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|From a Skinned Knuckles Magazine column|
I write a monthly column for Skinned Knuckles Magazine, a journal for classic car restorers and collectors. firstname.lastname@example.org In one recent column I told the story of the Pow-R-Lube system. You may find it of interest.
Getting Your Money's Worth.
Case History: 1979 Dodge
One of the advantages of working as an auto mechanic for over 20 years is coming across good used vehicles with plenty of miles left on them for practically nothing. This is the story of a 1979 Dodge wagon (225 slant six engine) I acquired in 1984 for $100.
The car came in on the back of the wrecker with a bad transmission. The family had planned to give it to their daughter for college but she refused as she thought it was ugly. They decided to buy her a new one and get rid of the Dodge. They asked for $100 and I happily wrote them a check.
The service records on the vehicle showed it had been well cared for and the body and interior were in perfect condition. With only 75,000 miles on the clock, I decided it would make a good loaner for my business if the transmission repairs didn't cost too much.
I have always liked the Chrysler Torqueflite tranny as it is a snap to remove from the vehicle and very easy to rebuild. This one was no exception. I had it out of the car and on the bench in under 30 minutes. Removing the front pump, I immediately saw the problem. The pump gasket had blown between the intake and exhaust ports. The large 'O' ring around the pump assembly had held so it was not loosing any fluid but hydraulic pressure had dropped to the point where the front clutch pack (high gear) had burned up.
The rest of the tranny checked out ok as low, second, and reverse don't need nearly as much hydraulic pressure to engage solidly. Just as in a standard shift, a bad clutch will start slipping in high gear long before slippage is noticeable in the lower gears since the transmission has a greater mechanical advantage in the lower ratios.
Replaced the front pump gasket, frictions and steels in the front clutch drum, installed a new filter and pan gasket and buttoned it up. After re-installation, the transmission performed perfectly. Total cost of parts was under $25. I drove it home that same evening.
The next morning I was feeling pretty pleased with myself until I started it up. The engine produced a low rumbling sound that went away completely when the oil light went out. Every good mechanic knows what that means - loose main bearings.
When an engine is started cold, it can take several seconds for oil pressure to reach the rod and main bearings. It is during these few seconds that most engine bearing wear occurs. The experts say that each cold, dry start can produce as much wear as 500 miles of normal driving. Also, some drivers have a habit of revving the engine under these conditions thus exacerbating the problem.
I developed the habit of not allowing the engine to run above idle 'til the oil light went out when starting up in the morning and thought no more about it for several months. Then I saw an ad for a prelube system in a national magazine that claimed to eliminate the 'dry start' by pumping oil throughout the engine before each start automatically. "Good deal!", I thought. "Just what the doctor ordered for the Dodge wagon."
So I sent away for information on several such systems and quickly discovered they were poorly designed, cheaply built, produced hardly a trickle of oil, and cost too much. And worse, they used cheap rubber hoses and spring clamps that could easily come loose or burn if routed near a hot manifold and result in loss of lubrication that would quickly lead to catastrophic engine failure. So much for that idea.
But it did get me to thinking. Why not put together a good prelube system myself and give the Dodge a chance for a long, happy life? I decided to keep it simple and use a passive accumulator system consisting of just 4 components; an AeroQuip stainless steel braid over Teflon hydraulic line, a 12 volt solenoid valve, a plain steel tank, (the accumulator) and a control module to turn the valve on and off at the proper time.
The hydraulic line is connected to the engine at the oil pressure sending switch port and routed to the solenoid valve. A tank is connected to the other port of the valve. When the engine is running, oil flows through the line, through the valve, and begins filling the tank, compressing the air in the tank as it fills. Oil flow continues until pressure in the tank equals engine oil pressure. The solenoid valve acts like a check valve when it is off so that oil from the engine can flow into the tank but oil from the tank cannot flow back into the engine, therefore, pressure in the tank will always equal the highest pressure the engine has developed while it was running.
When the engine is stopped, engine oil pressure drops to zero but the tank holds about a quart under pressure. (About 50 psi on the Dodge.) The next time the ignition is switched on, the control module opens the solenoid valve allowing oil to flow from the tank back into the engine's lubrication system. The module continues to deliver 12 volts to the solenoid valve for about 15 seconds to insure oil reaches all critical engine components. This is called the prelubrication cycle.
The engine may be started as soon as the oil light goes out or the oil pressure gauge (if so equipped) reaches it's maximum reading. The control module has now shut off the solenoid valve so it functions as a check valve again and engine oil pressure recharges the tank preparing it for the next prelube cycle.
The Dodge wagon is now 19 years old and had accumulated well over 300,000 miles. The engine has needed no work except for normal maintenance items such as spark plugs, plug wires, belts and hoses, a valve cover gasket, a water pump, and of course, regular oil and filter changes. The vehicle still uses no oil between changes, has even compression across all cylinders, and I've never heard the main bearing noise again. Not bad for a $100 car and I'm sure my customers who use it as a loaner are none too careful with it.
I should mention that the radiator failed early on and I replaced it with a double row Dodge truck unit that dropped right in and has provided much better cooling than the original. No doubt this a factor in the long, dependable service obtained from this vehicle.
The point of this article is that a good prelube system makes sense and can dramatically extend the service life of any engine. Many over-the-road diesel truck engines, diesel locomotives, and marine diesel engines come factory equipped with prelubrication systems so why not cars? The answer is planned obsolescence. Detroit wants you to buy a new car every few years. They have no intention of putting themselves out of business and design their vehicles accordingly.
I believe in getting as much service as possible out of a vehicle and have put forth the time and effort to design and build an industrial quality prelube system. To help others, I have put together construction plans and a parts list along with a list of suppliers for all the components and posted it on the internet. The information is free and available to anyone with a computer and internet access. Here's the e-mail address: email@example.com
What, no computer? Send a large self addressed envelope and 2 stamps to the address below.
P.O. Box 608,
LaPlace, La. 70069
Last Update: April 2, 1999