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MG MGA - Spark Plugs - MGA

Good morning Gents,
Can somebody please tell me what the correct type of spark plug is for an MGA Roadster, Year: 1957, engine: 1500cc.Thanks.
Cheers .......

MP PAIN

One of the favourite plugs seems to be NGK BP6ES. That's what I use and have been fine.

Steve
Steve Gyles

I have always used NGK BP6ES like Steve and these seemed fine.

I have though recently changed to a slightly cooler NGK BP7ES plug because of the much higher state of tune of my new engine.

Cheers
Colyn
Colyn Firth

Thanks to both Steve and Colyn for the Info. I will check the Auto-Parts stores in Brussels, Belgium and go for NGK spark plugs. Thanks again Gents.
Cheers,
Mike
MP PAIN

I have been using NGK Bp6es ever since I bought my MGA. The engine runs ever so smooth and starting first time every time.

Frank
F. Camilleri

Interestingly considering what Colyn said I was advised to change from NGK BP7ESs as my engine is in standard tune, i.e. they are only for tuned engines. The same MG/Triumph expert advised Champion N9YCs which I am now running although don't notice much difference one way or the other.

Looking at sparkplugs.co.uk and their explanation of the symbols the NGK and Champions use a very different range of numbers for hot/cold so 9 in Champion is probably the same or hotter than 6 in NGK.

Does anyone know how champion and NGK heat ranges compare?

Paul
Paul Dean

I changed from the NGK BP6ESs to the BP7ESs because I had an unexplained head gasket failure on my 1950cc 140 bhp engine and I hoped that running a cooler plug would help to keep the combustion chambers a little cooler and hopefully prevent a recurrence. (so far so good)

The downside of the BP7ESs is that they can oil up in certain unusual circumstances.

I found this out when descending an exceptionally long mountain pass in the Pyrenees. I was mostly using engine braking to control the speed and after a 40 minute 8 mile descent, the engine wouldn't run cleanly at the bottom of the pass.
The plugs did clear after a mile or two of normal driving hough.

So I agree that the BP6ES is the best bet for a B-Series engine in a more normal state of tune.

Colyn
Colyn Firth

Colyn. Your incident is interesting as my reason to change from BP7ESs was rather similar. Coming back from MGA Reg event at Ilkley in May I took the old road over Shap for fun of the climb but immediately over the top the engine was missing dreadfully. The running gradually improved over next 100 miles or so and plugs were very black. No problems since changing. I do also think I was running rather rich at time.

Paul
Paul Dean

I ran a basically stock MGA engine for a couple of years in a race group I ran. I used BP8ES plugs, as the engine was run between 4500 and 6200 exclusively and never had any issues with it - might have been able to use BP7ES, but the NGK heat ranges seem to be broad and as long as your plugs read correctly and there is no misfiring...

The race Twin Cam engine runs B9EV, but they are for 12:1 compression and up.
Bill Spohn

This thread was discussed between 09/09/2018 and 17/09/2018

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