Smoke/oil blowing out oil fill tube

[SteveR.]

I just swapped a used engine into my '30 Tudor. It is blowing a lot of smoke from the oil fill tube, and even spits small droplets of oil out. I assume that means bad rings, and that I'd have to pull the head and pan to remedy the issue, is that correct?

The engine makes better power than the one it replaced, runs smooth, starts easy, etc., is there any other remedy to stop the oil spitting and blowby? I think I've seen heavy steel wool stuffed in the top of an oil cap, maybe it was for this reason?

[Railcarmover]

Crankcase pressure is compression blowing past the rings. Make sure the tabs on your filler cap 'stand' the cap off the tube...steel wool works to control the mist.those after market flex tube fillers ducts the smoke /spray underneath the car.My engine has a second vent tube on the upper rear of the valve cover..PO put it in ,I left it,it cant hurt.

[30 Closed Cab PU]

Is it perhaps missing the filler tube/cap baffle?


Is the smoke actually coming out of the tube, or is it the mist getting on hot engine parts and smoking?


Oil smoke out the tailpipe, and are the spark plugs OK or showing burning oil?






Steel wool should probably not be used, over time it disintegrates. I can not remember if you can use copper or brass pads. Some people use a sock over the tube for misting .
To see if it is blowby an old trick is to tape a plastic bag over the breather tube. It should puff in/out, but not blow off the pipe or split the bag.




Another thing you could easily try is to perform a compression and/or leak down test for diagnosis.

[Richard in Anaheim CA]

Don't put anything in the oil filler tube. It will only push the oil out the rear main.Make sure the cap and tube are allowing the crankcase to breath freely.Use any 10-30, 10-40, 20-50 detergent oil you use in your modern cars.

Put an old gym sock over the cap and tube. Now go out and drive it couple of hundred miles vigorously. Climb a few hills. You don't have to do it all at once.

The sock will become a mess. Throw it away as many times as you need to. Keep an eye on the oil level and don't let it go below the add mark.

If your condition is not greatly improved, you can now think of taking the engine apart.

RICHARD
ANAHEIM CA.

[chrs1961815]

You never want to put anything in the oil filler cap as it is vented and allows the engine to breathe. If it is plugged, the pressure will go out the rear main with an oil leak. Another point of interest is to make sure nobody pushed the cap down and bent the tabs.

Do you know what design filler tube is on the car? The later ones are the best, though Ford never quite did get the blowby issue solved.

[aermotor]

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Check that the oil is not over filled, not all dip sticks are the same. It is safe to run at a known 3 1/2 qts. for this check.

John

[Dutie]

Hello Steve, Ive had the same issue with mine spitting some oil occasionally, all my baffles are their. Steel wool is a NO NO, bad choice. Ive been using a stainless steel scrubby for about 5 or 6 years now without any breathing issues, no chance for it to come apart or break up. Stuff it in a pipe of the same size and blow through it, no restriction at all. Good luck with yours and hope this was helpful. Happy Motoring ! Dutie

[SteveR.]

Mine is spitting a lot of oil, enough that it is dripping off the oil pan after driving. I assume re-ringing the engine is inevitable, but hopefully not worse than that?

Oil is not overfilled per the dipstick, it is about 1/4 quart low.

It does have the baffle in the dipstick tube.

I'll do a compression test. If re-ringing/honing is necessary, is it as simple as dropping the oil panel, unbolt the con rods, remove the head and push the pistons out the top?

[Railcarmover]

Yup,provided it doesn't have a ridge at the top of the cylinder.If its a babbit engine it might have shims under the rod caps.If your going that far do an 'overhaul',check and adjust main bearing clearances,change piston ring hone cylinders and adjust rod bearing clearances,clean oil pump and lap valves..freshen it up all the way around.

[katy]

It does have the baffle in the dipstick tube.

???

[rotorwrench]

I have one of those old aftermarket oil filler caps that has a flexible draft tube that can be aimed back toward the rear so it oils a different part of the engine compartment.