I want to replace a set of spark plugs do they come with the right gap in the electrode or would I need to adjust the gap myself , sorry for silly question

I'm guessing you will need to set them yourself Seb. Haven't done it for years myself, but an easy job if you have a set of feeler gauges and know what the gap needs to be.

Should come pregapped. Just get on a site where you can put in your car details and it should come up with the right plug.

I'm guessing you will need to set them yourself Seb. Haven't done it for years myself, but an easy job if you have a set of feeler gauges and know what the gap needs to be.

Oh pooh

Should come pregapped. Just get on a site where you can put in your car details and it should come up with the right plug.

Now that sounds better

Make sure you check them though, put feeler gauge in to desired thickness, if too thin .....wiggle ! if too loose hit on the floor until closer !!

Is it obvious my last petrol car was an mg metro in 1987?

Owners manual not tell you? Opie oils do plugs so try that site.

Oh pooh

Make sure you check them though, put feeler gauge in to desired thickness, if too thin .....wiggle ! if too loose hit on the floor until closer !!

Is it obvious my last petrol car was an mg metro in 1987?

Owners manual not tell you? Opie oils do plugs so try that site.

Seb, honest mate, it really is not difficult.......I know this as I can do it

Got a set for the Leon from TPS and they were correctly gapped, I did check before I put them in.

Lovely thanks dudes

It is worth to make the gap slightly smaller to get better top end power, but we are tallking slight amounts. At high RPMs spark has low energy and descresing the gap helps to address it. Larger gaps help lower end power. Dragsters use massive gaps with ignition systems producing sparks stronger than an average arc welders

Whatever you do DO NOT BANG ON THE FLOOR lol. Not only you make them dirty (especially if the floor is a garage concrete floor!) but will likely damage them. Use small steel hammer. Plugs have to be kept surgically clean. Any crap making its way deep into the plug will heat up and can cause detonation. Also, your cylinders do not like sand in them

Use a PROPER plug gap tool to adjust the gap . Try not to jar them as it might crack the porcelain ,letting in moisture and problems in wet weather . i'd have thought the bit about energy in a spark varying might have been true in the old days of points/coil and Dizzie, but with electronic systems I'd have thought spark would be constant, one of the reasons for us old timers using CDI systems on ye ancient cars . It certainly was one reason given in an electronics magaizine article on CDI units, when they designed one to overcome all of the failings of commercial units. Cracking unit, only failing on cars with ballast resistor was current drain ,which meant using two ballast in parallel to stop voltage drop to unit art high revs .

CDI units are good in providing very good spark for a short duration. They run into problems at high RPMs as they still spark all right but that spark has low energy. If sized properly they are fine. There's a equation to size the system to suit your motor somewhere, need to find it.