, that's the easiest of the whole 6. the middle plug, i'd done from up top, but, by far, the most difficult plug was the one closest to the front of the car (#4, I think). Anyone that gets this one from the top is MacGuyver--I found that I couldn't contort my hands and arms to get at it, even with the lower IC tube loosened up. I found that what worked best for me (and this was at night, with a flashlight under the car), was to go in between the steering linkage arm and the lower IC and come from around the exhaust manifold and there was a small but visible 2-3 inch area where I could see the plug, and could properly seat the ratchet and plug socket by supporting the back of the ratchet while I loosened it.
The issue with ratchets, for me, was that sometimes I needed more leverage to loosen some plugs with a bigger ratchet, but the bigger ratchet wouldn't always fit in that particular area. So, with the smaller one, I really had to struggle to loosen some. The tough thing is also having to one hand it--not being able to support the ratchet with another hand.
The condition of the plugs were good--nice and golden. No idea how long they've been in there, but they're probably good for some more mileage. One thing that i'd also noticed was that one plug was fairly loose, and that I think I may have been losing a little bit of compression/ boost from it.
Michael Mattix
SCCoA Member
I agree with most who have mentioned all from the top as I have looked at doing it from the bottom, but I didn't see how (at that time). I have a 95, so the driver's side was easy peasy for 5 and 6. For cylinder #4, I had to hop up on the engine (I'm right handed). For 1-3, remove intake and accessory belt and slide AC Compressor forward. Tight, but like most said, it will scuff up your arm pretty good.
Your 95 runs the AC lines a little different too, try a 90 and those stupid lines run right along the inner fender right where you need to get. I can;t do it, whne in Toronto one of the club guys had long thin arms and he was the ticket. He did mine and said I could have done my 95 2 1/2 times it took me to do a 90
Mike8675309
Registered User
Watch for rebates from Autolite on their XP platinum plugs. They are unique in the industry in that not only do they have an iridium center electrode but they have a platinum coated side electrode. Perfect for long life with waste spark ignition systems like ours.
I run the APP764 on my stock motor, or the XP104 when a rebate is available. All with stock gap. On a high performance motor (high boost, lots of methanol) I would run the XP103 with the largest gap that you can that doesn't result in misfire.
I just changed the plugs on my 90 a month ago and it is a pain in many ways if your have anything other than slender fore arms.
On the passenger side I got the back two from below and the front one from on top.
On the drivers side I got them all from underneath.
Next time I may try to pull some stuff off for the passenger side as it really tore up my hands and arms digging in there to essentially change the plugs by touch.
I lost a impact universal joint on this last plug change. It landed on the k-member and disappeared. Not sure where it went and never found it after a good hour of searching with a magnet.
I use this socket wrench with flex head.
I use a impact universal joint like this:
I use a spark plug socket like this
And extensions like this, usually 3 of them in various combinations with the universal joint.
I run the APP764 on my stock motor, or the XP104 when a rebate is available. All with stock gap. On a high performance motor (high boost, lots of methanol) I would run the XP103 with the largest gap that you can that doesn't result in misfire.
I just changed the plugs on my 90 a month ago and it is a pain in many ways if your have anything other than slender fore arms.
On the passenger side I got the back two from below and the front one from on top.
On the drivers side I got them all from underneath.
Next time I may try to pull some stuff off for the passenger side as it really tore up my hands and arms digging in there to essentially change the plugs by touch.
I lost a impact universal joint on this last plug change. It landed on the k-member and disappeared. Not sure where it went and never found it after a good hour of searching with a magnet.
I use this socket wrench with flex head.
I use a impact universal joint like this:
I use a spark plug socket like this
And extensions like this, usually 3 of them in various combinations with the universal joint.
Key for me was having a large assortment of high quality ratchets, extensions, wobbles and sockets to pick from - don't forget the reach tools/magnets to retrieve dropped sockets that don't make it to the floor. That and patience. Want to get real tricky? Buy an inspection camera to snake into each cylinder to see/record conditions inside.
Hardest part was getting the old wires off the plugs. Specialty pullers won't fit/reach, so it was a combo of twist & pull.
I've worked on everything from busses to stationary power plants and I don't recall anything with less room to work than the engine bay on an SC. Although I've heard that on the V8 Vega you had to lift the engine up a bit to get to the rears.
Hardest part was getting the old wires off the plugs. Specialty pullers won't fit/reach, so it was a combo of twist & pull.
I've worked on everything from busses to stationary power plants and I don't recall anything with less room to work than the engine bay on an SC. Although I've heard that on the V8 Vega you had to lift the engine up a bit to get to the rears.
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1FSTBRD
Registered User
You lost a ratchet socket, Mike? I don't feel so bad for dropping my socket down into a place where I almost couldn't find it, which was in the area right by where (I think that it's) the coolant line goes to the oil cooler. There's a little space there where it gets wedged in between the lines and the metal below it. Twice! It fell into the exact same place when the socket fell off when I was doing the plug by the A/C compressor.
For what it's worth, i'd bought a FlexLite flashlight/ magnetic pickup tool a few months ago, and it helped immensely when i'd drop something into a ridiculously difficult place to get at. Both ends are magnetic, but the non-LED end has a super powerful magnet. Not only that, but the ability to angle the light on it was super handy to help seeing into difficult, tight spots. I don't want to turn into an advertiser for the FlexLite, but it's one of the handiest things that i've had for both this job and things like doing my lower intake manifold on my 'Stang. There's been a couple of times where a bolt/ nut/ screw/ fastener/ bit/ socket has fallen into some really tight, impossible to reach place, and having that light with the magnet on that end has bailed me out of some situations where it's saved me tons of time.
For what it's worth, i'd bought a FlexLite flashlight/ magnetic pickup tool a few months ago, and it helped immensely when i'd drop something into a ridiculously difficult place to get at. Both ends are magnetic, but the non-LED end has a super powerful magnet. Not only that, but the ability to angle the light on it was super handy to help seeing into difficult, tight spots. I don't want to turn into an advertiser for the FlexLite, but it's one of the handiest things that i've had for both this job and things like doing my lower intake manifold on my 'Stang. There's been a couple of times where a bolt/ nut/ screw/ fastener/ bit/ socket has fallen into some really tight, impossible to reach place, and having that light with the magnet on that end has bailed me out of some situations where it's saved me tons of time.
Mike8675309
Registered User
Only my second tool lost to an SC in the black hole that is the K-member. I lost the impact swivel. Laying under the car and reaching around, and then fishing with a magnet and just couldn't find it. I figure it'll fall out or be there someday when I pull the motor out.