Spark plug service interval for blobeye STI.
 

Hey Guys,

Just wanted to share a thought with you, now I know a lot of people will most likely respond with "may as well change them anyway" and I totally get how nice it feels to take out your dirty old spark plugs and put some shiny new clean ones in.

With that said the plugs recommended for our blobeye STI's are NGK 3500 PFR6-B, now the service interval is every 5k miles and I plan to do it every 4k miles

These plugs are fitted to many cars that have a very long interval inbetween services so it got me thinking about the lifespan of these plugs.

At first I was thinking well they are obviously good for at least 12k miles, so I was planning to change my plugs every other service and perhaps clean them inbetween.

Now the company I work for sell millions of NGK plugs so I decided to have a word with NGK technical buffs, the guy I spoke to seemed very clued up and he said that these plugs inparticular have an approximate lifespan of 50-60k miles.

The primary reason for a plug to fail is when the gap increases through the wear and tear of the core, the 3500 plugs are platinum which is a very dense/hard wearing metal which I believe was intended to increase the service intervals over the standard plugs.

He also said that there should be no need to clean carbon deposit from the plugs but he would recommend checking the gap. (0.8 I think is the spacing)

So theoretically you could change your plugs every 3rd service and still be no where near the maximum lifespan of the plug.

I will most likely change mine every other service, but with the money saved perhaps I will buy a new air filter inbetween services, lets face it its more important to the health of the engine.

It's your car and your money so ultimately your decision, but it is my belief that we should think twice before throwing away this precious metal every 4-5k miles.

MY PRECIOUS!

David.

Where did you get that information from?:wonder:
The service recommendation for plugs is 30,000miles or 3 years.
Most people change the plugs at a lower mileage.
If the car is modified the nominal upgrade is NGK PFR7B with the gap at 0.65-0.7mm

(Incidently, the original fit is NGK PFR6G and not B)

JohnD

Its bad practice to clean modern spark plugs as you can damage them. If you have the correct heat range they are self cleaning providing your engine is healthy.
My mapper (Bob Rawle) suggests spark plus are replaced every 10k as they go stale and you lose performance.

John D, we have many catalogues for NGK and those are the correct listing, they are also the plugs that Subaru in hastlemere fitted to my STI so I am pretty sure 3500 is correct.

5k is whats generally agreed to be the service interval for the car not spark plugs specifically but most people seem to do the plugs at the same time as the oil.

The car is not modified, and the PFR7 is a different temperature range which does not effect any of the above.

You can clean plugs with brake cleaner if you have to and you will do no harm whatsoever, but I don't want to get off topic as I said before there is no need for cleaning.

0.8 was off the top of my head hence "I think" =)

D

10k or 1 year what ever is first

1 year? where did you pluck that one from?

Service not spark plugs, there 20k/30k

Yes but most people seem to change the plugs at every service, I was only trying to point out that the lifespan of the plugs is no where near exceeded.

I'm not sure about the "1 year" thing they should be good until they are worn out.

Most garages will order a "service kit" which consists of plugs/oilfilter/airfilter/cabinfilter (fuel if it isn't a "lifetime" filter), unless they are aware of the cars history it's just simpler for them to do the full service.

The only time a garage will not have the plugs included in a "standard service kit" is for diesels as glowplugs last so much longer.

I think plugs are scheduled for every 3rd or 4th year in the service book on newages?

Very rare for any of the "Service kits" supplied to us to inlcude plugs on any car.

Seeing the majority of cars have iridium or platinum tipped plugs, they are no longer a regular/standard service item. But are either a additional service item or in the case of scoobs, done on every other major service (i.e: oil service-->standard service-->major service).

Ain't broke don't fix (especially notable that everytime you disturb a "coil-on-plug" type coilpack you can inadvertantly damage it), unless your car is running mega rich or guzzling oil and they've fouled up with crap. ;)

Aren't plugs like £30? Unless new plugs can harm performance/reliability I don't really see the issue in doing them every service just... well, just because.

^^ well I've been in sales for some 6 years now and most of the garages take the full shibang with plugs included.

Doesn't matter just for anyone who is changing the plugs with every service you may want to consider leaving them alone =)

Fonzey's the type of person this was aimed at hence the opening statement "may as well change them anyway" .

JohnD

Yes John it is a waste of money that's why I posted this as I'm sure fonzey is one of many that throw away perfectly good plugs.

Nice info about that gap I didn't know about that, my car is just a standard prodrive at the moment.

I'm thinking about a sports cat and a remap, don't want to mess with her too much. D

cheap *******s..... just whip them out once a year.

You'll already have a sports cat on your car as part of the ppp bud.

Nice one jack, is there anything worth doing before I fork out for a remap?

How deep are your pockets? :D

It all depends on how much you want from it?

Basic things would be a decent panel filter, colder plugs (7b's), non resonated centre section. That should see you upto around 340 - 350bhp.

Did you get my pm?

330 sounds reasonable I think that's only an extra 30 more but I like the idea of the power being spread out a bit more across the band.

If I had the money I'd get a faster spooling turbo but I can't justify it.

Non resonated center pipe, does that sound good? :)

Exactly what he said. No need to change every couple of k's

yeah and doesnt it piss you off when they send everything back bar the oil filter