Need Help with Spark Plugs - '87/L98
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From: Decatur Al
Need Help with Spark Plugs - '87/L98
This is my first time to change out the plugs on my 1987 L97 engine (stock). Helms says that the plugs are supposed to be tapered. The owner's manual says to use FR3CLS. The newer Delco xref to the FR3CLS is a 41-629 (that's also what is currently in the car). Bought 8. They are not tapered! Should I be using a different plug?
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From: Decatur Al
I just read somewhere that GM discontinued recommending tapered-seat sparkplugs for aluminum heads because they tended to freeze up and were difficult to remove.
Do we have any spark plug experts out there who can chime in on this??
If I now have to use the gasketed spark plugs, what torque do I use. The recommended value for the tapered plugs (22 ft-lb) would no longer apply.
Do we have any spark plug experts out there who can chime in on this??
If I now have to use the gasketed spark plugs, what torque do I use. The recommended value for the tapered plugs (22 ft-lb) would no longer apply.
Le Mans Master
Joined: Oct 2003
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From: seattle WA
well its been awhile since I changed the plugs on my 87, a year or so, can't remember about the taper part. But, I for one have never used a torque wrench on plugs, just tightened til snug+. Curious how many guys actually torque them-been doing tune ups for 40+ years.
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From: Oxnard CA
St. Jude Donor '05
Originally Posted by rick lambert
well its been awhile since I changed the plugs on my 87, a year or so, can't remember about the taper part. But, I for one have never used a torque wrench on plugs, just tightened til snug+. Curious how many guys actually torque them-been doing tune ups for 40+ years.
however I do put antiseize on the plug threads also.Bob
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From: Decatur Al
Thanks for the response, everyone! I'm glad I didn't buy the wrong plugs! Will be putting them in tomorrow night (if I can figure out how to get #2 and #8 out!).
As for torquing things down, I'm not very mechanically minded. I can follow directions, but I'm not good at ad lib'ing. So, for me, something like "snug, but don't overtighten" leaves me in the dark! But "torque to 22 ft lbs" is very clear.
Hope everyone had a wonderful Thanksgiving!
As for torquing things down, I'm not very mechanically minded. I can follow directions, but I'm not good at ad lib'ing. So, for me, something like "snug, but don't overtighten" leaves me in the dark! But "torque to 22 ft lbs" is very clear.
Hope everyone had a wonderful Thanksgiving!
Le Mans Master
Joined: Oct 2003
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From: seattle WA
Sorry, when I say snug-I generally tighten them with a ratchet to the point I know there seated well then give it a 1/4 turn more. 20 pounds is not alot of pressure-if you have a bathroom scale-push it with your hand and watch it climb to 20 lbs. I guess it's just having done it so often it becomes second nature. 
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From: Decatur Al
Thanks everyone! Changed my plugs today. The #2 plug had the electrode almost touching the post (about .10 mm clearance). Maybe somebody had dropped it on the ground before installing it?? The #5 plug looked black. But this is the one where I had previously found the wire boot not pushed down all the way on the distributor cap. All the rest were picture-perfect (slightly brownish around the base and on top of the electrode).
Put the new ones in and they made a world of difference! (Coffee doesn't splash out of my cup at idle any more!!!!)
With a few PM's from some of you, I got some great ideas about reaching #2 and #8. I was able to go through the wheel-well opening to get #2 (never noticed that opening before!) and I used an open-end wrench on the back of the sparkplug socket to get #8.
Another job learned with help from forum members! Thanks all!
(Found this link to spark plug pictures...
http://www.dansmc.com/Spark_Plugs/Sp...s_catalog.html )
Put the new ones in and they made a world of difference! (Coffee doesn't splash out of my cup at idle any more!!!!)
With a few PM's from some of you, I got some great ideas about reaching #2 and #8. I was able to go through the wheel-well opening to get #2 (never noticed that opening before!) and I used an open-end wrench on the back of the sparkplug socket to get #8.
Another job learned with help from forum members! Thanks all!
(Found this link to spark plug pictures...
http://www.dansmc.com/Spark_Plugs/Sp...s_catalog.html )
Last edited by BamaVette87; Nov 29, 2004 at 11:12 PM.
