Plug Diagnoses Please

[danc30]

I pulled my plugs tonight to diagnose the mysterious pressurizing coolant system when cold.

Any input on how to correct what I am seeing with the plugs I just pulled.
Pics just loaded in my gallery are a lot higher res than I can attach to the thread.

#4 is a shiny brown and was wet with fuel. # 7 doesn't look right to me, all the rest look like they are doing well.

I'd post pics here but they can only be 39kb.

Any input is greatly appreciated.

Dan

[LMH]

I don't think they look too bad Dan. Maybe slightly rich?
Larry

[FWB]

if your running pump gas they look right where they are supposed too, a little brown.

[Night Enforcer]

danc30, in order to give you a good comment on your plugs, a couple of questions are in order. How many miles on the plugs? How much initial timing? Total timing? Type of fuel, oxygenated or not? Did you add any fuel additives to the present tank of gas? Intake manifold type? Compression ratio? Carb set up? Cam? Did you idle a great deal before pulling the plugs? Type of igition system? All of these will influence the look of the plug and influence the proper reading of a plug.

I can give you a couple of comments that might be helpful until all the info is available. Generally from the photos, the plugs look ok. They show you to be running a bit fat which is probably where you want to be to avoid detonation with todays fuel. It also appears that you might be running a hair too much timing. I can't tell for sure from the pictures. There is what is commonly called a burn mark or timing mark on the ground strap. From some of your photos the burn mark appears to be way down the ground strap toward the threaded portion of the plug. This usually means too much timing. The burn mark should be toward the apex of the curve of the strap near the top to be "right on" in most applications. Also without being able to see all the way down the center ceramic coated electrode to where it bottoms out, it is hard to say exactly if your air to fuel ration is close. #4 could be that way because of the manifold runner/carb set up at idle. The flash from the camera can cause all kinds of color mis-interpretations, but #7 might have a little "coolant burn off" indicated on the ground strap and the electrode tip.

I just saw your other post. It sounds like you may think it is a head gasket issue. I am not sure that's the case but here are some tips. Have your run a pressure test on your coolant system? A head gasket leak will often times show up. You might want to run a cylinder leak down test on the #7 as well as the others when it is cold and then again when it is hot right after you bring the car back from a run. Most of the time with a blown head gasket you will get water in the oil and oil in the water. How does the oil on the end of the dip stick look? Any oil in the coolant? Does the coolant smell a little like exhaust gases when you release the pressure in the morning when it's cold? One of the simplest ways is having a radiator shop perform a simple test on your coolant to determine if it has combustion by-products in it.

In the good old days we would pull all the plugs, pressurize the coolant system to its max with a coolant system pump, disconnect the coil and turn the engine over with the starter. You will be suprised at how easy it spins without compression. After a few short runs, if the head gasket was leaking, coolant would begin to dribble or spit from the cylinders affected.

Good luck. I hope some of this info helps.

[Ron61]

Dan,

Night Enforcer has some very good ideas. The plugs will vary in color, gas on them and etc, depending on how they have been driven and what type of gas you use plus any additives. The # 7 plug is the only one that looks a little odd to me and the could be the flash. The way I used to check mine was put in a new set, run them for a while and then make a hard run and shut the motor off just as NASCAR does. Then pull the plugs and check them. Also because of our lousy gas, I changed mine more often than most people.


Ron

[RICK LAKE]

danc30 Dan looking at the plugs I see no coolant issues. There would be a chalky material on the plug or it would be cleaner than new. You have fire in all 8 cylinders. Which manifold are you running? There are some manifolds that have a 10-40 cfm differents in flow. Is this a single and dual plane. It's all about matching ports. IMO the center 4 cylinders are going to get more A/F than the outer 4 cylinders, 1,4,5,8. Did you call KCR and ask about the prssure problem with the coolant?? The problem I think is a pin hole or weak spot between the head gasket, 1 cylinder and a coolant passage. If you really want to equal out the cylinders and pick up a little HP, Joe Craine will balance the ports of your manifold. Takes about a week, looks like jewelery when you get it back, motor runs smoother. The other thing to get is an intrared temp gun for checking the heat temps on the exhaust manifold with the car running, EGT can vary 20-100f degrees and give you the same thing with different sparkplug colors. I am going with the fact the car doesn't blow black smoke out the sidepipes, no missing, no backfires, basic things. Does the 1 wet sparkplug smell like gas?? Are you using any antisieze on the spark plug threads? This will also cause problems with the sparkplugs not firing correctly. Get 5,000 miles on the motor then we will know after the breakin if the Jetting needs to be changed. Installing an A/F meter in both side pipes is the best tool for checking for Lean or Rich conditions of the motor at all RPMS. Lets find out about the preesure in the coolant system first than look at the other things. Rick L. Ps Dan I am not a big fan of NGK plugs, Put a new set of Autolites in the motor and road test for 100 miles then pull them and lets see what they look like. Check the plug gaps.

[CJ428CJ]

Here's some great information on reading plugs: http://www.4secondsflat.com/Spark_plug_reading.html

[danc30]

Wow, lots of great info here. Thanks everyone.
Night Enforcer-
Approx 1200 miles on the plugs,
Initial timing is either 18 or 22 and the total is 38. Keith said the total should be 38 all in. My dyno tuner also said this was good.
93 octane pump gas (contains 1-10% ethanol)
1 can of Klotz octane boost per tank (1 ounce per gallon)
RPM Performer intake
10.5:1
QFT 950 DP
Camshaft Comp Cams Custom Hydraulic Roller - Duration 248/252 Lift .630 Lobe separation 110
Idled for about 1/2 mile in my neighborhood to get to my house. Revved once before shutting down.
MSD 6-AL w/ MSD billit distributor
I took the plugs ut last night and replaced the cap. If the system doesn't pressurize again, I will flush it and re-fill. I will then do a collant sytem pressure test to see if it holds.
What pressure should I pump it up to?
Oil dipstick looks fine, just changed my oil 150 miles ago and no coolant in it.
No exhaust smell in the air escaping the cap when released.

Dan

[danc30]

Rick L.,
RPM Performer manifold,
Didn't ask Keith about the coolant issue until I elimnate anything I could've caused (dye)
No black smoke out the exhaust, doesn't miss or backfire
Wet plug did smell like fuel. It was a little loose (not really snug) when I went to take it out.
I did use anti-sieze opn the plugs but made sure it wasn't on the first 4 threads. (tried my best anyways)
All the NGK's are gapped at 40 now.

What autolite would you reccommend and at what gap?

Again, thanks all for all the responses.
Dan