DDK - Die Deutschen Klassiker

I have been running my 911L 2.0l motor on Bosch WR5DC+ 7992 +15 spark plugs which are stamped made in Germany. The new plugs I have been sent this time are the same designation but are stamped made in China. Think the've all come "The Green Spark Plug Company". The car is not raced or rallied just normal driving on all types of roads, short and long journeys.

In view of adverse reports about quality of some replacement classic motor parts from China what are peoples views and experience of the Chinese products.

I'm sure which type of plug to use has been covered before but would be good to hear what people are using now and particularly what spark gap? people are finding best. I've used 16 - 20 thou so far with these plugs without problem accept the usual carboning if the engine idles a lots and does get run hard for a while (usually when it's having work done and only moved about the drive etc.)

Have just picked car up from having the Chain tensioners renewed. One had failed as descibed in my post about a month ago "Engine knocking - Bad!". Replies to that were appreciated.

Thanks in anticipation

Graham D

I'm a big fan of NGK plugs - use them in all my cars.

For 911 engines I've always used BP7ES - with a gap of ~0.028"

.

Another opinion from me...

I've used Bosch for 30 years in a variety of 911 engines, carbs, mech and elec injection, road and race.
No reason to buy Bosch, just happens to be what Type911 sell, or what Halford used to.
Never had a problem that I know to. They work (as in no mis-fires) and keep their gap over good miles, ie still 24 thou after many K's of miles.
They do have screw-on connectors which is irritating as they always come loose.

As to the gap, I use the gap given in the Haynes manual for a given engine type/size which I think is a reflection of the ignition system that car would have.

I have a feeling this question is rather like "what is the best oil to use", very difficult to say which is.

China must be suppliers of a lot of parts for all manner of cars, not sure the 911 flat six generally is that special or sensitive to what make of plug, heat range maybe?

Anyway, just my take on your question.

My 2$c worth is that I’d be less worried about Bosche plugs from a reputable dealer that say Made in China, as they’re most likely genuine Bosche. I’ve had loads of ‘guaranteed genuine’ NGK that are very poor rip-offs (from fleabuy), especially the porcelain sections.
Peter

I was going to add that I've never had a 'top' snap off, the porcelain part, on these Bosch and over the years some must have been German made and China.
As you say, the Chinese factory could well be a Bosch plant.
Not all Chinese parts are rubbish, they can (now) make very good parts.

I was told years ago by my grandfather - "made in germany isn't an indication of quality, its an indication of where the item was made.."

Same with Chinese - yes there's a lot of Chinese crap and tat available, but some of the most advanced machining centres, biggest forges, and fastest production is in that part of the globe, hence some of the biggest companies in the world (like Bosch for example) are manufacturing components (right through to complete systems or products) there now

I wouldn't be afraid of genuine brand items manufactured in China, I'd be more worried about knock-offs (ie fake NGK plugs) regardless of their place of origin

smallspeed wrote:
... but some of the most advanced machining centres, biggest forges, and fastest production is in that part of the globe, hence some of the biggest companies in the world (like Bosch for example) are manufacturing components (right through to complete systems or products) there now

- agree entirely.

Regarding the fake NGK (& other) spark plugs on ebay, I usually get mine from Eurocar Parts & there are a few easy-to-spot giveaways that indicate a genuine vs fake NGK plug outlined on the NGK website:

naively , I never even thought about fake plugs ... I've always bought from decent motor factors though

Great NGK diagram.
Buying from a reputable source is our only real assurance?
We started a large Chinese factory (Ningbo, China) about 15 years ago making door locks, the last industry I worked in before getting out of the rat-race, and after a lot of QA effort they make locks as good as any we did in Willenhall. 85% of UK production was transferred to Ningbo due to costs.
An awful lot of doors in your houses are secured by China made locks if they comply to BS / En 3621. (geek)

The European spectacle industry has been hammered over the last few years by non original Chinese made copies of many (originally) quality items flooding the market. There are a lot of similarities with the spark plug market. Possible long term damage slowly destroying a vital component after you thought you’d bought the right thing. I mean, genuine Bosch plugs and genuine Ray-Ban’s both for a tenner.
Not possible is it.

Regards
Mike

Poor quality NGK Plugs have been around since the Mid-Seventies.

Our Local 'Motorists Discount Centre' was almost giving them away.

The quality was dismal with the electrodes being poorly positioned and varying from plug to plug.

The rumour at the time was that they were rejects but there were far too many available and Champion suffered from a similar problem.

I don't think these plugs were necessarily Made in China but they were almost certainly counterfeit.

Fram had similar issues with oil filters but poor quality Lucas points were probably made in Birmingham

What intrigues me is the Plug Gap recommendations specified in the original Workshop Manual.

The Bosch Plug recommended in early engine is a W250 P21 and the gap is specified at 0.35mm (0.014").

This seems unusual and I would like to understand why such a small gap is specified.

And I thought that 14 thou was a Haynes miss-print!
Recently found out that magneto ignitions need a very different gap to non mag systems (2 stroke engines), something to learn every day.

fetuhoe wrote:
What intrigues me is the Plug Gap recommendations specified in the original Workshop Manual.

The Bosch Plug recommended in early engine is a W250 P21 and the gap is specified at 0.35mm (0.014").

This seems unusual and I would like to understand why such a small gap is specified.

- whereas the recommended gap for the alternative Beru 260/14/3 S plugs (2.0 911L & 911S)* was 0.5mm & for the Champion N 6Y plugs was 0.55mm

* but 0.6mm for the 2.0 911T


However, by the time the 2.2 litre engines appeared, the recommended gap became 0.6mm for all makes of plug for all models ...
.

I think that the 0.6 gap was first specified on the 1969 911T which had a Bosch HKZ ?