spark plug gaps

[Godzilla]

last week i changed my plugs to BCR8ES ones but never closed the gap just left them as they cam out the pack , now she starts fine etc but when idle when cold its abit lumpy i think should i close the gap up abit .

also the old plugs i took out had oil on 2 of em around the ceramic bit so was thinking a problem with seal etc, but removed em toay after a week of use and boosting like normal and there absolutly fine no oil ,am i right in thinking all oil seals etc shoulb be fine,

 

[stumo]

you want to run as big a gap as you can, so if it's not causing a problem i'd leave the gaps where they are.

It all depends on when you take plugs out as to how they can look, if you took them out after it idled for a while then they might look a bit oily but if you took them out after a run then they might not look oily. what that means is just cos they might look oily doesn't mean they have oil on them.

 

[PobodY]

If there's oil on the ceramic, that'll be from a spill on the rocker cover - the ceramic sticks up, and the thread goes down.
It's not in the least common to have grotty plug tops after they've been in a while. I think it's safe to say your seals are fine; it's more if the plug tips are all black (incomplete combustion - running rich); oily (leaky rings most likely, or excessive oil vapour coming back in through the breather); or white (indicating it's too hot - possibly running lean).

I don't know the answer to the gap, but will be very interested to hear what the response is. I was thinking of changing the oil and plugs within the week.
Do you have uprated cams? The idle will always be a little lumpy with them, and turbo engines to tend to burble and hunt a bit; it's a function of high back-pressure on the exhaust caused by having an impeller in it. - It's what makes them seem that little bit more alive than a N/A engine... The thought of that sound makes me smile.

 

[Godzilla]

oh right thanks,

also im going to get a compression test kit but what size is the spark plug thread.

 

[stumo]

If there's oil on the ceramic, that'll be from a spill on the rocker cover - the ceramic sticks up, and the thread goes down.
It's not in the least common to have grotty plug tops after they've been in a while. I think it's safe to say your seals are fine; it's more if the plug tips are all black (incomplete combustion - running rich); oily (leaky rings most likely, or excessive oil vapour coming back in through the breather); or white (indicating it's too hot - possibly running lean).

I don't know the answer to the gap, but will be very interested to hear what the response is. I was thinking of changing the oil and plugs within the week.
Do you have uprated cams? The idle will always be a little lumpy with them, and turbo engines to tend to burble and hunt a bit; it's a function of high back-pressure on the exhaust caused by having an impeller in it. - It's what makes them seem that little bit more alive than a N/A engine... The thought of that sound makes me smile.

what the feck are you on about?

keep takin the pillz :der:

 

[Godzilla]

Pobody- my plugs are black but i no its running rich due to the smell of fuel ,

not sure if its got uprated cams (doubt it though) the lumpy idle has only started this week since i put silkolene pro S 10w50 in and the new plugs.

does anyone know what size fixing i should get with a compression test kit,

 

[PobodY]

what the feck are you on about?

keep takin the pillz :der:

Which bit? I talk so much sh1t sometimes that I even confuse myself.

What I meant was that the ceramic bit is sticking out the top of the cover. If you've got oil on it it's from the outside of the engine and not the cylinder. Most often that's because you've spilt oil into the gap between the cams.

Sooty sparkplugs have always meant that there is incomplete combustion in the cylinder. Which normally means it's too rich.
White (ash covered) sparkplugs have always meant that the cylinder is too hot. Which normally means it's too lean.
An oily spakplug can mean that you're getting oil in the cylinder... but that doesn't mean that the rings are gone, it could just be that it has come back through from the vent into the indcution hose.
A normal (healthy) plug should be greyish and reasonably clean.

Uprated cams will give you a slightly lumpy idle.
Turbos to tend to cause a bit of exhaust 'pop'... maybe 'hunting' was the wrong word to use. I'm not saying that you should see the tacho dancing up and down, I'm just saying that it will never be perfectly smooth and static at idle... and that I like that sound.

EDIT: I've used the search tool... HKS 264s - Lumpy idle with heat range 8 plugs... that sounds quite topical (but the threads more about a dirty MAF) - another thread that mentions lumpy idle with uprated cams.

 

[vizi0n]

I've gapped my BKR7E at .028-.030 and so far it seems to work well