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20th February 2019, 16:53
#21
Had a bit of time yesterday so I checked the spark plugs and cleaned up the throttle body just to get an idea of the state of the engine.
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I must say I wasn't disappointed with the condition the plugs and throttle body were in, gave both a quick clean and closed her back up. Sadly it didn't fire up but it was because the battery was drained (11.74V) so I might have to replace the alternator and/or battery in the near future...
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20th February 2019, 17:06
#22
How often do you change the plugs?
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20th February 2019, 17:37
#23
Originally Posted by
LastOne
How often do you change the plugs?
I'm planning on using a 50K kilometer interval, worked fine for my Colt CZT which used NGK iridium plugs as well.
These looked fine after cleaning them up, going to replace them in about 10K kilometers I think.
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20th February 2019, 18:21
#24
Originally Posted by
Entharion
I'm planning on using a 50K kilometer interval, worked fine for my Colt CZT which used NGK iridium plugs as well.
These looked fine after cleaning them up, going to replace them in about 10K kilometers I think.
That's much too long, and don't be fooled by the service intervals quoted by Opel - they are unrealistic, just to convince vehicle fleet managers that the cars will be cheap to maintain. The plugs in the Z20NET take a hammering because when one cylinder reaches compression TDC, all 4 plugs receive a spark, and how that spark reacts tells the ECM whether knock is occurring, so in other words the plugs work four times as hard compared to an engine that has a separate knock sensor. That's why you'll never see a clean looking plug in a Z20NET no matter how recently it was fitted. For about €35, it's not worth trying to economise with old plugs.
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20th February 2019, 22:04
#25
Originally Posted by
LastOne
That's much too long, and don't be fooled by the service intervals quoted by Opel - they are unrealistic, just to convince vehicle fleet managers that the cars will be cheap to maintain. The plugs in the Z20NET take a hammering because when one cylinder reaches compression TDC, all 4 plugs receive a spark, and how that spark reacts tells the ECM whether knock is occurring, so in other words the plugs work four times as hard compared to an engine that has a separate knock sensor. That's why you'll never see a clean looking plug in a Z20NET no matter how recently it was fitted. For about €35, it's not worth trying to economise with old plugs.
Do al 4 coils fire at the same time? :S what a weird system... Is it just to avoid detonation or is there a particular reason for this?
In any case the wear and electrode gap looked fine, no signs of a too rich or lean mixture, just a bit of carbon buildup as is to be expected.
Also what would you recommend as an ideal interval?
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20th February 2019, 22:20
#26
No more than 20k, and no more than 15k for oil changes. Changing the plugs on the Z20NET only takes 10 minutes so it's good to take advantage of that.
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20th February 2019, 22:29
#27
Originally Posted by
LastOne
No more than 20k, and no more than 15k for oil changes. Changing the plugs on the Z20NET only takes 10 minutes so it's good to take advantage of that.
I should make clear the above is 20,000 km and 15,000km rather than miles, as the OP is in the Netherlands.
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21st February 2019, 12:27
#28
sorry but iridium plugs can be taken out, cleaned up and re-used as long as the burn pattern on all of the plugs is the same... so i would double the amount to 30k KM... and before you all attack my opinion... I used to use them on a highly tuned mk3 vr6 and a cleanup would make them last twice as long with no problems whatsoever... for the people that want to know how much bhp my vr6 had.. it went from 191bhp to 221.3 bhp and that included having the engine blueprinted, stronger conrod's different pistons etc etc etc... i also used colder burrning NGK iridium spark plugs and like i said i would clean them after the normal change period... and at 60k i would change them. The car went on the rolling road with plugs that did 45k+
so clean if they all have the same burn pattern if they don't that is when you replace. otherwise you are just chucking away money.
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22nd February 2019, 16:40
#29
Originally Posted by
northpole
sorry but iridium plugs can be taken out, cleaned up and re-used as long as the burn pattern on all of the plugs is the same... so i would double the amount to 30k KM... and before you all attack my opinion... I used to use them on a highly tuned mk3 vr6 and a cleanup would make them last twice as long with no problems whatsoever... for the people that want to know how much bhp my vr6 had.. it went from 191bhp to 221.3 bhp and that included having the engine blueprinted, stronger conrod's different pistons etc etc etc... i also used colder burrning NGK iridium spark plugs and like i said i would clean them after the normal change period... and at 60k i would change them. The car went on the rolling road with plugs that did 45k+
so clean if they all have the same burn pattern if they don't that is when you replace. otherwise you are just chucking away money.
I've had good results with iridium plugs, they're designed to last a very long time, so I'm inclined to agree with you.
Originally Posted by
LastOne
No more than 20k, and no more than 15k for oil changes. Changing the plugs on the Z20NET only takes 10 minutes so it's good to take advantage of that.
I'll think I'll check the plugs every 20K, if after cleaning they look good enough to go another 20K I'll put them back in and keep the €35 in my pocket.
I do change my oil every 10K though, it gets too black too quickly for my taste... And past experiences with having to replace the timing chain tensioner because of old engine oil tells me that's the way to go.
Completely unrelated question though;
Because the movement of the engine seems to cause a rattle on high-load acceleration and is slowly destroying my exhaust hangers I'm looking at replacing the engine mounts soon.
What brand do people reccomend for this? And does anyone have experience with the poly inserts from Powerflex?
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22nd February 2019, 16:57
#30
Originally Posted by
northpole
sorry but iridium plugs can be taken out, cleaned up and re-used as long as the burn pattern on all of the plugs is the same... so i would double the amount to 30k KM... and before you all attack my opinion... I used to use them on a highly tuned mk3 vr6 and a cleanup would make them last twice as long with no problems whatsoever... for the people that want to know how much bhp my vr6 had.. it went from 191bhp to 221.3 bhp and that included having the engine blueprinted, stronger conrod's different pistons etc etc etc... i also used colder burrning NGK iridium spark plugs and like i said i would clean them after the normal change period... and at 60k i would change them. The car went on the rolling road with plugs that did 45k+
so clean if they all have the same burn pattern if they don't that is when you replace. otherwise you are just chucking away money.
That's great and dandy. If it wasn't for the fact that you're ignoring the unique ignition system that Saab have deployed on the Z20NET. In simple terms, experience of iridium plugs on some other engine, whether that be a Mitsubishi Colt or a Model T or whatever isnt particularly relevant.
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