Pre-oiling devices?

[strelnik]

I have an engineer friend who has some very old ( 1930s) cars that he drives rarely.

Before starting them, he empties out the oil, checks it, then fills his pre-oiler with the correct amount of oil.

He unscrews the oil pressure sending unit, plugs in the oiler and pumps engine oil back inside at about 30 psi until the correct amount is in the car.

He claims this reduces that initial destruction which comes from dry bearings.

I'm thinking this may be true if he used 1930s vintage oil, but modern oils stick to where they are, unless the car stays unused for years. So there would not be a need for this oiler.

Does that sound about right?

I'm thinking about this for our cars that go into winter storage and are not used for several months.
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L'audace! L'audace! Toujours l'audace!

[CraigInPA]

Modern oil is made to better tolerances than the stuff in the 1930's. Back then, there was 30w. Today we have multi-viscosity oil (10w-30, for example). The multi viscosity oil allows some to "stick" to the engine interior surfaces, due to its heavier weight. But, over time, even that will naturally migrate down to the oil pan (due to gravity), so the top end might be starved for oil on start up. This, however, takes much longer than the time you'd store the car for the winter.

You didn't say how often the cars sit before he drives them again. If I was letting my car of the 1930's sit for a year between uses, I would definitely consider such a procedure before starting the car. Re-building some of those engines (especially the 12 and 16 cylinder ones) is a $10k+ specialist job that you'll want to avoid.

A reason I can think of to do the described procedure on a car driven regularly has to do with the nature of oiling systems in cars of the 30's and older. Most are "splash lubrication", relying upon the engine internals and the cars movement to move oil around inside. There were no oil pumps, and no oil filters. Pieces of metal shed from the internals would, in theory, eventually make their way to the oil pan. Cars driven short distances, or ones started and not driven, are susceptible to getting the metal bits shed at the top of the engine getting stuck there. Eventually, one will get sucked between a bearing surface and an operating part, destroying the bearing. For cars of this vintage, you'll find recommended oil changes to be as short as every 100 or 200 miles. The idea was to get that dirty oil out often.

There have been offered various retrofit systems to add a filter to some older cars, but they are generally ineffective due to the lack of pressurization of the engine oiling. I had one of these on my '41 Packard. When I'd change the filter, I could see that only the bottom half of the filter ever touched the oil.

[mondshine]

Strelnik-
As I mentioned in an earlier post, I have been using an Accusump on my Thing for over 30 years.

"An Accusump is an oil reservoir that is connected to the engine's oiling system. It is designed to deliver pressurized oil to an engine before starting to eliminate dry start scuffing (pre-oiling) and to discharge its reservoir of oil during low oil pressure surges to protect against engine damage during demanding racing conditions. It installs simply with only one oil line connecting it. The Accusump's design includes a piston. On one side of this piston is pressurized air and on the other side of the piston is the reserve of oil. To hold this reserve of oil in the Accusump when the engine is not running and there is no pressure to hold it, a valve is installed on the oil line."
Here it is, next to the driver's seat:

You can see that the valve is closed, so there is about 50 PSI of air pressure ready to push the piston and the oil behind it into the main oil galley when the valve is opened (before startup). Once the engine is running, the cylinder will re-fill. If, for some reason you were to lose oil pressure, like at high RPM on a curved freeway on-ramp, oil in the Accusump would flow to the engine to supplement the momentary loss. If , for some reason the oil pump were to quit, the Accusump would give you an extra 10-15 seconds to shut down before catastrophe strikes.
At my last upshift before shutdown, I let the engine reach ~3500 RPM, and close the manual valve; pressurizing the Accusump for the next startup.

One word of caution is that the manufacturer (Mecca, now Canton Mecca) recommends an oil filter that does not bypass (Canton Mecca filters do not), to prevent dirt, released in bypass situations, from damaging the Accusump cylinder and piston.

The Accusump is plumbed into the full flow circuit with a T fitting and a check valve to direct oil flowing from the Accusump to the oil galley and not back to the pump. Here's the sketch:

I installed this Accusump over 30 years ago when I bought my Thing; in that time, the piston seal was replaced once. Accusumps look a little different now, as do the oil filters since Mecca became Canton Mecca, but they function the same way as always.

Sometimes I drive my Thing every day, and sometimes it sits for two weeks without being started. I live near Detroit, so the Thing is in storage from October 'til May. I like the idea of having full oil pressure before the engine is started, but that's just me.
Good luck, Mondshine

[strelnik]

[mondshine]

Strelnik-
PM sent.
Do a search online for Accusump, and Canton Mecca filters.
There are no local suppliers as far as I know.
Mondshine

[WD-40]

[mondshine]

Rather than drain all of the oil, I keep the Accusump "charged" when I drain the sump. That way, the engine can have full oil pressure before starting.
I realize that some of the old oil is mixed with the new oil, but with a good filter, the old oil is still pretty clean. The oil I use is green (in color) and it's still green when it's drained. I think it's a good compromise to have immediate oil pressure at startup, especially after the oil has been drained.
This year, I have driven under 6000 miles (including 1600 miles to KTE in Branson, MO & back) so I routinely change oil in Spring when the car comes out of storage, and in July, in preparation for a long drive.

When I change oil, I stop filling between the lines, then start the engine, check for leaks, re-charge the Accusump, shut down and let it sit for a while before topping it up. I have a 1.5 qt. deep sump, and find that oil level about .25" below the top line is the happy zone.

Good luck, Mondshine

[Juanito84]

Wow! I'm glad I found this post! Actually I was thinking of how to make something like this before I found this post. I think the piston in the oil accumulator is unnecessary if it's installed in an upright position. All I think I need is a container that holds around a quart and can handle 100psi and +250* F.
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