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Tech / General EngineIs your car making a strange sound or won't start? Thinking of adding power with a new combination? Need other technical information or engine specific advice? Don't see another board for your problem? Post it here!
I am a cunning shade tree mechanic with air tools and have done just about everything but the spark plugs in an air conditioned, smog pumped 1989 305 TPI in the 3rd gen looks tough.
I managed to replace to spark wires from the top and bottom of the car but the plugs?!
I am thinking of a few ways and would like advice on which might be less frustrating
1. Remove the exhaust manifolds and get at them - lots more work but I can get some new gaskets in there and its mostly from the top, save for two exhaust flange bolts. The passenger side needs to have the smog pump stuff removed also. Geez.
2. I will be replacing the motor mounts soon and I will be lifting the motor up a bit to replace them. Has anyone ever tried this to have better access to the plugs? Most of them would be done from the bottom.
3. I dunno.
Last edited by Tootie Pang; 03-05-2017 at 08:32 AM.
Thanks. I saw that in another post too. Looks like they last twice as long-ish. Are they OK for nitrous kits? I won't be doing any power adders to my car, save for maybe long tubes and NOS.
Last edited by Tootie Pang; 03-04-2017 at 08:53 PM.
I wouldn't have recommended any sort of fancy "this will made more HP" type of plugs. The majority of that marketing is just hype to buy expensive plugs. I run NGK copper race plugs in my engine and they ignite the fuel just fine. My car also isn't a high mileage vehicle so I can justify replacing plugs to different heat ranges etc if required.
Your local auto parts store should carry normal platinum plugs. You might even be able to get them at Walmart. Just get whatever the cross is for the copper plugs normally used for your engine.
Copper plugs should be replaced about every 2 years with an average driving of around 10,000 miles a year. Platinum plugs should last at least 5 years with the same mileage but they can also last a lot longer.
$65 for 8 plugs is just over $8 each. Copper plugs should be around $3 each. If they last at least twice as long, the cost is around the same except you don't have to change them as often.
+1 for underneath the car. It's doable, albiet no fun at times.
I'm a fan of the ACDelco Rapidfires, but the delco copper plugs are great too. I don't like to buy brands like 'champion' etc, but NGK is good for iridium plugs .
Thanks all. I read up and Platinums last about twice as long as Coppers and Iridiums another 15% over that. Coppers make the most power but in non-race motors, the differences are within the dyno tolerances and since my only hope is to never do this again, I am going to go in for the longest life plug.
I put NGK plugs in my car about two years ago and immediately took them out and put in ac delcos. Something about them didn't feel right. They were all gapped correctly as well.
As for removing them, pulling the exhaust manifolds will make this a hell of a lot harder than it needs to be when in reality its pretty easy to begin with. just do the front three plugs on each side from up top and then the back two plugs from underneath. shouldn't take more than 40 minutes. put a small amount of anti seize on the plug threads when installing.
+1 for underneath the car. It's doable, albiet no fun at times.
I'm a fan of the ACDelco Rapidfires, but the delco copper plugs are great too. I don't like to buy brands like 'champion' etc, but NGK is good for iridium plugs .
+2 for underneath the car.
+1 for AC Delco Rapidfire.
I can barely get my hand in there with the air injection lines. Shouldn't I remove those?
You don't remove anything on the car. You put the car on jack stands and go at it from underneath.
Having an assortment of ratchet extensions and swivel adapters can save you a lot of headache. It's about having the right tools for the job.. makes things 1000x easier.
the A1 Autos vids have saved me a few times. occasionally they will be doing a specific unrelated task but by watching them youll learn how to pull apart something thats had you stuck for days!
and for anyone following along, you can also go buy a cheapo spark plug socket (just make sure the internal hex goes all the way down) Then cut half the length off it and drill the end out so the plug can fit through. Then you can use it with a wrench from underneath.
Alright I did it last night. Thanks to everyone for the great advice. Here's my takeaways.
1. The general process is I broke the spark plug loose and then inched it out- sometimes with the wrench, sometimes with fingers, both hands. It's a lot of grip adjusting. Air tools are too big. It's done by hand and ratcheting.
2. The pass-through wrench was invaluable.
3. I could not torque the plugs
4. All plugs were done from the bottom except for 1 and 3
5. I could never see the actual see the spark plug hole.
6. The No. 5 Plug was a bear. Brake line, smog line, O2 sensor, heat shield. Geez how many things can Chevy put in this area?! Using a cut vacuum line to hold the new plug while inserting is very helpful.
7. DISCONNECT the BATTERY. The starter is down by 4, 6, and 8. It think it has a HARD connection to the +12V battery. You do not want your wrench hitting it while connected.
8. I needed to gap the iridiums. You cannot pry on the electrode tip at all. Just work with bending the ground tip with some needlenose pliers.
9. Use anti-seize on the threads and dielectric grease on the boots.
10. Tools: pass through wrench, standard spark plug socket and ratchet.
11. Be careful that the plug wires are not resting on the exhaust.
Last edited by Tootie Pang; 03-09-2017 at 08:50 AM.
I probably should have said that along with using shortie pluigs you should (if you're allowed to smog wise) pull those smog lines while you're there doing #8
When you say "8" are you talking drivers side front cylinder? I am used to fords which this is the case, but for this Chevy, it seems to be that that 8 is 1, the front passenger is two, then driver's second from the front is 3, then 4. "8" was fairly easy.
