---------------------------------------------------------- Engines-List Digest Archive --- Total Messages Posted Wed 07/05/06: 2 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 05:37 AM - Re: Max. Oil Consumption (Joe Trampota) 2. 07:03 AM - Lycoming oil flow (Bernard Despins) ________________________________ Message 1 _____________________________________ Time: 05:37:54 AM PST US From: "Joe Trampota" Subject: RE: Engines-List: Max. Oil Consumption --> Engines-List message posted by: "Joe Trampota" Depending on the severity anywhere within the 1st 5 hours JT -----Original Message----- [mailto:owner-engines-list-server@matronics.com] On Behalf Of steve korney Sent: Monday, July 03, 2006 6:26 PM --> Engines-List message posted by: "steve korney" --> How many hours after an oil change would you say the oil would start to turn dark on a good engine... Best... Steve ----Original Message Follows---- One of the visual signs that you have blowby is the rapid darkening of the oil color after you have changed the oil... Blowby/glazing simply lets the combustion past the rings/cylinder born directly into the case ,,, hence black/discolored oil.. JT ________________________________ [mailto:owner-engines-list-server@matronics.com] On Behalf Of Rhonda Bewley Sent: Monday, July 03, 2006 9:06 AM Gary: Blowby as described by Archie below, typically occurs when the cylinders become glazed. This is often caused by allowing the engine to get too hot (usually a long run up on the ground.) If this is the case, you should be able to have the cylinders cleaned up by your engine shop or a good cylinder o'h shop. Rhonda ________________________________ [mailto:owner-engines-list-server@matronics.com] On Behalf Of Archie Sent: Monday, July 03, 2006 8:54 AM Not likely, Gary, but possible. Usually a blowby problem. With antiquated iron ring designs, and very liberal end gaps, this is to be expected. Keep in mind, that as the rings wear in, the gaps also increase, accentuating the blowby. The "perfect" engine has none. We have no break in on race engines as such. No time for that when racing so we use the latest technologies in piston rings. A leakdown of more than 2-3% indicates hp loss and mandates investigation. ----- Original Message ----- From: Gary Casey To: engines-list@matronics.com Sent: Monday, July 03, 2006 9:11 AM Subject: Re: Engines-List: Max. Oil Consumption I once saw in similar equation published by Continental. Yes, indeed, they could have made it much simpler, but I'm pretty sure all the extra numbers just convert pounds to quarts. 4 quarts per gallon and the density is about 7.4 pounds per gallon. And everyone (including me) must have stopped at OSH and asked them the same question about oil level. I was told that the top quart or two were there mostly for long ferry flights where any increased oil consumption during the flight would give maximum capability of arriving. Don't know, but in a flight behind my IO-360 I burned 2 qts. in an hour's flight. If the flight were much longer I would have needed all 8. The reason it seems to blow out the first quart or two is (supposedly) that during initial climbout the oil level is higher at the back and gets into the gearcase, where it is slung up to the top of the engine. And as some have mentioned, a sudden change in consumption is almost more important than the consumption rate itself since in aviation it seems that any unexpected change is a bad change. I'm trying to figure out my newly-overhauled high-compression IO-540, which started off not burning too much oil (good sign I thought). But now with about 15 hours on the engine I'm getting what seems to be ever increasing blowby. Now the oil drops on the gear leg are real drops, not just oil dark spots. Broken ring? Just curious -- why wouldn't it just be simplified to: .00324xBHP=consumption in qt. per hr. ________________________________ Message 2 _____________________________________ Time: 07:03:39 AM PST US From: Bernard Despins Subject: Engines-List: Lycoming oil flow --> Engines-List message posted by: Bernard Despins I'm trying to figure out how the oil system in my Lycoming O-540 works. I know there is a great deal of variability between models, but I wonder if someone can help me make sense of what I've found. From the back of the sump, there is an finger screen in the oil pickup tube and from there the oil goes up to the pump. From the pump it goes to two possible places, oil cooler or oil filter. Lets assume the oil is cold and the vernitherm (located next to the oil filter assembly) is open. Since it is open, oil flows past the vernitherm and onto the outside surface of the filtering element inside of the oil filter. It returns down the middle of the filter and goes to the right side oil galley. This is the location of the oil pressure valve which regulates pressure by dumping any excess to the sump. If the oil is getting hot, the vernitherm closes and more oil is forced from the pump into the oil coolers. The return from the coolers is into the left side oil galley. This is all the information I can deduce from the exterior of the accessory case. I'm sure there are more details that I'm missing. For example, it would seem that only the right galley gets filtered oil and only the left galley get cool oil. My attempt at describing the system also seems to imply that oil is either filtered or cooled but not both at the same time. Can somebody please assist me in filling in the missing passages and make sense of all this? Thanks. Bernard Despins