Puff O Smoke at take off.

[kybishop]

I have noticed that if I sit for a short bit idling, like you do at about any stop light, I get a puff of smoke out the back when I take off. Sometimes more than others, more so the longer I sit.

Well, I have ruled out my tires. Smoke would come off the back of my 74 Challenger when I took off but I am pretty sure that my tires are not breaking loose on take off.

I do notice a bit of oil consumption but most everyone does. It is not severe but I have not tracked it yet to know for sure how much I am using.

The puff of smoke I know is oil burning. My question is with it building up at idle then burning off at take off. What is the most likely culprit here as far as the cause? Where would the leak down or failure most likely be happening?

Thanks.

Kevin

 

[atomicshawn]

Possibly leaky valve stem seals. How many miles on the engine?

 

[kybishop]

150,000 miles on it. It has been maintained very well, I have the records since it was close to new.

 

[atomicshawn]

Does changing the oil have any effect on the amount of smoke?

 

[kybishop]

I honestly have not driven it far enough or owned it long enough to change the oil yet. Runs great, smooth and stong. No knocking or ticking.

I was planning on switching to synthetic Mobile 1 5-40 which is what I am running in my other vehicles.

 

[B Legit]

Almost positive it is your valve stems seals. I had the same symptoms on mine at 183,000 and when I rebuilt my head it was gone. You could experiment with different viscosity's of oil but it will only be a band aid.

 

[atomicshawn]

From my experience the symptoms you are describing are indicative of a leaking valve stem seal or seals (also called valve guide seals). They are seated around the top of each intake and exhaust valve guide and, when working properly, permit only a small amount of all the oil that is splashing around the top of the cylinder head to move down between the valve and the guide. When they begin to fail, too much oil is allowed and oil begins to collect on and around the bottom of the valve stem. When the engine isn’t running or just idling the oil can sit and collect relatively undisturbed. At startup or under increased throttle, depending if the leak is on the intake or exhaust side, the oil that has collected drips into the combustion chamber or out into the exhaust, burns, and creates that “puff o smoke”.
Other problems can cause oil smoke like worn piston rings, or something simple as an overfilled crankcase. You could have a problem like this, but it seems the smoke is more consistent with these kinds of issues.

The reason I ask about the oil change is that its been my experience with engines with leaky valve stem seals the smoke decreases with new oil, and synthetic can actually make it worse. There are reasons for this but that’s another discussion.

Its difficult to tell for certain if your seals are leaking. You might see evidence on the spark plugs. If the exhaust side is leaking, if you remove the manifold you can see burned oil on the valves and passages.
Note that my experience with this is limited to other manufacturers and this is the first time I have heard an ’80 owner describe what you are seeing. Hopefully someone with more insight will chime in here.

 

[atomicshawn]

Almost positive it is your valve stems seals. I had the same symptoms on mine at 183,000 and when I rebuilt my head it was gone. You could experiment with different viscosity's of oil but it will only be a band aid.

Hopefully someone with more insight will chime in here.

Voilà... I write slow.

 

[yoopercharged]

very common for the valve seals to leak on these rigs. Mine does. The longer you idle, the more blue smoke that puffs when you take off. I put an oil strainer in the PCV hose to catch some of this oil vapor.

 

[B Legit]

Voilà... I write slow.

You are just more detailed than I am

 

[yoopercharged]

https://forum.ih8mud.com/80-series-tech/449629-installed-oil-seperator-my-80-a.html

 

[kybishop]

Excellent fellas, many thanks.

 

[MRaySmith]

Puff of smoke

BTW, my 95' 80 is doing the exact same thing. I believe to be very common with 80's. I did switch to a different non-syn, viscosity oil and had a noticeable improvement. I have not installed the oil catch after PCV, but will this weekend.

 

[kybishop]

I did not think there was much to the high mileage oils, until now.

I had the puff of smoke at take off after idling for a bit. I was using a regular quality oil. I would add a bit to keep the level good.

I switched to Mobil One high mileage and I no longer have a puff of smoke at any time. No smell of burning oil and consumption has just about stopped.

Just found it interesting the drastic change by just going with the Mobil One high mileage oil. I figured it was just a gimmick, the whole high mileage thing.

KB

 

[floridan surfer]

I used to have fairly significant smoke. I suspected the valve stem seals. Someone recommended synthetic oil; I switched and the smoke basically disappeared. This was many years and many miles ago, no problems since.