Spark plugs... - The 1947 - Present Chevrolet & GMC Truck Message Board Network

*ZmOz* · 04-12-2005, 10:31 PM

Yesterday I decided to pull one of the plugs on my '79 C20/454 to see how it looked. I think they needed to be changed some time around 1985.

Anyway, I changed all but the front and back plugs on the driver side. I could not get to the front and last plug with any configuration of sockets I have.

Does anybody have any tips on removing these?

Also, what would cause a plug to look like this?

That's a Bosch platinum with unknown mileage...

screwballl · 04-12-2005, 11:39 PM

hmm carbon buildup, slight melting, i would say anywhere from 20-100K miles on them and they look like that from the length of time left in there.... i would check the new plugs every oil change and see how they look, replace them each time if it is rough until the roughage is mostly gone. also theres some feul additives to help but not sure what to recommend there...
this post is just from my experience, others may see it differently

MylilBowTie · 04-13-2005, 01:16 AM

Looks to me like its very oil fouled but the glare from the flash might have made it look different. Intake gaskets are leaking oil into the cylinder heads, valve seals / valve guides, or very worn out rings and possibly very clogged oil returns in the cylinder heads. Does it have headers?

Do they all look like that?

*ZmOz* · 04-13-2005, 01:28 AM

The pic makes it look much more oily than it is. It's a little shiny, but not much. The others are very dry and covered in soot, but obviously I haven't seen the two I couldn't get out. No headers...yet...

MylilBowTie · 04-13-2005, 01:34 AM

http://www.nightrider.com/biketech/spkplghnbook.htm

There are some pictures of spark plugs of varying conditions.

See how long the new ones stay clean, then you should be able to get a better reading of what its doing. What cylinder did the bad one come out of?

MylilBowTie · 04-13-2005, 01:36 AM

Heres a better link. http://www.dansmc.com/Spark_Plugs/Sp...s_catalog.html

Hoods69BadBowTie · 04-13-2005, 02:21 AM

Zmoz-"Anyway, I changed all but the front and back plugs on the driver side. I could not get to the front and last plug with any configuration of sockets I have. Does anybody have any tips on removing these?"
Just a regular spark plug socket should work, unless they started to get stripped or something. Can you tell how they look. What exactly is happening? You can't reach them or they seem to be a different size?
-Later

*ZmOz* · 04-13-2005, 02:30 AM

Quote:

Originally Posted by MylilBowTie

[url]What cylinder did the bad one come out of

I don't remember now...but it was on the passenger side bank.

Quote:

Originally Posted by Hoods69BadBowTie

Just a regular spark plug socket should work, unless they started to get stripped or something. Can you tell how they look. What exactly is happening? You can't reach them or they seem to be a different size?

I can get a spark plug socket on them fine, the problem is I can't get a wrench of any sort in there...let alone move it with some serious force.

*ZmOz* · 04-13-2005, 05:14 PM

Does anybody know where I can find the firing order for this engine? I just noticed I got a couple of the plug wires mixed up last night...

Hoods69BadBowTie · 04-13-2005, 05:30 PM

Should be in your manual if you have one. Should also be on the intake manifold.
So you can get the sockets on to the plugs you just can't get any force behind it or get a wrench on it to give it force?
-Later

*ZmOz* · 04-13-2005, 07:32 PM

Quote:

Originally Posted by Hoods69BadBowTie

So you can get the sockets on to the plugs you just can't get any force behind it or get a wrench on it to give it force?

Yep. I guess I'll have to take off the little manifold for the smog pump, that's mostly what is in the way.

Found the firing order on the manifold. Still running kind of rough so I hooked the cylinders up 2 at a time to see how they ran...#6 is dead. I think the dirty plug came out of that cylinder.

Hoods69BadBowTie · 04-14-2005, 01:58 AM

Dam, yeah that spark plug looked pretty toasted!!

