Just bedding in a rebuilt motor, it's run about 3 hrs. Noticed bubbling alongside #2 & #3 plugs - I am aware there has been problems with malformed threads on new plugs, these are Motorcraft, so I am not surprised they are leaking. I will change the plugs.
But I am baffled by the bubbling, because it's oil pumping past the threads. #2 has ended up sitting in a good teaspoon of oil. Will this sort itself out as I run the motor in, or is there a problem with the rings? I didn't do the rebuild so can't testify to ring fit etc.
Yes, there has been an ongoing problem with spark plugs threads.Try wrapping some aluminum foil around them like you would a water pipe. Then see if they foul. Newly rebuilt engines can do some odd things.
And, the bubbling is caused by escaping compression. As the rings seat this should stop. You may also have worn/eroded threads.
I really don't think that what you're seeing is oil. I think it's carbon, mixed with gasoline and other exhaust gunk. If you really had that much oil going through your cylinders the car would smoke like crazy.
I admit it makes no sense, Jerry, but l have seen this numerous times. And no excessive exhaust smoke. My T roadster, now owned by a good friend, does this.
They will pump oil if not sealed, I use the old #5 rector seal. KGB
Wouldn't a coating of anti-seize compound on the spark plug threads provide some benefit, including reduction of compression seeping thru' the spark plug threads?
I've seen it too. Sometimes this goo will come up around head bolts when a head gasket is leaking. I still don't believe it's oil though. It's usually a sticky substance that reminds me more of tar or pitch.
Jerry, Ive seen that, too. But,if this is a product of combustion,, one would think it would come out the muffler. Once upon a time, l bought an old buzz saw rig.With running T engine. It was really sludgedup .i put fresh oil and some Rislone the stuff was called in it too. The crap that pumped up past the plugs was emphatically oil and Rislone.
Check the oil level in the engine too just to make sure it's not over filled. But as stated above: if it was straight oil she'd be sending up smoke signals galore.
Think about it folks. The 1/2 inch plugs and head have threads that are for pipe fittings. They generally do not seal well when assembled dry. But a light application of engine oil on the threads when fitting and tightening may help stop leaking for small amount of time.
I had this and cleaned the threads and put the champions in place of the autolite plugs and no more issues. I just had the bumbling but it wasn't oil. I think the 2 piece plugs were $33.00 each but the work and look right. Tim
I've now also changed to Champions, no more bubbles. It was definitely oil, not carbon and combustion by-product water. No obvious oil smoke or consumption, but we'll see what happens as I drive a bit more. I used to do wedding hire in a 1926 Rolls 20 which needed regular plug changes, you could see a black oil lake on top of the pistons but it started and ran just fine.
It can't be oil. Think about it for a second. There's no way it wouldn't be smoking if it was. Once oil was in the cylinder it would burn. No smoke? It's not oil but some mixture ( as suggested) of fuel and carbon or dirt .
OK, I'll put the dodgy plug back and collect the result and examine it carefully.
Oil, when you lose any compression it will suck the oil past the rings and pump it out, if you loosen the plug a little more you will really see it. KGB
It is emphatically oil. The fact that it does not smoke like my old 40 horse Case traction engine burning coal is one of those great mysteries.But they do not smoke badly out the muffler. It amazes me that there are T people out there that have not witnessed this phenomenon. No disrespect intended
Probably the large thread plugs. Wrap teflon tape around the threads and screw the plugs back in.
Fuel: processed crude and it's a solvent. Carbon: a by-product of improperly burning the above mentioned fuel. Dissolves in fuel. Mix thoroughly and I defy you to identify it as strictly engine oil. Which by the way also comes from crude. He's not blowing smoke, he's not fouling plugs. it's fuel & gunk.
You can also use Teflon tape. My plugs did the same thing after my engine was rebuilt.
I'm with Harold S. on this topic - anti-seize or never-seize, whichever term turns your crank. Someone correct me if I'm mistaken but isn't Teflon tape for H2O applications ?
While anti seize or similar would likely work, aluminium foil has been my standby for worn plug threads. I have had to chase down so many fuel feed/leaking carburetor etc. problems due to the well meaning use of Teflon tape on fuel connections (not by me) I cringe at the sight of a roll of the stuff.
So, I am to understand that these by-products of combustion are present ONLY if there is compression lost due to worn threads/loose spark plugs? Why? If it is always present, what happens to it? Why does not every model T, or any other internal combustion engine not have this stuff running out the exhaust constantly? Or is it just our crude, low compression primitive stuff?Were that the case, the EPA folks would long ago had, and rightly so have gnashed their teeth and writhed on the ground in agony until all old cars were legislated out of existence
Even today with the improved/cleaner fuels in use how many carbon incrusted Model T block & piston pictures have you seen posted here? Dozens over the years by my count. No modern high compression engine looks like that even after thousands and thousands of miles. It's an inefficient low compression 100 + year old engine design and is "dirty" as hell. No it is not caused by compression leaking past threads. Yes every engine produces it but the newer ones burn it off before it collects as it does in a T. Don't even think of getting the EPA involved unless you really want to be regulated off the road permanently.
Charlie B I understand these old engines are dirty as hell. As soon as you start one up with fresh oil in it, the afore mentioned by products of combustion make the oil black. No matter how clean it is inside. What I want to know is where it goes if it is not coming out around the threads? If the amount that is coming out of Jems'engine all turned to carbon, in no time the combustion chamber would be crammed full. Yes, they carbon up. Also, that carbon in the combustion chamber and baked on top of the pistons in the several dozen T, A, and tractor engines without air cleaners(that had not been apart in modern times, anyway)that I have either parted out or got running over the decades is to a great extent road and field dust. Crude oil is highly combustible. Oil fields used engines that burned crude. Smoke from oil field fires is visible from outer space. Again, why they do not smoke I do not understand.And eventually engines that do this do foul plugs. And a question, Charlie. No disrespect meant. Have any of YOUR antique cars, T or otherwise pumped 'by-products of combustion'out around the spark plugs? I am not trying to be nasty.How often have you seen this with your own eyes? And how the devil or why would I get the EPA involved?
It gets shoved out the threads by compression. It goes down the exhaust pipe and out the muffler on the exhaust stroke and as far as gas engines go the T is right up there with any comparable motor of that era for poluting. I've seem bubbling in the plug wells when water was present from an engine cleaning. I have NEVER seen what Jem describes and I still don't believe it's oil. I'll repeat: he's not fouling plugs and he's not smoking. It's not oil he's seeing. Don't bother getting uppity about the EPA. You brought it up and I don't see what crude burning engines or oil fires have to do with anything here.
Well, my junk pile stand-in engine carries a constant pool of oil in the No.2 plug socket.
I burn a lot of oil with it too. Have to put a quart in it every 10 miles or so.
Just locked in a contract with the County to fog for mosquitos and oil the roads around
these parts !
I have the exact same problem, my 26 pumps oil out of number 2 and 3 . I does smoke when it's cold but once it's warmed up it stops but still pumps oil, it fact more so. I took it on a long run thinking that it would get nice and hot and burn excess oil away but still a pool around the plugs. They are champion plugs, with a tapered thread. The plugs do oil up after a while.the compression is 50 psi on all cylinders. I was considering putting a new set of rings in ,the new type with an oil scraper ring. I have std cast iron Pistons , I have tried never sieze on the threads it didn't work, also a gasket sealer that never worked either. I'm also at a loss as the compression is good.