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Spark plugs

Applies to Classic 900, 9000, 9-3 and 9-5 models

Golden rules
When to change the plugs
How to change the plugs: procedure and tools required
Plug application chart - select the correct set for your SAAB
Anorak facts: top up your knowledge

Golden rules for SAAB spark plugs

Firstly, years of experience proves beyond doubt that for the very best results use only NGK (or SAAB) spark plugs in the 4 cylinder B202, 204, 234, 205 & B235 engines. The exception to the NGK rule would be 6 cylinder cars which are SAAB adaptations of existing GM designs. For the V6 petrol powered cars, original equipment would be Bosch plugs.

Secondly, be advised that cars fitted with Direct Ignition MUST be fitted with resistor type plugs and that when the Direct Ignition unit is removed it MUST be stood upright at all times. If for any reason the unit is placed upside down or gets knocked over accidentally, it must be placed upright and left for at least 40 minutes before starting the engine (unless you really want to spend £200 or whatever on a new one within a fortnight or so...).

Thirdly, some special variants require special plugs. For instance, the 9-5 Aero uses a different spark plug as does the 2.0 litre B205 engine fitted with the SAAB Tuning kit (190 bhp instead of the standard 150).

When to change the plugs

With spiraling fuel costs (it doesn't help that VAT is charged on every litre you buy), it makes sense to maintain your engine at peak efficiency. Correctly gapped spark plugs and clean air filters will help enormously in this respect.

The type of use, operating environment and general health of the engine will determine the life of a spark plug but in the vast majority of cases, spark plugs should be expected to last 10-15,000 miles but will have passed their optimum performance level long before the latter mileage is reached. IMPORTANT! Note that worn spark plugs have a bad effect on direct ignition cassettes and that when a new cassette is fitted, failure to fit new spark plugs at the same time will invalidate the warranty.

How to change the plugs: procedure & tools required

Tools required:

  • Torx keys
  • Spark plug socket, extension and ratchet wrench
  • Feeler gauges
  • Wire brush

Method

We have used a SAAB 9-5 for this article but the procedure is similar for the 9-3 and 9000 with Direct Ignition (DI). Cars with distributor ignition are similar and most of the advice applies equally well to 4 cylinder cars. The V6 9-5 isn't too hard to work on the spark plugs but beware of undertaking a plug change on the 9000 V6 because access to the rear cylinder bank requires partial dismantling of the plenum chamber. More often than not with the V6 9000, it will be found that the plugs are submerged in oil due to a leaking cambox cover (these can warp). Whichever engine your SAAB is fitted with, be advised that this job is best carried out with a cold engine, as plugs even on an engine that has been run only a short distance may be too hot to touch.

Remove the screws, then release the wiring for the DI cartridge

Start by releasing the red clip on the Direct Ignition cartridge using a screw driver. Next, undo the four fasteners (usually Torx type machine screws) that secure the Direct Ignition unit to the cambox cover. Carefully lift the unit clear and stand the unit UPRIGHT away from the working area in such a way that there is no possibility of it falling or being knocked over. If you are working on a V6 9000 or NG900 do take extra care with the plug leads - there should be a puller on one of the leads that you need to use to remove each one in sequence.

Take care when removing spark plugs: use a vacuum if the chamber looks full of grit

Ensure that there is no grit or dust inside the plug chambers before undoing any of the spark plugs. If the area looks suspect, use a suitable vacuum cleaner and crevice tool (see photo). You don't want grit, dirt or anything else in the combustion chamber.

Remove all the plugs and place them on a flat surface in the order they were removed. Check for signs of burning or damage. As a rule, plugs should be a uniform gray colour.

If the plugs are the correct colour, the gap is within specification and there is no sign of wear on the side electrode, you could probably reuse the plug. In this case, use a wire brush to clean the thread of the plug (your objective is to remove all traces of carbon). As a rule, we never re-fit old plugs except where we know the mileage since the plugs were last checked is nowhere near 10,000 miles.

Always use the correct plug: note that 9-5 Aero models use a special platinum plug

Always install plugs carefully! To avoid cross threading, tighten by hand very gently, then 'nip' the plug. The correct torque setting for this is 28n/m or 21lbs/ft. Refit the DI cartridge (or plug leads on cars with conventional ignition), tighten the x4 securing screws and refit the wiring connector to the DI cartridge (note that you need to push the red part inwards). Collect all your tools up and the job is done.


