Having a set of new NGK BP7ES plugs in the spares drawer, I threw them into the new engine to use. I have read about issues with the quality of the plugs but have never had a problem myself to date....

Like I said, no problems to date....

All of a sudden I had a problem with the engine not firing, I had spark at the dizzy, I had spark at the lead ends, but no spark on three of the four plugs. I thought they might be fouled so gave them a good old clean up...still they were dodgy. They've been converted into high voltage insulators
Anyways, I decided to change them out for a set of Bosch plugs and looked for their equivalents, now Bosch have changed their part numbers, so the job is a little bit more challenging, but I will only mention the old numbers for now.

The equivalents for the NGK BP6ES (std mini plug) is the Bosch WR7DC if you read the literature at Supercrap, If I change the C to a P I get the WR7DP (New Bosch part number: P8-4) platinum plugs (25 as opposed to 17 for a set of four). I thought I might throw caution to the wind and try a set of the platinums.

Can anyone see why not? I realise they are designed for longevity, not for any supposed increase of FULLY SIK POWA or anything else as ricey as all that. But can anyone think of a reason why they would be a poor choice on a 40 yr old A-series for only 25 bucks a set? After paying an arm and a leg for so long, it's kind of like being offered MOBIL 1 full synth for 20 bucks and not picking it up...

Here's a picture of the tip with a super sexy background , I figure it's a little shrouded being covered on all sides except the tip, but can't figure out any other problems if the gap is 25 thou as it should be. From the factory it's about 30 thou, but this is easily fixed, there's no exposed and easily damaged tip like there once was, they've changed that design to the more protected tip as seen below.

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SooperDooperMiniCooperExpertEngineering

All garage work involves equal measures of enthusiasm, ingenuity and a fair degree of irresponsibility.

I had a set of platinums on my e-type and they gave no end of trouble. They fouled and ran cold. Evenetually I chucked them for Japanese (!!!!) NGKs and the problems went away.

It appears not all NGKs are created equal. I always buy from repco now as I have had oddities from stupidcreep

I've never had a problem with NGKs.

Must just simply be a bad one?

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1964 Morris 850, 1330 Supercharged - 81.8hp atws.
1975 Leyland Mini S 1100S powered - Nice and reliable.
1977 Leyland Mini LS - Project LS-T

Maybe. Could have been the fact they've been stowed away in my workshop drawer for 2 years, but they had to be replaced regardless I guess. Perhaps they bounced around in there too much

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SooperDooperMiniCooperExpertEngineering

All garage work involves equal measures of enthusiasm, ingenuity and a fair degree of irresponsibility.

I stay away from resistor plugs, I find old ignition systems don't like em.
I now run Bosch W7DC in the Minis, as I too have had a few dud NGKs.

Even the CDI ignition on my Evinrude 70HP outboard doesn't like resistor plugs, and it's got 40,000V+. It wouldn't even get on the plane with Champion's latest `you beaut' QL77JC4 (which replaced L77JC4)... so it's got standard type NGKs now.

<Edit> Mick if you want to clean your oiled plugs, light up the oxy or the LPG torch, heat the end of the electrode & insulator up- when the insulator gets to red the crap will vapourise off it.
Let plug cool, good as new.
This maintenance tip has been brought to you by DrMini ST Parts...

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

is the problem with the ngk plug just the fact its a 7?

I was told that Bosch no longer make a non resistor plug

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Well when my stocks are gone I'll be looking for another brand then

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

I was not able to find a non-resistor plug on the (very sparse) Bosch shelf.

Doc; I gave them a good clean using turps and a copper bristled brush. I figured at first they had fouled, and then figured they must have shorted to ground instead via the built up soot, but no dice, nil spark.

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SooperDooperMiniCooperExpertEngineering

All garage work involves equal measures of enthusiasm, ingenuity and a fair degree of irresponsibility.

try NGK BP6EY's Mick, they do quite a good job

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http://www.youtube.com/watch?v=nDMkVq1jRGU

Yeah I've had a bucket of BP6 plugs (although what's the difference between the BP6ES and BP6EY plugs?).

I used a colder plug a lot with the last mini to try and reduce the effects of run-on as much as I could. I had an idea at one stage that the plugs weren't helping.

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SooperDooperMiniCooperExpertEngineering

All garage work involves equal measures of enthusiasm, ingenuity and a fair degree of irresponsibility.

Mick you should never use a metal brush on the insulator, it leaves metal particles which are conductive.
Go burn the plugs like I said, it really does work.

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

The BP6EY is the same heat range as the BP6ES ( mr obvious)
The 1st difference is i havn't had any of them "stop" working , the other is there is a "V" groove in the electrode which is supposed to give a wider spark.

The important thing is they dont just "stop" working like the "ES" plugs were when i was using them. I'm not turning back now.

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http://www.youtube.com/watch?v=nDMkVq1jRGU

Cool Doc... I will, and I get to play with FIRE

I've got the platinum now anyway. I'll chuck them in first and see what goes bang. Call me a trailblazer...

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SooperDooperMiniCooperExpertEngineering

All garage work involves equal measures of enthusiasm, ingenuity and a fair degree of irresponsibility.

I pulled a set of the twin electrode ones out of the BMW that had done 100,000 ks and chucked them into a 1275 eng with elect dist. They worked quite well. The engine never started so well before.

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