Engine Oil

Rotary Engine Chat......Got A Problem With Your Rotary Engine.... Need Help...?
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DKWW2000
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Re: Engine Oil

Post by DKWW2000 » Thu Feb 21, 2019 8:21 am

The main problem is changing to Synthetic in the engine after it having been using Mineral for the past 30+ years, it has in the past been known to causing the housing seals to expand & cause to fail. As far as I am aware if used from start on a Rebuilt/New engine it is fine. I have always used mineral in all rotaries ever owned & also premixed @ 3-400 to 1.
RX7 FB S3 - RX7 FC TII Vert
Rotaries Previously Owned:-
2 x NSU Ro 80s - 2 x S2 RX7s - Suzuki RE 5 - DKW(Hercules) W2000 - Norton (Krauser) Commander

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gt_james
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Re: Engine Oil

Post by gt_james » Sun Feb 24, 2019 5:23 pm

This is generally not a problem with modern oils. The vast majority of modern oils have a very high compatibility with older seal compounds, and all seals used in rotary engines in RX7s are compatible.

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Re: Engine Oil

Post by ian65 » Sun Feb 24, 2019 7:44 pm

I've always used mineral in a rotary, both turbo and N/a engines.... they were designed to run on mineral so that's good enough for me. It's more important to change it frequently.... you'll get better protection from some £14.99 mineral multigrade and changing it every 2000 - 3000 miles than you will putting £50.00 fully synth in it and leaving it for 20,000 miles.
When I used to restore and run Spitfires I used to use cheapo oil from B&Q and change it every 2000 miles and it came out as clean as it went in.
Maybe in FD's where the engine is more highly stressed there's a case for more advanced oils but 12a's have always seemed to run fine on mineral... in over 30 yrs of running these cars I've only had one engine give up on me and that was because it was a 90,000+ miler already on it's last legs and I bolted a turbo onto it and ragged it.
1986 Series 3 13B Turbo II
http://rx7fb.com/viewtopic.php?f=2&t=2400
1992 Peugeot 205 1.9 GTI
1975 Honda SL125 Street Scrambler

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