oily spark plugs

[xkeithx]

i just got a datsun 280z from a friend, it had been sitting for a few months and i guess it just needed a battery and the clutch needed to be bled. i got it running and drove it home, the engine ran nice and smooth. i had been taking it out every other day or so, just driving around the block, and like the 4th or 5th time i drove it it just stalled.. now whenever i start it it feels like its missing or something, i pulled the spark plugs and they are all coated in oil. does this mean i need to rebuild my engine?? i mean, it ran fine before, when i drove it home. i havent changed the oil or anything. the only thing i did to the car since i got it was put a new battery in and top off the clutch fluid, and fill the gas tank. the wires seem fine, what type of spark plugs should i get? whats the difference between the resistor and non resistor plugs? i was looking at the ngk plugs because i know thats what everyone seems to rave about in this forum, but which one? there are many different kinds that i have seemed to find that fit a 78 datsun. i live in california, and it can get to 100 degrees outside.. i dont know if that makes a difference or not. also, what type of oil should i put in? since i havent changed the oil since obtaining the car, i know it should probably be first priority. what grade should i get? synthetic or non synthetic? thanks guys.

keith

[2ManyZs]

If the car has been sitting for a long period of time, the first thing you should do is to change the oil and filter. Don't bother with synthetic, it is a waste of money with an engine of unknown mechanical condition. Just buy a good brand name oil and filter. 10w/30 or 40 would be a good start as far as what weight to use.

The second thing you should do is to have someone do a compression test on the engine. A leakdown test will tell you more about the overall condition of the engine than any other test you can do. It may have worn rings, or bad valve seals, or a combintaion of a few other things. This may be part of the oily condition on the plugs. Do this first before you bother buying new plugs.

You need to find out exactly what compression you have, and how well the rings are sealing and what shape the valvetrain is in before you worry about whether you will need to do any major work to the engine.

[beandip]

Keith , congrats on the new car. I was wondering are you sure the plugs are oil fouled or could they be fouled by to rich a mixture of fuel? Do change the oil and filter and I would change the fuel filter also . Now if you only have been driving vary short distances like you said just around the block you could have just fouled the plugs because it was always running cold and on the rich start up cycle and never warmed up sufficently. As far as plugs resister plugs are for a car that has a Radio so that they wont effect reseption. NGK work the best , they were the first things I changed in my car .

[xkeithx]

yeah actually now that i think about it, i think they were just fouled by a rich mixture of fuel. i got the ngk's, put them in, and the engine was still having that weird problem where it would miss. i replaced the cap and rotor, and then it started up very nicely. so i guess it was just the cap and rotor contacts that were bad. i still havent replaced the oil, i havent really had time to drive the car, or do any work on it. i just need to get it registered and replace the bald tires before i really drive it. but since its just sitting, should i wait till everythings ready to go before i change the oil, or does it matter? and when i do change it, should i run the engine first to warm it up, or just drain it cold? i want to get as much sludge as possible out of the engine so it will be nice and clean.

[Ed]

Since it's been a while since the last oil change you can try changing the oil twice. First warm the engine up for about 10 minutes. Drain the old oil replace the filter a cheap filter will do. Add 5 quarts of fresh new Castrol 10-30/40. Run it again for about 1 hour,(go for a drive) let the oil really work it's way around. Then drain it again. It's kind of like washing the inside of the engine. You'll see when you drain it again, all the junk that didn't drain the first time. Now install a quality filter and add another 5 quarts of castrol 10-30/40. And you are ready for action. I know it seems kind of redundant to change it twice but this is the only way to be sure you have clean oil throughout the entire engine.

[laffeaux]

Speaking of cleaning the engine out...

A friend of mine recommended adding a quart of ATF and running it for a 10 minutes or so and them changing the oil. According to him the detergents in the ATF clean out a lot of the deposits.

I've been reluctant to try it. Anybody else ever hear of this?

[2ManyZs]

I have heard of it, but would advise against it. It would only contaminate the new oil since you will not be able to get every bit of it out of the engine when you drain the pan.

You would be further ahead to use some kind of additive like Rislone or something like that instead of using ATF. ATF is only good in transmissions, it has no place in the crankcase of an engine.