1994 960 3ltr Spark plug choice

father ted · Post by **father ted** » 08 Feb 2015, 03:11

Do's anyone here have the definitive answer to which spark plug should be used on the 6304 engine. I have had conflicting advice about the use of double/triple tipped plugs but these cannot be adjusted and they have a much bigger gap than is recommended for this engine.
I am currently using a set of Volvo triple points which i acquired from ebay but due to ignition system fault codes recently has got me to wonder if they are in fact the correct plug. Being "old school" i prefer the single tip plug that i can adjust if required. Thanks for any advice.

93Regina · Post by **93Regina** » 08 Feb 2015, 19:28

father ted wrote:definitive answer to which spark plug...6304 engine.

Absolutely Not...there are two answers in Volvo's pocket book!

For high speed driving - Volvo 3517629

For normal driving - Volvo 3517980

Bosch - FR 7 DC/FR 6 DC
Champion - RC 9 YC/RC 7 YC

I think above numbers translate to

Bosch FR7DC
Champion RC9YC

Post by **precopster** » 09 Feb 2015, 02:33

The misfires are more likely failing coil packs which are beginning to have broken insulation. Check the boots for white powdery marks. The plug choice is not super critical on non turbo whiteblocks.

DEWFPO · Post by **DEWFPO** » 22 Feb 2015, 14:27

I've used the standard OE Volvo (Bosch) tri-electrode plugs in our 1995 964 and 1998 S90. They've worked splendidly. If you need the P/N I can get it off a pack in the garage.

DEWFPO