cyl 3 and 6 burning oil

[ronclark]

Thursday my truck just started to burn oil lots of blue smoke. running pretty rough.
today i pulled all the plugs and found I am burning lots of oil in 3 and 6 and low compression. the rest of the spark plugs are perfect.
There no water in the oil, so i am wondering if the valves went bad? but then why the two back ones
as far as codes its EGR which is gone, air temp sender, and low compression in cyl 6.

 

[n_grimm]

That's a strange one. Usually bad valves wouldn't make it burn oil. B ad valve seals would that wouldn't lower the compression. Do you have a lots blowby whey you unhook the pcv valve? Any work done to it recenlty?

 

[dave2575]

Has your truck been sitting for a while? (or is it a daily driver) How many miles are on it? Do both 3 and 6 cylinders have low compression? whats your compression test readings? whats your oil pressure? I agree with Grimm about the seals possibly leaking and that they would not cause your low compression. I hope its not your piston rings. let us know any more info that you find.

 

[ronclark]

That's a strange one. Usually bad valves wouldn't make it burn oil. B ad valve seals would that wouldn't lower the compression. Do you have a lots blowby whey you unhook the pcv valve? Any work done to it recenlty?

Its not my DD but I do drive it a few times a month. i live in a small town so most of my driving is on the interstate and back roads on weekends
I do have some blow-by.
there been not engine work for along time, i just put in a Dana 35 after my brother hit a curb and bent the front axle
I put new heads and re-ringed the engine about 5 years ago and it has about 40,000 miles since i did that.
I have about 70/90 psi in the two back cylinder.

 

[Psychopete]

Add a little oil to the cylinders and re-compression check. If better, rings are not sealing and/or busted.

 

[RustedRanger]

I know it's not the "right way" to fix anything and many here probably disagree but if it is bad rings you can try Restore for the oil. It works really well,it raised the vacume in my engine by 2-3 inches. I have seen it work with my own eyes,about 13 years ago my dads mower sucked in a carburator screw that stuck on the top of the piston and he "rebuilt" it. By that I mean he changed the gaskets and rings but didnt bore it out and replace the piston. It smoked like a mosquito fogger! He dumped in Restore and let it sit and run and after about 15-20 minutes no smoke. It is still running today after about 13 years.

 

[Big Jim M]

Howdy Rusty

I know it's not the "right way" to fix anything and many here probably disagree but if it is bad rings you can try Restore for the oil. It works really well,it raised the vacume in my engine by 2-3 inches. I have seen it work with my own eyes,about 13 years ago my dads mower sucked in a carburator screw that stuck on the top of the piston and he "rebuilt" it. By that I mean he changed the gaskets and rings but didnt bore it out and replace the piston. It smoked like a mosquito fogger! He dumped in Restore and let it sit and run and after about 15-20 minutes no smoke. It is still running today after about 13 years.

The smoke most likely came from the oval shaped cylinder and the new ROUND rings not fitting precisely! After a few hours the rings and cylinder will WEAR to fit. Smoking from a rering job is common at first running..
In other words... I HIGHLY doubt the restore did one damn thing cept maybe stole your money. But that may just be me.
Big JIm

 

[Big Jim M]

Howdy Ron

Its not my DD but I do drive it a few times a month. i live in a small town so most of my driving is on the interstate and back roads on weekends
I do have some blow-by.
there been not engine work for along time, i just put in a Dana 35 after my brother hit a curb and bent the front axle
I put new heads and re-ringed the engine about 5 years ago and it has about 40,000 miles since i did that.
I have about 70/90 psi in the two back cylinder.

The first question on all our minds: Do you KNOW how to check the compression? Did you take out ALL the plugs and open the TB? If not then you are incorrect in your readings.. While the plugs were out did you check ALL cylinders to have a comparision from high to low?
Big JIm

 

[n_grimm]

I've honed and re-ringed a few old engines that should have been bored out before. They run ok for a while and then they are just as bad as before. I think a lot of the problem is the cylinder taper where the cylinder wears more on the top than on the bottom of the stroke. Because of that, the rings expand and contract as the piston moves up and down probably taking the tension out of them. I have noticed when taking some apart later that carbon makes them stick in the compressed position so they don't seal when they get to the top of the bore. That's why it's a good idea compare the ring gap as you slide it down the bore to see if it is acceptable. I'm sure I'm not saying anything you don't already know. But I wonder if something that dissolves the carbon on the rings might help. Not much to loose.

 

[RustedRanger]

Uhhhh Big Jim...the rings didnt get changed either. And I guess the vacume on my 2.9L went up 2-3 inches after using Restore was just my imagination?? Maybe a miracle?? Magic?? If you haven't used it then butt out.

 

[Big Jim M]

Crawdads go backwards!

Uhhhh Big Jim...the rings didnt get changed either. And I guess the vacume on my 2.9L went up 2-3 inches after using Restore was just my imagination?? Maybe a miracle?? Magic?? If you haven't used it then butt out.

So then which of your posts contain a lie? In the first post, which I responded too, your wrote:

"I have seen it work with my own eyes,about 13 years ago my dads mower sucked in a carburator screw that stuck on the top of the piston and he "rebuilt" it. By that I mean he changed the gaskets and rings but didnt bore it out and replace the piston."

So when I SEE with my own eyes that new rings were installed in an OLD cylinder... Then when you didn't like my EXPERIENCED post you get out of shape.. Ya can't have it both ways..

MY experience with reringing says new rings in an old cylinder WILL tend to cause a bit of smoke for a while until the new rings "seat" themselves and make a good seal.

ALSO my experience with a "miracle in a bottle" tells me there are lots of bottlers out there harvesting the money tree..
Big JIm

 

[jhammel85]

Just get back to topic.....

Like Pete said, Add a little oil to the cylinders and recheck. This is where I'd start. Try that and let us know what you find.

 

[RustedRanger]

Sorry for the mistake Big Jim...mistake,not lie. Once again...if you havent tried something then you don't have much right to comment if it works or not. Actually I don't believe my dad replaced the rings,that's been awhile. And "a bit of smoke" is not a cloud ascending 15-20 feet in the air while at idle. And (again) why did my vacume increase on my 2.9? Restore has made a difference on every motor that I have put it in that had a lot of miles and it's worth a try if someone doesn't have the money to rebuild an engine.

 

[ronclark]

The first question on all our minds: Do you KNOW how to check the compression? Did you take out ALL the plugs and open the TB? If not then you are incorrect in your readings.. While the plugs were out did you check ALL cylinders to have a comparision from high to low?
Big JIm

well this afternoon i followed what Big Jim said here is what i got.

1 175
2 160
3 20 with oil 70
4 165
5 160
6 180

i cleaned 3 and 6 spark plugs and been driving it, it does not seem to be burning as much oil not sure why that is. 3 and 6 are still covered in oil but not baked on like thy here before i cleaned them.
its sure sounding like i got broken rings then.

 

[kimcrwbr1]

It could be a sticking valve I would try and seafoam it and put a quart of ATF in the engine oil for about 100 miles. Then change the oil and filter and seafoam it again. Did you do the compression test when the engine was up to temp. I dont believe you have to mess with the TB but pull all the plugs and crank on it until the pressure stops moving up usually three revolutions. If it is sucking oil down the guides you can change the seals without pulling the heads just use your compression tester fitting to put air in the cylinder to hold the valves up. In the tech library under 2.8 V-6 explains how. #3 looks pretty bad tho and the overall spread is more than 5% but I would try the chemical treatment first to try and bring those numbers up to spec. I prefer bone yard engines if you find one that had a engine fire are always still good put a gasket set on it and swap it out