Access Fiero Front Spark Plugs (Page 1/4)
David88 OCT 05, 11:51 AM
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!
fierofool OCT 05, 12:12 PM
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.
David88 OCT 05, 12:44 PM
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.
fierosound OCT 05, 02:24 PM

quote
Originally posted by David88:

My idea for an access hole....



Don't forget to post pictures.


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steve308 OCT 05, 04:20 PM
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.

Patrick OCT 05, 04:44 PM

quote
Originally posted by David88:

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).]

oneinch OCT 05, 08:16 PM
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.

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Stanton
'88 Formula, red on gray

eti engineer OCT 05, 09:07 PM

quote
Originally posted by David88:

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.
Dennis LaGrua OCT 05, 09:14 PM
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.

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[This message has been edited by Dennis LaGrua (edited 10-06-2021).]

eti engineer OCT 05, 09:36 PM

quote
Originally posted by Dennis LaGrua:

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...

Later....