SLP's special spark plug socket is just a Craftsman spark plug socket with the 3/8" square drive hole drilled out, and about an inch of length cut off. A pawnshop Craftsman socket can be modded the same way for a lot less money.
Yep. Turns out the SLP socket is waaaay overpriced. You can cut down a spark plug socket as long as you have a flat ratcheting wrench to drive it.
If I didn't have the ratchet ability, the handle stroke is so short for some plugs,it would have added 30 minutes and lots of frustration. Literally more than one plug was, move the handle, back one click, handle, back one click. ONE CLICK. But I could just keep going. Imagine turning, lifting wrench, moving wrench, lowering wrench, repeat 1,000 times.
The shortened socket is really only required with headers. With the stock manifolds, it's just a matter of extensions, and patience. On serpentine thirdgens, with the OE oil cooler and AIR injection, it's virtually impossible to do the plugs from the top. From underneath, 2 & 4 require reaching over the crossmember and forward to get at the plugs. Fortunately, after doing them a couple times you get a feel for it. Literally, because you have to do it by feel.
The shortened socket is really only required with headers. With the stock manifolds, it's just a matter of extensions, and patience. On serpentine thirdgens, with the OE oil cooler and AIR injection, it's virtually impossible to do the plugs from the top. From underneath, 2 & 4 require reaching over the crossmember and forward to get at the plugs. Fortunately, after doing them a couple times you get a feel for it. Literally, because you have to do it by feel.
I disagree. Pass through wrench saved my sanity with OEM manifolds- from the bottom. Yeah, up top, forget it.
Call me crazy but doing the plugs on these cars doesn't seem hard to me, I did it when I was 16 years old about 1.5 before I had to leave for work. I did it on my bone stock 86 305tpi and then a year later I did it on my brothers bone stock 92 305tbi.
the front six all come out fairly easily from the top and then just jack the front up real quick and get the last two from underneath. the hardest part would be making sure the plug wires are firmly pressed on to the plugs after they're in.
I replaced the plugs recently on my '86 Iroc 305 TPI w/ all original engine bay including smog equip. Did it the same day that I did valve seal replacements.
It was definitely a PITA...like the OP, loosened with a spark plug socket, then backed most of them out by hand. It ended up being an over/under combo, part of them done while under the car, and some I was able to thread in from the top side through the engine bay. All in all wasn't too bad, just a pain with all the moving around and crawling under a car without a lift. Hardest part, unrelated, was threading the fitting on the air hose into those holes when doing the valve seal replacement. Yikes!
I just deleted all the emissions crap on my 86 TPI before I tackled the plugs. Swapped the plug wires to the top using an MSD universal kit. With all that plumbing out of the way it's easily done from the top. It was a bear to get all the smog pump piping out of the thing but it's super easy to work on now. Had a chip burned, deleted the "smog reactor" pump, and threw away about 30-40 lbs of useless, rusty, steaming garbage. With the serpentine system it's now a real pleasure to work on - what it should have been from the factory.
With an inexpensive chip from one of the many suppliers ($65) I deleted the ninth injector, EGR, smog reactor pump, adjusted for new larger injectors, etc, etc. This way you can just rip stuff out and dumpster it. This crazy talk about keeping all the crap "original"..... Yeah no one is going to care ultimately. It's not like that stuff added to the beauty of the engine bay or something. It is just a bunch of outdated crap. With modern OBD-II cats you don't need any of that stuff to pass a tailpipe sniff. A little denatured alcohol and modern cats is all it would need.
Rick
Last edited by GeneralDisorder; 03-30-2017 at 11:45 PM.
Ive seen frames rust out on cars before seeing that much rust on the motor!
Do you live close to the ocean or something?
Car came from Jersey, had a couple winters driven, but not many. Certain areas on the car are perfect, some are "ok", and others are bad. The floors are good, though..
Heads come off and go to the machine shop next week for a full refresh. Motor mounts are being done at the same time.
Not a cheap mistake, but the car will be better for it I guess.
My Formula has 13k miles on it with original plugs and wires. I just could not get the rubber wire caps off the plugs, they were bonded to the plug. Had to cut them off with a box cutter. Two rear from the bottom and the rest from up top side.
It was a miserable job. If I had a lift it would have been easier.
I don't know if this would have helped in that situation but I've see some of the plug boot pullers they sell. Not a one are for tight spots.
I just take the open end of a 7/16 wrench and slide it on the plug from the side under the boot,then use that to push the boot off while I pull. You can get a lot of force generated that way.
Then use dialectic grease on the installation.
These part # are for my "E" VIN, 5.0, TBI, Auto.
They might be different for yours.
Here's my favorite cap ,rotor, plug and wire combination.
Summit only charges me the Cost, a $10.00 handling fee and no tax on any of my purchase's so far.
It usually is delivered in less than three days.
MSD Cap and Rotor kit = $31.16 https://www.summitracing.com/parts/msd-8406/overview/
I just realized that my MSD wire kit came with plug markers and I didn't install them because I didn't know what they were . Learn something new every day. Also didn't know about the passthrough plug socket, gonna have to get me one of those!
I've been doing hands on stuff since I was 10 years old. I'm 48 now and just got that dang pass through wrench setup. Love it. Where's it been all my life?!
03-04-2017, 08:03 PM
Hooray for no emissions and long tube headers. 
