VCCA Home Forums GENERAL DISCUSSION General Discussions Old Films Question

I've been viewing some of the old films of street traffic in the 40s, 50s and 60s that come up on Youtube. Some have been colorized and some make the cars look a little different. That is expected but one thing finally dawned on me as peculiar. It is the cleanliness of the streets. Where in the world is the oil streaks down the center of the lanes and the large concentration of oil drops near bumps? I don't see a speck of oil anywhere and there were some 216 engines seen. Even some 37 and 38s. Were too!

It looks like the lanes have been holly stoned and are as shipshape as an old sailing frigate.

What's going on here?

Best,

Charlie

I am really enjoying those too. Most of the old photos that I see of highways have the streaks down the centre.

This is an example. There are others that are with even more free from oil droplets.

Best,

Charlie

This here one is much more better of what I was speaking.

Best,

Charlie

In that last film segment I noticed that there were some indications of the center oil stripe on the driving lanes. It is not a big difference but there is a consistent shadow down the center of each lane. I also noticed some shadows of oil stain along the parking lanes in some areas.

I expect that the digitalization and colorization removed a lot of that detail. You can see some unusual color changes as cars change their position in the film.

The most important point of remember is that it is obvious that Chevy engineers knew what they were doing when they design the rear main bearing leakage into pre-40 engines. In the era most roads were unpaved. So these cars actually helped with dust control on the majority of those roads. In fact by the 1950’s people who lived on gravel roads were paying a service to spread oil on the section of road in front of their house to help control the dust. And the service use to be free!

The first examples definitely has the stains in the middle of the pains.

Another possibility could be that many of the highways of which you speak were made of concrete rather than asphalt paving, with the result that the dark oil and grease stains tended to show up easier on the white/light gray surface. Just a thought!

Alll makes of cars tended to leak oil back then. You willl, also see black going up big hills where the blow-by blew out oil. I remember seeing that when I was young.

I must have a rare 216. :-)

Although the bottom of the flywheel cover has a light film of oil on it, I never see oil on the pavement or concrete where I have been stopped.
Admittedly, it spends most of it's time parked behind the house on an area of gravel, but at all other times it is stopped in parking lots and the driveways of people I visit.
I've put 700 miles on the last oil change of very light oil and the oil level has maybe dropped 1/16" on the stick.
And a lot of that has been 50 miles/hour on the freeway with a 4.57 rear end!

I'd been thinking I should pull the main caps and see if I can remove any shims,
but now I'm thinking I'm not going to go anywhere near that rear main!

The only significant leak I have is an inner hub seal on the H052 axle.
And that all seems to stay in the wheel with a little on the inner side of the tire.

Not bragging, as the only things I've touched are the pan gaskets and rear end cover...
just saying, I must be lucky to have a rare one! :-)

Hi Ole,

Sorry that I missed this detail. What year is the 216?

And I completely agree with the “don’t fix it if it ain’t broke” approach for the bearings. If the rods are not knocking and you do not have oil leaks, things are good!

Hi Rusty
Somehow I missed seeing your above post until now.
My 216 is in a 1946 3/4 ton and appears to be original to the truck with an ADCA prefix on the serial number.
When the head was off for new valves, springs etc, I noted it had been rebored to .040 over with cast iron pistons.
I had the pan off and removed the last of the rod shims. The rods probably ought to be tighter, and at some point I may try to take .006" off the caps and install new shim packs for a "new start" on the adjustments.
I do think I will leave well enough alone with the mains.
It's certainly not the quietest and smoothest 216 I've heard, but there is no audible "bottom end" noise at any speed. And by my calculations I've had it up over 3000 rpm quite a bit.

You might find this interesting:
Dad drove a 1937 Chev truck which his dad bought new.
He told us how fast he used to drive empty to get back to the combine for the next load, and we've calculated that he often had to be hitting 4000 rpm!

I agree that 4000 rpm can be a bit overwhelming for these engines. I figure that my '37 is running at about 2800 rpm at 60 mph with the 3.73 rear axle. That is pretty comfortable.

