... for engine codes ED, GD, GE (1975-1979)

Service and specifications

| A | Value | Notes | | --- | --- | --- | | Inspect every | 10,000 km
(6,000 mi) | From "So wird's gemacht":
- Inspect: 10K km
- Replace: 20K km | | Replace every | 24,000 km (15,000 mi) | The FI engine originally used long-life spark plugs. If NGK plugs are used, their replacement interval is 30,000 mi. (48,000 km). | | Type | NGK B5ES | Modern replacement of recommended types in the Owner's Manual (see appendix for reference). Part number codes:
B: 14 mm thread
5: heat range (lower is hotter)
E: 19 mm thread reach
S: copper core center electrode.
Trivalent metal plating on the threadprovides anti-corrosion and anti-seizing properties. Longevity: 30,000 mi. (48,000 km). Other than old stock, only the BR5ES (with 5 kOhm resistor) type is currently available | | Air gap | 0.7 mm (0.028") | FI gap is wider than carbs' (0.6 mm) | | Torque | 30 N·m (22 lb·ft) | NGK recommends 18-21.6 lb·ft (25-30 N·m) for aluminum heads. There is also a spark plug torque discussion at The Samba forum. | | Thread size | M14 x 1.25 x 20.8 mm | Diameter x pitch x hexagon size. | | Thread reach | 19 mm | | | Hex socket size | 21 mm | |

Installation tips

  • Do the removal and installation with a cold engine. Metal expands when it's hot. The aluminium heads expand more than the spark plug when heated up, with the consequence that the spark plug can be fastened in place.
  • Clean up the spark plug holes before installation. You don't want to torque against dirt or debris.
  • Finger tight the sparkplugs first, then use a torque wrench set at the specified torque.
  • A good tip is to only remove one spark plug wire at a time. That way there is no chance of possibly getting the spark plug wires mixed up.
  • The firing order for all air-cooled Volkswagen engines is 1-4-3-2, so make sure the plug wires go around the distributor cap clockwise in that order.
  • You can install with the fingers and mark the position with a sharpie. Then torque as specified with the torque wrench. Once finished, you can watch how much of a turn the mark did (should be roughly 1/4).

FAQ

Should I use a spark plug with RFI suppression resistor?

In short, with stock ignition, VW busses do not need spark plugs with integrated resistor. This is because the ignition circuit already contains the additional resistance: the rotor cap has 5 kΩ resistor, and each spark plug connector has an integral 1 kΩ connector. That said, resistor spark plugs can be used (see more below).

Going back a bit, fuel injector systems since the early eighties were designed to use resistor spark plugs to reduce radio interference (RFI) that could affect sensitive electronic systems. Not all vehicles featured the integral resistance in the ignition wiring as the Type 2 bus.

At the time of writing (2017), spark plug manufacturers have phased out non-resistor spark plugs and only the resistor type is available. Non-resistor spark plugs are still available from old stock, though. So if you want to be close to stock, the non-resistor option is still that option available.

That said, the additional (generally 5 kΩ) resistance added by the spark plug resistor is probably not critical. What the additional resistance on the line does is to affect the spark line section of the secondary circuit's voltage waveform by varying its slope. In short, as long as a value of 20 kΩ is not exceeded:

Spark or burn section (spark duration): the amount by which this line slopes away from the horizontal is directly related to resistance in the plug and coil HT leads (ignition supression). [...] The total resistance between the centre terminal of the coil and the centre electrode of the plug should not exceed about 20 kΩ [...] Actual resistance is not critical but anything more than 30 kΩ may cause problems.

Testing your ignition with an oscilloscope, Electronics Today International, February 1977

Richard Atwell performed and documented some tests with varying rotor cap resistance as well. As it's a series circuit, the results can be extrapolated to be similar for varying spark plug resistance. The result was that with an increased resistance (up to the stock 5 kΩ of the rotor cap) a more optimal waveform was generated.

Understanding the ignition system, Richard Atwell (scroll down to the "Which rotor" section for the results)

Finally, to conclude that resistor plugs can be used nevertheless in VW busses, here is a quote from Bosch's spark plug documentation:

Resistor spark plugs can be fitted in non-resistor applications. Bosch recommends fitting a resistor type spark plug for every application.

Can I reuse the crushable gasket when reinstalling my spark plugs?

Plug manufacturers recommend the use of a new gasket any time a plug is reinstalled after inspection or cleaning. You can purchase 14 mm gaskets such as these:

That said, many bus owners have reinstalled spark plugs without replacing the gaskets over the years, so in a pinch, you can also do the same.

