I've been working on my engine for quite some time, cranking it over to ck. timing, and i realized that unlike modern engines, unless the engine is running at idle at best, there is no oil going to the bearings, pistons and piston pins without the crank going fast enough to splash oil in their direction. am i correct? even running the oil pump with a drill won't do anything but fill the oil pan gutters and go no further if the crank isn't moving fast enough.
comments. worried that i might do damage to the bearings, i dropped the pan and lubricated as much as i could get to with valvoline racing oil and put the pan back on. i got the engine running a few days later so all is well and lube-ing
The oil will pump up the the bearing in a few seconds. There is always oil in the rod troughs to throw around in the engine. Running it at a fast idle will get the oil going in a hurry unless your using a heavy oil Thats why 10W-30 is a good bet. It is like #10 on the start-up and will be circulating in seconds.
what i was trying to explain and warn people about was if i keep cranking the engine and i cant get it started, then the crank and rod bearings never get oil because the oil never gets splashed hard enough to splash up to the cylinder walls, rod bearings and crank bearings so eventually im running them dry unlike modern engines that have oil go through internal oil passages in the crank that will lube the bearings if the oil pump is turning, even if the engine doesnt start and splash the oil around in the crank case.
We must assume the engine builder was smart enough to use assembly lube in excess. All bearings, the cam, and cylinder walls should have assembly lube used liberally.
Ron, I believe that most people don't realize that it takes a very long time for oil to leave a space between metal parts. The surface tension tries to keep the oil molecules next to each other. That is despite the forces trying to squeeze them out. It also keeps a thin oil film on the surface of metal like the cylinder walls. The thickness is dependent on the viscosity which is temperature related.
What the above actually means is that lubrication remains between the parts despite movement even though more lubricant is not added. The fact is that an engine can run at slow speeds for extended times with no or little damage and no oil flow. Many of us have seen it demonstrated at swap meets, county fairs, etc.
So yes providing oil FLOW to engine parts is nice but not critical in the early stages of engine operation.
How about a 'real life' experience. Year before last we had our '27 Coach on the Louisiana 4 cyl tour. Third day out 85 degree weather, I chanced to look down to see Zero oil pressure. Stopped ASAP, opened the hood to find no oil showing on dipstick. The old oil filter had split open.Later, after bypassing the filter it took 4 quarts to reach dipstick full( oh s---). I figured we might as well finish the tour,engine ran fine next two days. Got home and dropped the pan. Pulled the center main and rod caps on each side expecting to see burned journals or damaged babbit. Nope. Everything looked fine,with proper clearance! Since then, have put another 200 miles on it, runs great with no funny noises. What,me worry? I drive Chevys!!! Dan
Dan, I am really glad you posted your story. It illustrates that even zero oil pressure for a short period doesn't mean destruction. Maybe it will help comfort new "old" Chevy owners that their miniscule oil pressure does not predict impending disaster.
Over decades the automotive supplier industry have convinced us that we need to use their "super" product or our engines will be instantly destroyed. Oil pressure and flow are the critical factors in their claims. How many claims can we remember that increased pressure means longer engine life?
After reading the above postings you can understand how I can run my engines with the oil pan off to locate strange noises. The engine is run with the pan on and full of oil. The oil is drained and the pan removed. The engine is started without applying any throttle. You can run the engine for up to a minute at idle which gives you sufficient time to check for any problems.
good info, i had no idea how long the engine was not run before i purchsed it and how long the werer trying to start it before i purchased it. i dropped the pan wgen i purchased it and lube'ed it then manually.
i now have it running and swapped out the oil pump and now have about 4-6 psi at idle.