A big difference between your '46 216 and mine is that your actually has a rear main seal. That replaced the slinger design in 1940. That explains why you have minimal rear main leakage.

My 1934 and 1939 wih no rear main seals that I had did not leak

Unlike Chrysler products Chevrolet never had anything but standard size piston and bearing in US production engines.
They did start using under sized main bearings in 1956.

I am out of tricks to stop the leak in mine. The bearing clearance is about .0015". I cut the groove in the front portion of the lower bearing. I put a thin coat of sealant on the shims, I have cleaned the slinger disc completely. I have cleaned the slinger cavity in the block. I cleaned the slinger cavity in the bearing cap as well as even removed the check ball to clean it and the drain passage.

I know it is not my valve cover gasket leaking because the area at the rear of the valve cover is dry. And I still use a quart of oil every 200 miles. I know that most of it is leakage. There is no blue smoke out the exhaust.

The only thing left is maybe the plug in the block at the rear of the cam shaft. Until I do the clutch I will not know if that is the problem. I will just keep adding oil. I never bother to change it at this rate!

If there is oil consumption at that rate the trail would show up at idle and may even be a visible spray. Remove the clutch cover, let the engine idle while you watch the area and hold a piece of paper under the flywheel. I have also seen the expansion plug at the end of the camshaft leak especially if the cam has excessive end float.
Tony

Hi Rusty
A quart in 200 miles does seem pretty excessive... now.

But years ago that wasn't out of the ordinary for some engines like the flat head V8 F*rd. Especially after they had a few thousand miles on them.
In fact, their operators manuals offered all kinds of excuses for why they used that much oil, like gasoline dilution in the crankcase being burned on longer drives etc.
F*rd used to have a special paragraph in the manual with a title like "A word about oil consumption" or something like that. :-)

But it's a lot for a 6 cylinder Chev.
If you are seeing oil dripping from the rear of the engine, the plug behind the camshaft is quite possibly a source.
If I were you, there are 2 other things I would look at:

If I remember right, there is an expansion plug in the rear end of the main oil gallery in the block on your engine. Later engines had a threaded pipe plug.
This plug is unfortunately hidden behind the bell housing and will be no fun to access.
It is however my opinion that this is very likely the source of a leak as substantial as yours.
Maybe someone else such as Gene could offer their opinion on this?

Also, have the main bearings been replaced in the past?
The reason I ask is... when new bearings of the rough type requiring line boring were installed, it was very important that the bearing taking the end thrust was cut in such a way as to position the slinger correctly in the groove... with a specific clearance between the slinger flange and the block/bearing cap.
If this wasn't done correctly, too much oil would make it's way past the slinger.
This was true for engines such as the 3 bearing engine in 1929, and I assume it to be true for the 216 in 1937.
Again, maybe someone with more experience will weigh in?

I regret that both of these suggestions involve a lot of work to correct.
But at least they are 2 more places to look.
And if one of them turns out to be the problem... and you decide to just live with the leak... at least you can stop looking! :-)

Hi Ole,

Many thanks for the additional details to consider. I agree that the expansion plug at the rear of the camshaft is the potential culprit. Gene has suggested that in other posts.

I do plan to look at the rear of the engine when I do the clutch work within the next month or so. I agree that overall it is a lot of work. It will not be much more work to remove the flywheel housing when I am doing the clutch. I expect that i will be removing the flywheel anyway to have it surfaced.

I have considered the slinger position in the cavity in the bearing cap and block. It seems to be centered which I thought was appropriate. The crank endplay was within spec so I just left things as they were. There were no signs that the slinger had ever rubbed either face of the cavity.

I will start a new thread when I get into that project.

Charlie,

I just caught the pun or double entendre in the title for your post. When you used the work "films" were you talking about the old movies or the old oil films that were left on the road?

Pretty tricky there!

The streaks of oil on the streets probably started to go away after PCV systems were installed.