Went lean, burned sparkplug. Screwed?

jumbojimbo

jumbojimbo

New member
I had a little problem at Nelson this weekend and I'm wondering if I am screwed. '86 ITC Civic, stock carb.

I lost a cylinder during Sunday qualifying. Pulled the plugs and the number 4 spark plug is shown below. The other plugs were fine, no metal, very clean and nice.

When I pulled the fuel filter it was full of tank foam. So my thinking is that I lost fuel pressure and it went lean.

Would it make sense that this was the cause? Does it make sense that only #4 was affected?

It seems to me that when we swapped plugs a few weeks ago at ORP that 4 had the least carbon and 1 had the most. Am I making that up, or is it normal for 1 to be richest and 4 to be leanest? If so, does it make sense that only 4 would be affected?

Now the worse question: how screwed am I and what do I do about it?

I ran the car about 1.5 laps of qualifying after the plug went bad. I didn't immediately realize I was down on power, I was getting passed by fast cars and I was trying to stay out of the way.

Replaced the bad plug and the car starts right up. Seems to run fine. I decided to go ahead and run the race and hope for the best. I started the race, the car seemed to run fine and then on lap 2 I lost power again. I figured I was completely screwed, so I went straight to paddock. Doh! The wire from plug 1 had come off. Put it back on, runs ok again.

So, the car ran hard about 3-4 miles after the plug was burned. It warmed up a good 10 minutes in grid, ran a pace lap and about 1.25 miles of hard running before the plug wire came off. Then ran the rest of the lap and into paddock.

What do I do now? How damaged is the head likely to be? Not to mention the piston and cylinder walls. And what, if anything, should I do about it? Is the damage already done? Is there any point in pulling the head off to stare at the damage? Or do I just run it and hope for the best?

Thanks in advance for any advice you can give.

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Jim, what plugs are you running? Those cars can be very particular about their plugs. If it's not happy, they do kind of like to burn them up, but it most likely won't cause any additional damage. if it does. I've burned up several, but that was back when I was running Champion's in the thing. It's had NGK's for years now and I haven't lost a plug in long time. FWIW, when it has burned one up before, it doesn't ever seem to damage anything else.

Why one burns up before another, there doesn't really seem to be any rhyme or reason to it.
 
Find the problem and fix it; your motor should be fine.

These are nightmare problems because it is either fuel related (lean-out) or ignition (over-advanced). You can definitely "lean-out" one cylinder; damaging ignition issues would affect random cylinders.

This type of stuff ruined my entire season last year. I burned up plugs (completely destroyed)--sometimes more than one in about 10 different track seeions last year. Turned out to be a part in the distributor.
 
For some reason I seem to remember the carbed head being leaner on 1 and 4 than 2 and 3... but I might have it backwards.

R2 is right about plugs, and you may already know this. When it comes to off the shelf plugs, there probably isn't anything finer than an NGK product... plain and simple. Don't waist your time on Bosch... their plugs are outright crap. It's not hard to pick the cars out that are using them at the track.

I don't know how long you've been driving an EW Honda, but you also want to check out the carb and the issolator plate. Make sure you don't have any vac leaks anywhere. How is the carb jetted?

Fuel pressures?

How old are your plug wires? You can spend a lot of money on those too, but again, the NGK wires seem to perform just as well as a high dollar set.

Yes it's possible that you could damaged a piston, but probably not likely. If your concerned, find someone with a boroscope and take a look inside the head. Another option would be to take the car to a dyno... expensive, but cheaper than hauling it to the track, only to be disappointed and damge the car more.

Lastly, if you need a few spares, let me know. I have a race head, carb and some other goodies that I need to get out of my way.

hoop
 
R2 Racing said:
Why one burns up before another, there doesn't really seem to be any rhyme or reason to it.
Click to expand...

Being carbed, is #4 furthest from the carb? Is the runner just slight longer? It may also be that #4 runs just slightly hotter then the rest. Being right on that edge of lean, at some extra length and the hotter cylinder and it would be the first to go :shrug:
 
IMO, only use NGK plugs in Honda's. Ive heard horror stories about using other plugs in Honda's.:blink: Its what my civic came with stock and we've never had a problem with them.:D
 
Thanks for the replies. I like the answers so far. Makes me hopeful that I am ok. I do use NGKs. Mostly because that is what the DPO used.
 
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