Has anyone ever cut a hole in the engine bulkhead to gain easier access to front bank of spark plugs from inside car. If plugs very tight or corroded they are a pig to get at blind just reaching around engine. I wouldn't have thought it would be structural and could be done if no pipes or wiring is in the way. Maybe GM missed a trick by not making an access panel!
I remember someone doing that, but then that would let a lot of heat into the passenger compartment as well as the possibility of carbon monoxide. There is also a heat shield on the firewall that would be an issue.
Frozen spark plugs is a good reason for keeping the decklid weather strip. Without the strip, leaves and water go direct to the engine. If the strip's in place, one can remove the collected leaves before opening the decklid, and it also diverts water away from the engine.
The Fiero has stood for many years and water must have got past weather strip, the plugs are badly corroded and seized with hardly any hexagon left. Was thinking of using something like these damaged nut extractors but porcelain part of plug would have to be broken off, not a problem as they are being replaced anyway. If better access was available it would be much easier and if heat could be applied to remains of plug that would also help. If cutting an access panel the ECM and wiring could be in the way and would have to be moved. My idea for an access hole would be to make a cover slightly larger, secured with screws into captive nuts welded in place and also sealed. Would have been good if GM had come up with something like that in the first place, don't suppose they were interested in making future maintenance easier.
Welcome to the 'trial by fire' that many if not most owners who do their own work have come to know and hate. My suggestion is to take a couple of days to first, use compressed air to blow out as much junk as you can from around the plugs. Second, use copious amounts of a liquid wrench type of product and let it soak in. Again, do this for a couple of days. Also remove the dogbone and use a well anchored strap to rock the engine forward a couple of inches. An inspection mirror or borescope is helpful. Apply heat if you can. Torque slowly when you get the socket on whats left of the plugs. Good luck and yes an access panel would have been nice.
If better access was available it would be much easier and if heat could be applied to remains of plug that would also help. If cutting an access panel the ECM and wiring could be in the way and would have to be moved. My idea for an access hole would be to make a cover slightly larger, secured with screws into captive nuts welded in place and also sealed.
IMO, "better access" to seized spark plugs and broken exhaust manifold bolts etc on the front bank is more easily accomplished by tipping the back of the cradle down, rather than creating a firewall access panel that in itself could lead to potential issues.
quote
Originally posted by David88:
The Fiero has stood for many years and water must have got past weather strip, the plugs are badly corroded and seized with hardly any hexagon left. Was thinking of using something like these damaged nut extractors but porcelain part of plug would have to be broken off...
You might want to check out the solution used in This thread for a very similar spark plug problem.
[This message has been edited by Patrick (edited 10-05-2021).]
After you get your plugs changed, I think it'll be a good idea to pull the EVEN plugs annually (at least) to free them up, clean them, just to check on them. You don't want this problem returning.
------------------ Stanton '88 Formula, red on gray
Has anyone ever cut a hole in the engine bulkhead to gain easier access to front bank of spark plugs from inside car. If plugs very tight or corroded they are a pig to get at blind just reaching around engine. I wouldn't have thought it would be structural and could be done if no pipes or wiring is in the way. Maybe GM missed a trick by not making an access panel!
I don't know if you have removed your decklid or not, but I have found that doing this has given me more than enough room to get the spark plugs out. I have included a picture of the room I have. If you want more room, like suggested in here, too, undo the dogbone and pull the engine back a bit, too, but be careful you don't put enough force on it to break or tear a motor/tranny mount. They are not the most stout pieces I have ever seen.
I just put my cradle back in, in case you are wondering why it is so clean there. I plan on paying attention to that area and keeping it clear. Now that I fully understand how this car is built, I have a better idea of which areas require some attention now and then.
There is a tool that you can purchase that fits in the place where the dogbone is. It is called an engine tilter. You insert the tool and then tighten it as it pulls the engine rearward. It opens up space on the front side so changing the plugs becomes easier.
------------------ " THE BLACK PARALYZER" -87GT 3800SC Series III engine, custom ZZP /Frozen Boost Intercooler setup, 3.4" Pulley, Northstar TB, LS1 MAF, 3" Spintech/Hedman Exhaust, P-log Manifold, Autolite 104's, MSD wires, Custom CAI, 4T65eHD w. custom axles, Champion Radiator, S10 Brake Booster, HP Tuners VCM Suite. "THE COLUSSUS" 87GT - ALL OUT 3.4L Turbocharged engine, Garrett Hybrid Turbo, MSD ign., modified TH125H " ON THE LOOSE WITHOUT THE JUICE "
[This message has been edited by Dennis LaGrua (edited 10-06-2021).]
There is a tool that you can purchase that fits in the place where the dogbone is. It is called a cradle tipper. You insert the tool and then tighten it as it pulls the engine rearward. It opens up space on the front side so changing the plugs becomes easier.
