Platinum Plugs ??

Amark · 03-26-2003, 11:04 AM

So what is the consensus of opinion on platinum plugs?

I was having problems w/ cold starts. The car was hard starting & when started it would stall 2 or 3 times before it would hold an idle.

I switched from Bosch copper core to Bosch platinum & bumped the gap to .040. I am running a Blaster coil, 050 dizzy w/ Pertronix ignition & Dell 40 carbs.

Now that I have changed the plugs and the coil the car starts with hardly any cranking and holds a cold idle without stalling.

I have seen some threads that recommend not using platinum plugs because of the small size of the electrode. Is that recommendation based on the use w/ the weak factory point type ignition? Seems like all modern cars run platinum plugs and a high-energy ignition system. My daily driver 98 Suburban has over 80,000 miles on a set of platinum plugs and they still look and run like new.

Jake Raby · 03-26-2003, 11:08 AM

They are JUNK.......I run regular old, copper cored Bosch Supers in all the engines I build.......

The damn platinums foul in a heartbeat!

Amark · 03-26-2003, 11:22 AM

They would not work w/ the factory Bosch coil. I changed to a Blaster coil and am not experiencing any fouling problems. They have been on the car for 6 months.

Why would they foul? Doesn't platinum conduct way better than copper?

Jake Raby · 03-26-2003, 11:27 AM

No matter what it is supposed to do.....it just don't....

You should not have to make a coil change to make a set of spark plugs work....

Just something else to be sold for a profit......

I have ran a set of copper cored plugs for 12 years before, and never fouled one....that engine was built in 1988 and saw over 100K on the old Bosch plugs. After they were in for 7 years I was afraid to remove them, afraid of stripping the plug holes....I finally got the guts to do it, and did strip one hole.....still runs great, 2nd set of plugs......The engine was a TIV in a bus....

douglas robbins · 03-26-2003, 11:38 AM

Copper is a better conductor than platinum. Platinum is preferred because of its longevity. But in terms of performance copper is a better conductor. If you absolutely hate changing your plugs then go with platinum. If you need 100% performance go with copper.

Douglas

jkeyzer · jkeyzer's Garage

Does the conductivity really matter?

When people are using 1-2k ohm resistance spark plug wires, resistive plugs, resistive rotors, etc. for electrical noise reduction, does a few ohms difference between copper and platinum actually make a difference?

I can see how the Bosch platinum plugs would foul easily since they only have a tiny speck of metal showing on the end, but what about NGK platinum plugs which still have big electrodes?

Jake Raby · 03-26-2003, 11:48 AM

I just stick with the Bosch Coppers, no matter what.....They have proven them selves to me in everything from stock engines, to 350BHP Turbos......

Jared at Pelican Parts · 03-26-2003, 01:07 PM

In my 325is, I switched to Bosch Coppers, and instantly my idle improved over the previously installed Platinums.

Scott S · Scott S's Garage

Jake -
I am getting ready to do a spring tune up. What part number copper plugs do you use? My car is a 2.0 with a webcam, MSD, compufire and dual 44's choked down to 40's. It also uses the slightly higher compression "euro" pistons.

Thanks!

chibone_914 · 03-26-2003, 02:09 PM

I agree with Jake and Jared. BOSCH Supers are the way to go. The platinums just don't hold up very well in air-cooled motors. The copper tipped supers are far more forgiving and are much less likely to foul out vs the platinums.

Dave at Pelican Parts · Dave at Pelican Parts's Garage

Throw the cheapie Bosch platinum plugs into the lake for the old "float test". If any of them float, retrieve them for further study. (Same procedure I recommend for single-carb setups and 009 distributors!

)

They tend to foul easily, particularly on older cars with open-loop fuel systems like ours that like to run a little rich. And the quality is very very questionable. They like to fall apart inside the engine--not exactly where you want extra bits of metal or ceramic, is it? I know several people who have had the platinum speck come un-bonded from the center electrode and get lost inside the engine.

One 944 owner believes that a Bosch Platinum coming apart is the cause of his losing an engine. Completely--it's not saveable when one of the cylinder bores gets a chunk knocked out of it...

The +4s and -2s (or whatever they're called) are the same junk plugs with extra electrodes. Junk + 4 still == junk...

W7CC is, I think, the plug called for in stock 914 motors.

--DD

Amark · 03-26-2003, 02:34 PM

Quote:

Throw the cheapie Bosch platinum plugs into the lake for the old "float test". If any of them float, retrieve them for further study.

Dave, I guess that sums it up!

Mike D. · Mike D.'s Garage

What about NGK plugs? I've been using BP5ES, NGK plugs for years. I thought this was pretty standard in air cooled community.
-Mike D.

Jake Raby · 03-26-2003, 05:01 PM

NGK is okay, but "Nippon" parts in a "Kraut" engine is kind of scary.

When we dop the 12mm plug conversions on our 2.0 heads, we have to use NGK plugs, since no one else makes them....They are motorcycle heat range plugs, and work great..

Dave at Pelican Parts · Dave at Pelican Parts's Garage

NGK is a reputable maker of spark plugs.

In general, so is Bosch. They took a really bad turn when they came up with those cheap platinum plugs. But their copper plugs are fine--their silver plugs are $$ but are really good. And I hear that their old platinum plugs, which are hard to find and $$$$$$, are really very good indeed! They do have more than that one tiny speck of platinum, though.

Thankfully, the Japanese and Germans use the same thread sizes and specifications. Otherwise, it would be really scary to put Jap plugs in a Kraut car. Note that they use different bolt-head sizes for bolts (and nuts) larger than M6. The Japanese-spec M8 bolts use a 12mm wrench, while the ones in our cars use a 13mm one. (Which makes me keep both evens and odds in my toolbox... Rats.)

--DD

exc911ence · exc911ence's Garage

Quote:

Originally posted by Mike D.
What about NGK plugs? I've been using BP5ES, NGK plugs for years. I thought this was pretty standard in air cooled community.
-Mike D.

I just put a set of NGK BR6ES in my 2.0L... what's the difference between them and the BP5ES plugs? Heat range?

Plays with cars · Plays with cars's Garage

I've been running Bosch W7DTC plugs in my 2.0L for about 5 years and have been very happy with them. They have a classic copper center electrode, but have 3 side gapped ground electrodes. Without any other ignition modifications there was a definite improvement in idle quality with these plugs.

Dave at Pelican Parts · Dave at Pelican Parts's Garage

Quote:

Originally posted by exc911ence
I just put a set of NGK BR6ES in my 2.0L... what's the difference between them and the BP5ES plugs? Heat range?

Yes. I don't remember which are colder and which are hotter. I've seen a web page with that info on it, but I don't remember where. You might try a search on "NGK information" or similar terms to locate it...

--DD

DuckRyder · 03-31-2003, 05:51 AM

I agree with Jake and Dave. Old german ignition systems do not seem to like Bosch DP plugs.

Every BMW I have ever owned ran best with Copper or Silver.

Question, I got both BERU and Bosch for the 914 from PP, Is one better than the other?

Amark · 04-03-2003, 04:22 PM

So I pulled the platinum’s & put in a set of W7CC Bosch Supers.

Took the car through emissions station today and it failed. No problem w/ CO, the HC failed. Allowed 400 ppm and put out 415 ppm. CO was 2.65% w/ 3.25% allowed.

I wonder if the new plugs are making the car run dirty. The platinum plugs looked way hotter than the W7CC's. I was running the platinum plugs w/ a .035 gap, the copper plugs came gapped at .028 and I left them that way.