Bosch Super 4's.......

[Tom]

Plugs are nice hard steel. The head is soft ally. Both metals expand at different rates which helps them seal. If you overdo them they can jam due to the different expansion.

Also if you overdo them you can damage the sealing washer on the plug.

You have to be a true ham fisted moronic gorilla to fook up the head but they really don't need to be that tight.

 

[Stuart]

Tom,

thanks, I don't reckon I could have over-tightened the plugs....I'm not strong enough to be a "true ham fisted moronic gorilla!"
It was just that the old ones were only hand tight (if that), I figured they shouldn't be as loose as that, so just used the common sense approach, but I'm certain nothing was damaged.

Car still seems to run better, it'll be interesting to see the MPG when I fill up. As long as it isn't using more fuel than before I'll be well pleased.

 

[Matt]

I had bosch then changed to champion one's when i serviced it - think the champion's are better on my particular car anyway

 

[Tom]

They will have felt better as they were new.

 

[Stuart]

Anon,

although all the filters were changed I guess you're thinking the air filter change could make things better.
In fact the old air filter was kept clean, but as I was doing everything else I replaced it anyway. Standard air filters only a few quid so seemed daft not to replace it.
Obviously the whole package would help, but I'm sure the Super 4's were the main factor hence my recommendation.
Hope that clears things up for you.

 

[Stuart]

The Super 4's and new oil/filters haven't made much difference to MPG. I didn't think they would because the old plugs/filters weren't in bad nick.
Anyway, I did drive to the East Coast and back covering 192.5 mls, a reasonable distance to make a judgement. My 1.6SX Brava did 37.35 MPG.
The same run before the plugs etc was 35.9 MPG, so not much in it, but at least it's in the right direction.