| [GMCnet] : Engine oil control. There's alot more then just opinions. [message #277847] |
Thu, 14 May 2015 20:31  |
BobDunahugh
Messages: 2465
Registered: October 2010
Location: Cedar Rapids, IA
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This is an endless topic for discussion. I'd like to get some people to just think about this topic deeper. And no argument. Bob
60 years ago it was just let the oil fly. It's bound to lube everything at some point. It's become a science in it's own right. The manufactures are trying to get rid of every bit of power loss in the internal combustion engine they can. A 1/4 of a HP loss here. Another 1/5 there. It all adds up vary quickly. ( In my competition engines. I'm looking for every little pony I can find. Because being the first loser. Isn't as much fun as winning.) Sorry. Back to the subject at hand. Oil has mass. Mass has weight. And any extra oil that is in suspension. In the crank case, around the cam, and under the valve covers uses up horse power. The first order of business for oil is to keep all parts lubricated. Any extra oil be on that point is a source for power loss. A second use of that oil that's put into suspension. Is to help cool the pistons. And it doesn't take much oil to do that. Lets say you put 50% more oil into suspension to cool the pistons. That will only increase pisto
n cooling by 5 to 7%. And 403's or 455's have never had issues with to much heat build up in pistons. You don't want the oil control rings on the pistons to have to deal with too much extra oil. Engines that have to much oil in suspension. Will also burn more oil because the oil rings get over loaded. This also adds more mass to move. More power loss. In short. With excess bearing clearance. You will have an engine that burns oil. Rebuilt, or not.I've done alot of work in this area. As I build stock, and road race engines as a hobby. So you may say. That's different then what our 455's, and 403's engines do. SORRY. But the same laws of dynamics apply. I've put tiny camera's in all areas of the inside of engine's while running them on Dino's. I don't know of any GMC engine builders that have done this type of research. I've learned were, and how to put baffles to control oil.( My 403 will get a baffle some day. ) I've seen for myself how stock, and high volume pumps pe
rform under different conditions, and loads. In stock, and race engines. Some engines I build run 13 to 1 compression. Need 110 octane leaded fuel. Operate in the 6 to 8,000 RPM range all day long some times. Dino in the 240, to 250 HP range out of a 164 cubic inch GM engine. With no turbo assist. In these extreme engines. I shorten the length of the stock GM oil pump gears by 23 percent. Thus reducing the volume of that stock GM oil pump. I modify the relief valve, and spring. I want that pump to believer the amount of oil the engine needs to survive, plus 5% extra to go back to the bottom of the pan by way of the relief valve. With proper lubrication. Your main, rod, and cam bearings will never come in contact with any shaft. If you really want to increase the amount of oil passing thru your bearings. In a good condition engine. Increase the relief valve pressure. I just know that GM spent alot of time, and money to design the stock pump 40 some years ago. And o
ils are so much better over all those years. The HV pumps require 50% more horse power to run. And that extra oil is just pumped directly back into the bottom of the oil pan.There are some builders that put High volume pumps in all their rebuilt engines. That's fine. There are situations that they're useful. I've had engines that I've had extra oil go to the thrust bearing. The stock pump had the capacity to handle that. I'm not saying that these builders are wrong. But I'd like to see the data that a high volume pump is required in a mostly stock 403 or 455 engine is based on.As for oils. Use what you think is right for you. I use standard 10/30 oil for diesel engines. My 78 403 Royale with enclosed 24 ft trailer with car inside will gross out at around 20,000 lbs. My engine has never been rebuilt. And has 153,404 miles on it with a stock oil pump. A few years ago I pulled my oil pan to check the clearances of my mains, and rods. They were still at GM factory specs.
The people at GM knew what they were doing. Time has proven that. Bob Dunahugh Member GMCMI
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