The time has come to change my spark plugs as per Manufacturers schedule. It really applies to any modern vehicle, but in my case an Alfa 147 1.6 TS has 8 plugs costing about £60 in total.
If the engine sounds good and revs just fine, the emission figures are okay, the cars performance appears acceptable and not noticeably deteriorating, the exhaust plume is clear, the mpg figures are good, then why change the plugs.
Surely, there would be some sort of evidence that would indicate deteriorating spark plugs.
After all, we don't change many other wearing components on a car just because they might have worn too far, e.g, suspension components, steering wheel stalks, hinges, fans etc. With these we wait until they show evidence of failing.
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It's known as preventitive maintenance. The car may be running fine one day and a misfire develop the next or possibly a breakdown. If you are willing to take the chance then you could wait until the car starts to misfire, allowing unburnt fuel to enter the Catalytic converter, ruining it and costing you £200 on top of the £60 for the plugs and if the car shuts down due to the misfire, you could end up with a recovery bill too.
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And we don't do preventative maintenance on valve seats or piston rings where any serious deterioration could also ruin the cat or two or three that seem to be fitted to cars these days.
In a bizzare way, because the Alfa TS engines have 2 plugs per chamber, both would have to fail to cause serious damage downstream...
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"And we don't do preventative maintenance on valve seats or piston rings"
So you never change your oil?
£60 for how many thousands miles use seems reasonable to me. Despite what you say you will probably notice a difference when they are changed.
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The best bet, surely, is to fish 'em out, examine them, and if they need replacing, then do it.
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Fish 'em out, eh?
Not so easy these days with modern engines and deeply buried plugs!
My daughter's car - an elderly "R" plate Daihatsu Charade 1.3GLS, recently gave little advance warning of spark plug trouble - just a slight misfire one afternoon. Next morning it just would not start.
The home recovery mechanic had a devil of a job to extract the plugs. When he looked the gap was enormous! He re-gapped them and then had a real struggle getting them back in!
It was enough for her to get to her local garage where a new set of plugs and an "engine service" was enough to transform the car. I TOLD her she should have it serviced months back.
Lesson learnt, I think.
Regular servicing does pay.
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just a slight misfire one afternoon
How do you judge a misfire?
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My car has six plugs which should be changed every 60k at a cost of approx £75 just for plugs (OK I am not in trade) - changing them is a 2 hr job and first time I had them changed by a Mobile Autotune man who I know and trust -unfortunately he got wrong plugs - this I knew when he had finished and said plugs were £10 lot- so 10k miles later I did them myself with correct plugs - 2hrs was an optomistic time. - I can see now why dealer changes them at 56k when cam belt is changed.
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My local Indie changes the plugs at annual service - NGKs normally - just the normal type £3 each - franchise installed long life plugs @ £12 each and at 6 x each change I am happy with the NGKs and under £20. Done this for 5/6 years and no problems with plugs.
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>>After all, we don't change many other wearing components on a car just because they might have worn too far
I think that's where the clue is. The reason for changing them is the distinction between the cost of replacement and the severity of the resulting failure.
Oil: cheap - new engine: expensive.
Plugs: cheap - won't start in winter: expensive
Suspension bushes: expensive to replace - slow failure, so noticeable and thus replace as-and-when
Cambelt: expensive - new engine: very expensive, plus fatal failure.
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I believe you should change spark plugs for the following reason -
The gap in the plug increases with use.
This gap determines the upper voltage needed to strike the spark (before the "burn" starts)
In a typical wasted spark installation there are two of these to light up in series, so the total secondary voltage is briefly in the region of 40 Kv
There is a maximum voltage an ignition coil will take before its internal insulation breaks down (this figure is likely to be lowered if you economise with the coil construction).
If you exeed the maximum voltage, and the breakdown bridges a few turns inside the coil, the coil driver in the ECU will die fairly soon.
Consequently, if you've popped the ECU it's a good idea to change the coil(s) too.