Spark plug application chart

Many years of running countless SAABs has convinced the author that nothing but NGK spark plugs will do. Accordingly, below is set out the NGK plug specification, as compiled by the author. It has been checked thoroughly but readers who spot mistakes are encouraged to advise us accordingly and without delay. During the production run of both spark plugs and cars, changes have been made so that some types that were recommended when the vehicle handbooks were printed have been discontinued and superceded - the table below reflects these changes.

Engine
Application
Spark plug
B202 900 Classic 16v to 1993 (except turbo) NGK BCP5ES
B202 900 Classic 16v turbo to 1993 NGK BCP7EVX
B202 9000 injection (except turbo) to 1993 NGK BCP5ES
B202 9000 turbo to 1993  
B204 9000 injection (with DI) to 1997 NGK BCPR6 ES11
B204 9000 Turbo (with DI) to 1998 NGK BCPR7 ES11
B234 9000 Turbo (with DI) to 1998 NGK BCPR7 ES11
B308 9000 3.0 V6 injection to 1996 NGK FR7LDC
B204 NG900 injection 2.0 (except DI) to 1998 NGK BCP5 EVX
B234 NG900 injection 2.3 non turbo to 1998 NGK BCP6 EVX
B204 NG900 2.0 turbo to 1998 NGK BCPR 7ES11
B258 NG900 2.5 V6 to 1997 NGK FR7 LDC
B204 9-3 2.0 injection to 2000 NGK BCP5 EV
B234 9-3 2.3 injection to 2000 NGK BCP6 EV
B205 9-3 turbo NGK BCPR7 ES11
B205 9-3 2.0 Aero HOT NGK PFR6H-10
B235 9-3 2.3 Viggen NGK PFR6H-10
B205 9-5 2.0 LPT* NGK BCPR7 ES11
B235 9-5 2.3 LPT NGK BCPR7 ES11
B235R 9-5 2.3 Aero HOT NGK PFR6H 10
B308E 9-5 V6 3.0 turbo to 2001 NGK BKR7E-11

 

*PLEASE NOTE that some 9-5 B205 engines were fitted with the optional SAAB Tuning kit (192 bhp). These cars require SPECIAL plugs. Use of incorrect specification plugs WILL result in reduced performance:

Engines with green injectors should be fitted with: NGK PFR6 H10 plugs

Engines with red injectors should be fitted with: NGK BCPR6 ES11 plugs

Cars with the Tuning kit are quire rare and we have owned just one that has been so equipped. Usually, there will be an addendum to the Owner's Handbook with the information but the acid test is to pull the ECU and check for part number 400127286 (check with us if in doubt: we have the 2010 Parts System)

The author doubts very much that this information is available anywhere outside a SAAB dealership!


Anorak facts: top up your knowledge

SAABs Trionic Management System is the sort of thing that normal owners don't really need to know about. Even so, it is rather clever! Cars fitted with direct ignition actually use the spark plug as a sensor. Better still, on icy mornings when you start the car and back it out onto the road and turn the engine off, the DI cartridge discharges 40,000 volts through each plug to remove soot deposits (cause d by a rich starting mixture) to ensure that when you come to start it again, it will fire instantly.

Multi-electrode spark plugs may look good and probably last longer than conventional single electrode plugs but do not produce multiple sparks, as only the least worn ground electrode will actually spark. These are NOT really suitable for SAAB applications and the author has found at least one car with a baffling misfire that was traced to a set of these plugs which were gleefully binned.

The author knows at least one cost conscious SAAB owner who runs a 9-5 with an LPG conversion. Apparently, there are two special NGK plugs developed for use with gas. NGK plug BPR6EIX-LPG is a resistor plug that has been treated with different metal components or plating to both thread and electrode in an effort to improve service life when running on gas.

There is a long tradition of tweaked and tuned SAABs that reaches way back beyond the arrival of the first turbo-charged cars to the legendary two-strokes, which enjoyed considerable competition success. In the UK, owners have a good choice of tuning equipment available off the shelf and there are specialists such as Abbott Racing or SAAB Flight who will happily build you a 'one of a kind motor' in any stage of tune you require. Some radically modified engines may require different (colder) plugs but the advice here is a consult a specialist before changing from the standard recommended plug.


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