Spark plug replacement time....

[Steve Tinker]

My Porsche handbook recommends the spark plugs in my 2001 3.2l engine to be replaced every 80,000 km (48,000 miles) or every 4 years.

I've driven only 30,000 km (19,000 miles) since I replaced the existing plugs, but now the magic 4 years is up.....

What's the consensus about changing the plugs every 4 years - valid or not ???

[BTfd2e93]

i personally just inspect mine .... if it looks ok, (not much corrosion ... not covered in soot etc ... gas leakage (the white part near the coil side of the plug hasnt turned brown/yellow)) .. i just let it be

[trimer]

Originally Posted by Steve Tinker

My Porsche handbook recommends the spark plugs in my 2001 3.2l engine to be replaced every 80,000 km (48,000 miles) or every 4 years.

I've driven only 30,000 km (19,000 miles) since I replaced the existing plugs, but now the magic 4 years is up.....

What's the consensus about changing the plugs every 4 years - valid or not ???

Although only 19000 miles...mine were 10 years old and looked great. More concern around the coil packs than plugs on my end...

[BYprodriver]

I think it's optional at this point, definetly no hurry. I do mine when I'm in the area. Always notice the improvement with new plugs though.

[san rensho]

I read that as plugs age, the gap gets bigger and the coils have to work harder to generate the necessary voltage leading to premature coil failure. Plugs is cheap, coils, not so much.

[Mark_T]

Have you tested that theory (by gapping your plugs, and then re-checking the gap 1,2, or 3 years later)? I think you'd be surprised by how little, if any, they changed.

I can't speak for the Boxster because I haven't checked, but I pull the plugs from my lawn mower and snowblower every year and the gap is always still bang-on .030"

[mnc-i]

Reference spark plugs.

I have a 1999 Boxster, so my interval between spark plug changes is 30,000 miles.

I personally enjoy changing mine, but I wonder if I can go up to 48,000 miles between changes as recommended for a 2001 3.2L.

Plugs are cheap and each time I replace mine, I see very little wear/degradation.

Just my thoughts

MNC-I

[trimer]

I am still seeing a chiropractor and massage therapist 4 months after changing mine...tight squeeze and a lot of pulled muscle on a couple of those...lol.

[Steve Tinker]

I can understand mileage affecting plug degredation, but the time limit is not at all clear to me.

What affects the efficiency of a plug made up of metal alloys and ceramics over a 4 year period screwed into an alloy cylinder head, unless electrolytic action between the threads of the plug and cylinder head is a potential probem.

[jsceash]

Six plug is less than $50. 1 coil pack $60. No brainer change the plugs.

[BYprodriver]

Originally Posted by Steve Tinker

I can understand mileage affecting plug degredation, but the time limit is not at all clear to me.

What affects the efficiency of a plug made up of metal alloys and ceramics over a 4 year period screwed into an alloy cylinder head, unless electrolytic action between the threads of the plug and cylinder head is a potential probem.

New electrode has a sharp edge that makes it easier for the spark to jump to ground.
Worn electrode rounds & smooths that edge making a less concentrated arc.

I did read somewhere the time limit was to minimize danger of stripping head threads while removing sparkplugs.

[Steve Tinker]

Ahhh - back to that thorny question of using / not using anti-seize on the plug threads.
I do, but Porsche says not to.......

[Trey T]

^I use a small dab of anti-seize on all aluminum head I work on

[JFP in PA]

Originally Posted by Steve Tinker

Ahhh - back to that thorny question of using / not using anti-seize on the plug threads.
I do, but Porsche says not to.......

Porsche's rational for that has to do with the type of anti-seize compounds that used to exist vs. what you can get now. Old types were not particularly electrically conductive, which could lead to misfires because the plugs were not properly grounded; new types are metallic (usually copper or aluminum based), which are conductive. Use a small amount of anti-seize and your cylinder heads will thank you. We have been doing it for decades and have never had a misfire, a plug come loose, or one pull the threads out of an expensive cylinder head..........

[lkchris]

More to the antiseize story ...

Published tightening torque figure assumes dry threads.

Antiseize is a lubricant and you'll have no idea how tight you get them but it will be over tight and risky unless you adopt a lower spec.

[JFP in PA]

Originally Posted by lkchris

More to the antiseize story ...

Published tightening torque figure assumes dry threads.

Antiseize is a lubricant and you'll have no idea how tight you get them but it will be over tight and risky unless you adopt a lower spec.

Not really; fastener manufacturer's like ARP have published several white papers on the subject of dry torque inaccuracies when compared to using different lubricants; in every case, a lubricated fastener was correctly torqued while the dry fasteners were not. Lubrication aids in obtaining consistent torque values, not detracts from it.

[Trey T]

first of all, antiseize is safe on aluminum. you don't use a lot, just a dab of ~3/8" dia and spread a bit.

dry thread but is free of carbon? In my early years of car experience, I avoided the antiseize compound on sparkplugs and getting in and out is very sticky and draggy (lots of friction). Aluminum is rather soft material, so soft that you don't typically use cutting oil/lube to cut drill aluminum. Sparkplug threads are steel and much harder (relatively speaking for you material engineers out there) and can damage the aluminum if seized.

I mean you can thread chase the hole but that's only if the car is running really bad w/ carbon soots everywhere.

Originally Posted by lkchris

More to the antiseize story ...

Published tightening torque figure assumes dry threads.

Antiseize is a lubricant and you'll have no idea how tight you get them but it will be over tight and risky unless you adopt a lower spec.

[eicheldp]

Any recommendations for an anti-sieze compound to use. I plan on changing my plugs right after I flush the brake system.

[Steve Tinker]

I've been using Loctite Nickel Anti-seize for years, but there's Coppercoat and aluminiun based compounds too.
I tend to use the high temperature anti-seize stuff, then I can use it on exhaust clamps and brake parts - makes removal very easy even after several years of high temps.

[jb92563]

Porsche issued a bulletin advising NOT to use antiseize on plugs because it could insulate the ground of the plug and reduce performance or cause in the worst case cause misfires.

I don't have the details but saw it in a Pelican DIY for replacing plugs.