'Burnt' ceramic on spark plugs

[simonc]

Hi all, last week, after a quick blast to Singapore on a pork run, I noticed the engine was 'hesitant' to start, meaning it caught after a second or two. Then I noticed it almost stalled if I was sat waiting at traffic lights. It didn't actually stall, but the revs really dropped off then came back.
Anyway, as I have been taking a few days off, I took it down to Jason's place and explained my situation. He took the plugs out and we saw how the ceramic bit, where it joins the metal part, was brown-ish around the circumference of the plug.
Luckily he had a spare set of plugs and fitted them straight away. (Sorry, I foolishly forgot to take a photo )
As a result the engine was super smooth and the hesitation had gone.
I'd just like a feel from you guys on what the cause of the 'burning' is. BTW, the plugs were the iridium type and had been in place for near as dammit, a year. Is this a normal wear and tear thing or should we look at the root cause of the burnt plugs?
Thanks ever so much, Si.

[vanzep]

just to check your saying the spark plugs were burnt on the ceramic?
you sure its not oil on the plugs - this causes the plugs to look burnt
if it is oil then i would say your spark plug seals need replaced - ive seen this on many ludes over the years the 4 seals are not expensive and so do get genuine honda ones.
ive tried the iridium spark plugs before and they work ok but the platinum ones are what is specified for the lude and last at least twice as long so i would stick with them.

[simonc]

vanzep, thanks Nick. I'll check with Jason on Monday and report back.

[dwallis92]

I agree, it's likely just oil on the plugs. Not had the opportunity to try iridium plugs on my BA4 yet (theyre going in next) but i've been running Super4s for over 10,000miles now and they're still going strong. Was going to change them last week but they look mint so decided to wait for new Ign Leads to arrive before replacing so I can try see the difference with fresh leads. Probably won't notice a difference but it will be interesting to see.

Typically you get Single Platinum, Double Platinum, Copper, and Iridium plugs. Single Plat is usually a platinum coated centre electrode and a nickel side electrode. Double Plat is as you would expect, both electrodes are coated in platinum. Copper plugs are pointless and crap, forget about them completely. Whereas Iridium plugs NORMALLY have a solid iridium centre electrode and platinum coated side electrode.

The Iridium plugs aren't the most durable of plugs due to the lower melting point and higher susceptibility to oxidisation than platinum, however while working effectively they give you a much stronger spark than double platinum plugs. It depends entirely on what you want from your plug. If you are increasing the amount of fuel that you want to burn a stronger spark is a must, so iridium is a great option but be prepared to change them every 6-8 months (more often if you spend a lot of time at high rpms). If you just want a good plug thats going to deliver a consistent spark and last at least a year then it's advisable to go for double-platinum plugs. In my opinion though Bosche Super4s offer the best of both worlds, they give stronger spark than double-platinum but are more durable than iridium. Like I said, last 10,000 miles in my BA4 and nearly 2 years in my Starlet and there's still no reason to change them in either car, I will try post a pic later to show how clean they are.

Personally I don't really listen to what manufacturers recommend as they tend to recommend whatever their sponsors sell. Best example of this is oil, nearly every manufacturer will recommend you use expensive stuff such as Mobil1 or Valvoline, I tried a nearly £60 bottle of Mobil1 in my Starlet the first time I serviced it (did a thorough flush first), and within a month the oil had fouled up (was dark and smelled burnt). Year later I serviced it again and used a £25 bottle of Castrol GTX (with only a light flush), 8/9 months later the oil was still really clean and had only just began fouling. Goes to show just because it's expensive or Honda say use it doesn't mean it's going to do your car any good.