Just One More Spark Plug Question!

[The-Acre]

I picked up a new set of plugs today (NGK iridium) and as I understand it the gap is set so doesn't need altering. Is that correct does anyone know?

Thanks

Phil

[steve2006]

Yes they are preset to 1.1mm (0.044") IIRC, tend to forget as don't change them very often :D

[The-Acre]

Yes they are preset to 1.1mm (0.044") IIRC, tend to forget as don't change them very often :D

Great, thanks.

Phil

[abs66]

Damn! 1.1mm. I wonder if that's what's wrong with my gas install. I'm sure I read somewhere they need to be gapped at .75 or .80mm!

I'm sure I read they were pre gapped at .80mm.

Now I'm confuzzed !!

[The-Acre]

Damn! 1.1mm. I wonder if that's what's wrong with my gas install. I'm sure I read somewhere they need to be gapped at .75 or .80mm!

I'm sure I read they were pre gapped at .80mm.

Now I'm confuzzed !!

After looking on the box it does have a picture saying not to adjust, and as Steve says they are pre set to 1.1mm.

Does an LPG system use the same plug. and would 0.30mm make a noticable diffrence?

[abs66]

Yes it would make a significant difference as LPG needs a healthy spark. Information I got was that the plugs were gapped at .80 already but I might have been lead up the garden path.

Looks like I will have to pay the garage more money to check the gaps as I no longer have the correct tools for removal of plugs since some kind git broke into my shed and pinched my tool box!

[The-Acre]

Yes it would make a significant difference as LPG needs a healthy spark. Information I got was that the plugs were gapped at .80 already but I might have been lead up the garden path.

Looks like I will have to pay the garage more money to check the gaps as I no longer have the correct tools for removal of plugs since some kind git broke into my shed and pinched my tool box!

Be interesting to know if it makes a difference. Let us know won't you.

[steve2006]

The spark plug gap makes a lot of difference, the wider the gap the higher the electrical voltage required to jump that gap which in turn means a more powerful and hotter spark.

A narrower gap means a lower voltage is required and therefore a less powerful and cooler spark.

A narrower gap also means the spark will occur earlier as the coil does not have to charge as much before it discharges so can affect timing.

As mentioned all modern plugs have preset gaps and are non adjustable, I wouldn't fancy trying to adjust those with multiple electrodes for the same gaps all round.

[abs66]

Well it appears my ngk iridiums were all supplied with a .80 mm gap so no adjustments were made today as this is the gap recommended by the LPG guys on different LPG forums.

Although I've not solved my rough running, it does highlight that you should atleast check the gaps on your plugs incase they are incorrect or not all the same.

Right I'm off to shout at the LPG installer.

Steve, as you may realise I keep getting delayed coming over for one reason or another so would you like me to send a deposit via paypal so you know I'm serious?

Cheers

Pete

[lukie]

The spark plug gap makes a lot of difference, the wider the gap the higher the electrical voltage required to jump that gap which in turn means a more powerful and hotter spark.

A narrower gap means a lower voltage is required and therefore a less powerful and cooler spark.

A narrower gap also means the spark will occur earlier as the coil does not have to charge as much before it discharges so can affect timing.

As mentioned all modern plugs have preset gaps and are non adjustable, I wouldn't fancy trying to adjust those with multiple electrodes for the same gaps all round.

Just for reference LPG conversion do not like multiple electrode spark plugs, use normal plug's with 0.70 mm gap ;)