Is this plug fouled out?

mthomas58 · 03:13 PM

Car developed a sudden rough idle yesterday and significant loss in power. Problem diagnosed by pulling plug wires while running - no spark at number#6.

I ordered new plugs, cap and rotor yesterday from our host. Had the alternator out last weekend and noticed some corrosion on one of the cap terminals so figured it time to replace. I pulled a couple of plugs this AM. No 6 and 5 shown below. What do the condition of these two plugs indicate?

Thanks!

Gunter · Gunter's Garage

Mileage?
Never rebuild?
Excessive valve guide wear?
Compression/Leakdown?

Brother · 07-04-2007, 07:45 AM

#6 is fouled something awful. Are you sure you didn't drop that in the mud before you took a picture?

#5 looks good. I can't really tell the color too well.

carnutzzz · 07-04-2007, 07:51 AM

Looks like the time I accidently cooked a Hot Pocket (tm) for 20 minutes instead of the usual 2. Blaaaaaaack Pocket!

Here is a pretty good site that helps with analysis of plug condition.

http://roadstarclinic.com/content/view/70/127/

tonythetarga · 07-04-2007, 07:54 AM

#6 looks oiled up and not fouled in the typical sense from too much fuel. #5 looks OK but needs a brushing from what I can see.
You might want to consider having a compression and/or leakdown done.

CRH911S · 07-04-2007, 08:41 AM

A different view perspective is needed but based on what I see here there appears to be trace amounts of oil entering #6. Isn't the firing order 1,3,5? I don't think #5 is oil related.

mthomas58 · 07-04-2007, 09:01 AM

Quote:

Originally posted by Gunter
Mileage?
Never rebuild?
Excessive valve guide wear?
Compression/Leakdown?

155k
never rebuilt
Valve guides worn for sure - oil consumption 1qt every 600 miles
Compression/leakdown not done yet (need to do it)

Brother · 07-04-2007, 09:05 AM

Well, this starts to explain your oil consumption.

How do the others look? Did the car start running better with new plugs?

CRH911S · 07-04-2007, 09:09 AM

Switch #1 injector with #6. Or better yet pull the #6 injector and have someone photograph the stream/spray and post. Use caution too!

mthomas58 · 07-04-2007, 09:15 AM

New plugs don't arrive from Pelican til Friday and don't plan on doing anything till I get the new plugs in. I've only pulled 2 so far so don't know the condition of the others yet.

john walker's workshop · 07-04-2007, 09:18 AM

crusty burnt on oil deposits on both plugs. top end rebuild time. oil use is usually pretty high when you see something like that, maybe a quart in 300 miles or thereabouts.

mthomas58 · 07-04-2007, 10:18 AM

Quote:

Originally posted by carnutzzz
Looks like the time I accidently cooked a Hot Pocket (tm) for 20 minutes instead of the usual 2. Blaaaaaaack Pocket!

Here is a pretty good site that helps with analysis of plug condition.

http://roadstarclinic.com/content/view/70/127/

This appears to be me. (from the link)

Oil Fouled

Symptoms of oil fouling include black oily coating caused by poor oil control. This situation is more severe than what is seen with the ash-fouled spark plugs and usually represents advanced engine wear. When the oil enters the combustion chamber and covers the core nose of the spark plug, the spark no longer arcs across the gap. Rather it takes the easier path to ground by tracking down the oil on the core nose. This results in a complete cylinder misfire condition. Check for worn valve guides, valve stem seals and/or piston rings. Replacing the spark plug may help for a short time, but the new plug will soon foul.

mthomas58 · 07-04-2007, 10:21 AM

Quote:

Originally posted by john walker's workshop
crusty burnt on oil deposits on both plugs. top end rebuild time. oil use is usually pretty high when you see something like that, maybe a quart in 300 miles or thereabouts.

JW, thanks for weighing in! I knew I was in for a top-end rebuild when I bought the car....it's just a matter of "when" (i.e. when I have the $$$)

mthomas58 · 07-04-2007, 10:30 AM

Quote:

Originally posted by john walker's workshop
crusty burnt on oil deposits on both plugs. top end rebuild time. oil use is usually pretty high when you see something like that, maybe a quart in 300 miles or thereabouts.

Would installing new valve seals buy me any more time for a top end?

RSR Seal Installation

Thanks!

Miguel Antonett · 07-04-2007, 10:43 AM

It is time to do some work to that engine and save some $ - if you don't soon, then it might be really expensive...

john walker's workshop · 07-04-2007, 01:13 PM

cheaper and less hassle to buy time with a few quarts of oil and a few sparkplugs. keep the plugs and plug changing tools in the car. the seals that are on there now may well be still flexible, but the valve stems move around so much in the worn guides that the seals can't keep a decent contact around the valve stem and oil gets sucked in. so new seals are kind of a waste of time in a case like yours.

RWebb · RWebb's Garage

and remember the valve is cooled in part thru the stem

loose stem = minimal heat transfer away from stem = hot stem = weak stem (maybe =) broken stem = big piece of metal bouncing around in the combustion chamber = big money & maybe big big big money (new crank)

mthomas58 · 08:15 PM

Quote:

Originally posted by Brother
Well, this starts to explain your oil consumption.

How do the others look? Did the car start running better with new plugs?

New plugs arrived today. Changed out 6, 5 and 4 and started car to see of #6 is firing. All appears OK now.....will complete plug change out of 1-3 tomorrow along with new cap and rotor.

4 & 5 looked the same. Idle seem a little higher than normal on test start-up (1,100 vs 900???) Just checked PO service records....these plugs have 45K on them.

Holy crap.....plug changes are somthing else in these cars! Had to pull A/C compressor aside to gain access. No plug tool in tool kit.......duct taping std plug socket to swivel adapter and 3" socket extension worked well along with using a 6" length of 3/8" OD fuel line over plugs to get threads started. Great tips from the boards!

Thanks!

Miguel Antonett · 07-06-2007, 04:05 AM

It is all part of the learning curve... it gets easier as you go.

Joeaksa · 07-06-2007, 05:25 AM

As well you might want to keep the RPM's down until you do the valve job. Not saying to keep it under 3000 RPM's but would not take it ANYWHERE near the redline either.

As posted above by RWebb, part of the heat transfer from the combustion chamber goes through the valve stem to the valve guide and into the head. If your guides are loose enough to allow a lot of oil like this into the combustion chamber and foul the plugs, then its also loose enough to not center the valve completely everytime the valve closes. This causes more wear on the valve head and seat as well as more stress on the valve stem.

Drive the car as needed but the longer you drive it, its possible the overhaul costs can get higher, sometimes much higher. If its driven long enough that a valve stem breaks and ruins the head, piston and cylinder (and possibly the crank and case as well) then your costs go sky high.