VCCA Home Forums TECHNICAL - 1945 AND EARLIER 1929-1932 Oil leak

JYD enlighten us I have never heard of this "check valve" I thought oil leaks were the engineers way of making you renew the oil.

In the rear main bearing cap is a tapered hole with a ball bearing. This is a check valve. And, the goofy way that it is supposed to work is when the car goes up a steep grade, the ball bearing rolls to the back of the tapered hole, blocking the hole, thus preventing the oil in the pan from running out on the ground. If the ball bearing gets stuck in the back of the hole, then the oil that is returning to the oil pan through the rear main bearing, is blocked and the oil has no where to go except on the ground. Most fellows remove this ball bearing check valve in the rear main bearing cap when they rebuild their engines to avoid this possible oil leak.

Good idea, Florida is so flat the ball would not work that much anyway.

Hey - I've seen that when I did my rebuild! I believe I also read about that at the same time in the old straight-6 manual (as usual, it only describes what it was, not why it is there.) :rolleyes:

It's a single bar that hold the ball bearing in place, right? So, you're saying dudes who do it the right way snap off that bar and pull the bearing out?

(P.S. does this mean that some Model T owners do it the opposite way and install a check valve in their rebuilds...?)

Yep! There is a vertical pin that holds the ball in place. And, nope, the model T dudes, (like the dudes that worked on Donald's car), don't do it the opposite way, they just install the rear main bearing cap upside down! :eek: :eek: :eek: :eek:

I have never removed the ball on any of the engines that I rebuilt and don't know of any one that does. Exception might be the left coast dudes that also machine rods for inserts and make numerous other internal modifications. I have found that the original way Chevrolet put the engines together was OK and they run without problems for at least 25 years while in my possession.

If the ball is removed and the car is parked on an incline the oil seep out .It isn't as important when the engine is running as the oil level is lower then.

That is true about parking a car on an incline if you live in San Francisco!

Also, sounds like old Chipper Dipper needs to get out more often! Over the past 15 years or so many of fellows that I have talked with concerning this oil leak problem (east coast, west coast, mid-west) have removed the ball bearing check valve to eliminate the above described oil leak. :eek:

If you use a good motor oil and keep it clean what are the chances of the ball sticking? I guess if you parked up hill and let it set for a few years it would be a problem above 50% of the time?