Engine Builder Shop Solutions: July 2012
Shop Solutions published in each issue of Engine Builder Magazine are awarded a free one year membership to the Engine Rebuilders Council (ERC) and a prepaid $100 Visa gift card.
Olds V8 Distributor Gear Lubrication Problems
When building an Oldsmobile V8, especially a performance engine with a high volume oil pump, it is a must to drill a small squirter hole in the rear galley plug by the distributor gear. A hole .025˝ to .050˝ in diameter will do wonders for gear lubrication and save a lot of headaches in the future.
Jeff “Beezer” Beseth
Newtown Square, PA
Another Way To Keep Gaskets In Place
For gaskets that won’t stay in place, especially oil pan and intake manifold gaskets, I use a glue stick. An advantage of using a glue stick is that it is neat, so you won’t end up with a mess.
Rogers Performance Automotive
Simple Ways To Reduce Back Pain
A shop owner in Kansas, who has, like most machinists, suffered with back pain for most of his working life, found some simple solutions for recurring back pain. A critical issue in machine shop design is that most guys don’t pay attention to the height of work surfaces. Most metal benches come stock with a work surface height of 34˝. This means that if you are of average height, you will need to bend forward to work comfortably. Spend an hour assembling a head while hunched over, and you will feel the strain in your back.
So how tall should your bench top be? This depends somewhat on your height, but a good rule of thumb is to elevate the height of the work surface to the height of your belt. For the Kansas shop owner who is 5´11˝, that’s about 40˝. Shim the legs with sturdy wood or metal and experiment with the surface height until you find the elevation that is most comfortable for you. If you like to sit while you work, use a tall stool measuring 28˝ to 30˝. As this shop owner says, “a workbench is not a desk; go tall.”
Here’s another tip to save your back while standing at a bench: add a shelf or use a step stool to prop up one leg. Elevating your leg 6˝ to 12˝ will help straighten your back and reduce muscle strain.
Looking at the bottom line: happy, pain free workers produce the best results.
Sterling Bearing, Inc.
Kansas City, MO
Keeping Files Clean
To keep your files clean, rub them with white chalk (or any color for that matter) to fill up the grooves. This will keep out the dirt that causes files to be less effective. They will work just fine even with the chalk on them.
Kovach & Associates,
Performance Engine Building
Manufacturers Shop Solution: Oil Pressure vs. Oil Flow
The subject of pressure versus flow can be confusing because it’s hidden inside the engine, so let’s consider this principle in something we all use daily the water system in our homes. The maximum amount of flow is determined by the size of the line into your house if you have city water, or by the size of your pump if you have a well. The upper and lower limits of pressure are regulated by the city or by two electronic pressure switches on your pump.
Everything works fine, and you have water when you need it. But have you ever opened every faucet, including those outside? If you have, the pressure dropped considerably. The maximum flow available has not changed. With all the faucets open the resistance is very small, but the flow is at the maximum and the pressure is slim to nil. Pressure, relative to your house, is created by resistance to flow (e.g., the faucets being closed). When you have total resistance, all faucets are closed, and the upper pressure is limited by the city or the electronic switch, so the flow is zero.
Now let’s consider pressure vs. flow inside an engine. The size of the oil pump is designed to supply the correct amount of oil to meet the engine requirements. It produces a specific amount of flow at a given rpm. The resistance to that flow produces the pressure. There is never a time that duplicates all the faucets closed (maximum pressure/zero flow). The resistance to the oil flow is from the bearing and lifter bore clearances. When an engine is new, the clearances are tight and the pressure is good, just like a faucet that is cracked open enough to produce a small stream of water. As the bearings and lifter bores wear, clearances increase, resistance to flow decreases and oil pressure starts to drop.
When the pressure drops, we get our first signal that something is wrong in the engine. With the increased clearances/decreased resistance, the flow from the oil pump is at its maximum. This is like opening all the faucets in your house. Pressure is down, but flow is at a maximum. If we used a flow meter instead of a pressure gauge, we would see a gradual increase in flow as the bearing clearances increase with wear. But flow meters are more expensive and more bulky than oil pressure switches, making this method impractical.
A few comments about the relief valve in an oil pump: the spring pressure behind the valve determines when it will open. If it is designed to open at 60 psi it does not have an affect on anything below 60 psi unless it sticks open. If it does stick open the pressure will be low at idle but will build up to 60 psi at the point the valve opens.
If an engine has excessive clearances in any area other than rod bearings, the oil pressure will be uniformly low throughout the rpm range. If the rod bearings have excessive clearances, the oil pressure will be low at idle and will get worse as the rpm increases. Rod bearings turn in a circle rather than on an axis so they are subject to centrifugal force trying to pull the oil out of the bearing. The amount of pressure loss will vary depending on the actual clearances in every bearing and lifter bore.
This gives you an idea of how much flow increases with a small increase in clearances, and how pressure can drop when we exceed the flow available from the pump.
Melling Tool Co.
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locations serving engine builders/rebuilders across the U.S and Australia. Shop
Solutions published in each issue of Engine Builder Magazine are a free one year membership to the Engine Rebuilders Council and a prepaid $100 Visa gift card. Winners will be chosen by
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