ash fouling

[wobbedennis]

My 79 210 with a factory a14 is showing signs of ash fouling. it has been on the road again for almost a year, and the fouling, though minor, is present on all cylinders. other than the ash, the burn is great. what should I do to slow the ash build up?

[phearless]

ash? you mean whitish stains?

Pull your exhaust mani.... if those ports are stained white, too, you might have an exposed water jacket. White stains are tell-tale signs of coolant in the cylinders.

[datzenmike]

I could imagine coolant in one or maybe two but not all cylinders. Besides, I hear no mention of coolant loss or overheating, and nothing about steamy exhaust. It's hard for water with a few pounds of pressure to force it's way into a cylinder with 150+ PSI of compression pushing back and even more when firing. Usually the compression enters the cooling system and over pressurizes the rad cap and coolant is forced out.

 

I've seen lots of exhaust valves white (or at least very light) in color and it's normal. 

 

 

Before putting a wrench to it, post some pictures of the plugs. Could be just the oil from bad valve seals.... not bad enough to blacken the combustion chamber but slowly over time. The plug cleans itself of carbon but the 'ash' in the oil crusts on.

[phearless]

When I pulled my engine apart, I found the #3 cylinder had some wierd stuff going on.
The white stains I assumed to be from coolant in the cylinder. But, then again, I am a recovering rotary addict, so maybe I need to re-learn a lot of my recip knowledge.

[datzenmike]

Generally hotter exhaust valves tend to be white-ish in color while the cooler intakes are black or very dark. A dark exhaust valve might mean something is wrong in that cylinder and thwe valve isn't as hot as it should be... for whatever reason.

 

Coolant entering a hot combustion chamber will steam clean everything. I changed a h/g on my 620 and the piston top looked like new out of the box. The combustion chamber as well but there were some crusty thick carbon deposits that flaked off to the touch.

[phearless]

Gotcha. When a rotary pops enough seals to expose the water jacket to combustion, the chambers go cold, and you end up with calcium deposit-looking stains on everything. Sorry about the accidental mis-info.

[wobbedennis]

I have the standard carbon ring on the plug, the insulator is a reddish brown. there is a build up on them, it's hard, and it's on the insulator in a small spot.

[wobbedennis]

and I'll post pick as soon as I can

[Rays74]

The one time I've seen this was from using crappy fuel.........:)

[zed]

Years ago I used an oil additive in my Toyota 4x4 - it caused hard grey/white ash to form on the plugs and in the combustion chambers...