A friends opti died in his '92 so he relpaced the plugs, wires etc. He bought the top of the line "Bosch" platinum whatever's and when he was all done, the car ran like a pos.

After much aggravation he had it towed to the dealer. They ran a diagnostic on it and discovered that the new Bosch plugs were defective, shorting and not firing consistently.

Makes you wonder huh?
:mad

 

I bet heads will roll in QA for that SNAFU. :cuss

 

I wouldn't buy platinum plugs. From what I hear they are pretty bad.
Had them in my old vette, and my mechanic shat a brick when he saw them, and said they weren't supposed to be in vettes. So I don't know.

 

?

:crazy: :crazy: :crazy:

It'd be nice to get some technical input on this one huh?

 

AC Delco platinum plugs have been the factory installed plug since 1993. I don't know what your mechanic is smokin, but I have never seen any problems with the factory recommend plugs. If you stick to what is known (and tested by GM) to work, you will have less problems. :cheers:

 

Also, the way the spark plug hole is angled in the L98/LT1/LT4 heads, a spark plug using the conventional L-shaped ground strap does a good job of exposing the spark kernel to the air/fuel charge. The open electrode types like the +4's and Bosch plat2's are not the optimum design for our cars' heads.

 

Thanks for the info

 

Lani did you ever find a source to buy the black high temp plastic spiral cut spark plug wire guards from?

I'd like to know if you did, in case I need to source some sometime...:D

 

Bosch plugs suck. I've heard it before, and this just further builds my opinion against them. My 'vette mechanic swears that they're nothing but poopie. I would tend to believe him, he sees 'vettes day in and day out... that's his profession.


[Modified by GDP, 11:24 PM 5/19/2003]

 

Did anyone think that the box of plugs had been dropped before you got them? maybe even the whole case? Its the real world people this crap happens. One of my techs wont use Bosch in anything he claims they are junk swears by AC/Delco, so the other day when I did a tune up on a car and it had a misfire he says something about I must have used Bosch , I just told him to scope it for me and find out what cylinder was missing and I would get another plug ordered. Actually found 2 bad plugs and they were Delco not Bosch like he thought I had used It happens to every brand. As far as platinums in a Vet or not, its not about the car its about the ignition design some cars will act adversly to the lower resistance of a platinum plug verses a copper core that it was originally designed for, and vice versa.

 

Bada Bing. Same thing a GM master tech told me: stock LT1 ignition system designed for platinum plugs, said use only platinum or can substitute the new iridium designs since iridium plugs have lower resistance not higher. Said that although copper is better conductor, its the diameter of the electrode *end* that establishes resistance-- smaller diameter at end of electrode means easier to push spark through i.e. lower resistance.

I've tried new sets of the stock AC 41-906, NGK TR-55 (copper), and NGK TR-55ix (iridium). The TR-55ix's feel better than the AC 41-906's which felt better than the NGK TR55's. But what do I know?... :D




[Modified by Lone Ranger, 8:05 AM 5/20/2003]

 

I use Auotlite plugs only.
Carbon plug wires are crap. Why carbon plug wires? Radio.
Bosch plugs, NGK plugs, not in an American car. AC plugs are "cold" plugs and tend to wear out quicker than Autolites. Autolites are a "hot" plug and burn better and longer than a "cold" plug. Hot plug, cold plug, anyone know the difference?
Platnium plugs, iridium, sodium plugs??????????BS.
Plug life can run to 100,000 miles. What killed the plugs in early cars was the lead in gasoline. Once the lead was gone the plugs last a lot longer. No more burn out. But what does happen is the the gap increases with mileage.
The longer you run a plug the wider the gap becomes. Eventually the spark shorts to the head. Thus creating a high speed miss.
American engines need American plugs. They're engnieered for American cars. I hate changing plugs thats why I use Autolite plugs.
Bosch, NGK, good in Nipper cars only.
YMMV. Of course I could be wrong. It wouldn't be the first time.
Buy American. :flag

 

So which AC Delco part no. 41-913 or 41-904 ? ? ?

 

Thanks

:thumbs:

 

Better throttle response, better low-end pull.

You apparently drew a tech that was less than competent or at least was not concerned with doing a good job. That does not mean they are all that way. There is no doubt in my mind that someone who has earned official recognition/documentation of their auto mechanic skills probably knows more about automotive mechanical issues than I do, so I have a tendency to at least listen to their advice and thoughtfully consider it.

Unit for unit Iridium has a lower resistance than platinum but slightly higher than copper, but due to its hardness it can be made to a much thinner diameter than a copper electrode and as such can render a fringe benefit of equal or lower resistance than a larger diameter copper electrode. This is how I understand it.

No.

Yes.

'cause opinions are like... well you know... every body has one.

Agreed, mostly. The hazards of AC platinum seem to be the possibility of the platinum pucks departing the spark plug and going hither to parts unknown within the motor. Maybe they will, maybe they won't but once I heard the stories it bothered me until I removed them and verified they all still had their pucks. I then put in the iridium spark plugs.

Agreed.

Too many subjective opinions out there with no hard data to back up the claims (from guys like me ;) ) it'll never happen...

Yep.

Time to find another service shop and/or mechanic, preferably a Corvette intensive shop.

I call it adding my $0.02 worth :D

:cheers:

 

Wow, how 'bout those Mets?

:lol: :lol:
:thumbs:

 

I like the TR55ix's best so far. For a more reliable version (no magic flying pucks) of the stock plugs I have heard the Autolite double platinums are good.

Finders keepers! 'Specially if they gave me my car back all smudged up and funky.
That's why I like it here. While it may be time consuming, you can glean quite a bit of knowledge from lurking and participating here :yesnod:

 

For the AC Delco plugs:

'92 Lt-1- (41-904)
'93-95 Lt-1 (41-906)
'92-'95 ZR-1 - (41-913)Lt-5

 

I installed AC-Delco Rapid Fire spark plugs in the spring. Car is running good and I've had no problems with them.

 

Let me throw this into the mix for you Bosch haters and Delco only people. Take a look at your delco plugs if the print and stripe are blue they are made by a/c delco probably in Brazil ( in the American part I am sure:lol: ) if the print and stripe are green they are made by Champion (AKA the chrysler plug people)