86 GMG · 04-14-2005, 10:58 AM

As Far As Not Being Able To Take Out The Plug Does Your Socket Have A Nut Looking Item On The End If So Try Usins A Wrench On The Socket Instead Of The Ratchet, Mit Give A Little More Room. Be Carefullwatch Your Knuckles

*ZmOz* · 04-14-2005, 06:37 PM

Took off the distributor cap and it looks pretty new inside. Replaced the #6 plug wire. It still only fires randomly. Anybody have any idea why?

screwballl · 04-14-2005, 09:17 PM

usually i try to replace whatever possible from the cap, rotor, module, wires, plugs, HEI or coil... most of these parts are fairly cheap for troubleshooting. it being 26 years old it is hard to tell exactly where it might be.

04-12-2005, 10:31 PM	#1
ZmOz Account Suspended Join Date: Apr 2005 Location: OR Posts: 235	Spark plugs... Yesterday I decided to pull one of the plugs on my '79 C20/454 to see how it looked. I think they needed to be changed some time around 1985. Anyway, I changed all but the front and back plugs on the driver side. I could not get to the front and last plug with any configuration of sockets I have. Does anybody have any tips on removing these? Also, what would cause a plug to look like this? That's a Bosch platinum with unknown mileage...

04-12-2005, 11:39 PM	#2
screwballl Tonawanda 454 Join Date: Mar 2004 Location: Liquid Sunshine State Posts: 2,754	hmm carbon buildup, slight melting, i would say anywhere from 20-100K miles on them and they look like that from the length of time left in there.... i would check the new plugs every oil change and see how they look, replace them each time if it is rough until the roughage is mostly gone. also theres some feul additives to help but not sure what to recommend there... this post is just from my experience, others may see it differently __________________ 91 Chevy Suburban Tonawanda 454 R2500 - SOLD!!! 04 Dodge Durango 5.7L Hemi 2WD, 24K miles (as of July 2011) In the past 30 years about 90% of Fords are still on the road, the other 10% made it home. -------------------

04-13-2005, 01:16 AM	#3
MylilBowTie Right turn Clyde Join Date: Nov 2002 Location: Cincinnati, Ohio Posts: 2,911	Looks to me like its very oil fouled but the glare from the flash might have made it look different. Intake gaskets are leaking oil into the cylinder heads, valve seals / valve guides, or very worn out rings and possibly very clogged oil returns in the cylinder heads. Does it have headers? Do they all look like that? __________________ 1974 C25 LWB: 454 4bbl Carb / TH400 / 3.73 1992 Camaro RS 305 TBI Last edited by MylilBowTie; 04-13-2005 at 01:18 AM.

04-13-2005, 01:34 AM	#5
MylilBowTie Right turn Clyde Join Date: Nov 2002 Location: Cincinnati, Ohio Posts: 2,911	http://www.nightrider.com/biketech/spkplghnbook.htm There are some pictures of spark plugs of varying conditions. See how long the new ones stay clean, then you should be able to get a better reading of what its doing. What cylinder did the bad one come out of? __________________ 1974 C25 LWB: 454 4bbl Carb / TH400 / 3.73 1992 Camaro RS 305 TBI

04-13-2005, 02:21 AM	#7
Hoods69BadBowTie Chevys Kick A$$ Join Date: Jan 2005 Location: Zootown, MT Posts: 12,699	Zmoz-"Anyway, I changed all but the front and back plugs on the driver side. I could not get to the front and last plug with any configuration of sockets I have. Does anybody have any tips on removing these?" Just a regular spark plug socket should work, unless they started to get stripped or something. Can you tell how they look. What exactly is happening? You can't reach them or they seem to be a different size? -Later __________________ HOODS is what I answer too -'79, '77, '88 Pickup Sold, '85 Camaro, '83 T/A, '81,'83,'90 K5 Blazer All Sold -'79 3/4 ton "Big Yellow Bananna" Lifted 4spd. 39.5 TSL Swampers, The money Pit -'86 K5 Blazer Silverado 6.2 4" lift 35"s -'95 Ext. Cab Shorty 4" Tuff Country rolling 35" M/T's -'83 Monte Carlo T-Tops. 126,500 Original Miles -LATER I would rather push a Chevy then drive a ford!!

