GM Changed plug #s on C-5?
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Melting Slicks
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From: Lake Martin ALABAMA
GM Changed plug #s on C-5?
Got a set of plugs from the dealer..... the #'s were different from the factory ones I pulled out,
and they had longer porcealin electrode and a slightly (real small) longer reach.
The dealer showed me his microfiche info, verifying he gave me the correct plugs.
I presently have 82,000 miles on my '99, and it was running ok.. Just decided to change plugs, wires, belts.....just "in case".
The old plugs were in really good shape ..... probably coulda went another 20 thou. miles.................
Anyway, I installed the set.... the slight pinging I had in the car under heavy accel from day 1 when new
is gone now. The car accelerates quicker, but that just may be cause of the new plugs. I have since put
3,000 miles on the car, and am glad I went with the "stock" plug.
and they had longer porcealin electrode and a slightly (real small) longer reach.
The dealer showed me his microfiche info, verifying he gave me the correct plugs.
I presently have 82,000 miles on my '99, and it was running ok.. Just decided to change plugs, wires, belts.....just "in case".
The old plugs were in really good shape ..... probably coulda went another 20 thou. miles.................
Anyway, I installed the set.... the slight pinging I had in the car under heavy accel from day 1 when new
is gone now. The car accelerates quicker, but that just may be cause of the new plugs. I have since put
3,000 miles on the car, and am glad I went with the "stock" plug.
Safety Car
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From: Monticello MN
Re: GM Changed plug #s on C-5? (steve badalamenti)
Got a set of plugs from the dealer..... the #'s were different from the factory ones I pulled out
Ed
Burning Brakes
Joined: Dec 2000
Posts: 993
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From: Cincinnati Ohio
Re: GM Changed plug #s on C-5? (steve badalamenti)
steve badalamenti,
What were the original spark plug numbers and what are the replacement plug numbers?
Thanks (I own a 1999 C5 coupe I purchased new and I'm getting ready to change the plugs.)
1999 White C5 Coupe
What were the original spark plug numbers and what are the replacement plug numbers?
Thanks (I own a 1999 C5 coupe I purchased new and I'm getting ready to change the plugs.)
1999 White C5 Coupe
Safety Car
Joined: Oct 2000
Posts: 4,949
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From: Monticello MN
Re: GM Changed plug #s on C-5? (C5XTASY)
Got a set of plugs from the dealer..... the #'s were different from the factory ones I pulled out
Who manufactures the plugs and what is the new number on the plugs? Are they the Rapidfires by chance? Thanks!
Ed
Who manufactures the plugs and what is the new number on the plugs? Are they the Rapidfires by chance? Thanks!
Ed
Ed
[Modified by C5XTASY, 8:28 PM 4/28/2002]
Thread Starter
Melting Slicks
Joined: Apr 1999
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From: Lake Martin ALABAMA
Re: GM Changed plug #s on C-5? (C5XTASY)
C-5 Xtacy, yes, that is the plug they gave me.
At first I was leery of putting them in, because of the slightly (really small) longer reach.
I installed ONE, and ran the engine to see if it would be OK.
Of course, it was, and the engine runs great. By the way,
as soon as they went in, I noticed that the idle had also smoothed out. :yesnod:
At first I was leery of putting them in, because of the slightly (really small) longer reach.
I installed ONE, and ran the engine to see if it would be OK.
Of course, it was, and the engine runs great. By the way,
as soon as they went in, I noticed that the idle had also smoothed out. :yesnod:
Team Owner
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From: Western NY
Re: GM Changed plug #s on C-5? (steve badalamenti)
I've been reading all of the posts regarding the "disappearing puck" problem with the stock spark plugs, so I wanted to avoid the problem before it happened to me.
I put a set of Bosch platinum +4's in my truck late last year, and the SOTP dyno showed good results. Based on that, I got a set for my 2001 coupe, and put them in this past weekend. I was somewhat surprised to find Denso plugs used as original equipment. My car is a late build 2001.
