Thread: oil blowing out at high speeds

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.....hmmm, the 400 small block that I used to have in my '32 did this. So I'm interested in what others say about this. Everytime I'd get on it oil would be ALL over the place! I never really knew what the problem was as the motor blew up before I got it figured out {I'm not saying that's why the motor blew up}. Although when it did blow it broke the camshaft in half because of a bearing seezing so this could be an oil issue. I didn't have baffles in the valve covers so I put them in but it still did it {I tried two different types of baffles but still blew oil out}. Do you have baffles in the valve covers? Twice when I got on it the oil fill cap blew off & once the dip stick flew out! Someone told me it could be because the rings weren't seated so pressure was getting past the rings & into the oil pan. Then this pressure would release up to & out of the oil fill tubes. But what this was have with replacing a cam is beyond me.... Again, I'm interested in what others say..... good luck... Bill

Bill, Yes on the Baffles. I've tried two different types of valve covers and made my own baffles but that didn't solve the probelm.

Coming down a long grade on compression, does it smoke when you roll the throttle on far enough to maintain highway speed?
If so valve guides are probably worn.

If you roll the throttle on from low speed does it smoke and blow oil?
Rings are probably not sealing as well as they should.


If things look ok and you're on the highway, running 3000-3500 rpm (short gears) for a while, nail it and then smoke comes pouring out you have an oil vapor control problem.

You may even see a faint blue haze following the car while running at above normal rpm.


Aside from the above, this looks like it could be the problem: "I'm running a hose from my oil vent in my valve cover to my carb to take care of some blow by."

By oil 'vent' you mean PCV valve?

Or you're running a line from rocker cover oil filler cap to the PCV inlet bib on the carb thereby putting vacuum directly on the crankcase?

Or you're running a line from rocker cover oil filler cap to the air filter . . . and if so, does the line terminate inside the filtered area or inside the air filter, but not in the filtered area?

Take a look at this:

The line I'm running is not my pvc valve hookup , its on my other side on the engine and I'm using my vacuum from the carb to suck in blowbye which I never had until I put in the new cam. That took casre of blowby, and my valve guides are in good shape and the rings have seated OK as I'm not blowing any smoke out exhaust at any speeds. Take a look at the picture.

Which didn't come through. Let me try again.

Here's another picture

This one is from my PCV valve