Platinum Plugs

teamhavok2 · Post by **teamhavok2** » Fri Jul 20, 2007 3:46 pm

So i'm going to change out my haggard plugs and wires for a new set. I've been looking at plugs and usually get NGK's but saw that they were the same price for platinum plugs. Any thoughts on this? I know when my buddy worked at the Mercades dealership a brand new 'sports' SUV bought them for like 12 bucks a pop and couldn't even use them. Thanks

lucky · Post by **lucky** » Fri Jul 20, 2007 6:08 pm

AC Delco Rapidfires.
Delco says a #1 at .045 Gap.
Try a #3 at .060 Gap, you'll feel a difference in your throttle response.

And they're only $4.50 each at AutoZone.

I'm assuming 2.8

whipped · Post by **whipped** » Fri Jul 20, 2007 6:33 pm

Some of the platinums have a problem with losing an electrode, especially on DIS systems. After the platinum electrode disappears (presumably to scratch up your cylinder walls), it turns into a regular plug and lasts 10,000 miles.

AC Delco double platinum's work well..... The current best plug on the market are the Iridiums; I'm using NGK's. Not worth the $8+ a pop to put them in a duke though.

Xanth · Post by **Xanth** » Fri Jul 20, 2007 7:28 pm

I've always used Denso iridiums in my Hondas, wasn't sure if they were suitable for the 2.8

I've read a couple of threads about complaints of stumbling with normal Denso plugs, any idea if their Iridiums are fine in the 2.8?

whipped · Post by **whipped** » Fri Jul 20, 2007 9:11 pm

No idea. The only plugs I have heard (really) bad things about are the Bosch's.... well and Autolite. Generally speaking you should probably use the things closest to the OEM's. AC Delco, NGK is/was spec as OEM plugs circa 2000, not sure about any others. One of the issues with the Autolite in particular was their heat ratings didn't match what they should have been for GM cars. (Isn't autolite a ford product?)

Xanth · Post by **Xanth** » Fri Jul 20, 2007 9:31 pm

I think Autolites are by Fram, which is owned by Honeywell I believe.

I know Autolites arrive along with Fram whenever we get a shipment in.

jelly2m81 · Post by **jelly2m81** » Fri Jul 20, 2007 10:14 pm

YA, forget the Bosch, platniums and autolites like said above, I'd like to have a dollar for everyset of fairly new shit plugs like those I removed from someones Fiero to get rid of a mis-fire.

Can't go wrong with the Rapidfires like has been mentioned, I've put about 100k miles on 3 sets of them and never had any troubles.

lucky · Post by **lucky** » Sat Jul 21, 2007 10:11 am

Where I work we consider plugs to be not garbage, but wrong.
Bosch run great in Audi Vw Mercedes, but horrible in Fords.
Champions run great in Chrysler products, horrible in everything else.
Denso's and NGK's for asian cars, delco's for GM.

When customers ask for plugs we try to recommend as close to OE as possible and we usually have very few comebacks.

There are however some vehicles where this is not the case. Currently Saturn is recommending NGK for the 1.9's from 93-99, because other plugs cause the crank sensor to trip for some reason, for example.

teamhavok2 · Post by **teamhavok2** » Sat Jul 21, 2007 12:54 pm

I've been trying to find this low end stumble on my car since i bought it a few months back. The block in it is brand new but they used alot of parts of the old cracked motor. I changed the wires when i got them (but went cheap till i could figure out the stumble). There was alot of vacume lines not hooked up or just crumbled in my hand when i followed them. so i put in a whole new set of lines (ones that can atleast bend and under 20 years old) still showed vacume problems and found they used the old crush gasket and never glued it for the egr. Then about 3 days ago my 2.8 sounded like a lawn mower. So i got a new set of plugs and wires last night (went with ones that said Iridiums from NGK) and threw them in. When i got to the back 3 plugs it was obvious what the problem was. There was so much rust on the back plugs that it had to be arking. I dropped those new plugs and wires and took it out for a drive. I was told there's new performance pistons they put with the new block and now i can actually tell ha ha. I was so pre occupied by trying to get it up to a good running condition that i neglected the first rule of new cars... Must retune the car. Even if it had a new(ish) motor. Poor kid that i bought it from got so ripped off on the install.

