AndyK

I've been wanting to tackle changing my 10-year old plugs and now that it's getting nice and cool out, I figure I'll be able to get it done. After searching, I haven't found an answer to my question:

The manual recommends single electrode plugs. But it's old. Renntech says the new Porsche recommended plugs are 4 electrode. Do I need the 4 electrode Beru copper, or will the Bosch Super single-electrode plugs work just as well? I just want to get the right plugs, because I NEVER want to change them again!

savannah996

yeah im in the same boat. 45k miles. and probably on the original plugs, i need to get them out and look at them at least

1999Porsche911

The number of ground electrodes means nothing as far as the performance of the spark plug. Go with what is available and cheapest, correct heat range and gap. Platinum plugs provide no additional performance either but will last longer than standard copper plugs. You have to decide whether the premium price of platinum plugs is worth it.

NGK BRK6EK plugs are a good choice and have a copper core for best heat removal.

savannah996

well i wouldnt put in the cheapest plug as he said ↑. lol
use only high end (read expensive) bosch, or NGK racing platinum or iridium.

Macster

If you are going to the trouble to remove the plugs I'd just budget to replace them with new ones.


Since th engine has possibly 10 years and 45K miles of what I gather has been otherwise trouble free service from the plugs I'd just replace the old plugs with the same plugs, new of course. Why fix it if it ain't broke?

Be sure the old plugs are correct though. If not then I'd breathe a sigh of relief nothing bad happened and replace the wrong plugs with the correct ones.

Sincerely,

Macster.

soverystout

I changed mine out about 1 month ago. It was "fun". As fun as 6 hours can be.

I used plugs from Porsche (sunset porsche). THe outside of the box says Porsche but of course the plugs say bosch super on them. I used the 4 electrode as they are what the dealer uses for my year car.

One of the most useful tools I had was long (8 inch long) needle nose pliers with about a 20 degree bend to the end of them. They were awesome for gently pulling the rubber boots off of the wires that connect to the coils. I then used them to disengage the coil wires from the coils. It made the job much easier.

Things you need to have.

Lots of 1/4 inch and 3/8 inch extensions and swivels to get into that tight area.

savannah996

you forgot something on your list ↑ "patience" lol
6 hours, good GOD yall

Tippy

I believe the 4 ground strap plugs allow for the 100k mile interval. When I changed mine, all 4 sides of the electrode were worn from where the ground straps "point" to - the sparked jumped. I guess if you look at it from the 30k "normal" plug interval, with 4 ground straps, you can make 100k. Once one side is worn excessively on the electrode, another ground strap will be the shortest path, least resistance for the spark. All the plugs I've seen in aviation use 4 grounding straps.

Tippy

Oh, btw, I would drop the exhaust cans to gain easy access.

savannah996

oh yeah? thats cool info. didnt know that. are you a mechanic? if so what kind of engines did/do you work on?

Tippy

Built 100's of F-15/F-16 engines (brand witheld). Build occasionally on the weekends still.

Went to school and built a couple of flat-6's, none that were airworthy. These had the plugs. I remember the instructor saying there was a reason aviation plugs have 4 ground straps but I don't remember. I believe it was simply if you lost the gap or the strap itself, you have 3 others to depend on.

savannah996

cool. ill check into the 4 electrodes when its time for replacement. even though my plugs are from 2001, i only have 45k on them. as long as the factory plugs were platinums.?? (thats why i want to pull one) ill leave em alone.
i really doubt factory platinums with 45k would be wore out, the car isnt driven very hard.

RF5BPilot

The plugs on my airplane (and most of the ones I've seen) have two grounds that need to be gapped. But also note that, typically, Lycoming & Continental engines are amazingly crude -- essentially aircooled industrial engines from the 1940's. They're designed to run at slow rpm, under load for the equivalent of 200-250,000 miles. Having no advance to the ignition & manual leaning of the carburetors, they are prone to plug fouling.

I don't think there's much similarlity between their technology & a recent car engine. I'd just see what the factory recommends & just use it.

Lame opinion: as long as your plugs aren't fouling & you're not burning a hole in the top of the piston -- use what the factory recommends. There's not a lot of horsepower to be gained from screwing around with heat ranges or gimmicks on a well designed engine. The recommended plugs will burn the fuel. Claims that fancy designs will do a lot better is mostly marketing. If a simple plug change would get a lot more hp or efficiency, the auto manufacturers would be all over it.

But...it's your engine.

Torontoworker

The best product I've seen for changing plugs for a 996 is the magnetic socket you can buy from Pelican - I used one two weeks ago (borrowed) and it works great - better then the old type with the rubber inside them.

peavynation

Regarding multi-electrode plugs, yes, service life is increased a bit, but don't forget that there is still a single center electrode that will wear; longer life, yes, but I don't think 4 electrodes equates to 4 times longer lasting than a single.

I read some interesting things on multi-electrode plugs that bares mentioning here too:

1) Depending on the head design and sparkplug location, multielectrode plugs can actually disturb the combustion gas flow adversely degrading performance. Not sure if this would apply to the P-head design.

2) The extra metal of three more electrode can absorb and retain more heat, thus increasing chance of detonation.

Food for thought. I say use what P recommends.