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MG MGF Technical - Spark plug life expectancy?
|As I don't want to be off-topic on another thread relating to HGF here's my question|
I'd like to know what the life expectancy is for the standard spark plugs.
I know they are made of ... er ... is that titanium (?) and last at least 100 000 km.
My 1997 1.8mpi still has the standard ones fitted (as far as I know) and did 75 000 km.
What's your opinion?
|I posted this in the HGF thread ... change em now. Don't bother with the platinum ones. Use the standard double copper and renew every year subsequently.|
|I agree with Gaz - the platinum ones seem to struggle beyond about 30-35K from what's been posted on this BBS before. Not worth 11GBP EACH.|
|Thanks guys !|
In that case which model do you use (marque, ref ...)?
Is it a easy DIY job? (I'm about fitting a K&N in the coming weeks and the engine bay will be accessible)
|I use Champion or NGK (Rog Parker favours NGK). Personally I can't tell any difference between both.|
Changing them is relatively straight forward - just a little time consuming. Took me an hour to do them last weekend. If you happen to have the boot open as well remember to flick the boot lock catch to swicth off the light. I forgot and had a flat battery the next morning.
For my VVC I have Champion Double Copper RC9YCC.
I agree with everyone here that it would be a good idea to change the plugs. I did mine at 18k miles (24k klms?). Since you are going to uncover the engine to add the new filter and now also add new plugs, why not go the whole distance and change the HT leads at the same time. B&G do an excellent mail order service for silicone high performance HT leads.
I changed plugs and leads at the same time and thought the car was transformed with very much smoother running. Even lady wife notices from the passenger seat! Not sure how much the plugs added and how much was due to the leads but the total effect was great. If you are adding a K&N at the same time, I think you will feel like you have a new car!
Cheers and good luck
The high performance leads will only produce significant improvement if the ones you are replacing are old or have suffered reasonable degradation. Having said that I am about to replace the leads with the magnecor ones from B+G (but only cos I snapped the top off the orignal Lucas ones).
For your 97 car I'd probably change the leads as well (money permitting of course).
|For what it's worth:|
I've just changed spark plugs on my '97 Mpi during 40k Km service and feel a considerable improvement in engine response.
Don't know what spark plugs they have fit, but have been quite expensive (160.000 Italian Lire).
|Gian Marco Mazzocchi|
|Gian, if you didn't specify and they didn't ask, I guess the recommended Platinum things will have been fitted (especially at that price)|
Jerome - if you change the leads, you'll notice that they lie alongside a couple fo screws that go into the head: you'll get much longer life out of the leads if you cover those screw-heads with something - a little piece of rubber hose seems to be the usual trick. Keeps the heat transmitted up that screw from roasting the leads.
|OK OK, you convinced me!|
I'll check whether I can get Champion Double Copper RC9YCC
What tools do I need to change the spark plugs?
I'm not really a mechanic and don't really know how to gain access to them?
I feel confident with fitting the K&N but am quite afraid regarding the saprk plugs (is there any adjustement to be done at the electrode and other things like that I should know?)
Any advice are welcome
|You'll need a torque wrench with a 10mm socket (a proper spark plug socket has a rubber gland that grips the head of the plug so they're easy to remove once the thread is undone), with an extension bar: the plugs are very deep set. I forget the torque setting (though a vague memory says 23NM. A normal socket set is probably OK but make sure they're done up good and tight!|
Check the FAQ (either the link above, or Paul's new one if he's got that far!) for getting at the engine: it's pretty easy but time consuming. Then there's a black plastic panel across the top of the block, held by two screws, underneath which is the channel the leads run through.
Changing the HT leads is tickier - you have to get under the car to get at where they plug into the coils. Fiddly, but possible!.
|The platinum tipped standard plug introduced with the 1.8 engines has been extended to be the standard plug for all the K series now, at least all 4 cyl K.|
The standard plug does last for the specified period, BUT I have clear evidence that by the time you crack 20k miles there is a measurable drop in pluig perfromance that does take the edge of power, response and fuel efficiency.
Another aspect is that the when the plugs are past this point they create a greater resistance to the HT current jumping the gap, which does remain reasonable stable, and so if there is any other weakness in the HT system it now presents an easier p[ath to earth for the HT current.
The HT leads, especially VVC engines together with the rotor arm for MPi engines are areas where weakness occurs and often the problem manifests itself on cold wet moringins when the car will turn over but not start. Or when it does start it is rough as a dog until the engine is fully warm.
If replacing the platinum tipped plugs with copper core typres then whilst the 12 month change point for these is fine, note that if the miles go much above 9k in that period then you will be entering the same plug problems with these as you find with the platinum at over double that.
Spark plugs are the achilles heel of the engine and on the good performance of these depends the good results from the engine.
I favour NGK from a historical aspect when Champion lost their way and I could get 15 bhp more out of some engines on NGK than I could on Champions. This test could be repeated and the same results seen so since then I have preferred them. I have since seen Champion drag thenselves back up into contention and in all recent tests I see no power difference between like new NGK or Champion plugs
Incidentally for those looking to go NGK then the standard K series spec copper core plugs are coded BKR6E and the standard platinum NGK is PFR6N11
|I have big problems on cold wet mornings starting my N-reg VVC (38K), and fully intend to replace the plugs this weekend when the service is done. I am grateful to hear that people who are exchanging the platimun plugs for copper core are happy with the result, as I was uncertain about the change. I would recommend changing the HT leads as there is inevitably some damage over time, especially with the coating cracking or splitting. I usually find that they don't come off very well after a year or two on, and you usually end up splitting them anyway. With the K&N induction kit I'm having fitted at the same time as the plugs, leads and new fuel filter (fuel filter is another one of those things that can drastically reduce performance if not changed), I am gonna have to consider an LSD just to keep the horses on the leads!|
I recently changed my plugs, but stuck with the platinum ones when I found that B&G are selling them for only £4 each!
This thread was discussed between 01/02/2001 and 03/02/2001
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