the_supernerd

I just tuned up my '87 4x4 22R, and my sparkplugs have a white / light grey buildup on them. I read somewhere that burning oil slowly, such as a leaking valve guide, will cause this, but wouldn't that cause a black buildup? What could be causing this?

rworegon

Ash fouled deposits from burning oil and/or fuel additives during combustion. Worn valve guides/seals, rings....

Some good info:
http://www.aa1car.com/library/reading_spark_plugs.jpg
http://www.classictruckshop.com/club...park/plugs.htm

the_supernerd

Here is a better quality picture.

sb5walker

Like rworegon said, probably oil - motor oil contains calcium and often magnesium, some zinc and a few other minerals that can leave deposits like that. If you're burning a lot of oil, plugs will be black and oily, but if burning some oil but not a whole lot, it tends to form deposits like the ones in your pics. If you're using a fuel additive like Lucas, could also be that. How's your compression? How often do you have to add oil?

You might consider using a heavier weight oil. If you're using a 10W-30 / 5W-30, try a 10W-40 / 5W-40, or, if using 40 weight try 50. If you're using a diesel oil, you might try a non-diesel. As great as diesel oils are, most of them contain more additives than most non-diesel oils do.

You might try using a small amount of Red Line SI-1 Complete Fuel System Cleaner with each fill-up. Maybe an ounce each time. That product is almost 50% polyether amine, and a little of that stuff goes a long way.

If you're burning oil but compression is good, yeah, it might be the valve stem seals, and replacing them might solve your problem.

the_supernerd

Thanks for the link. My plugs have more buildup than the plug in the picture, and I have not seen this on any of my other vehicles. I am thinking I must be burning a small amount of oil. I have seen some smoke from my tailpipe under heavy load, but it seems different than a usually worn engine smoke. The engine will usually ping when I hit the second barrel of the carb, usually only above 4000 RPM. About the same time it pings, a big puff of smoke comes out of the tailpipe, then the amount of smoke seems to lessen and eventually stops. The pinging lessens or stops with the smoke. The pinging and smoking seem to be related, but I cannot see how that is possible without having two seperate problems.

rworegon

Have you given the carb a good cleaning?

the_supernerd

I usually use Castrol or Valvoline 10W30. I was adding about a quart every 500 miles because of a big leak, but the leak seemed to stop . Sludge plugging it maybe? Now I am adding a quart about every 1500 miles or so, but I assume it is still leaking a little since I never did anything to actually fix the leak.

I have never rebuilt the carb, but I cleaned the throat a few times and I also took out the fuel cut solenoid and cleaned it through the fuel passages there. I put some seafoam in the gas recently, but the buildup is on the plugs every time I have changed them for the last 50 or 60k miles, possibly more. I also put some Riselone in my oil about 20k-30k ago, but it has been changed many times since.

I checked the compression not too long ago, and if I remember correctly, it was 170, 165, 155, and 180. I just adjusted my valves and #3 was getting fairly tight, so there is a possibility it was releasing the compression slightly. I also assume the buildup on the plugs is also in the cylinders, which would raise compression (#4 is high, others could be worn more than shown).

sb5walker

I'd give Valvoline MaxLife 10W-40 a try. It contains seal-swellers that may help with valve seals (and others) so you'll likely burn less oil and leak less, too.

Yeah, if your plugs look like that, so do your piston heads, cylinder head and valves, and the buildup would raise compression, which by itself would increase pinging, plus the deposits would get hot and could cause pre-ignition. Suggest trying a good clean-out with a gallon of water with some isopropyl alcohol, per this post: http://www.toyotanation.com/forum/sh...70#post2946870

EDIT- and with that compression, your rings are probably okay, which means that your valve seals are the most likely culprits. Pulling the head would give you a chance to clean things out, but you might give the MaxLife a month or so to see if it will help, together with the water treatment and Red Line to try to clean things out.

On your truck, is there a vac line from the power steering pump to the throttle body? If so, check that line for ATF.

the_supernerd

I thought about trying a seal conditioner. I will remember Max Life next oil change. A few years back, I put about a cup of straight water down the carb and it ran a little better for a while. I never tried it with alcohol or for 30 minutes, that is a good idea. I do not have the idle-up valve in the power steering pump.