Smoke Under Load

[DreamRyder1963]

The past couple of weeks I have noticed smoke coming out of my exhaust will I'm accelerating quickly (half to full throttle). I think I might be burning some oil under these conditions. The smoke is white with a little pale blue. Short of rebuilding the engine is there anything I can do to fix this? Is it possible that oil is just getting past the valves under higher rpms?

[Carl Spangler]

Originally Posted by DreamRyder1963

The past couple of weeks I have noticed smoke coming out of my exhaust will I'm accelerating quickly (half to full throttle). I think I might be burning some oil under these conditions. The smoke is white with a little pale blue. Short of rebuilding the engine is there anything I can do to fix this? Is it possible that oil is just getting past the valves under higher rpms?

There are a lot of "mystery" products that claim to free "stuck rings":
GM Top Engine Cleaner, Marvel Mystery oil, Seafoam, etc.

Do a web search and you'll find a couple more aggressive methods which typically involve pouring some sort of solvent into each cylinder.

I recently used Seafoam in the oil and fuel for a new to me 71 SWB and I can't say anything negative about it. I ran a can through it just as a WTF lets see what this stuff does. The old 6 seems to run fine after the 'treatment'.

cheers
JohnG

[DreamRyder1963]

I know seafoam does want it claims at lest of the carbon removal side of things. I might try it on my next oil change. I am wondering since it only does it when I hop on it (not every time either) if I should just keep an eye on my oil levels.

[bob8619]

The smoke is while accelerating or after you let your foot off?

[DreamRyder1963]

The smoke is while accelerating. If I lift off the smoke stops.

[Longhorn 70]

White smoke is usually ATF or water (steam). If you have a TH350 or TH400 it could be a leaking vacuum modulator on the transmission.

[DreamRyder1963]

Its a three speed. When we installed the headers a couple of days ago, we found that the dip stick is way loose. Could this be causing it?

[dubds10]

Had the same thing happen to my 350/350 but only when I'm stompin on it and doing 80-90mph. Don't find it when I stomp on it at low speeds. Figure just oil working it's way to where it shouldn't be lol I think my 350 needs a little rebuild though as it feels tired.

[Longhorn 70]

I guess that rules out the modulator. Check the PCV valve too. If they are clogged or the line leaks it can cause this. Does the engine have a lot of blow by? Pull the oil filler cap and rev the engine. Put your hand over where the cap goes. Do you feel pressure??

[DreamRyder1963]

I think I have a small leak where the hose from the pcv attaches to the carb. Oil slowly puddles on the intake directly below the hose.

[swamp rat]

Originally Posted by DreamRyder1963

I think I have a small leak where the hose from the pcv attaches to the carb. Oil slowly puddles on the intake directly below the hose.

I believe that would suggest ring blow by, time to run a compression test, first dry and record all cyl's, then add a squirt or two of oil one cyl at a time and check again, if the compression goes up it points to bad rings, if it stays the same it points to bad valves, timing chain ect.

[DreamRyder1963]

I tried revving the engine will sitting still but nothing happened. I believe the leak at the pcv is due to an ill fitting hose but I will try the compression test. If it is ring blow by what are my options.

[geezer#99]

Two questions.
How many miles do you travel between oil changes?
How much oil do you use between oil changes?

[DreamRyder1963]

I have only had the truck long enough to change the oil once. I need to due it again. It uses about a quart a month but I think I have a leaking oil pan.

[geezer#99]

Let's rephrase that.
So how far do you drive in a month?

[DreamRyder1963]

Around 1200 miles a month

[zeldman]

Another possibly is worn valve guides or valve seals. The old rubber mushroom valve seals are known to dry out and get hard and let a little oil get into the cylinder.

[geezer#99]

One drop of oil leaked every 100 feet equals one quart of oil every 1000 miles.
Which means if your motor was leak free you'd go about 2200 miles on a quart.
I don't think there's anything wrong with your rings or valve seals.
If you rev it standing still and see no smoke just keep driving it. Fix the leaks.
You're likely showing a little smoke from the oil burning on your pipes.

[mrolds88]

Originally Posted by Carl Spangler

There are a lot of "mystery" products that claim to free "stuck rings":
GM Top Engine Cleaner, Marvel Mystery oil, Seafoam, etc.

I dont know about the other products, but the GM Top Engine Cleaner REALLY needs to be used outside.

[hugger6933]

If your leak is due to blow by or your losing compression due to the blow by the options you asked about are pretty limited to a freshen up of the cylinders by either replacing the rings or the pistons and rings depending upon the situation and how drastic it is once you get inside it. If it is running pretty good otherwise, most likely you will just need to rering it with some fresh bearing and gaskets and a valve job and have a really decent motor, but you have to be careful these days cause the crate motor prices can be cheaper than building your own if too much work has to be done. Unless it is a matching number motor or something like that you may need to do a line item comparo just to keep an eye on the pennies. Jim

[DreamRyder1963]

The engine is very strong. I checked the oil today and its still full so I can't be losing it very quickly. I will problaly throw a can of seafoam in it right before I change the oil pan out but besides that I will just seal the leaks and keep an eye on it.

[DreamRyder1963]

I wanted to give everyone an update. I didn't notice a change with the seafoam but I adjusted the valves and now it doesn't smoke. Some. Of the valves were very loose so I guess that was the problem all along.