My 2180 Volkswagen now has 23 hours on it since rebuild and first flight. I have been using a 30 weight oil. When the 25 hour inspection and oilchange comes about, what weight multi-grade oil do you recommend. All of my temperatures stay well within the recommended limits.
Bill Page [email protected] N880AB ----- Original Message ----- From: <[email protected]> To: "KRnet" <[email protected]> Sent: Sunday, June 25, 2006 11:15 AM Subject: Re: Re: KR> oils and stuff > Hello Phil > Thanks for the email and tell Ron I appreciate the time it took him to > reply, and the length of his explanation. He is busy running a business > so I know he made some sacrifice, even if it means sleep! LOL > > I will agree that all oils have improved over the years, they would have > to. It would be stupid to not include advances in straight weights found > in multi's. And some of Rons points about the merits of single visc oils > I also agree with. I believe all engines should be broken in on single > visc oils. The multi's do have too many additives that can end up burnt or > not providing enough cushion lube to closely machined parts. We are also > making some broad statements, because Oil Companies are known for changing > oil and fuels to suit different climates AND different markets. > > The early 70's engines and late 60's engines are probably the best know > around the world. Most other engines are measured against these engines. > However, they are two full generations back from today's advanced engines. > Those engines were kept at 160 to 165 degrees because water pump, > radiator, coolant, and oil technology could not keep them cool if they ran > hotter. This has a negative effect on fuel atomization and combustion > chamber efficiency. Here we need things to be the hottest it can be > without causing the fuel to flash ignite or become complete vapor prior to > entering the chamber itself. > > Late 90's and engines of the 2000's are designed to attempt to maximize > these parameters. They have thermostats that do not open until 195 degrees > and are fully open between 205 and 210F. Then system hovers the temp > between 205 and 220 relying on thermostat, and the coolant properties and > pressure to prevent the coolant from boiling over. These modern multi > oils also need over 140 degrees before they even begin to activate the > additives within them. An engine maintained at or near 160 will never be > able to benefit from a multi oil and will in fact do damage. However, this > engine will also have a short life due to this low temp, as engineers of > late have found, due to the fact that the metal is "cold" too much of the > time effecting everything from the fuel atomization to the strength of the > crank. Mixtures will have to be richer, which causes more cylinder wash, > shortens any oil's life. The crank is weaker possibly as much as by half, > due to the fact that areas not flexing are around engine temp, while areas > flexing and working are going up in temp, with a more brittle metal. I > have always been told by those that know that metals break faster in the > winter than summer. > > A quick check of the temp ranges of operation for single vs multi will > reveal that there is no way a single visc oil can run well in a modern > engine because it cannot adapt from 0 degrees in winter to operation > internally of 250 degrees, and then switch to temps of 70 degrees to 130 > degrees outside driving underhood temps to 400 degrees and internal temps > back up to 250 degrees. And all this with an engine that is designed to > begin driving after only a warmup of 30 seconds. > > Single visc oils can be used regularly if temps are paid attention to and > the weight adjusted accordingly. Most people do not go to the trouble > hence the need to develop oils that adjust for you. My fear is that since > alot of our readers do not know, they will not know the difference and > that could cause an engine failure. I agree that lack of such know how > should be a screening tool for not allowing these people into the air, but > somehow they make it up there any how. More and more builders are using > engine combinations with modern settings, clearances and metals and need > these multi's to survive. A case in point is the use of the Geo Metro 3 > and 4 cylinder engines. These engines MUST use the thinner 10w30 or 5w30 > oils or their valve train will fail very soon after they are put into use, > causing catastrophic failure. Their oil return holes in the heads do not > provide a large enough orifice to allow a thicker oil to circulate, common > among most all of the overhead cam engines. Depending on the version of > the vortec engine they may also have to use a multi oil to be properly > maintained. Single weight oils tend to be correct for too narrow of the > temp range, making the possible extremes go outside their design range and > begin breakdown. > > Especially in cases of engine sitting and getting part time use the > multi's are particularly necessary due to the fact that when the oil was > added it may have been summer but now is winter and a single visc will not > be able to handle the range of temps and may not pump