I put a set of Bosch platinum +4's in my truck late last year, and the SOTP dyno showed good results. Based on that, I got a set for my 2001 coupe, and put them in this past weekend. I was somewhat surprised to find Denso plugs used as original equipment. My car is a late build 2001.
Melting Slicks
Joined: Jun 2001
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From: Chicagoland Illinois
Re: GM Changed plug #s on C-5? (leadfoot4)
Now we gotta get more to chime in here...I thought Denso plugs were used in '99's due to a shortage of the Platinum AC's...I have an '01 and bought some RapidFire #12's but have not placed them in the engine yet...Now we here that '01's might have Denso plugs??? What the....???
Need more info...
1. Do the Denso's (Nippondenso) have pucks
2. Is this why AC was dropped and Denso's picked up/the puck problem???
3. Anyone tried the Platinum AC RapidFires in their Vette, yet???
:chevy :seeya
Need more info...
1. Do the Denso's (Nippondenso) have pucks
2. Is this why AC was dropped and Denso's picked up/the puck problem???
3. Anyone tried the Platinum AC RapidFires in their Vette, yet???
:chevy :seeya
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From: Western NY
Re: GM Changed plug #s on C-5? (silversport)
From what I can see, the Denso's have a slight "puck". In other words, all 8 of my plugs had a raised area about .015"-.020" thick on the side electrode. This is, of course, assuming that there wasn't a thicker "puck" originally, and all 8 of them blew off.
My S-10 pick-up, with the 4.3 liter engine, had AC's with the "pucks" as OE, and the "pucks" were much thicker on the AC's than on the Denso's. Considering that an earlier post mentioned that the plug gap should be around .040"-.050", I think it's a fairly safe assumption that my OE Denso's are still in good condition.
Maybe I should have checked them out before just buying a new set of plugs, but I just hate chasing back and forth to the parts store. I like to gather everything I need first, then attack the car until the job is completed.
[Modified by leadfoot4, 8:16 AM 4/29/2002]
My S-10 pick-up, with the 4.3 liter engine, had AC's with the "pucks" as OE, and the "pucks" were much thicker on the AC's than on the Denso's. Considering that an earlier post mentioned that the plug gap should be around .040"-.050", I think it's a fairly safe assumption that my OE Denso's are still in good condition.
Maybe I should have checked them out before just buying a new set of plugs, but I just hate chasing back and forth to the parts store. I like to gather everything I need first, then attack the car until the job is completed.
[Modified by leadfoot4, 8:16 AM 4/29/2002]
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From: Far NW 'burbs of Chicago
St. Jude Donor '13
Re: GM Changed plug #s on C-5? (leadfoot4)
FWIW, my 2001 Service Manual shows the desired gap as .060 regardless of which plug is used.
I bought a set of stock plug last week from the dealer, they have a Chevy part number that I don't remember, but the boxes say "AC-Delco 41-974"
When you open the boxes, the plugs are marked
"Denso PTJ16R15"
"12563707"
I guess that there is a tiny little puck on the part that you bend to set the gap, but the puck is so small I had to use a magnifying glass to be sure it was there.
Nowhere on the plug itself is there anything about Ac-Delco, only on the box.
[Modified by Gearhead Jim, 8:33 AM 4/29/2002]
I bought a set of stock plug last week from the dealer, they have a Chevy part number that I don't remember, but the boxes say "AC-Delco 41-974"
When you open the boxes, the plugs are marked
"Denso PTJ16R15"
"12563707"
I guess that there is a tiny little puck on the part that you bend to set the gap, but the puck is so small I had to use a magnifying glass to be sure it was there.
Nowhere on the plug itself is there anything about Ac-Delco, only on the box.
[Modified by Gearhead Jim, 8:33 AM 4/29/2002]
Melting Slicks
Joined: Aug 2000
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From: Newland US
Re: GM Changed plug #s on C-5? (leadfoot4)
From what I can see, the Denso's have a slight "puck". In other words, all 8 of my plugs had a raised area about .015"-.020" thick on the side electrode.
