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Smoking/Black Tailpipe


Mycroft

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About a week ago, I went for a short ride. When I got where I was going, I noticed a light cloud of smoke from my tailpipes. Same thing when I got home. I’ve driven a few times since then and noticed that when I start it up, it seems to run clean with just little white condensation puffs. After a few miles drive... smoke.

 

When I go to look, it smells rich. I can’t be certain of the smoke color but I think it is grey or possibly blue/grey. Too much green foliage in the background.

 

Tonight, on a whim, I put my finger in a pipe and came out with this...

 

post-24155-0-42270500-1531786186_thumb.jpeg

 

I have a 350 with a Holley 650. The oil is cleaner than any I’ve seen. She runs otherwise very well. Any thoughts?

 

Thank you in advance.

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About a week ago, I went for a short ride. When I got where I was going, I noticed a light cloud of smoke from my tailpipes. Same thing when I got home. I’ve driven a few times since then and noticed that when I start it up, it seems to run clean with just little white condensation puffs. After a few miles drive... smoke.

 

When I go to look, it smells rich. I can’t be certain of the smoke color but I think it is grey or possibly blue/grey. Too much green foliage in the background.

 

Tonight, on a whim, I put my finger in a pipe and came out with this...

 

attachicon.gif9BB8F8C9-7A63-479B-B3B9-DA61CFB81275.jpeg

 

I have a 350 with a Holley 650. The oil is cleaner than any I’ve seen. She runs otherwise very well. Any thoughts?

 

Thank you in advance.

 

How many miles on the engine? Can not tell by the picture is it "sticky" or is it "sooty"? Could be a carb running rich or valve guides or valve seals. I'm been dealing with the same problem. I pulled my intake only to find puddles of oil in most the head intake ports. So I just pulled the heads and back to the machine shop they went. The engine only has a few hundred miles on it. We are thinking a problem with the valve guides. Will know for sure in a couple days. 

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Thank you for the reply. The Monte has 98000 miles but the engine supposedly has less than 10000 on a rebuild.

I've since asked the wife to have a look at the smoke and she says it is grey with a hint of blue.

The oil level has definately dropped only after roughly 30 miles. The oil is still very clean and she still only smokes after she warms up. 

The black on my finger in the photo was oily/wet.

On a recommendation, I disconnected the PCV and plugged the hose but have notice no change with the exception of this clump of snot like oil in the passenger side valve cover breather...

post-24155-0-58930800-1532549944_thumb.jpg

 

I'm an admitted noob. I'm going to run a compression test whenever the weather breaks and I have some time. Even though this could cost, I find it interesting. 

 

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First...put the PVC back in, your only making it worse by not venting the engine. In fact it could be your whole problem. Make sure the pvc "rattles" and it maybe a good thing to just replace it now. Is this something new after driving with this set up for 10,000 miles? My first impression is that unless your engine has some work done to it a 650 carb maybe too much so you can start by reducing the jets to see what that gets you.

 

Being that you have black smoke these are my first choices. After that you may need to do a leak down test to see if the valves and piston rings are ok but that would seem unlikely.

 

Steve

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Thank you for the reply Steve. It's appreciated.

I only bought the car a couple months ago. She ran fine with the exception of a bog when punching the gas. Long story short, removing the AC cannister and capping the line got rid of the bog. The cannister was only attached to the vac. The other end was open, apparently creating vac leak.

 

The motor is bored 0.030 over and has apparently had some work done. Unfortunately, much of that is vague. It has a mild cam and at one time had a Holley 750. The P/O felt this was causing a bog... go figure. Could have been. Or it could have been the AC cannister? 

At any rate, she ran very well and then better after the cannister was removed. 

 

The PCV valve does rattle when you shake it. I disconnected it on a hunch that oil may have been sucking into the vac. line. It's now reconnected. I could certainly get a new one and give it a try.

 

I was going to do a compression test next but I understand a leak down test is the way to go. I've just been tied up with bad weather and life in general. I'll update when I have a chance to get back to it. In the mean time, I'll get a new PCV valve on order.

 

 

Thanks again.

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