initially when > started. Multi's will thin due to additives and circulate immediately. > Even looking at the popular Corvair motor, the temps it will operate in is > outside air maybe 60 degrees and then will be working hard climbing and > soaring to head temps of over 300 degrees. Single visc oils cannt adjust > for this wide variation in temps, so either you have one that handles the > low temp part, or the high temp, but not both. If singles could do this, > there would be no need for the multi's any more. If VW's are supposed to > operate similar to the Corvair, then you can see a single used after > breakin will sacrifice durability and longevity. > > Colin > N96TA >> >> From: "Phil Matheson" <[email protected]> >> Date: 2006/06/24 Sat PM 10:30:26 EDT >> To: "KRnet" <[email protected]> >> Subject: Re: KR> oils and stuff >> >> Colin Wrote :Just for the record I will say this is foolish and >> potentially >> catastrophic >> ---------------------------------------------------- >> This is a reply from Ron Slender VW Engines, >> >> >> Phill, >> I would like Colin to have a look at the article on oils I sent you. >> Agreed >> that the refining processes are much more advanced from years gone by >> however >> that applies to all viscosities of oil including single viscosity. >> The reality is that single viscosity oils handle a higher heat range >> better >> than a multigrade. >> Additionally a multigrade was primarily developed so that an auto engine >> could start at a relatively cold condition and gradually reach operating >> temperature which in most vehicles is around 160/180 degrees. >> >> Multigrade oils have a lot of polymers and additives to give the oil the >> viscosity but do nothing to help lubrication, in fact they break down in >> high temp conditions. >> >> Single viscosity can handle the higher temps better. Additionally the oil >> tends to "cling " better for cold starts much like the sticky Shell oil >> used >> for aircraft because not all aircraft are used every day. Some oils can >> drain off providing high friction starts until oil pressure is there. >> >> I believe that you have to know a lot about the environment the aircraft >> is >> operating in and recommend the oil according to the application. >> Additionally Phil's engine is basically new and oils that have friction >> modifiers and high range of viscosity will effect the running in of that >> engine. >> After Phill has reached 50 hours then he make look at alternative oil >> options. >> However we have used straight 30 ; 40 ; & even 50 (very hot conditions) >> and >> the Shell oil for aircraft for air cooled engines. >> We do not use multigrade because of the fear that friction modifiers are >> often used in these types of oils which inhibit running in. >> >> Colin, your article on HP and how it effects speed was very good >> demonstrating that hotting up an engine can only increase overall speed >> marginally. Without going into elaborate equations the power difference >> was >> 35 HP and the actual Torque increase using 2500 rpm as a constant the >> extra >> Torque created by adding an extra 35 HP was only 63 ft lbs and that was >> at >> full power. >> Same goes for our gear drive engines. We have the Torque that say a 100 >> hp >> creates at 4200 , the reduction drive multiplies the Torque by the ratio >> on >> top of this. As long as a respectable size prop can be used to benefit >> from >> the extra Torque gain then the advantages of a reduction drive is clear. >> Because of the extra torque gain take off roll is reduced particularly >> when >> loaded, climb out is great and cruise is probably achieved at a lower >> throttle setting because of the prop diameter and available torque. >> A reduction drive will not necessarily provide a higher speed because >> this >> is a character of the aircrafts drag as Colin explains. >> >> The propeller has not even been discussed. Fixed pitch is a compromise, >> that >> we all except as being the norm because anything else is expensive. >> Why not fit a suitable in flight adjustable propeller then you will see >> some >> performance. >> Trouble is the cost of one of those, but ...I would rather spend money in >> that direction then spend lots of $`s trying to squeeze out a few extra >> HP >> out of an engine for very little gain. >> >> Not quite with you on oil Colin but I did like your thoughts on HP and >> drag. >> >> Ron Slender >> >> >> >> >> >> >> >> Phillip Matheson >> 0408665880 (cell) >> VHPKR >> Australia. >> [email protected] >> NEW WEB PAGE >> www.philskr2.50megs.com >> >> http://www.vw-engines.com/ >> OLD WEB PAGE >> http://mywebpage.netscape.com/flyingkrphil/VHPKR.html >> >> >> >> _______________________________________ >> Search the KRnet Archives at http://www.maddyhome.com/krsrch/index.jsp >> to UNsubscribe from KRnet, send a message to [email protected] >> please see other KRnet info at http://www.krnet.org/info.html >> > > > _______________________________________ > Search the KRnet Archives at http://www.maddyhome.com/krsrch/index.jsp > to UNsubscribe from KRnet, send a message to [email protected] > please see other KRnet info at http://www.krnet.org/info.html >
