plugs & gaps

**960kg** · Tuesday 21st April 2015, 12:23

Originally Posted by MoleT-5R

I'm quite happy to run non-volvo plugs, but I do then change them more frequently then, the previous owner to me had major ignition troubles on my olive t-5r and spent a fortune between his local garage in wiltshire and a north london volvo dealership trying to sort the issues and me I've not ever had really ignition troubles until this last years of the 8 that I've owned the car and that I'm sure is really a boost issue, that hopefully will be sorted this week, so I'm ready to go and play with Claymore at the weekend...

As you say you change plugs more frequent then you can get away with Non Volvo ones but these usually give problems after 5000 to 8000 mls of use whereas you won`t get any problems with the Volvo recommended plug for your application.

Copper conducts better and is generally used in higher-performance/modified engines. In dedicated race cars resistor-less copper plugs are used.

Iridium and platinum plugs are chosen for their longevity only and if the pucker Volvo plug is chosen for your model the correct type platinum or iridium will be supplied as different engines use the different plug type.

You shouldn't gap iridiums because of potential damage to the tips. For that reason and their inferior conductivity, they aren't really used in modified engines. They are usually more expensive also.

If you are running more boost you might gap your plugs a little smaller from std. to 0.7mm Copper and Platinum type can be adjusted ok.....cos it`s the outside larger part that is adjustable so no damage ensues.

**Ettienne** · Tuesday 21st April 2015, 13:36

I have never bought plugs for any of my volvos and not had ignition issues.

I must be lucky, but a few of them have had good main dealer histories.

I'll most likely do the guls and olives plugs at some point.

**Saaamon** · Tuesday 21st April 2015, 14:21

Its good practice to check plug gaps before fitting.

**MoleT-5R** · Tuesday 21st April 2015, 19:25

Originally Posted by Saaamon

Its good practice to check plug gaps before fitting.

I'll agree with that, but does seem a waste of time a far as iridium plugs go, if your unable to adjust the gap on them.

**Orca2** · Thursday 30th April 2015, 01:05

I tried NGK iridiums and they were great , but they go off the boil after a few months , changed back to volvo ones after that and they seem to keep the performance up for longer.
Just my opinion of course.

**stutgart69** · Friday 1st May 2015, 00:16

Originally Posted by Orca2

I tried NGK iridiums and they were great , but they go off the boil after a few months , changed back to volvo ones after that and they seem to keep the performance up for longer.
Just my opinion of course.

I thought these iridiums were meant to last for about 80k miles?
I have them on my bike, came with the bike 7 years ago, and no issues with them as yet.

**Orca2** · Friday 1st May 2015, 00:21

They were noticably better than my old plugs but they pretty soon ran out of puff, the Volvo ones seem to keep it up longer, they are getting a bit tired now at about 18 k in. The NGK ones were shagged at about 8k .

**stutgart69** · Friday 1st May 2015, 00:25

Thats a whole 10x less than what they claim!
Are you using aviation fuel or something

**Orca2** · Friday 1st May 2015, 00:42

I use Shell V Power wherever it is available.

When the plugs are new the power builds very quickly and smoothly, it sounds kind of hollow and flat , when they are getting tired it doesnt rev as freely and the power is a bit lumpy, it makes a duller noise.

It is very noticeable, when you drive it a lot.