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so I take it ...

BrApple

No Life But CEG
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Gales Ferry, CT
a plug gap of 0.08 isn't good :blackeye:




but I still pulled 29 mpg on my last tank of gas :laugh:


for some reason yestreday when I was changing the oil I decided to pull the plugs since they have close to 100k on them as I think they where last changed around 104k .... plug 1 &2 had about a 0.08 gap where plug 3 and 4 were 0.05 as they should be. however those have part of the electrode tip missing back to the platnium on it.

only other odd thing was plug 1 and 4 had oil on top of them and down the threads, luckly I had already changed the valve cover gasket so I think it was just left over.

and for 100k the plugs didn't look to bad. the ceramic at the center of the plug was a nice lite brown and alittle bit of black carbon build up around the outside edge.

so I suppose its time for a new set of plugs and wires ....
 
nice! I could nearly stick my finger through the gap in the ones I just pulled out...
 
Hahaha! Dang, I should probably go and check mine, now :help:.


you should. I have only used about 1/8th of a tank and I have 94 miles on it already ....


well it appears from my notes in my blog about miles I pick up ~12 miles so far on the 1/8th tank ... last tank I had about 80 miles.
 
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The oil on the top of the plugs is more than likely from a leaking cam cover gasket. It doesn't take much of a leak to build up oil around the plugs over time. I helped my son change the plugs on his ZX-2, and he must have had a major puddle around all four, 'cause you should'a seen her smoke! btw, there's no place for an oil leak in the spark plug valley to go anywhere, so you should always take the boot off of both 1 and 2, then shine a light down one hole while you look down the other. Then do it again for 3 and 4. You can accumulate quite a bit of oil down there, and ALL of it goes down the spark plug hole when you pull a plug. A friend of mine who works on Zetecs says that once he suctioned a half a cup of oil out of the spark plug valley. Seems to me that would be enough to cause hydrolock in a cylinder coming up on compression. :eek:
Also, there's a web in the middle, between plugs 2 and 3, so that's why you need to do a 1/2 and a 3/4 check for oil.
 
Correct, that is the design of the valve cover gasket, and this is why oil will pool up in each of those cylinders in pair. I guess I am lucky, as my valleys are bone dry :cool:.
 
And actually, there's a reason why your 1 and 2 plugs had the big gap, and your 3 and 4 plugs didn't. It's because of the way the coil packs work. 1 and 4 fire together through the same spark generation, as do 2 and 3. BUT...
In an old-fashioned distributor ignition on a 4 cylinder with a single coil firing 4 times every 2 revolutions, and this spark being distributed through (you guessed it) the distributor, the spark was always going the same direction through each plug. But with the paired plugs on a single coil, you actually have one spark traveling toward the coil, and the other spark traveling away from the coil. In other words, the polarity of the spark is opposite in paired plugs. This means that one plug is throwing electrons from the center electrode to the side electrode, while the other plug is throwing electrons from the side electrode to the center one. That's why in Ye Olden Days the side electrode was always the one that burned, but in our ignitions the center electrode ends up being the burnt one half the time. So always check at least two plugs, and make sure they're the paired ones, either 1 & 4, or 2 & 3. That's also why you buy the plugs with exotic tips, instead of the cheepest ones that will screw in. :confused: Got all that?
 
Yup, half of each pair on twin tower coils is reverse polarity.
 
ahhhh...so this is why they say when you need to remove spark plugs, put them back exactly the way they came out. Makes sense. Thanks for the info.
 
ahhhh...so this is why they say when you need to remove spark plugs, put them back exactly the way they came out.
No, actually, you are supposed to do that because the spark plugs are supposed to tell you things. Like, lean or rich, too much advance or not enough, all sorts of things. This was MUCH more important in the days of carburetors and points-fired ignition. With modern F.I. (and O2 sensors) and electronic distributorless ignitions, sadly the art of "reading" sparkplugs has gone the way of water-witching. So, in Ye Olden Days, when every time you worked on the car, checking the condition of your plugs was SOP, you wanted to make sure that what you saw on one particular plug was entirely because of activity in that combustion chamber, so you always put a plug back into the same hole.
Actually, with our ignition, you could just about double the life of a set of plugs by swapping 2/3 and 1/4 after oh, say, 50,000 miles. But a new set of plugs every 50,000 isn't very expensive. ;)
 
well my valve cover gasket is relatively new. I'll have to check for oil again.

after adjusting the plugs and then changing them and the wires I pulled 360 on the tank, but the last quarter i wasn't easy on it and I filled up early.

anyway new O2 sensor ftw. mine was original from what I can tell, 204k. I swapped it at the end of the last tank of gas. so far i have been driving normally, ie not going for best mileage ... 1/4 tank used and it netted ~130 miles :shocked: thats slightly better then when I was trying for good mileage. The old sensor was rusty and must not of read well, however I never got a cel for it :crazy:
 
Still not close to me, I hit like 180 miles at 3/4 and now I am at 315 at a hair under 1/2, a new record... Start driving like Grandma :p

I will soon, but I am getting the same mileage if not better just driving the car like I normally do ...
 
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