Best Spark plug for the 850 T or V70 ?

[jblackburn]

Yep, .028" works well for the coppers.

[Red-Arrow]

The Gap size is just to optimism the spark time and intensity. Make the Gap too small and the spark pre jumps reducing complete combustion, this leads to Blackened plugs. Make the Gap to big and you get delayed ignition and wet plugs.

The most important thing is to have equal gaps on all 5 plugs, double or triple check the gaps when cold.

[cn90]

Copper is cheap and maybe on its way out.
Platinum as a material is more expensive than Iridium and is not better.
Platinum may be around for 10 years.
But I can see Iridium being the major player in the next 30-40 years.
Virtually all new cars leaving showroom these days have Iridium sp plug.

Search "NGK 6418 (BKR6EIX Iridium IX)".

BKR6EIX is about $6/each at your local autoparts store.

The following are excellent articles written by the American car guru Larry Carley.
Platinum ($1,000 per ounce) as introduced around 1985 or so. Iridium ($400 per ounce) around 2004 or so.
Read the discussion on Platinum vs Iridium. Personally I think Iridium will replace Platinum 10 years from now:

http://www.underhoodservice.com/Article ... ology.aspx

http://www.aa1car.com/library/2004/us30428.htm

[erikv11]

Where on Earth do you find plugs for $2 each?

fcpgroton etc.

[truvoice1]

I am shopping for plugs for my 850. Rock Auto (rockauto,com) has copper cores starting at $.99 each for Autolites, $1.26 for Bosch Super 7555 (FR7DC), $1.30 for Bosch Super Plus 7955,$1.59 for NGK BKR6E V Power, etc. For Platinum plugs they start at $2.18 for Autolites, $2.36 for NGKs, $2.48 for Bosch. The Iridium plugs start at $4.48 for the Autolites ad the NGKs are $6.30 each. They have a wide selection of brands to choose from, AND their shipping charges are very reasonable; especially if you can get your stuff all shipped from the same warehouse. I have used them several times in the past and they always have come through for me.

[rmmagow]

My LPT V70 had a set of very very old Volvo plugs in it when I bought the car at 155K. I pulled them out, put in a set I bought at Tasca Volvo and am just getting ready to cross 194K miles. Zero problems and along with Bougicord wires, a cap and a rotor the car's ignition system is flawless. Yeah, the plugs were over-priced, maybe $50+ for the set, but they work well and I know if I experience ignition grief it most likely will not be because I put in the wrong plugs. OTOH, I put in an aftermarket MAF and am suffering.

[oldschoolvolvo]

+1, i've run Bosch copper and Volvo OEM, never had a problem, changed every 30k.