That's what I discovered on my 2001 at around 22K miles. Several of the small pucks were almost completely burned away. None appeared to have the pucks "blown" off. Even when missing material on the pucks, the gap still was around .057-.060. :confused:
Maybe a happy medium would be a "single" platinum plug with only the center electrode being platinum tipped, as opposed to the "double" platinums, which also have the platinum pucks on the ground electrode.
Trying the new plug that Autolite is marketing for the 2001 Vette....AP5245. Not particularly impressed with the look of 'em, but the idle improved somewhat.
Will pull a couple of them in about 10K and see what they look like. They might surprise me, but I have a hunch I'll still be looking for a good replacement plug. Strongly considered the Rapidfires. Silversport, let us know how those work out for ya.
Good luck.
Mark
Team Owner
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From: Western NY
Re: GM Changed plug #s on C-5? (MDT)
If I remember correctly, I think that some of the past discussions on the forum mentioned "missing pucks" on some, but not all of the 8 plugs. Basing my opinion on this, I think that because my car has only 2700 fairly easy miles so far, and all of the plugs are consistent in appearence, my OE plugs were OK.
I've never seen a Denso plug "fresh out of the box", so I can't be 100% sure of what I'm looking at, however. The OE AC's that were in my S-10 had a more obvious "platinum puck" on the side electrode, so that's what I'm basing my observations on.
I've never seen a Denso plug "fresh out of the box", so I can't be 100% sure of what I'm looking at, however. The OE AC's that were in my S-10 had a more obvious "platinum puck" on the side electrode, so that's what I'm basing my observations on.
Melting Slicks
Joined: Aug 2000
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From: Newland US
Re: GM Changed plug #s on C-5? (leadfoot4)
leadfoot4,
You can get a good look at your plugs if you use a magnifying glass.
I ran AC-Delco 41-974 factory plugs in my 96 Z-28 (LT1). I changed them with fresh factory plugs a 87K. The pucks were all in place the gap was good, showed very little wear. They would have easily gone to 100K.
I changed the second set of OEM plugs at 152K with a 3rd set of OEM (stayed with the double platinum because they plugs are truely a biotch to change in that car without dropping the exhaust..so went for longevity.)
Now the second set only had about 65K on them and all but 2 were missing the pucks. Plugs showed quite a lot of wear.
I'm guessing that the pucks were blown off from detonation...maybe the mixture is going lean....the original fuel pump is in the car and I haven't taken the time to hook up my fuel pressure gauge.
Happily the plugs are an easy change in the C5, so not too much trouble to experiment with various plugs. Driving style, I'm sure is going to dictate very much which plug suits which driver.
I think the Denso is supposed to be a quality plug, but I didn't get very good service from them. I might just find a good copper core plug to go with next time.
Good luck.
Mark
You can get a good look at your plugs if you use a magnifying glass.
I ran AC-Delco 41-974 factory plugs in my 96 Z-28 (LT1). I changed them with fresh factory plugs a 87K. The pucks were all in place the gap was good, showed very little wear. They would have easily gone to 100K.
I changed the second set of OEM plugs at 152K with a 3rd set of OEM (stayed with the double platinum because they plugs are truely a biotch to change in that car without dropping the exhaust..so went for longevity.)
Now the second set only had about 65K on them and all but 2 were missing the pucks. Plugs showed quite a lot of wear.
I'm guessing that the pucks were blown off from detonation...maybe the mixture is going lean....the original fuel pump is in the car and I haven't taken the time to hook up my fuel pressure gauge.
Happily the plugs are an easy change in the C5, so not too much trouble to experiment with various plugs. Driving style, I'm sure is going to dictate very much which plug suits which driver.
I think the Denso is supposed to be a quality plug, but I didn't get very good service from them. I might just find a good copper core plug to go with next time.
