Thread: V8 Discovery spark plugs

best plug for rover v8 is ngk iridium.

Tombraider

best plug for rover v8 is ngk iridium.

please enlighten me oh great one?

i stoped thinking of them as soon as i saw the price!
and besides, when their free the NGK std ones are fine

phil

I have heard exactly the same thing... were you doing it through the blokes on the sunshine coast.

I heard about the irridium plugs and the dodey spark plug leads as well.

What do you reckon about the LPG conversion in general???

Austral told me DON"T DO IT!!! But guys on here have and are happy!!!

Cylinder head design (combustion shape) in the Rover V8 is rather poor for swirl.

If you remove the plugs and inspect them you'll find one side is rather sooty the other side is not.

Std plugs carbon up really badly on the Rover V8s and the Iridium plugs have an ultra-fine electrode which is highly resistant to this issue.

They also spark better, promoting better flame propagation in the chamber as they dont smother the spark.

Iridiums are a "fit for 150k" plug and therefore work out much more cost effective in the long run.

Personally, I found they have steadied the engines that I have had them in and there was a slight (only slight) improvement in economy - though not enough to worry about.

The major benefit was a more responsive engine, no more power, just "happier"

Cheers
Tombraider

Rumour has it they eat the plug leads.

I got a great sell from the LPG guy on all the stuff they do! Mainly replace all leads and plugs.

Why would they do that? He said they all need it.... some phenomenon only Rover DII V8's a re prone to....

maybe the new leads and plugs are their way of making up the loss of power using lpg,,,,

and a nice little earner-- $240 plus LEADS plus labour!!!

Apparently they replace them with really cheap ones. Old mate said they go better on the LPG that way.
Of course I believed him immediately and signed up!!!

Originally Posted by tombraider

Cylinder head design (combustion shape) in the Rover V8 is rather poor for swirl.

If you remove the plugs and inspect them you'll find one side is rather sooty the other side is not.

Std plugs carbon up really badly on the Rover V8s and the Iridium plugs have an ultra-fine electrode which is highly resistant to this issue.

They also spark better, promoting better flame propagation in the chamber as they dont smother the spark.

Iridiums are a "fit for 150k" plug and therefore work out much more cost effective in the long run.

Personally, I found they have steadied the engines that I have had them in and there was a slight (only slight) improvement in economy - though not enough to worry about.

The major benefit was a more responsive engine, no more power, just "happier"

Cheers
Tombraider

Mike, ever tried indexing the plugs ?
I used to buy copper washers, both taper and flat that came in slighly different thicknesses and IIRC, have the spark gap pointing at the exhaust valve.

Regarding LPG and plugs, I always used standard type copper core plugs in my 351C on LPG, (generally NGK, although I found the much maligned Champion Gold, then still made in the US to work very well) reduced the gap (LPG is harder to ignite than petrol, and therefore probably a candidate for a fine wire plug as voltage requirements are often reduced) and you also want to go at least one heat range colder. I used to run two heat ranges colder as that engine was running around 11.5:1 CR.