Vintage Minor Register

Forgive me as I'm coming at this blind as the car is currently in storage about 30 miles away, so I've not been able to remove and measure the spark plugs fitted. The plugs are NGK AB-6 and I believe they are 'short reach' plugs. Am I right in thinking that they're actually too short for a side-valve engine? If so, what's available on the market today that'll give me that extra length and is recommended for the SV Minor? I'm a little concerned that I might be causing damage by running the wrong type.

As an aside to the main question, would 'short' plugs reduce the efficiency enough to hit the economy (I'm getting a rather poor 29mpg), and would 'long' plugs help with hill-climbing, within the restricted parameters of a 90-year-old side-valve 847cc engine, of course. I'm not looking for a miracle but just wondering if the engine could be ever-so-slightly improved on the inclines with the added benefit of another 5-8mpg. The carburettor seems to be set correctly, with the plugs looking a nice biscuit beige colour, so I don't think the mixture is running rich. Thanks.

I can recommend Tim Green at The Green Spark Plug Company.

A few years ago now, he had a batch of 18 mm long reach plugs made and I bought a couple of sets, which I use. He may well still have some as I think he had a large batch made.

He would certainly be the best person to answer your other questions. Perhaps you could have a chat with him and post his advice here.

The website can be found at https://www.gsparkplug.com/shop/about

Thanks Ian. I did buy a set of Champion D16s from The Green Spark Plug Co. back in early 2017 a few months after I bought the car. After a very short time of use the car refused to start and remained off the road until I returned south from living in Shetland. It was only after getting an old-school mechanic who has worked on my 2CV over the past 20-odd-years had had the Minor for several weeks that he discovered the plugs were duff. A brand new set (the NGK AB-6 bought locally) has seen the car up to 1,700 miles since they were fitted at Christmas. I've no idea if the plugs were a faulty batch or not. I'll give him a try.

Interesting. I haven't really put many miles on the ones I bought so I can't really comment. Let's see what Tim has to say. I think he gave some quite complex instructions how to fit and start using them - on a little chit that came with them - if I recall correctly.

Here's his 18 mm plug offerings at the moment - looks like quite a selection.

https://www.gsparkplug.com/ignition/spa ... m-diameter

How many miles since your engine was rebuilt? Might it be a little stiff still?