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bottom middle plug in the picture. white crusty stuff on the insulator tip and side electrode and oil everywhere else.
94 Ford Explorer XLT, 140k, pushrod engine with hydraulic lifters
compression 185-195 on all cylinders
clacking from that side of engine under heavy load
burns ~1.5 quarts between changes
possible loss of power (i’ve never driven another Explorer so idk)
No check engine lightWhat exactly might be causing this spark plug and noise issue? :blink:
loose wrist pin scoring cylinder wall? collapsed lifter? (but what about the oil?)
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The plug in the lower center as well as the upper left have deposits from burning oil. Most likely worn valve guides. The plug on the lower right has pepper spots caused from detonation. It could also be the noise you are hearing under heavy load.
dang. thanks. when i look at those charts of different spark plugs mine never look quite like the pictures so i never know what’s going on.
tell me, what are these pepper spots? on the insulator tip?
well this sounds expensive. guess i gotta take care of at least the left head soon cuz it really fouls up that middle spark plug in a short amount of time. and i guess, at least as importantly, i gotta diagnose that detonation…
sht, could the computer be retarding timing cuz of the detonation, thereby causing my lack of power? sure wish this thing was OBD-II so i could just hook my scan tool up and find out!
oh, well maybe i should start with some higher octane fuel and see if it reduces the noise! right?
guess i’ll actually throw new plugs and wires in there too. i’ll do that first.The tiny spots on the insulator tip are actually tiny pieces of melted aluminum from the piston head. The lack of power could also be cuz the inside of the catalytic converter looks just like the oil fouled plug.
Just thinkin.
see if this helps.
http://www.ngksparkplugs.com/tech_support/spark_plugs/faqs/faqread.asp
[quote=”crypkilla” post=62020]
What exactly might be causing this spark plug and noise [“clacking” under heavy load] issue? :blink:
loose wrist pin scoring cylinder wall? collapsed lifter? (but what about the oil?)[/quote]A loose wrist pin like you described would have ruined the engine quickly. A collapsed lifter sounds more like a “tick” and it occurs as soon as you start the engine. Sometimes the tick will go away when you rev the engine or when it warms up.
The “clacking”, especial;y because it occurs under heavy load, could be pre-ignition (knock). Try running a couple of tanks of premium fuel and see if it goes away. If it ony occurs under heavy load (towing ?) then just run premium then.
If there any kind of external oil leak like from the valve cover ? There is a lot of oil on the threads.
If it was me, if you are only using 1.5 quarts between changes, I would ignore it. Swap the one plug with another cylinder every 10-20,000 miles. (I’m a cheap SOB !)
Thank you. It’ll be a week or more before I return from vacation and use up a tank of regular. Then i’ll see if premium confirms knock.
I have no external leaks. Valve cover would have to leak externally to get to the plug and it would be obvious. It is a lot of oil tho huh.
As someone above suggested, it may not be the original plug in question that has a knocking cylinder. Possibly the one to the right. So the excessive oil leak and knock may be unrelated?
As described above this definetely fits detonation and not lifters. Getting ahead of myself but what would cause this on a single cylinder? carbon build up causing hot spot? what else?
If you want to keep the vehicle and you can do the work yourself-pull both cylinder heads, inspect the tops of the pistons for abnormalities and replace the heads with rebuilt ones-internet searching can be helpful for cost savings. Replacing the lifters and pushrods is a good idea since it’s apart. If you can’t do the work yourself or afford to have it done you might contact a local vo-tech or large high school with an auto repair course/shop. Sometimes they’ll take on a project like yours for training purposes. Usually you supply the parts and assume all the risk! Make sure you ask how long they’ll have the car-it can get long in time.