With terminal nut?

TBD.

In the meantime, see https://www.ngk.com/glossary/8/spark-plug/R

Regular or recessed tip?

TBD.

In the meantime, see https://www.ngk.com/glossary/8/spark-plug/R

Which heat range?

TBD.

In the meantime, see https://www.boschautoparts.com/documents/101512/0/0/0ebd7cc0-b6f7-4590-99c5-ff1ee52a693b

Should I use anti-seize to prevent galling of the threads?

Sparingly apply anti-seize compound to the upper two thirds of the threads to lubricate them. Don't get any anti-seize on the plug electrode or it will foul

(Tom Wilson on How to Rebuild Your Volkswagen Air-Cooled Engine, pp138)

Plug manufacturers do not recommend the use of anti-seize, though, as it modifies the torque specifications. If anti-seize is used, they suggest reducing the torque values by 20 - 40 %.

Appendix: historical plug type cross-reference

Fuel injection engine

From type.com spark plug reference charts:

| Brand | # in Bentley | Alternate # | | --- | --- | --- | | Beru | 145/14/3L | - | | Bosch | W145M2 W8C0 [0 241 229 021] | W8CC0 [??]
W8CC [0 241 229 579]
W7 DTC [0 241 235 643]
WR 8 AC [0 242 229 534]
WR 7 DP [0 242 235 541]
WR 7 D+ [0 242 235 909, -946, -663] | | Champion | N288 or N5C (replaced N288) | N11YC | | NGK | - | B5ES or BR5ES (resistor) |

From "Reparaturleitfaden" Aug. '81 (V.A.G):

| Type/Engine/Feature | under 25°C| over 25°C | | --- | --- | --- | | 2/2.0 l/L-Jetronic | Bosch W8CO
Beru 145/14/3 L
Champion N288 | Bosch W8CO
Beru 145/14/3 L
Champion N288 |

information_source The old BOSCH number was W-145-M2 / W8C0. The new bosch number was W8CC0. They were a long life (obsolete) version of the W8CC with reinforced electrodes. Insted of having ~2.5mm electrodes, the W8CC0 had fat ~3.0 mm electrodes so the gap erosion was slower.

information_source Bentley shows Bosch W 145 T2. The current designation by Bosch is W8CC. The long number is 0 241 229 579. The 0 in the long number means, Made In Germany. Stock gap is 0.024 inch, 0.60 mm.

All engines

| Source | Engine | Conditions | Beru | Bosch | Champion | NGK | | :--- | :--- | :--- | :--- | :--- | :--- | :--- | | Haynes | 1.7L-1.8L carbs | Normal | ~~145/14/3~~
14-8 C | ~~W 145 T2~~
W 8 C | N. 88 | - | | Haynes | 1.7L-1.8L carbs | Tropics | 175/14/3 | W 175 T2 | - | - | | Haynes | 1.8L-2.0L FI | N/A | 145/14/3L | W 145 M2 | N 288 | - | | '79 owner's manual (US) | 2.0L FI | N/A | 145/14/3L | W 145 M2 | N-288 | - | | '79 owner's manual (DE/UK) | 1.6L carbs | Normal | 145/14/14-8a | W 145 T1·1/W8a | L88A | - | | '79 owner's manual (DE/UK) | 1.6L carbs | Heavy duty above 25°C | 175/14 | W 145 T1 | - | - | | '79 owner's manual (DE/UK) | 2.0L carbs | Normal | 145/14/3/14-8c | W 145 T2/W8C | N7 | - | | Bosch (2017) | 2.0L FI | N/A | - | W 8 AC | - | B5HS | | Bosch (2017) | 2.0L FI | N/A | - | W 7 DP | - | BP6ES | | Bosch (2017) | 2.0L FI | N/A | - | W 7 D+ | - | BP6ES |

From Reparaturleitfaden, Aug. '81

| Engine | Fuel delivery | Normal conditions (< 25°C) | Heavy duty (> 25°C) | | :--- | :--- | :--- | :--- | | 1.3L-1.6L | Carbs | Bosch W 8 A
Beru 14-8 A
Champion L 88 A| Bosch W 7 A
Beru 14-7A | | 1.7L-1.8L-2.0L | Carbs | Bosch W 8 C
Beru 14-8 C
Champion N 7 | Bosch W 7 C
Beru 14-7 C | | 2.0L | Injection | Bosch W 8 CO
Beru 145/14/3 L
Champion N 288| Bosch W 8 CO
Beru 145/14/3 L
Champion N 288|

Further reading