04-13-2005, 01:28 AM	#4
ZmOz Account Suspended Join Date: Apr 2005 Location: OR Posts: 235	The pic makes it look much more oily than it is. It's a little shiny, but not much. The others are very dry and covered in soot, but obviously I haven't seen the two I couldn't get out. No headers...yet...

04-13-2005, 01:36 AM	#6
MylilBowTie Right turn Clyde Join Date: Nov 2002 Location: Cincinnati, Ohio Posts: 2,911	Heres a better link. http://www.dansmc.com/Spark_Plugs/Sp...s_catalog.html __________________ 1974 C25 LWB: 454 4bbl Carb / TH400 / 3.73 1992 Camaro RS 305 TBI

04-13-2005, 05:14 PM	#9
ZmOz Account Suspended Join Date: Apr 2005 Location: OR Posts: 235	Does anybody know where I can find the firing order for this engine? I just noticed I got a couple of the plug wires mixed up last night...

04-13-2005, 05:30 PM	#10
Hoods69BadBowTie Chevys Kick A$$ Join Date: Jan 2005 Location: Zootown, MT Posts: 12,699	Should be in your manual if you have one. Should also be on the intake manifold. So you can get the sockets on to the plugs you just can't get any force behind it or get a wrench on it to give it force? -Later __________________ HOODS is what I answer too -'79, '77, '88 Pickup Sold, '85 Camaro, '83 T/A, '81,'83,'90 K5 Blazer All Sold -'79 3/4 ton "Big Yellow Bananna" Lifted 4spd. 39.5 TSL Swampers, The money Pit -'86 K5 Blazer Silverado 6.2 4" lift 35"s -'95 Ext. Cab Shorty 4" Tuff Country rolling 35" M/T's -'83 Monte Carlo T-Tops. 126,500 Original Miles -LATER I would rather push a Chevy then drive a ford!!

04-14-2005, 01:58 AM	#12
Hoods69BadBowTie Chevys Kick A$$ Join Date: Jan 2005 Location: Zootown, MT Posts: 12,699	Dam, yeah that spark plug looked pretty toasted!! __________________ HOODS is what I answer too -'79, '77, '88 Pickup Sold, '85 Camaro, '83 T/A, '81,'83,'90 K5 Blazer All Sold -'79 3/4 ton "Big Yellow Bananna" Lifted 4spd. 39.5 TSL Swampers, The money Pit -'86 K5 Blazer Silverado 6.2 4" lift 35"s -'95 Ext. Cab Shorty 4" Tuff Country rolling 35" M/T's -'83 Monte Carlo T-Tops. 126,500 Original Miles -LATER I would rather push a Chevy then drive a ford!!

04-14-2005, 10:58 AM	#13
86 GMG Registered User Join Date: Apr 2005 Location: Tulsa Oklahoma Posts: 943	As Far As Not Being Able To Take Out The Plug Does Your Socket Have A Nut Looking Item On The End If So Try Usins A Wrench On The Socket Instead Of The Ratchet, Mit Give A Little More Room. Be Carefullwatch Your Knuckles __________________ square body trucks an addiction or an investment either way they consume all my extra time and money

04-14-2005, 06:37 PM	#14
ZmOz Account Suspended Join Date: Apr 2005 Location: OR Posts: 235	Took off the distributor cap and it looks pretty new inside. Replaced the #6 plug wire. It still only fires randomly. Anybody have any idea why?

04-14-2005, 09:17 PM	#15
screwballl Tonawanda 454 Join Date: Mar 2004 Location: Liquid Sunshine State Posts: 2,754	usually i try to replace whatever possible from the cap, rotor, module, wires, plugs, HEI or coil... most of these parts are fairly cheap for troubleshooting. it being 26 years old it is hard to tell exactly where it might be. __________________ 91 Chevy Suburban Tonawanda 454 R2500 - SOLD!!! 04 Dodge Durango 5.7L Hemi 2WD, 24K miles (as of July 2011) In the past 30 years about 90% of Fords are still on the road, the other 10% made it home. -------------------



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