I pulled a plug today. 9000 miles since I owned the car. Looked toasty tan with a rusty orange tip. Running a tad lean? Car came with pertronix installed and beru rev limited rotor. Current plugs are WRC77 Bosch Supers. Any recommendations?

Ideally, the tips should be a tan brown.

Bosch WR7CC and WR7CC+ are the standard Bosch plug.

Many teeners prefer the NGK plug over the Bosch. Standard NGK for the 914 is the BP5 or the BP6 (which runs a bit cooler than the BP5).

Not "BP, and not "5" BPs are extended tip, which are not specified (WR7CCs aren't extended tip, either). B6ES is the correct plug.

The Cap'n

Have a look

http://www.ngk.de/nc/en/product-finder/pro...914/B6ES/17707/

The extended tip can create thread issues because the plug thread gets covered in carbon and then digs out the threads in the head on the way out...

Rich

Not to hijack, but on this topic I called my FLAPS and they only have the BR6ES. They said the R was for "radio" but that the plug is identical and would work. Is this true?

R is for resistor, but the resistor is for reducing EMI which can manifest in radio noise.

Okay, thanks, I'll find the ones without the resistor.

Okay, I'm not getting something, as all the major Porsche parts suppliers seem to recommend the BP5ES and the BP6ES for 914's. I've used both plugs with no problem. So they're all wrong?? Why would they recommend a plug that isn't right for the engine? Someone please clarify.

In addition to John's questions in the post above, I called four places and none have the B6ES. The local Porsche parts guy wrote:

"As from NGK. The B6ES (7410) are discontinued. They specify to use the 4922 Which is the BR6ES - "

Resistors aren't a bad thing. Usually they're left off on all out race cars (think big track, sponsors, high dollar motors) who use solid core wires and carbs (EFI doesn't like EMI).

My point is, don't seek out non-resistor plugs thinking it's an 'upgrade'.

Just like higher octane fuel, changing it up without a VERY specific reason is a waste of time/money.

I've been following this thread nervously thinking that I bought some wrong plugs last month
Click to view attachment

Timothy,
I wouldn't worry for one second. Unless you're going to race your 914, the 5's will work just fine. They run a bit hotter than the 6's, but many suppliers and mechanics use them as the regular plug for 914's, and recommend the 6's for racing or spirited driving only. I have 5's in my teener now.

Thinking about it, the 5s should be fine, especially with the gas we have today. For purposes of clarity, the tern "extended reach" or "extended tip" does NOT refer to the length of the threads, it refers to the tip configuration. The terms "hot" and "cold" refer to the heat transfer properties of the spark plug, NOT the temperature of the electrode. Beyond all that, the plugs should be changed around 6000 miles. The change in 1974 to a 10K mile interval was made to satisfy the US bureaucracy, and does NOT reflect any changes in the engines or the quality of the spark plugs. As far as the parts guy the "R" stands for "Radio", why am I not surprised? He works at a FLAPS, right? Probably couldn't get a job at McDonalds ..................................

The Cap'n