If you have Plug leads, they should be kept in good order too for the same reason - when they go high resistance, or open circuit, you get large sparks inside the lead core.
Makes a set of plugs seem a bargain.
For reference, look at the waveforms on this site:
tinyurl.com/3pvz78
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I'd be worried about them getting stuck if left in too long. When I had petrol cars, I always used NGK as they had cold-rolled threads instead of died/cut threads so were more forgiving on aluminium heads.
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When I had petrol cars, I always used NGK
In the land of the free, where they change their oil at 3000 miles, it is common to leave NGK Platinum plugs in for 100,000 miles.
Some people on this forum > www.dodgedakotas.com/boards/gen/17257.html report NOT changing their plugs for a lot longer than 100,000 miles!
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In "the land of the Free" they change their oil early because 1. they don't drive as fast as us and the oil never gets hot and 2. the quick oil changes are done by sucking it out from the dipstick and rarely include a filter change.
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If you want to skimp on maintenance, then you've picked the wrong car.
I am generally a defender of Alfa Romeo on here, and I believe they can be as reliable as any other marque... but they do not tolerate mistreatment well, especially not the TS.
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Plugs do deteriorate, although much more slowly than in the days of contact-breaker ignition (from 6,000 miles then, they now last around 20,000).
I would agree with BazzaBear that Alfas are generally sensitive and pernickety in the ignition department, and it's cruel to neglect them.
I seem to remember Alfa Romeo used to specify Golden Lodge non-adjustable three-electrode plugs that cost a bit extra. Don't know if they still do.
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It's only £60! Not much more than 10 gallons of unleaded. Skimping just means you'll get worse fuel economy, worse performance. You won't have noticed as they will have deteriorated gradually over time. Italian cars don't tolerate lack of maintenance so you'll just get a much bigger bill later. If you want a car to ignore then buy a ford or a toyota :-)
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Because Alfas have a soul, it'll remember and bite you in the wallet elsewhere later on. No rhyme or reason where and when though.
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Just a comment on the need to change 8 plugs on the lfa twinspark.
4 Of the plugs are standard type (change regular intervals)
4 of the plugs are longlife type and are only changed at longer intervals.
Not often all 8 get changed together in the life of the vehicle.
Definitely not worth skimping either!
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4 Of the plugs are standard type (change regular intervals) 4 of the plugs are longlife type and are only changed at longer intervals. Not often all 8 get changed together in the life of the vehicle.
News to me AFAIK they all get done at the same time 60K, they are a different style of plug.
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News to me AFAIK they all get done at the same time 60K they are a different style of plug.
I think this is right (although forgive me if I'm wrong, it's 4 years since I owned my QV). They are ALL long-life plugs, anbd should be changed every 4 years or 60k miles - which seems a pretty long life to me. £60 every 4 years isn't a cost I would resent.
The report of different change schedules for different plugs might be down to owners choosing to use cheaper plugs and change them every 2 years - I know of several people who have made this decision, or had their garage make it for them.
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I've had Alfa TS engines for over ten years and am shortly going to be on my third plug change. £56 for eight OE plugs is good value.
It was really a hypothetical question. To the same extent I would never fit cheap plugs. I'm not rich enough for that.
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Does Alfa Romeo still specify Golden Lodge 3-electrode plugs, or do Alfas now use these modern plugs with slightly funny-looking electrodes, like my early-90s Ford?
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Does Alfa Romeo still specify Golden Lodge 3-electrode plugs or do Alfas now use these modern plugs with slightly funny-looking electrodes like my early-90s Ford?
Alfa haven't used Golden Lodge since the 8 Valve twin spark in the very early 155's around 95ish.
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I should have also said, while I was harping on: the internet shop shop4parts is often very good on price for Alfa stuff, although I can't say for sure they are for the spark plug sets.
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And just rechecked my info on the 2 sets of plugs.
1 is listed as irridium, 1 set is listed as platinum.
1 set is std life (replace at set interval) and 1 set is extended life, replace at extended life interval. Sorry but no mileage provided for the remaining info.
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