I didn't know this. Good thing to know. Do you have a source? Once I was thinking about cutting a hole in the firewall, but once I got the cradle out of my '88 and looked at what is in that space, I think it would have been a bad idea. The tools I have allow me to get the plugs out with the decklid removed, so I think I will leave things alone. But it would be nice to have the tool you speak of, just in case... Let me know if you have a source...
After blowing out debris and soaking the plugs, use a pick to loosen the buildup around the plug hex and repeat the compressed air blowout of debris and the penetrating oil. Repeat this cycle until the plug recesses in the head are free of all debris and a spark plug socket can fully engage the hex.
Remove the air inlet tube to the throttle body and access the front bank by reaching your left arm into the space below the rear window from the driver side. There is plenty of room for your arm and the ratchet, a short extension and the plug socket.
I have removed several sets of frozen and corroded plugs this way. Just take your time and be sure the socket is completely seated around the plug hex and fully seated into the plug recess.
I no longer use the original R 42 TS spark plugs I use the AC delco 41 809 because the shells are stainless steel and it does not rust for years and no problem with the ignition.
[This message has been edited by claude dalpe (edited 10-06-2021).]
This is what the pros use It is an engine tilter made by Lisle.
You remove the two dogbone bolts, replace it with this tool and just tighten it to move the engine rearward. It provides quite a bit of working space to replace the plugs.
[This message has been edited by Dennis LaGrua (edited 10-13-2021).]
I no longer use the original R 42 TS spark plugs I use the AC delco 41 809 because the shells are stainless steel and it does not rust for years and no problem with the ignition.
That's a good find.
For now, my car works with the R42TS, so I think I will stay with those, but it's a good suggestion in general.
Cutting holes in the firewall doesn't sound great to me.
That said, I was able to use a bar clamp to pull the engine away from the firewall. I removed the dogbone mount, and reinstalled the mount bolt. Then I used the bar clamp between that bolt and the trunk wall.
But this does not prevent to solve the problem with Stripped spark plug hex by rust ! Here is why I use the AC Delco 41-809
Yes and no. Rusted plugs probably get rounded due to the fact that the threads have corroded and stuck in the head making the plug very difficult to remove. Using copper anti-seize on the threads will prevent that from occurring. In the very unusual situation where the spark plug hex does become rounded, then a proven solution was posted Here.
Those stainless steel spark plugs are very nice, but no doubt overkill for the vast majority of Fiero owners.
[This message has been edited by Patrick (edited 10-08-2021).]
Do you have a part # of the tool. I see KD tools was taken over by Gearwrench and I could not find it on their site.
My bad. The engine tilter tool is made by Lisle P/N 22550 . I purchased it 12 years ago. Not certain if its made anymore but you may find one on eBay. Works like a charm.
------------------ " THE BLACK PARALYZER" -87GT 3800SC Series III engine, custom ZZP /Frozen Boost Intercooler setup, 3.4" Pulley, Northstar TB, LS1 MAF, 3" Spintech/Hedman Exhaust, P-log Manifold, Autolite 104's, MSD wires, Custom CAI, 4T65eHD w. custom axles, Champion Radiator, S10 Brake Booster, HP Tuners VCM Suite. "THE COLUSSUS" 87GT - ALL OUT 3.4L Turbocharged engine, Garrett Hybrid Turbo, MSD ign., modified TH125H " ON THE LOOSE WITHOUT THE JUICE "
[This message has been edited by Dennis LaGrua (edited 10-08-2021).]
The Fiero has stood for many years and water must have got past weather strip, the plugs are badly corroded and seized with hardly any hexagon left. Was thinking of using something like these damaged nut extractors but porcelain part of plug would have to be broken off, not a problem as they are being replaced anyway. If better access was available it would be much easier and if heat could be applied to remains of plug that would also help. If cutting an access panel the ECM and wiring could be in the way and would have to be moved. My idea for an access hole would be to make a cover slightly larger, secured with screws into captive nuts welded in place and also sealed. Would have been good if GM had come up with something like that in the first place, don't suppose they were interested in making future maintenance easier.
Hi David, if you can avoid it, don't cut any holes in the frame. If I had to go down that path, I'd probably just remove the cyl head.
Just noticed a response from Patrick with the spark plug extractor as I was typing up this response. That is EXACTLY what I would recommend too. All you need to do is just spray the ever living hell out of those plug holes with PB blaster or some kind of penetrating oil first. Let it sit for a few days, just keep doing it a couple of times a day (it will all burn off when you've replaced them).
You can also get a bit more leverage if you remove the "dog bone" / engine strut and pull the engine a bit more closer to you.
Patrick I think you are not happy with my idea of spark plug.
You say: Rusted plugs probably get rounded due to the fact that the threads have corroded and stuck in the head.