Good luck.
Mark
Team Owner
Joined: May 2001
Posts: 87,357
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From: Western NY
Re: GM Changed plug #s on C-5? (MDT)
MDT,
What a coincidence, I have a 1996 Z-28 too! I'm currently using AC Rapidfires in the Z with good results, however I've only got 40,000 miles on the car, 15,000 on the Rapidfires.
The plugs are a pain to change in that car, but I opted to drop the exhaust system. Plugs wires are a real treat, if you haven't changed yours yet. The drivers' side isn't bad, but the other side makes up for it.
[Modified by leadfoot4, 5:08 AM 4/30/2002]
What a coincidence, I have a 1996 Z-28 too! I'm currently using AC Rapidfires in the Z with good results, however I've only got 40,000 miles on the car, 15,000 on the Rapidfires.
The plugs are a pain to change in that car, but I opted to drop the exhaust system. Plugs wires are a real treat, if you haven't changed yours yet. The drivers' side isn't bad, but the other side makes up for it.
[Modified by leadfoot4, 5:08 AM 4/30/2002]
Melting Slicks
Joined: Aug 2000
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From: Newland US
Re: GM Changed plug #s on C-5? (leadfoot4)
[QUOTE]
MDT,
What a coincidence, I have a 1996 Z-28 too! I'm currently using AC Rapidfires in the Z with good results, however I've only got 40,000 miles on the car, 15,000 on the Rapidfires.
The plugs are a pain to change in that car, but I opted to drop the exhaust system. Plugs wires are a real treat, if you haven't changed yours yet. The drivers' side isn't bad, but the other side makes up for it.
leadfoot4,
:) If the Vette gives as good service as the 4th Gen F-body, then I'll be happy. :D
First plug change on it I did without dropping the exhaust. :cry The second set I dropped the exhaust (definitely the way to go) since I was replacing ignition wires, Optispark, waterpump and timing sprockets and chain.
She was still running well, did the above as part of preventative maintenance...but the timing set really brought back a noticable increase in performance. Have a new fuel pump laying around for installation when the time comes. 155K and doesn't use any oil between 6K changes...always used Mobil 1 after 4K break in period using Mobil dino oil.
Even though the LT1 and the LS1 are completely different engines, I would hope that the LS1 is as good a long term engine. Maintenance, maintenance...maintenance. That's the key.
Good luck with the cars.
Mark
Team Owner
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From: Western NY
Re: GM Changed plug #s on C-5? (MDT)
MDT, It sounds like we've gone down a very similar path. The timing cover seal was leaking on my Z, so I figured I'd change the timing set since I was in there. I had a problem with that, however, as the cam gear was not machined to the same dimensions as the OE piece. When I tightened the gear, it would lock up against the camshaft retainer plate, preventing the engine from turning over...What a pain!
I also changed the distributor cap and rotor over this past winter. The cap looked fairly good, but the rotor was toasted. I also sent the injectors out for a clean up. Three of them were clogged to the point that they couldn't be cleaned, and had to be replaced. The suspected cause seems to be the non-use over the winter, allowing crud to build up and solidify. I don't know, as I'm not an expert there, but I've used Red Line's injector cleaner regularily, and use a fuel stabilizer for the winter. I also change the fuel filter annually. Oh well, it's runnin' real good now, so I guess I'll just enjoy it !!
Happy motoring to all!
I also changed the distributor cap and rotor over this past winter. The cap looked fairly good, but the rotor was toasted. I also sent the injectors out for a clean up. Three of them were clogged to the point that they couldn't be cleaned, and had to be replaced. The suspected cause seems to be the non-use over the winter, allowing crud to build up and solidify. I don't know, as I'm not an expert there, but I've used Red Line's injector cleaner regularily, and use a fuel stabilizer for the winter. I also change the fuel filter annually. Oh well, it's runnin' real good now, so I guess I'll just enjoy it !!
Happy motoring to all!
