hi guys, just bought an S70 N/A and joined this forum, still trying to learn about this car...

but one thing that is confusing me, is what type of spark plug is right for this car? I've been getting all sorts of different information...

namely...
NGK that recommends BKR6EKUB which is 3 electrodes (gap 1.5mm)
Bosch website recommends FGR7DQE+ which is 4 electrodes (gap 1.4mm)
but the Volvo User Manual recommends FR7DC which is SINGLE electrodes and recommends 0.7mm gap!

so I'm really confused as to what gap is right for the engine? Or is the reason for all these different gaps due to their different 1/3/4 thongs designs?

 

Get the oem plugs from FCP. They will be delivered gapped.

 

hi rspi, thanks for the quick reply, in the end I bought the Bosch FR7DC+ and gapped them to 0.7-0.75mm (they were approx 0.85mm when I took them out of the box)

I didn't get from FCP coz I needed them quick as the car was misfiring badly and when I checked the plugs and the engine had 3 wrong plugs (F7LTC 2mm longer than OEM!) and 2 original volvo ones in there that was worn badly...



now I'm getting occasional misfires only when the engine is hot, checked the spark wire and resistance seems to be ok (wires dated '97) so I'll check rotor and cap next when I have time... hopefully that's the source of the problem...

 

Man, get the wires, rotor and cap. You may want to get the plugs as well. Misfires suck. There is also a chance that you have a bad knock sensor or some other problem. Have the codes read and post them.

 

Ya that's what I'll do when I get around to it, I've bought those code readers from the eBay but are still waiting to receive them after 2 weeks so when they arrive hopefully I'll be able to do some diagnostics and work out why, as the car is only missing when hot and at idle it doesn't miss under load so I'm not really suspecting coils, wire, rotors or caps at the moment and I don't want to start changing everything for no reason if they're working well for environmental and financial reasons

 

How many miles does the car have? I hardly doubt you will be replacing those wires, rotor, cap for nothing. The wires are 14 years old.

 

The original plugs on some Volvos are 3-electrode plugs. NGK is also one of the OE suppliers for Volvo, as is Denso. Volvos don't usually come with Bosch plugs from the factory. A lot of parts stores will, however, push Bosch plugs for them because of a mentality that European cars take Bosch plugs, and NGK and Denso are for Japanese cars.

 

yeah i noticed that some OEM items does look a bit like the identical NGK versions...

but i was just a bit confused when they have different spark gap for different spark plugs which have different number of electrode, as I thought the reason for multiple electrodes were for the purpose of providing more sparking area but just thought it defeats the purpose of multiple electrodes when you increase the spark gap, wouldn't that put more stress on the engine/ignition system?