Help! Spark plugs fouling

[Orion24]

Dear experts,

I own a 26-year old Nissan 120Y car. All was well until an engine cylinder was damaged; after I had it repaired the engine started fouling the spark plugs. The guy that repaired the cylinder tells me that it has nothing to do with it and it is because the engine is old and burns oil. However no such problem existed before the cylinder was repaired. What I have also noticed after the repair, is that the engine "tap" (the thing I open to throw the oil inside), was damaged and oil was leaking from there to the spark plugs from outside the engine. I do not know if it could get to the gas chamber from the outside, but it surely did touch the plugs.

The last time a spark plug died, I insert a new one (code: NGK BP5ES) and immediately pulled it out. It was wet with oil as high as 2cm.

Another thing, is that it is hard for the the engine to make a cold start. I need to try 4-5 times to succeed. Not sure if it has to do with the spark plugs.

Any suggestion guys? (Appart from buying a new car). I can post pictures if necessary.

PS: Do you have a suggestion of what oil I should use with this high mileage engine? (Not too expensive)

[public]

First what happen to your cylinder?

Oil on the outside of the motor could be filling up the plug hole area, but that would not be able to get into the combustion chamber while the plug is installed. This would need to be cleaned out then clean and install your plug. Then you can see if it still fouls(it could have just fouled due to oil draining in there when you took out the old one). If it does then you have a problem with your rings and possibly the repairs.

Was a replacement head installed? You could have gotten one with bad valve stem seals and/or guides, Seals should be changed and the valve guides should be checked any time you use a junk yard head. Good Luck.

[Orion24]

Originally Posted by public

First what happen to your cylinder?

Oil on the outside of the motor could be filling up the plug hole area, but that would not be able to get into the combustion chamber while the plug is installed. This would need to be cleaned out then clean and install your plug. Then you can see if it still fouls(it could have just fouled due to oil draining in there when you took out the old one). If it does then you have a problem with your rings and possibly the repairs.

Was a replacement head installed? You could have gotten one with bad valve stem seals and/or guides, Seals should be changed and the valve guides should be checked any time you use a junk yard head. Good Luck.

Thanks for the response.

I'm kind of a noobie and I don't know what exactly was wrong with the cylinded and if it had a replacement head installed or not. I need to ask to find out.

As for cleaning the spark plugs, I've done it a lot of times and they are still fouling, but I have not cleaned the oil from inside the combustion chamber.

[public]

If you have cleaned them and the hole they go in, then you got internal problems. That means rings, or really bad valve guides and seals. Make sure that they are the correct plugs and that the gap is correct. If they are the correct plugs you may want to go up to a higher heat range until repairs can be made.

[Orion24]

Oh crap. More bad news today. It really seems to be an internal problem. I think I need to visit a repair shop.

I cleaned the oil in the plug holes, the car was fine for a while, but then, after I stopped it and restarted the engine, a spark plug was not working and lots of smoke was coming out of the exhaust pipe. I stopped the car shortly afterwards and all spark plugs were full of oil (but none was dead). Eitherway I changed them all, but the problem was not immediately solved. I let the engine off for 20 minutes and when I restarted it all plugs were working. After some running the smoke stopped coming out of the exhaust pipe as well.

And this is something I've noticed before but never paid attention to it: I never had any problem to occur while the car was running. All problems appeared right after I stop the engine and restart it. And in fact, the engine does take 4-5 times of trying in order to start.

[public]

Get oil in there after shut down, and smoke upon start means that the oil is coming through the valve stem seals. The valve guide may or may not be bad. Good news is that you can change valve stem seals without removing the head. When you go to a shop be certain to tell them that it smokes really bad upon start up. Or just print this reply so you will know what to ask for. Good Luck.

[383PhoenixAm]

I think it might be a better handled question if you were to find out exactly what had been done to the engine when you had taken it in. It should be the shop's responsibility if they did something to your car.

[Orion24]

Thanks a lot for the help guys. It is sad that you can't fix the car yourself, because you need a whole garage of tools. I'll send it to another mechanic and tell him to check the valve stem seals / valve guides.

@383PhoenixAm, what you say is correct, but it is difficult to do in practice. Anyway I'll be happy to see my car healthy again, without having to pay a fortune, cause my dad really has no intention of paying much more for this car.

[Orion24]

Appart from this problem guys, I really feel the car needs a major tune-up. So far I have recently changed:

- Spark plugs
- Plug wires
- Engine oil & oil filter
- Fuel filter
- Air filter

and from what I read I'll also change the distributor cup and the thermostat that does not work. Do I also need to clean the distributor or something and how (or with what) do I clean it? Are there any other wearable parts that I have to change for maintance (everything is too old). And is the 20W-50 engine oil the proper for such a mileage engine, or shall I use 15W-50?

[public]

It needs more than a tune-up. This will not fix your oil issues. A tune-up will not make any difference.