Platinum spark plugs, Yea or nay?

[Rickf1985]

I am wondering what the general opinion is on platinum plugs. I am getting down to the engine in my nightmare and I have a recurring miss that is going to cost me at the emissions inspection. The carb is non-adjustable so it is a possibility but I want to rule out everything else while I am at it. The cap and rotor are new and the wires appear to be pretty recent. I have not ohmed the wires yet either. I pulled a plug and it is a Bosch Platinum. I have not had a lot of good luck with these in either my 454 in my boat or the replacement 502 in the boat. Substantial loss of power over the Autolites I usually use. What are your thoughts/ experiences?

Rick

P.S. I will be checking the wires and carb but I wanted to get this out there so I would know whether it is worth buying a new set of Autolites.
And don't even mention Champions! I wouldn't use them in my worst enemies lawn mower.

[ClydesdaleKevin]

Nay.  454s, and 350s for that matter, LIKE the El Cheapo standard AC Delco type plugs.  Waste of money to buy anything else for 454s and 350s.

AC Delco plugs last longer in 454s and 350s.  They don't foul as easily, and are WAY cheaper, so go with those or the equivalent.

Just make sure you gap them right first, and they'll last you a LONG time.

Kev

[cncsparky]

I agree on the Champions, and always read about bosch and Chevy's not working well together.  I like NGK plugs, but like Kev hard to beat original AC plugs for our old 454's.  Platinum is up to you, advanage is they don't wear out as fast.

[TripleJ]

I wouldnt run a platinum plug in an engine that didnt call for them specifically.  The only advantage of platinum is that they can potentially last longer before wearing out, but Im pretty sure they are more sensitive to fouling and acting shady

[Rickf1985]

Although Autolites are my first choice I will go with the Delcos. It appears that the easiest way to get to the plugs is through the wheelwells.
Rick

[Oz]

Spent $64 on NGK Iridium IX.  Not a Chevy but it didn't matter, it was a waste of money.  Went back to the stock, cheap ones.  No difference in any way, shape or form.

[Stripe]

Hehe, I forgot to say I got the AC/DELCO plugs for mine.  The platinum ones went into the newer vehicle.
BTW, The link I provided is where I bought MY carb.  Plug AND Play!  No tweaking or adjusting...

[cncsparky]

I put in platinums or iridiums if they are original.  Here is what I will put in mine soon.

http://www.sparkplugs.com/product.aspx?zpid=10199

This is just a standard replacement plug.  Could be a AC-D, or Champion, or whatever.  I prefer NGK, they just seem like a quality plug to me.  Others must agree, most performance Chevy forums I've read over the years like them too.  Was a Champion plug guy, until I got a set with crooked center electrodes.  AC-D's would be a second choice for me, but I doubt they make plugs anymore, probably outsourced to who knows.

[Froggy1936]

Well I have the perfect test going then . Due to the extreme difficulty with installing plugg on my Chev 350 with headers (have to remove L/F tire Then 1 plug on ea side has to be loosened or tightened with a box wrentch in the end of a spark plug socket ) cannot use a universal type socket . But anyway due to this difficulty i have installed Bosch platinum plugs hopeing they will go 50000 mi without removeing . So far about 1000 mi with no problems . I will add report on plugs if any problems arise . Frank Picture is of original engine new 1995 350 seems worse

[Oz]

The driver's side of a 440 ain't no picnic for changing either.  The longer you can go, the less hassling with that. 

[tiinytina]

I've had Bosch platinums in my toyota Taco 2.7cyl... and I'm still on my first set after 250K...Numerous sets of wires (now finally racing silicone)  but I use AC Delco's on Gone. 
Tina

[Rickf1985]

WOW! I didn't mean to start a debate! I know that certain vehicles do not like platinum plugs, older Jeep Cherokee's being one of them. They would not idle worth a darn and would fail emissions every time. Not just one car but every one I had to inspect. Like I said in the beginning I tried them in my boat with the 454 and then the 502 later and I lost power both times. I do know that they run very well in the Japenese engines and I think this is due to the higher compression ratios and advanced timing.

[DonD]

Funny NGK story

Was doing some telephone eq. install in an NGK factory. Going to be there for a while, had my portable radio playing. I could barely hear it over the factory noises, the boss came to me and asked that I turn OFF the distraction! It was slowing the workers production. :-0

[cncsparky]

I think one of the big differences with later model vehicles and platinum/iridium plugs is EFI.  With more precise fuel control, the plugs are going to last longer, ie less fouling.  The smaller contact area on these plugs may get fouled easier on a carbed engine, negating any effect of a longer lasting plug and possibly foul out causing some problems.

[Froggy1936]

I looked up my receipt (mostly due to comments about cost) I bought my Premium Bosch Platninums @ Pep Boys 1/13 They were only $2.99 ea ? I dont think that is expensive ? This engine is TBI injection 1995 Chev . Idle speed is computor controlled along with timeing and advance !  All manufacturers went with fuel injection because carbuerators were way to hard to control at all temperature,s and speed ranges for emmissions to be where they wanted them . Frank

[cncsparky]

Just to throw a wrench into the discussion  .  Realized the stock plug that I linked earlier was not a projected tip plug.  Projected tips tend to work well in pump gas, lower compression engines.  As long as it clears the piston, valves, etc.  I run this same plug in my boat engine, a bored and stroked 454.  Advantages include running cleaner, lasting longer, doubt there is a noticeable performance difference but is supposed to make a few hp. 

http://www.sparkplugs.com/product.aspx?zpid=10180


"Projected plugs initiate the flame-front closer to the center of the combustion chamber, which has an effect similar to advancing the timing. This lets the total ignition advance be reduced, decreasing the chances of detonation while providing superior throttle response. A projected plugÂ's longer core nose provides a hotter plug at low speed to help prevent fouling. As engine speed increases, the incoming air/fuel mixture flows across the core nose tip, providing charge cooling that effectively reduces the heat range for increased top-end detonation resistance."

Read more: http://www.carcraft.com/techarticles/spark_plugs_tips/#ixzz2zfpzefcP

[TripleJ]

FWIW I was under the coach with the wheels off today, so I changed out the spark plugs while I was there.  Some time in the past someone had put autolite platinum tip plugs in there.  They actually checked out ok, no visible wear and good color.  It also ran just fine, this was only preventative maintenance.

I have no idea hope long they were there, but they looked pretty old. Very rusty, etc. 

[ttd512]

In the 454, the cheap AC delco is the way to go. BTW the miss is generally due to wires. even if they ohm ok, the insulator could be damaged due to heat usually close or touching engine. replace the wires. but replace them with a good quality set, I have been burned several times by cheap wires.

[Stripe]

And the cheap wires got burned by the hot engine, Lol..

[kenwautoone]

I agree on autolites on mopers, best thing I ever did was add an msd box and electronic ignition. Better burn plugs last longer , no fouling.starts instantly cold or hot