I hate blue smoke. Anyways I have a couple of questions if you care to answer...

[lbrowne]

Ok. 89 240sx with about 110k miles.

For the most part the car runs fine. If you try to start and go without letting the car warm up at all...yeah she'll spew a little bit of blue smoke. Not huge clouds but I notice it...and thats all I need.

Now today while waiting outside a bank just idling, when everyone got back in I went to go and sure enough...and cloud of blue smoke dumped out.

The car had been running for about 20 mins at that time. After that initial cloud...no more. Even stopped in a parking lot and had someone rev the car while I watched...not an *ounce* of blue smoke.

Is this signs of a ring(s) gone?

I think next oil change I'm going to go to 10w30 from 5w30.

[lbrowne]

Also as a footnote when I first got the car...and before I did the timing chain kit heres my analysis of vertain items when I did a tune up.

Spark Plug closest to the front of the car: very black and gunked up - it was a solid black coating....basically I think oil is getting to the combustion chamber er sumthin from there. I'm going to check that same plug now and I expect something similar.

[PapaSmurf2k3]

run a compression check. if its lower on that cylinder than yeah, your rings are probably toast.

[IvoryJ30t]

im going with valve guides.

[lbrowne]

valve guides being the easier of the 2 to fix? I know replacing rings is a motor teardown operation...I have no idea about valve guides..

[PapaSmurf2k3]

yeah just do the compression check, and pour a little oil down the cylinder of a low compression cylinder, and if that raises the compression, its your rings.

[lbrowne]

when you say that...exactly how is that done?

[PapaSmurf2k3]

buy a compression checking gauge, pull the plugs, screw in the gauge, and crank the motor a couple times. (thats the basic) i think 240sx.org has a detailed method in the faq page. make sure you write down your compression for each cylinder because your probably going to forget them.

[lbrowne]

cool...will do.

gotta go get that tool now

[lbrowne]

Check that, neither looks like a job I can do myself. Bah!

I swear getting a used KA and tuning it up/replacing old parts would be cheaper way to go.

[Structure240sx]

my daily/beater, 91 celica, is like that. after sitting it will puff out some smoke but none after that. i think its the valve seals jsut cuz of gravity i think. sittin there oil isnt goin to climb up the cylinder walls. it would be cheaper to fix then the rings. buy a whole head in good condition and put that on. it will be cheaper than having yours pulled fixed then put back on

[DAEDALUS]

I agree--most likely valve stem seals. Those can be replaced without pulling the head on *most* cars.

[lbrowne]

Maybe I shouldn't worry about it since its not like she bellows out blue smoke the entire time you drive her.

I'm just picky about having my car running correctly

[AzurE]

valve guide seals....happens when you let it idle for a while or on heavy deceleration(high vacuum sucks oil thru the valve guides). synthetic oil will help some, FHS pure synthetic oil will stop it.

[lbrowne]

Correct me if I'm wrong, but Synthetic I thought was the worse oil to put in your car if you're having oil problems. That it will actually exploit your problem.

Not to flame you but judging by your post couint I'm not sure if I'm going to take what you say as serious...unless someone else chimes in.

[rousie13]

Yeah I thought I read that if you switch to synthetic while you're having oil problems, it might make it worse, like you said. If your not, then switching is fine. I switched when I had 165k on the clock. Not positive though, just coming to mind that I read that somewhere.

[AzurE]

The blue smoke is from burnt oil. it soots up your valves, converter, tail pipe, rear bumper. synthetic oil has a higher burn temperature, pure synthetic has an even higher burn temp. my 92 with 178k was a smoker, burned about a quart every 500 miles. i switched to mobil1 and it cut the smoke in half, still burned about a quart every 1000 miles, wouldnt pass emisiions...the converter was choked. i tried the HFS and it doesnt smoke any, its about a half quart low at 5000 miles when i change it. - Its expensive stuff, i dont sell it, y.m.m.v.

[lbrowne]

You've made a very interesting point, is there anyone else that can verify?

[180fan]

well for syn, check how much of it is detergent, mobil 1 uses different percentages of engine cleaner for different oil weights, so no not all synthetics will strip the waxy build up you've accumulated from using naturals. Synthetics also don't burn as well, reason I know that is because I've spilled a little oil onto my exhaust manifold before, the mobil 1 took a hell of a time to burn off while the naturals would burn off pretty quickly. it's always in the same place too, the little dribble that runs off the side of the oil filler on the sohc dammit. dunno though, no real empirical evidence to support it, but just from observation

[lbrowne]

The blue smoke is from burnt oil. it soots up your valves, converter, tail pipe, rear bumper. synthetic oil has a higher burn temperature, pure synthetic has an even higher burn temp. my 92 with 178k was a smoker, burned about a quart every 500 miles. i switched to mobil1 and it cut the smoke in half, still burned about a quart every 1000 miles, wouldnt pass emisiions...the converter was choked. i tried the HFS and it doesnt smoke any, its about a half quart low at 5000 miles when i change it. - Its expensive stuff, i dont sell it, y.m.m.v.

I would like someone else's opinion on this, any other out there?

I willing to try it if I'm not going to do more damage.

[PalmerWMD]

Try Mobil1 0w-40.

Wont burn as easy and is also thicker at operating temps yet still flows well enough for a canada winter.

Fred..

[lbrowne]

if this oil doesn't burn...where does it go since its somewhere where its not spose to be when it is beloowing out my exhaust pipe....see my concern?

[PalmerWMD]

Every motor burns <some> oil, with "tight" motors its so little, you don't notice it even in 5000 miles, with "loose" motors you can notice it easily.When you see blue smoke that means its burining.

I don't fully understand part of your question, are you saying you have already switched to a 40 weight group IV synthetic? (no flame just confused)

Fred...

[POS_S13]

try using a synthetic blend oil

[lbrowne]

I run regular 5w30 oil

Sometimes my car blows blue smoke if left idling for a long time and you for that initial part of first gear. or if you start her up and take off without letting her warm up. other than that, no blue smoke at all.

someone suggested here to put in the synthetic cuz it doesn't burn as easily. well my question is, the oil as i think of it, is getting somewhere where it shouldn't be in order to be burned off...ie the combustion chamber er whatever. but what little gets in there...gets burned off and is sent out my tailpipe.

well if i get a less likely to burn oil (synthetic), isn't this oil still going to get where the normal oil was getting...but now instead not burning off...but just collecting there?

can you see what i'm talking about now?

[PalmerWMD]

If its thick enough it wont get there as easily.

Fred..