Hi

my name nick and I’ve had my evo 8 for 2 months now. Need a little help if I may ask here?

it’s a 2005 evo 8 running around 600bhp. Yesterday it started spluttering, almost like it was missing. It only happens/noticeable when boosting at higher speeds. Slow, it feels ok.

I’ve removed all the spark plugs and noticed 2 plugs looked like the photo attached. Any advice on what’s causing this? I also noticed the 2 cylinders the dirty plugs came from, have a bit of fresh oil on top of the cylinder, I’m assuming it’s the spark plugs seals in the rocker as it’s directly below the plugs.

many thanks

 

Hey Nick / Welcome @sasha1712

So these attached pics are not from your engine correct? The above pics show the threads buried in oil residue which is likely that caked on mess on the electrode

Your plug threads are that contaminated w/oil as well?

Cheers, Joe

 

Hi joe. Thanks for the reply. The pics are of my actual plugs.

cheers

 

Oh i see.

Can certainly understand the electrode condition as oil is obviously leaking down the plug & into the combustion chamber, coking that oil to the plug

We have some very experienced engine guys here & hoping they will chime in

 

how long those plugs been in there?

 

not sure tbh.

 

So by looking at the picture. Have you removed the valve cover lately? The round gaskets that sit on top of the head to prevent oil getting into the plug area are probably not seated or worn out. Will that cause you plugs to look like that? No, I don’t think so. But the first thing I’d do is pick up another set of plugs. Then after the car is running pull the coils and look down the plug hole to see if there is oil. If so you may have an issue like below picture.

 

thanks for the advice. I’m going to order a rocker cover and spark plug gaskets and a set of plugs.

The plugs I’ve removed are ngk BR8ES. I’ve been reading up and wondering if the ngk BR8EIX Are a good choice for my setup? Running around 600bhp.

many thanks

 

better plugs. Their the iridium version, disregard the “9” for mine

 

what gap should they be set too?

cheers

 

.20-.22 disregard my “9” in the iridium plugs. The 9 is a step colder.

 

i was wondering 🙌

 

Be very careful setting the iridium gap it’s pretty tough to set.

 

you could probably run the “9” but no not required for 500ish.

 

You could probably run the iridium plugs the way they are out of the box. But if it runs rough I’d close the gap. The BRP8 are set to the right gap out of the box.