Me I think : The R42TS spark plugs are prone to rusting due to the water falling on them by the deck lid and your idea of installing anti-seize copper is very good idea for those who don't want to install 41-809 because they are more expensive (approx. 6X) But you have to change them less often.
Me To have peace in mind I use 41-809 spark plugs.
Patrick I think you are not happy with my idea of spark plug.... they are more expensive (approx. 6X)
Claude, maybe you've misunderstood me. I've already said that those stainless steel spark plugs are "very nice"... and I meant it! But as you yourself have stated, they are 6x the price of regular plugs! That's a premium price! I'm way too cheap to spend that much on spark plugs when I can use a few cents worth of anti-seize on regular plugs and not have any problem down the road.
I always take the decklid off when I am changing spark plugs. That little bit of room make a huge difference.
That certainly works, but removing the deck lid, putting it back on and realigning it perfectly, is a difficult one man job.
------------------ " THE BLACK PARALYZER" -87GT 3800SC Series III engine, custom ZZP /Frozen Boost Intercooler setup, 3.4" Pulley, Northstar TB, LS1 MAF, 3" Spintech/Hedman Exhaust, P-log Manifold, Autolite 104's, MSD wires, Custom CAI, 4T65eHD w. custom axles, Champion Radiator, S10 Brake Booster, HP Tuners VCM Suite. "THE COLUSSUS" 87GT - ALL OUT 3.4L Turbocharged engine, Garrett Hybrid Turbo, MSD ign., modified TH125H " ON THE LOOSE WITHOUT THE JUICE "
Removing by yourself is easy. Putting it back on by yourself sucks.
I put corrugated cardboard (large flattened box) on the roof for protection (when the decklid is placed on it), and stand in the trunk for removal and re-installation of the open decklid. Piece of cake.
[This message has been edited by Patrick (edited 10-11-2021).]
Had the same problem getting the OEM plugs out on a 48,000 mi car. It was best to use the hinged headed ratchet that is shown in the Fiero service manual. I would just tighten then loosen the plug slightly till it finally backed out. Of course do this after blowing the sand, dirt or whatever out of the plug recesses.
I just recently replaced the plugs after 28,000 miles. Having used antisieze on the threads certainly made the job way easier. I use antisieze on all plugs I install in everything from lawn mowers, boats to every car ever owned. It doesn’t take much antisieze to be beneficial.
I always take the decklid off when I am changing spark plugs. That little bit of room make a huge difference.
this is easier than the other suggestions, removing the decklid and putting it back on will give good access I have done it myself with no help, sounds like at least two others have done it and agree
but it's your car, time and effort, and you are free to struggle with it however you want
I stand in the trunk and hug the engine. I have more of a problem dropping tools than changing the plugs.i did mine yesterday and my knees are killing me. They were in there for 4 yrs. At 65 I'm getting tired of working on car's. Make it stop please. oh car show tomorrow. Cool
I stand in the trunk and hug the engine. I have more of a problem dropping tools than changing the plugs.i did mine yesterday and my knees are killing me. They were in there for 4 yrs. At 65 I'm getting tired of working on car's. Make it stop please. oh car show tomorrow. Cool
I'm 71, 72 in Feb., and I know your pain. It's a labor of love and hate, but it's like a drug I can't do without!!! I just put my deck lid back on by myself, but didn't have any issues. I'm 6'-3", though, so maybe that helped. I have to pull it again, anyway. I have a cracked exhaust manifold and of course it's the front one.
I did the original post but have now sold the Fiero and the guy who bought it told me how he got the corroded front spark plugs out. This is in the UK and the guy has had many Fieros with over 30 years experience, he said it was not easy but just about possible. The car had stood for many years and he said the spark plug hexagon had corroded away almost completely, he didn't think penetrating oil would work as it most likely wouldn't get past the plug taper seat to the thread. He removed the rear cradle bolts and loosened the front cradle bolts, then by jacking the car up somewhere near the doors the engine rotated backwards and opened up a gap between the front of the engine and the bulkhead leaving enough space to fairly easily access the plugs. He then broke the plug porcelain and with a small punch chipped carefully away at the remaining porcelain, vacuuming up the broken bits until eventually what was left of the porcelain and centre electrode could be pulled out. After all this he made an extractor by grinding an old lathe tool or piece of square tool steel with a reverse helix and not too much of a taper in case it expanded the remains and made it even tighter when he tapped it into what remained of the plug. The sharp corners cut into the metal and he turned the end of the tool he had made with a socket and out came the remains of the plugs without any heat or penetrating oil. It took many hours as you can imagine but saved having to take the head off which would have been the alternative. The moral of this story is to use anti seize on the plug thread and maybe a shield to deflect water away from the plugs in future. At least my old Fiero lives to run another day.
But as you yourself have stated, they are 6x the price of regular plugs! 
That's a premium price! I'm way too cheap to spend that much on spark plugs when I can use a few cents worth of anti-seize on regular plugs and not have any problem down the road. 
