The Model T Oil Funnel and Lubrication System

A brand new 1914 Model T Ford engine is mounted on the “burn in” stand, one of many in the nearly new Highland Park plant. The large electric motor turns the engine for a minute or so, in order to establish sufficient bearing clearance for the oil to circulate. Prior to the burn in process the engine was filled with oil for the very first time.


The Ford Model T engine is very simple in design and construction yet at the same time very sophisticated in its function, planning  and execution. The lubrication system is elegant and effective. Let’s look at how it works and what we need to do to keep it working.

In the illustration above #1 points at the upper petcock on the engine / transmission pan. The red in the picture denotes the oil in the engine pan. To check the oil in your Model T the car should be parked in a level place for at least 30 minutes. Open the upper petcock. Remove the oil filler cap. Pour in a small amount of oil. Wait 30 seconds. If oil starts to dribble out of the upper petcock the engine is completely full of oil.

There is also a lower petcock. This is the lowest “safe” level for the oil system. You can open the lower petcock. If oil flows out of the lower petcock it is safe to operate the engine. If the oil level is anywhere between totally full (oil dribbles out of the top petcock) and safe (oil pours out of the lower petcock) you can drive the car.

Always make sure both petcocks are closed prior to driving the car.

Oil is circulated inside the engine by a combination of gravity, splash, drip, and centrifugal force. It is important that the oil in your Model T not be too thick for prevailing outside air temperatures. The engine and transmission bearings and bushings depend on oil for their longevity. Thick oil won’t reach bearings as quickly or effectively as thin oil. Let’s look at how various parts of the engine and transmission receive their life blood.

Above we can see the oil funnel as it was in the first 1909 Model T Fords assembled in the fall of 1908. The funnel and oil tube are brass, soldered together. The rotating flywheel / magneto / transmission assembly (removed so that you can see the oil funnel) throws oil in every direction, scooping it up from the oil sump centered below the spinning flywheel. The transmission area is immersed in oil coming from every direction. The small funnel is the recipient of oil dripping down from above. Oil runs down the tube to be deposited in the front of the engine pan just behind the crankshaft / camshaft gears.

Above, the 1912 T engine now has a steel funnel / tube assembly that is slightly larger. This size funnel was continued through 1924 with no significant changes.

During 1924 Ford engineers experimented with a funnel that is twice as large as the earlier version. Fortunately their testing result report has survived until today. We always replace the early small funnels with the later, larger version. The difference in oil system performance is undeniable.

Let’s continue looking at how the oil lubricates the engine components. After the oil is deposited in the front of the engine pan it overflows into the front oil “dip”, a recess in the oil pan (pre – oil door) or in the oil inspection door (mid 1911 – 1927).  The crankshaft and big end of the connecting rods pass through these pan “dips” and by doing so they cause oil to “splash” in all directions. This splashed oil is deposited on the cylinder walls, on the underside of the piston, and all over the cam shaft and pushrods. This splashed oil lubricates the pistons and piston rings.

Oil raining down from the undersides of the pistons makes its way into the upper connecting rod pin or wrist pin bushings. The entire inside of the crank case is filled with a fine oil mist.  This oil mist is drawn into the valve spring chamber by vacuum, or more properly, by atmospheric pressure. Air pressure is lower than atmospheric inside the valve chamber because all of the valves are subject to vacuum during each intake stroke. There are no valve seals in a Model T engine, so some of the vacuum leaks around each valve stem when the cylinder is on its intake stroke.

On pre – 1914 engines there are no drain holes drilled in the floor of the valve chamber. This caused the 1911 – 1913 “closed valve” engines to consume a lot of oil as the valve spring chamber could fill up completely with il on long drives. Ford began drilling a 3/16″ hole in the bottom of each valve chamber  (yellow arrow above points to the hole in the floor of the rear valve chamber) beginning in 1914 to fix the problem. A wise engine builder drills these two holes in the earlier engines while they are apart for a rebuild.

Above, Lang’s and other Model T vendors offer an accessory oil screen that fits beneath the transmission access door on mid – 1911 and later cars with the trapezoidal shaped door.  This screen also has a magnet in the center of the screen. It does a great job of trapping lint from the transmission bands. It is important to clean this screen every 3 – 400 miles. It can become plugged with lint and will decrease oil flow to the transmission bushings if the car is driven with the screen plugged.

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