M42 oil consumption

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Originally Posted By: toneydoc
Go to petroleum quality institute site and look for low NOACK numbers. Don't know if that will help with consumption.


That's why I was running ST 20w-50 until it got really cold. Its NOACK is really low...
That's part of my consideration... Will a lower NOACK if oil is "consumed" create a situation where there is more unburned oil coating and passing through the system? Id assume that a lower NOACK will be more volatile and more prone to combusting well...
 
Originally Posted By: Astro14
At 173,000 I wouldn't be worried about the cat. Run whatever you like.


Except that I have to pass emissions every other year (sniffer test), and the next one is may 2015...
 
Originally Posted By: JHZR2
Originally Posted By: Astro14
At 173,000 I wouldn't be worried about the cat. Run whatever you like.


Except that I have to pass emissions every other year (sniffer test), and the next one is may 2015...


I understand, but the numbers that a model year '91 has to hit are pretty easy, right? Different than the more recent cars. Frankly, I don't think the cat is working anymore anyway. Not at that mileage. And I think you'll pass without it...
 
Originally Posted By: JHZR2
Originally Posted By: toneydoc
Go to petroleum quality institute site and look for low NOACK numbers. Don't know if that will help with consumption.


That's why I was running ST 20w-50 until it got really cold. Its NOACK is really low...
That's part of my consideration... Will a lower NOACK if oil is "consumed" create a situation where there is more unburned oil coating and passing through the system? Id assume that a lower NOACK will be more volatile and more prone to combusting well...


The lower NOACK oils will help the oil consumption if you're getting the oil good and hot on every drive. They will lose less volume at constant high temps versus a typical NOACK oil of 12% to 15%.

Have you looked into the intake past the connection to PCV system to see if the oil is being consumed in that fashion, or are you convinced that the oil loss is through the rings or valve stem seals?

Valve stem seals, you should be seeing smoke on throttle chop.

BC.
 
Originally Posted By: JHZR2

So the question really becomes if Im better off running a lighter oil that will likely burn easier,


TC-W3? That should burn pretty clean
wink.gif


Actually maybe you should put some in the gas and see if a UCL helps the consumption any. 200:1, I'd say. Can't hurt.
 
Originally Posted By: Astro14
Originally Posted By: JHZR2
Originally Posted By: Astro14
At 173,000 I wouldn't be worried about the cat. Run whatever you like.


Except that I have to pass emissions every other year (sniffer test), and the next one is may 2015...


I understand, but the numbers that a model year '91 has to hit are pretty easy, right? Different than the more recent cars. Frankly, I don't think the cat is working anymore anyway. Not at that mileage. And I think you'll pass without it...


The car has no EGR so NOx can be an issue. It passed with flying colors last time...
 
Originally Posted By: Bladecutter


The lower NOACK oils will help the oil consumption if you're getting the oil good and hot on every drive. They will lose less volume at constant high temps versus a typical NOACK oil of 12% to 15%.

Have you looked into the intake past the connection to PCV system to see if the oil is being consumed in that fashion, or are you convinced that the oil loss is through the rings or valve stem seals?

Valve stem seals, you should be seeing smoke on throttle chop.

BC.


But if the lower NOACK oils are making their way into the CC and cat converter, they will also be less likely to volitilize and combust, so they could build up more over time too...

The car doesnt have a PCV, just a breather into the intake. Theyre all clean and good.
 
So driving on the interstate, judging by headlights, it seems that driving along, all's clear, but if I press the throttle hard (but not floored) I'll get smoke. If I let off the throttle then get back on it reasonably hard, nothing.

Every diesel ive ever driven has let a little smoke in the headlights when getting on the throttle. I'm not sure if I should read into it at all.

All this done around 70 mph/3000 rpm, which is how much of my driving is.

Thing is, it's cold out. Go a little richer/cooler in a step transient, and what's to say it's oil?
 
I bet you have really good compression. And without and egr system probably fairly hot egt. I bet you are burning it clean! Cars that smoke have issues with the whole ring set( not just the lower oil control ring like in saturns and possbily in your case) and therefore low compression and lower egt so it does not burn clean and viola smoke all the time.
 
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Originally Posted By: JHZR2
I want to keep track of things and not ruin it. My hope is it goes to someone at a trade school or something like that to mend the rust and work the engine.


A little attached to this vehicle? Once you sell it, why care? Just an inanimate object, afterall. You got your use out of it.

Yet I still keep buying "good" oil for mine... and haven't flipped it on CL either.

I take it that the plugs stay looking clean?
 
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