ejw71 Posted February 7, 2004 Share Posted February 7, 2004 As synthetic oils are costly but allow for extended change intervals it seems it's a wash out economically vs regular motor and trans oils. It's claimed to derease friction and increases gas mileage. Seems like it would take many a zillion miles to save a gallon. Seeking knowledgeable info. Thanks, Ed Link to comment Share on other sites More sharing options...
Guest Posted February 7, 2004 Share Posted February 7, 2004 Hi ED for me synthetic oils has saved me $4.00 a day on gas it dose not burn as much oil as it did runs cooler and this truck runs all day 5 days a week. so from $30.00 to $26.00 i save on gas and i dont add as much oil if i add so i save on that. But on rubber rocker cover gaskets if you get the synthetic oil on the gasket befor you put it on you will not get a seal it will leak all the time that is my info that i know frist hand. hope that help. Thanks Elio P.S. The math $4.00 a day saved with synthetic oil times 20 day =$80.00 For the year it is $960.00 that is just the gas plus what i save on the oil to. Link to comment Share on other sites More sharing options...
mjs-13 Posted February 7, 2004 Share Posted February 7, 2004 Synthetic oils are wonderful for newly rebuilt engines (after break-in) or new vehicles. Many new vehicles are designed specifically to use synthetics. I use synthetics exclusively in my road race GT-350 for transmission and rearend. Given the fact it is changed every race and its 14 quarts, I use good ole Valvoline in the engine. I would not use synthetic is an older engine with miles over 50K. At this point you already have worn the engine enough that the benefits of synthetic would not be worth the cost. Synthetics also are of a lower visocity and will leak more if your engine already leaks. Try one of the "high mileage" oils now marketed with wear additives, seal expanding properties and viscosities for higher mileage engines. Chevrolet has not made a "V-8 Production Installed" engine with Forged pistons since the L-89 Tuned Port Corvette engine in the mid-late 80's. This statement will get everyone fired up but go look at the information. Late model LT-1, LT-5, LS-1 do not use a Forged piston. There is one piston that is a "modified type" of forging in a late model engine however it is not a true Forged piston in the true meaning of the word. There are "Forged Pistons" in several of the V-8 crate engines offered by Chevrolet. These engines are not subject to the same durability/use standards as those for current "production line installed" engines. Forged piston engines are set up with loose clearances when cold and "tighten" as they warm up due to thermal expansion. Ever notice how "dirty" the oil would get in old cars and how fast that happened? Loose clearances at cold startup caused hydrocarbons by the rings and walla, dirty oil! Thats why old oils had so much detergent in them. Older engines also used more oil than today's engines. Piston and piston ring technology has taken GIANT leaps to account for this wonderful change. Engines today use little, if any oil. Today's "GM production engines" use different types of pistons such as hyperutectic pistons, even in high horse applications. Use of these different pistons allow for much tighter cold start clearances, are much quieter and longer lasting. Also gone are many of the "long skirt" design pistons seen on many performance pistons of the 60's and 70's. Cold start is where most damage occurs. Cold start is where synthetic oils shine as they can be designed for specific characteristics. Many of our cars came with "cast pistons" as Monte's were not generally delivered with "HIPO" engines that saw the installation of Forged pistons in the early 70's. Synthetic oil would help if we could go back to when the engine was new. Late in an "engines" service life, don't waste the money. If you rebuild your engine with cast or forged pistons and plan on keeping your car, by all means use synthetic after break-in. Given today's piston technology, I would not build a "street" engine with Forged Pistons. To many BETTER/cheaper alternatives in the market today. I would change a "good/properly operating" transmission or rearend today to synthetics fluids. Manual transmission work especially well when filled with the properly recommended synthetic transmission fluid. Rearends rarely, if ever, get any service so go ahead and change to synthetic and you are good to go for as long as you will own the car. Don't forget the proper "posi" additive if recommended. Read the back of the synthetic rearend fluid bottle. Some already contain the needed friction modifier in the fluid. Maybe others will chime in but "I" believe synthetic oil is great stuff for specific applications. I use Mobil 1 and have for years. Look at what you plan to do with your car and make your own decision! Link to comment Share on other sites More sharing options...
72MC Posted February 7, 2004 Share Posted February 7, 2004 I agree with mjs-13. I changed my truck over to syn oil at 50,000 miles. A tractor/trailer mechanic I know and respect said that would be the threshold for an older engine. He said I should change every 10,000 miles. I couldnt accept that amount of use on oil so I began changing at 5,000 and as my experience grew with the syn, I am changing the oil now at about 8-9,000 miles. The oil doesnt look bad and the truck has 140,000 miles on it. No burning oil or any sort of problem yet. There is one problem to watch for when changing over on an older engine. There will be a reseatting occurring in the first 5,000 miles. You will consume some oil in the changeover. It freaked me out at first but got back to normal in about 5,000 miles. One good aspect was my pressure dropped about 4lbs and the temp dropped a couple degrees. I changed my wifes car over at 10,000 miles. This same T/T mechanic told me to break new engines in on natural oil then change over. Her car has 130,000 miles on it and again, no problems. I, however, have not changed the Monte or the Olds over to syn. The Olds has to many miles and the Monte only sees 2,000 miles a year. If you use syn, ONLY USE MOBIL 1, it is the best. My opinion. - Dave Link to comment Share on other sites More sharing options...
Guest Posted February 7, 2004 Share Posted February 7, 2004 Synthetics are great. I run Royal Purple in my Monte. It does increase power over conventional oil.run synthetics in the tranny though. Been there done that. I ran some Royal Purle tranny fluid and it hurt my 1/4 mile times alittle. I also run Royal purple gear lube also. The oils great stuff though. I felt an immediate difference in power after the first change and it got better the more I ran it. My engine though likes to eat sythetics more than conventional oil for some reason. But to me the added performance is worth it to me. Some engine from what I understand react this way to synthetic oils. Jon. Link to comment Share on other sites More sharing options...
kc8oye Posted February 7, 2004 Share Posted February 7, 2004 now.. I don't have my book infront of me.. but IIRC my 3100 has forged pistons in it. which is why the darn thing piston slaps like crazy when its cold. a little bit later I'll look for the book and verify Link to comment Share on other sites More sharing options...
mjs-13 Posted February 8, 2004 Share Posted February 8, 2004 I do stand corrected on Forged Pistons. I said "GM" engines in my post when I was thinking about and meant to say "Chevrolet V-8 engines". I have edited the post above to reflect Chevrolet V-8 engines. Link to comment Share on other sites More sharing options...
Guest Posted February 8, 2004 Share Posted February 8, 2004 I have a 440 in my Dodge truck. For many years I ran synthetic oil in it. I switched to the Hi-Mile oil and it started using a lot more. I switched back to synthetic and the oil consumption went back to what it used to be. Link to comment Share on other sites More sharing options...
ejw71 Posted February 8, 2004 Author Share Posted February 8, 2004 Thanks fellas, Will be using synthetic in all rebuilt engines from now on. Ed Link to comment Share on other sites More sharing options...
Ian Posted February 8, 2004 Share Posted February 8, 2004 My '95 Z28 has had Mobil 1 in it since it was new, and it has 107000 miles on it. It does not use much between oil changes, but it does leak a little. Ian Link to comment Share on other sites More sharing options...
Guest Posted February 8, 2004 Share Posted February 8, 2004 Thanks fellas, Will be using synthetic in all rebuilt engines from now on. Ed I read an article about using synthetic for a new engine break-in. That is a no-no. It may cause trouble with the rings seating in. You can change to it after not too many miles. Link to comment Share on other sites More sharing options...
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