CincinnatiFiero · Post by **CincinnatiFiero** » Tue Jan 08, 2008 5:12 pm

According to an old issue of "Fiero Secrets" the delcos stick in the combustion chamber by 1 thread and the open part of the plug head faces the exhaust port, with autolite #23's the fit flush and face the intake valve, I replaced the champions that were in my 2.8 when I got it with autolites, they seem to run better. After I seamfoam I have a brand new set of NGK UR5's to go in though, which someone proved make 2whp more than Delcos.

Emc209i · Post by **Emc209i** » Mon Jan 28, 2008 1:36 am

A serious question then. I pulled my plugs yesterday to clean and inspect them. To my honest surprise, I found Bosch Platinum 4 plugs. When we built my motor, we had left the original AC Delco's in the motor, despite the fact that I had 6 brand new Bosch P4's in the box that came with the motor. We left them alone because of this issue. Somewhere in translation they landed in my motor, don't ask me how.

So looking beyond all of that, should I be seriously worried? The motor ran like a champ until I broke the front cover. Should I go ahead and pull them for a cheap set of AC Delco? I asked my mechanic and he despises Bosch as much as I've read, but he's not had much experience with the P4's. It won't be that hard to replace them, but what should I expect? Any info?

Pyrthian · Post by **Pyrthian** » Tue Jan 29, 2008 9:35 am

lucky80 wrote:AC Delco Rapidfires.
Delco says a #1 at .045 Gap.
Try a #3 at .060 Gap, you'll feel a difference in your throttle response.

And they're only $4.50 each at AutoZone.

I'm assuming 2.8

only open the gap if you have something OTHER than a stock coil. the stock coil already chokes as it is at around 4000 RPM. opening the gap only makes that worse. but - yes - with a MSD coil, you can open the gap to 0.065" - which is also what the 4-cyl specs the gap - for the same plug.

Xanth · Post by **Xanth** » Tue Jan 29, 2008 9:48 am

Emc209i wrote:A serious question then. I pulled my plugs yesterday to clean and inspect them. To my honest surprise, I found Bosch Platinum 4 plugs. When we built my motor, we had left the original AC Delco's in the motor, despite the fact that I had 6 brand new Bosch P4's in the box that came with the motor. We left them alone because of this issue. Somewhere in translation they landed in my motor, don't ask me how.

So looking beyond all of that, should I be seriously worried? The motor ran like a champ until I broke the front cover. Should I go ahead and pull them for a cheap set of AC Delco? I asked my mechanic and he despises Bosch as much as I've read, but he's not had much experience with the P4's. It won't be that hard to replace them, but what should I expect? Any info?

I've heard quite a few complaints when using Bosch Platinums with the Fiero ignition system. I'm running cheapo AC Delcos right now and they work great.

Kohburn · Post by **Kohburn** » Tue Jan 29, 2008 10:43 am

GNK's

i had a delco blow the ceramic core out of the threaded metal housing.. it aperantly worked itself lose and there wasn't much metal holdign it in. it bend that back and popped out. may have been a fluke but i don't trust them anymore.

i tried platinums on a fiero - they burned out in about 6000 miles.

best plugs i ever used were torqumaster plugs... smoother idle, more power, and never wore out as long as i had em. but they are about 12$ a pop

Series8217 · Post by **Series8217** » Tue Jan 29, 2008 4:28 pm

I wouldn't use platinums with a DIS motor. Apparently they don't like being fired "backwards" which happens with wasted-spark ignition.
I use AC Delco iridium plugs. They seem to last forever. I think GM says they're good for 100,000 miles. GM switched from platinum to iridium in a service bulletin a while back, due to the platinum ones falling apart.

The Dark Side of Will · Wed Jan 30, 2008 1:48 am

CincinnatiFiero wrote:According to an old issue of "Fiero Secrets" the delcos stick in the combustion chamber by 1 thread and the open part of the plug head faces the exhaust port, with autolite #23's the fit flush and face the intake valve, I replaced the champions that were in my 2.8 when I got it with autolites, they seem to run better. After I seamfoam I have a brand new set of NGK UR5's to go in though, which someone proved make 2whp more than Delcos.

I don't think the threads are indexed in the cylinder heads well enough to know where the electrode is inside the camber, even if they are indexed that well on the plug, which I doubt as well.