Spark plug theory...

[JDaniel]

Just a few spark plug questions I could not find the answers to in the archives.
I've been running Bosch WR7DC plugs in my '87 911, with a .7mm gap. The motor runs smooth, and the plugs look good whenever I check them, except 1 plug that gets slightly fouled (#6).
Is there any reason to try the platinum WR7DP plugs? Do they offer any increased fouling resistance, or is their only benefit increased durability?
What happens when you increase or decrease the gap?
Thanks...


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Dan Tolley
1987 911 Coupe
http://www.cheaterswayside.com/911/gallery.asp?sort=0&userid=294

[JDaniel]

anyone????

[island911]

"anyone????" ?. . .maybe what you should state is:

The Platinum plug are far superior to the old technology copper. Anyone still using copper should hang there head in shame, sell their 911, grow a mullet, and buy a Boniville.

if that doesn't get replies, what will.

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'81 Platinum Metalic SC COUPE

[BER]

Dan,

I use Bosch W7DC's in my '84 Carrera and like them a lot. They are cheap and I replace them frequently (usually every six months).

I have tried the WR7DP plug, but I personally did not notice any significant difference...so I stay with the cheaper non-resistor copper's.

Regards, Bruce

[Jens Wendorff]

I use the Bosch W7DC or WR7DC. The resistor makes no difference.

I don't think that you can improve an engine which is designed for copper plugs heavily by using other sorts. The fuel distribution and ignition are not that sophisticated.
The reason why modern cars use platinum multi-electrode plugs is simply that they allow a smoother burning process in combination with computerized high-pressure fuel injection and that they give the car manufacturere there chance to increase their service intervals.

jens
'76 2.7 CIS with '73 body conversion

[jlauver]

What about NGK BPR-6ES? This 1s what my mechanic is recomending for my 85. If not he said to stick with the coppers because the car is burning some oil and the said the platinums will foul much quicker.

[movin]

Can we use a non-resistor plug? will doing so cause any radio interference?

[Roland Kunz]

Hello

The main benefits from platinum is the wider temperature band witch his helpfull for rce and turbo engines.

A other there longer life.

They are more critical to weting.

Spark plug gap is something you can expermentate but it can cost the piston.

Before you try to trouble shoot by renewing the plugs check the wires and the valve lash.

I prefer NGK followed by Champion and Bosch. Beru has a mixed quality. If it is made in france it is low. Made in germany is good but mostly the 4 electrode X version.

Grüsse

[MMBRAZIL]

talking of plugs....my car has something curious.
Every time I was the car and let a good amount of water get in the engine, or when its parked and rains, when I start the car I get one piston missing. Check the distributor cap/rotor and nothing, what I have to do is find which cilinder is misfiring and then take the injector off, run the motor for some secs, put the injector back on, and there u go smooth again.
looks like I get a flooded cilinder, but its random...never the same cilinder.
Anyone experiment this same problem? Any clues to where is the water interfering here?

[scottewid]

What is the resistor plug for anyway? Is it just to suppress radio interference? I've also heard that electronic fuel injection and sensors can be messed up by non-resistor plug interference. Not quite sure what to believe. Anybody have any insight?