what spark plugs?

Can anybody help? I have a series 2A with a series 3 petroll 2286cc 3-bearing engine fitted from an 88 inch airportable. I'm not sure what sparkplugs to fit. The old ones taken out are champion N12YC which have a long nose. When attempting to get some new ones I was asked for the engine compression ratio (which I have'nt got a clue) and was given NGK BP5ES which fit ok but have a short nose. The engine seems to run hotter now. Does any body know what my compression ratio is (engine 951XXXXXX type) and what plugs it should have fitted, and what the differance is between a long nose electrode plug and a short? Also, do you have to set the plug gap size yourself, or do they come pre-set, (as I never looked, I just put them in!). Thats my daft questions over. Thanks for your help.

I just checked and my AutoData lists the NGK BP5ES and the Champion N12YC. IIRC the Champion plug was the OE for the 2286 engine in the Series Land Rover.

I'm not good with Series engine numbers, but you will have either a 7:1 or 8:1 compression ratio.

The plug gap is factory set now.

An alternative plug to try would be the BP6ES.