TR2/3/3A Heavily carboned spark plugs in relation to a failed FO8 gasket?

[karls59tr]

When an FO8 gasket fails and allows coolant into the oil could this somehow cause the engine to run in such a way to heavily carbon up the spark plugs or are the two issues caused by different malfunctions?

 

[bobhustead]

You are on the verge of getting empirical answers to the question of what's wrong. Fuel richness can cause a sooty black crust, but two plugs (served by the same carb) would be affected. Oil is a likely culprit in your engine. That would probably be accompanied by blue smoke and the smell of oil trying to burn. Maybe antifreeze, but I don't know.
Bob

 

[karls59tr]

You are on the verge of getting empirical answers to the question of what's wrong. Fuel richness can cause a sooty black crust, but two plugs (served by the same carb) would be affected. Oil is a likely culprit in your engine. That would probably be accompanied by blue smoke and the smell of oil trying to burn. Maybe antifreeze, but I don't know.
Bob

When I pulled the plugs two of them were black and sooty and the other two were not as badly carboned and the center electrodes were still the white color but had a wet look. It's too bad I got the plugs out of order when I pulled them out but if the two plugs that were white and wet were side by side would that indicate that the FO8 liner blew between those two cylinders? But why the heavy carbon on the other two plugs? Unfortunately I can't pull the liners until Spring so that gives me 6 months to speculate.
Karl

 

[bobhustead]

Probably not possible to know exactly what went on in your engine. You'll fix it in spring.
Bob

 

[JHaydon]

Maybe antifreeze, but I don't know.

Been there, burned that -- (green) antifreeze stains the porcelain green and leaves a greenish-white crusty residue.

In my experience, wet plug(s) are simply a sign that the piston was on the intake or compression stroke when the engine was shut off. It's the fuel that would have burned on the next power stroke.

I *think* that carbon on one plug could be related to the loss of compression in that cylinder. Compression makes the fuel burn more efficiently (more completely / hotter / cleaner). Low compression therefore could (I think) leave an abnormal amount of carbon on the plug. If I'm correct, then it's just another symptom and not necessarily an answer.

Or, as Bob suggested, it could be oil in the cylinder(s). Oil doesn't burn as cleanly as gasoline does, so it leaves a mess behind. OTOH, oil burning *often* leaves the plug looking oily, like you used the spark plug for a drain plug.

Also, let's not forget the lesson from all of our medical drama shows: Two symptoms don't necessarily HAVE to be related. There could be 2 diseases happening at the same time. One fouled plug could have been a result of the low compression, but the other might have been misfiring from an ignition issue. Your engine may have been running on 3 for a while, but it wasn't until the ignition issue showed up that it became really noticeable.

Or... one carb has been running rich and was beginning to foul the plugs on 2 neighboring cylinders; then a bit of carbon broke off of one plug and lodged itself on the exhaust valve seat, ruining the seal and losing compression? (Maybe I should stick to writing fiction.)

 

[TFB]

When I pulled the plugs two of them were black and sooty and the other two were not as badly carboned and the center electrodes were still the white color but had a wet look. It's too bad I got the plugs out of order when I pulled them out but if the two plugs that were white and wet were side by side would that indicate that the FO8 liner blew between those two cylinders? But why the heavy carbon on the other two plugs? Unfortunately I can't pull the liners until Spring so that gives me 6 months to speculate.
Karl

Although the liners share a one piece 8 gasket there is no connection between the liners at the bottom like at top with the head gasket.A blown 8 gasket leaks to the crankcase not to an adjacent liner.
Tom

 

[karls59tr]

Although the liners share a one piece 8 gasket there is no connection between the liners at the bottom like at top with the head gasket.A blown 8 gasket leaks to the crankcase not to an adjacent liner.
Tom

I see your point. Would there not be coolant in one or two of the cylinders if an FO8 gasket failed or not necessarily? There was no indication of coolant in any cylinder when I pulled the head. Karl

 

[TFB]

The liners extend past the shelf for the 8 gasket joint,so coolant leaks into the crankcase,not up into the cylinder.
Tom

 

[sp53]

I do not think there would be a distinctive place where you could find a cause that is if nothing jumps out by now. One thing I might try would be if the oil pan is off and the water pump is on, would be to fill the area around the liners with water to see if the water leaks out at the figure 8 gasket with gravity. It is not really helpful, but it might be satisfying to see the leak.

Steve

 

[karls59tr]

The liners extend past the shelf for the 8 gasket joint,so coolant leaks into the crankcase,not up into the cylinder.
Tom

I wonder why there is evidence of coolant /oil leakage where the cylinder head meets the block on the drivers side of the engine? Dos that mean that after the FO8 gasket blew the mixture worked it's way up to the head gasket and forced it's way thru the gasket even though visibly there is no sign of a leak in the gasket? If the mixture got up that high would it not also get in the cylinders? This is driving me up the wall.

 

[CJD]

I think you are trying to read too much into the plugs. When the FO8 fails, it does not lift or fall...all that happens is a small section corrodes through, leaving the remainder just as it was.

When you have all the coolant in the oil pan, then the engine will not run properly, so any reading on the plugs is not note worthy. Water will work its way around the rings much easier than oil will. If the head gasket had failed, then you would have a lot more evidence of water in the cylinders.

It is possible that the head gasket failed between the pushrod gallery and the outside of the block, resulting in oil on the left side of the block. It is also possible that the head gasket failed between the coolant jacket and the pushrod gallery...but that should not have left the entire radiator and engine dry of coolant.

 

[TFB]

The only place for coolant to go if the 8 gasket leaks is down into the crankcase.There is no way to work its way up to the head gasket once its leaked to the crank case.
The coolant can leak at the head gasket into the cylinders , lifters or oil passage to head..
Evidence of coolant/oil leakage where the head meets the block is a head gasket leak.
If you have the head off and the protrusion and cylinder walls look good and the car wasnt smokeing,and you dont have water dripping out the pan drain with some water in the block,and it sounded good when ran with the fresh oil,I think I would put in a new head gasket and try that out.
Tom

 

[sp53]

Yes good point Tom. I would think if you clean up the water jackets around the liners and vacuum that gunk out, you might be able to see where it is leaking from the top. If not, well yeh through on a head gasket and see what happens cheaper and easier.
steve