If this route is not for you then go the suggested cheap route of swapping out plugs every so often and bumping up the fuel grade a notch. You also might want to run a few bottles of Chevron Techron through the fuel system, that product has helped improve a variety of unfavorable operating conditions for me over time.
lo and behold, i’ve run premium (91 octane) gas and the clacking is gone. it had gotten pretty bad when going up hills or during heavy acceleration and now it’s basically non-existent. maybe the very faintest knock still when going up steep hills but im not even sure. I also paid attention, and knocking was always worse after longer drives when the motor is good and heat soaked.
so it seems we have confirmed detonation (that looks and sounds to be coming from the left bank) and we strongly suspect a worn valve guide on the same bank, middle cylinder (plus number one cylinder, right bank to a lesser degree). and i guess the two issues are unrelated.
so now to speculate on the cause of the detonation… and i’ll update more if i find anything under the valve cover pertaining to the oil leak. and i’ll see about diagnosing an exhaust restriction in the cat. i’ll start by watching manifold vacuum per this video and eventually hook a gauge directly to the exhaust. i should mention that my fuel economy is right where it should be and perhaps the amount of power is what it should be also. idk.
big thanks to wysetech for catching those pepper spots on the picture. i would have never noticed them in the pic if i hadnt been told to look for them. And i’ve never dealt firsthand with detonation or pre-ignition so i didnt realize when it was staring me in the face.
on another note i have a 78 Chevy Pickup K-30 with the 400ci V8 and it has the very same clacking issue and im now confident that it also suffers from detonation. I’ll be running premium in that vehicle as well.
Run a can of SeaFoam (available at Walmart) through an open vacuum line to the intake manifold while the engine is running. Either a PCV line or the brake booster line. On older vehicles these will be brittle and are likely to break, so be careful or have replacements ready.
A small funnel helps and you must hold the throttle open and maintain a high idle (2000+ rpm). I don’t car what the instructions say, use the whole can, but when you are down to the last 25% start pouring faster until the engine stalls. Let sit for about 30 minutes and re-install the hose(s). Then start the engine and hold the throttle at high idle until the smoke clears.
This process does cause quite a bit of smoke.
Buy an extra can of SeaFoam and dump the whole thing in your gas tank and fill with regular gas.
Let us know how this works.
I’m betting valve seals not valve guides. Easier and cheaper to replace. Remove vale covers. Remove spark plus. Insert a piece of cotton rope (long enough so that you can retrieve it) into the spark plug hole. Turn the engine over by hand until that piston comes up to top dead center and jams the rope against the valves. Remove the intake and exhaust rocker arms for that cylinder. Use a special tool, carefully remove the valve spring retainer and keepers. After removing the valve spring, the seal will come right off.
You will have to hand crank the engine backwards a bit to get the rope out.
Thank you. I am familiar with both procedures. And I’ve just found a TSB (technical service bulletin) specifically for my vehicle about “carbon knock.” And Ford recommends a similar procedure but of course with Motorcraft Carburetor Tune-up Cleaner. I’ll use Seafoam. But it says not to ingest enuf to stall the engine. Says use 1/2 to 2/3 can. Turn off engine. Let soak one hour. Finish can. Repeat two more times for a total of 3 cans.
I also realize that higher octane fuel is just a band aid and a diagnostic aid. continued use of higher octane can increase carbon build up and make knock worse.
Thanks for all the help so far guys. I’ll run the Seafoam and then regular gas and report back soon. I’ll also replace the valve seals and have a look around inside when i guide a chance, report when i do, then keep an eye on the plugs for continued oil fouling.
SOLVED:
until i disassembled it, I did not understand how the lower intake manifold gasket prevents oil from under the valve cover from entering the intake track. the lower intake manifold bolt nearest the #5 cylinder was finger loose. the lower intake manifold gasket even had discoloration where the oil was leaking past.I was burning at least 2 quarts every 3k miles. Plus my spark plug was fouling out, likely missing a little (but not majorly, im not really adept at diagnosing small misses, either way, everything is fixed and plugs and wires are new and engine idles/runs basically the same) and possibly causing the detonation (knocking) that i’ve been able to reduce with higher octane gas.
valve guides and seals did not need attention. i did not add any fuel system cleaner. power is same after fixing leak, and new plugs/wires. per Eric’c instructions on checking for exhaust backpressure, my exhaust system checks out perfect (21 inHG at idle and under sustained throttle input). i might just be expecting more power than a 94 Explorer was meant to offer. (also. breaks dont rub, tires are inflated, truck is empty, fuel is good, fuel filter is new, power and acceleration are steady and consistent, etc. etc.)
see my other thread for a pic and a few more details.
http://www.ericthecarguy.com/kunena/8-Service-and-Repair-Questions-Answered-Here/48096-accidentally-got-coolant-in-my-oil-little-help
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