|
help, synthetic oil change ???
OK, I'm new to the RX-7 as far as technical stuff goes. I have loved them for years and just bought a 79' for my husband for nostalgic reasons. I think I may have screwed up and allowed a friend to do a synthetic oil change on her before I surprised him with it and now it's smoking beyond belief. I need your help!
|
Most RX7 owners don't recommend using synthetics in these cars. Just have another oil change done and use a high quality oil. Oil of choice seems to be Castrol GTX in 10W-30. Don't use any oil additives. Should be OK.
|
the omp system meters crankcase oil into to combustion chamber to lubricate the apex seals. synthetic oil does not correctly lubricate the seals and will lead to a dead motor. i would suggest flushing the oiling system and using a quality non synthetic.
isaac |
Yea i heard something about synthetic being bad for rotarys. Ive been using quaker state high performance 10w30 and that seems to be doing alright. I heard somewhere that pettit uses a synthetic motor oil. is this true?
|
Originally Posted by flight_of_pain
synthetic oil does not correctly lubricate the seals and will lead to a dead motor. i would suggest flushing the oiling system and using a quality non synthetic.
Modern synthetics are fine. Older synthetics didn't burn completely inside the combustion chamber. This used to lead to massive carbon build up, hot spots and eventually detonation. Today's synthetics burn fairly well however certain weights have additional additives which can still leave deposits (mostly 10w40). As long as the proper oil weight was used, its fine. However, synthetic can expose any areas which make have a leak (but not leaking yet). Synthetic oils are much more efficient at carrying away gunk inside your motor. So, if some sludge had built up around an area, the synthetic make break down the sludge and carry it away now revealing a leak. This is the reason people say synthetics cause leaks; it technically doesn't cause them but it can expose them. |
maybe its not the syn oil that's the cause of this problem, maybe the person who changed the oil took it for a ride and beat the crap out of it.
|
Originally Posted by NOCTRNL27
now it's smoking beyond belief. I need your help!
|
From Royal Purple's website, a synthetic that Racing Beat recomends and uses.
http://www.royalpurple.com/techa/faqsa.html#re0 I heard that synthetic oil doesn’t burn like mineral based oils and will coat the inside of the engine with deposits. If this was a problem with synthetic motor oils in general, then all internal combustion engines using a ‘synthetic’ would experience increased deposits on internal surfaces. The opposite is actually the norm. Conventional four cycle motor oils will typically leave deposits of carbon and ash when injected into the rotary apex seal, corner seal, and side seal areas. Royal Purple’s motor oil actually burns cleaner due to the synthetic base stock being free of contamination and many of the additives being ‘ashless’. This may not be true for all synthetics but Royal Purple has been proven to work extremely well in rotary engines. Royal Purple’s formulation of synthetic hydrocarbon motor oil does burn at the nominal combustion temperatures experienced in both street and racing applications, whether normally aspirated, turbocharged, or supercharged. (500 – 1700° F idle to race rpms typical combustion temps) Will the synthetic oil effect the oil seals? No. Royal Purple’s Motor Oil is fully compatible with the elastomers found in rotary engines as well as more conventional piston engines. The oil seals, housing seals and other elastomers used in rotary engines typically consist of Buna N, Nitriles, Neoprene, or Viton materials which are also commonly found in piston engine cars |
Mazda did not reccoment using synthetic oils for the rotary in the 3rd gen for the following reasons.
1. The emissions testing done in order to be certified for sale in the United States was done with mineral oils. 2. The durability tests done on the emissions components were done using mineral oils. 3. Synthetic oil burns at a higher temp than mineral oil. Repeated short trips could lead to spark plug fouling. 4. Oil sprayed inside the rotor cavities can contact the the rotor oil seal o-rings. Long term exposure to synthetic oil may cause these seals to swell and deteriorate. |
.
Originally Posted by Mahjik
Straight from the Racing Beat Rotary Performance Technical Manual:
"The Mazda factory does not recommend the use of synthetic oils in their rotary engines - specifically addressing this issue in the Owner's Manual. In 1979, Racing Beat began testing synthetic lubrication products. Without a doubt, the best synthetic oils do perform well in extreme heat (over 300 F) and extreme cold (below 32 F), but by the nature of Mazda's rotary engine, the oil temperature never exceeds 250 F without severe engine damage due to other factors. In Souther California, we have difficulty seeing the low-temperature benefits: however, when we put synthetic lubricants in the engine, transmission, and differential in our IMSA GTU race car, we immediately saw what we later found to be a common result: The oil temperature in all three locations dropped 5 to 10 F for the same operating conditions. This is apparently due to two factors: reduced friction between sliding surfaces, and reduced foaming. As we continued to use synthetic oil products it became clear that they genuinely reduced wear. We also found benefits in street use. On two occassions, cars with "scratchy" transmissions synchronizers were completely cured by a change to synthetic gear lube. After many years of experience with these products we have observed only one problem: because of the reduced friction, the time necessary to break in an engine, transmission, or limted slip differential (standard differentials are no problem) is excessively long, so we recommend using mineral oil in all three for a time to ensure rapid break in." |
Originally Posted by BackyardSog
Mazda did not reccoment using synthetic oils for the rotary in the 3rd gen for the following reasons.
1. The emissions testing done in order to be certified for sale in the United States was done with mineral oils. 2. The durability tests done on the emissions components were done using mineral oils. 3. Synthetic oil burns at a higher temp than mineral oil. Repeated short trips could lead to spark plug fouling. 4. Oil sprayed inside the rotor cavities can contact the the rotor oil seal o-rings. Long term exposure to synthetic oil may cause these seals to swell and deteriorate. |
LIke I said some swear by synthetics, but backyardsog is right
|
Why don't we all take it the easy way and just use the RX8 engine oil from Mazda?
It's tested for rotaries, widely available, probably engineered by Idemitsu (who is the only oil supplier still investing in rotary technology lubrication), etc.. and for those who want to take it the high performance way, they can add an OMP adaptor and use 2-stroke for better lubrication. The only thing you could argue is the better effect of synth oil on the turbo's. |
Basically
|
another oil thread = another syn vs dino argument...
if you want to play it safe, just go with a high-quality dino oil... if you think you can trust the abilities of synthetics to burn completely, and you think the benefits outweigh any risk there may or may not be, use a high-quality synthetic oil. personally, i use Idemitsu... |
| All times are GMT -5. The time now is 04:53 PM. |
© 2024 MH Sub I, LLC dba Internet Brands