Tuneup for my 93 850

jamesspringer · Post by **jamesspringer** » 23 Sep 2010, 15:30

Does anyone have recommendations for types of plugs? The prices vary online from $4.95 a piece to $18.70. Is there really that much of an advantage in getting the more expensive plugs?

Should I replace the plug wires cap and rotor?

Post by **asc325is** » 23 Sep 2010, 15:38

go to autozone and get ngk. the cheapest one they have. they work awesome. IIRC the gap is 0.28

replace the cap and rotors atleast. the wires will show wear when they are ready to be changed.

jamesspringer · Post by **jamesspringer** » 23 Sep 2010, 15:48

Thanks. NGK plugs are only $2.29. That sounds a lot better

.

Post by **Ozark Lee** » 23 Sep 2010, 16:18

On a N/A car I run Bosch coppers, they are even cheaper but it is critical that the gap be 0.028 and error to the low side when gapping them. They are under $2.00 each but you can normally only get them at NAPA. They changed numbers recently but they used to be FR7-DC and I have not committed the new number to memory yet. Out of the box they will come gapped closer to 0.035 to 0.040.

Avoid like the plague the Bosch +2 or +4 platinum plus plugs that you can't gap. The car will never run right with them installed.

...Lee

Post by **charlyW** » 23 Sep 2010, 16:32

I like my +4 Platinum Bosch Plugs didnt like the £12 each though

NGK made my T-5 run badly odd how there is such a difference from the USA and UK Spec

Skottynan · Post by **Skottynan** » 23 Sep 2010, 17:17

Copper only

jamesspringer · Post by **jamesspringer** » 24 Sep 2010, 08:18

Thanks for all the replies. I priced actual Volvo plugs at $30.12 for a set of five from a dealership but the closest dealership is an hour away. I think I will try the NGKs first.

Next question: How important is it to get the torque right? The manual lists the correct torque at 18.4 ft. lbs +/- 3.7 ft. lbs and says to "use the correct torque". I have never needed to torque a plug before and don't even own a torque wrench but then, I have never worked on a Volvo.

Post by **jblackburn** » 24 Sep 2010, 08:27

It doesn't matter. Spin it in hand-tight with the wrench, and then tighten it down a bit.

NGK's should work just fine, just make sure to set the gap!

jamesspringer · Post by **jamesspringer** » 24 Sep 2010, 13:04

Well, I changed my mind at the counter and went with Ozark Lee's suggestion of Bosch Coppers (Bosch Super Plus copper core plugs, Autozone cat. # 7955). They came pre-gapped to 0.033 to 0.036 so I think those were what you were descibing. I gapped them at 0.028 (perhaps a shade less on some - between 0.027 and 0.028) and I'll update after I install to tell you all how it worked. Thanks for the help.

jamesspringer · Post by **jamesspringer** » 25 Sep 2010, 10:27

Well, it idles a bit better but still sounds a bit rough. Power is improved somewhat as well. Any other suggestions? It sounds like a sort of rythmic clunking that smooths out at higher rpms. How do I check if the timing belt is worn? Could a clogged fuel filter or dirty injectors be the culprit?