Hello every one !

Today My car threw a " Engine oil " light at me , I found it weird since I just changed the oil and it was a 75% between high and low when off and at High when On ". Checked the Dipstick and the Oil level was right at the L mark.

Ever since the oil change I have experienced overly smelly exhaust and today when I started my car the " engine oil " light came on , I quickly pulled out my spare quart and popped the hood and poured it down the oil spout . Then shut the car off and poured a half quart along with a quarter quart of lucas oil stabilizer ( Never use this stuff but that's all I had) . Light was off and my oil level is back at 75% from L to H . It It has been 890 miles since my last oil change .

I have a bad feeling my oil control rings have failed. The crazy thing is I don't seem to burn any oil at idle and my exhaust never puffs out smoke . I don't see any leaks ( although my oil pan has always wept oil , never enough to drop on the floor) .

What does happen is my car smokes when I rev it past 5700 rpm. I drive 80-90 mph every day and the car does reach 5200-5500 RPM regularly . Just recently I gave the car an " Italian tune up" and floored it hard at every stop light and made sure to get the trans to go up to 6700 rpm . I was having a dull throttle response and that fixed it .

Mind you I had issues with the stinky exhaust since changing oil, I added 4 qt of Castrol GTX 20W 50 .

I have a habit of letting the choke on my car every morning for 3-4 mins to help the car warm up and let the car idle for 10 mins . I leave home at 7 AM and it's always cold . If i don't do this the car will not warm up past the first hash and I **** gas away . On a cold day My temp gets right past the hash and will stay there .

Recent changes : New battery , New spark plugs , Switched to STP filter fork OEM ( I alternate between oem and STP )
Oil change .

Key note : I have NO OMP.
I accidently over filled my oil once by about a quart and it was marking like 10% above Full.

 

Blown oil control rings will show themselves most at high rpm and high vacuum. If they're really bad you'll get smoke out the exhaust during a stationary free rev.

Starting to go bad? You'll see smoke behind you during high rpm decel (in gear).

Since you have no omp, engine is tired or you are losing oil somewhere.

 

No smoke on decel but smoke on stationary free rev past 5700 rpm.

It didn't do this until I got new plugs and changed oil .

My engine got a rebuild 10k miles ago .

****.

 

Check your connection to the low oil sensor on the oil pan.

 

Fot leaks or that it's faulty ?

 

That it's faulty. I have also found that the CPU can go wacky and cause this. I have a 1985 that started life as an automatic that I converted to manual. The low oil light would come on but the oil pressure on the factory and aftermarket gauges read very well (over 60 PSI). I had also removed the auto tag on CPU. The issue didn't get fixed till I replaced that CPU. I had even tried a used and brand new oil level sender prior to replacing the CPU.

 

But my oil WAS low on the dipstick , it was right at L but on the bottom not on top.
I actually think I may not have filled the oil all the way up since I only put 3.5 qt in the oil change and the dipstick read high but I know I usually add 4.5 QT I also added the TALL STP oil filter that is like double the size of the small mazda one . It may have been on the low side to begin with and my engine may actually consume small amounts of oil to begin with .

I will monitor the issue .

I know for a fact the engine smokes out the rear for 5-6 seconds when I rev past 6 grand in Neutral.

Otherwise the car has run great since I changed the voltage regulator and spark plugs. It idles a tad higher than I'd like and I now have to prime the pedal 3 times to start up or the car dies but otherwise it idles incredibly smooth now And power is super responsive. If a rebuild is needed I will probably just buy a new ND miata . I'm about to swear in as an attorney ( Yay) so I can afford to buy another tiny sports car 😝

 

I'd say there is a good chance the oil control rings are going then. I'd fill it to the high mark and then monitor it every day. You'll find out really fast if it's the rings.

 

Will do.

In the literature It states the rings should smoke at 4000 RPM , but mine don't . Any ideas ?

 

The 1979 with the thermo reactor might burn the oil a little better than a catted RX-7.

When I bought my 1977 REPU, the rings where so bad it would drip oil from the tail pipe and not burn all the way.

 

I have a RB header , presilencer and muffler . That's why I'm surprised I'm burning oil THAT fast . It would be blatantly obvious but it's not.

I will tighten the oil pan down and check for leaks.

 

I ran a "good" used engine in my race car for awhile. It made good power but smoked enough under power and lift throttle to kill mosquitos in a four state area. Don't remember if oil consumption was an issue, but then I changed oil allot because - race car. Anyway, before a race at the end of the season I added an oil additive designed to address this issue (can't remember the brand, think it was called No Smoke or Motor Honey) to the 20W 50 Valvoline Racing oil I run. It worked. Smoke cleared up dramatically and the engine continued to run very well. Even won both races that weekend.

Later. I pulled the engine in the off season and did a minor rebuild. The oil control rings were toast. Moral of the story is that using an additive might tell you exactly what the issue is and clear it up. A band aid solution but it might buy some time.

 

Topped it off and put a half quart of Lucas oil Stabilizer. Hopefully that slows things. I might have broken some carbon off or carbon may have gotten lodged on a ring .

 

After 400 miles Oil level was reading half , so its burnt about half a quart in 400 miles .. That being said the level was right under F the day before.. I came home late last night ( no traffic ) and drove about 90 mph for the entire trip back home , at 90 mph the RPM is 5700 Rpm .
Today i let the car idle and held the revs at 3500 then 4000 then 5000 and at around 5500 rpm the smoke starts and at 6000 the smoke was unbearable.

What a crock , the oil control rings didn't even last 15k miles.

 

I've never replaced oil control rings myself, but reading up on it, the springs seems to be the hard part.

 

Lapped irons? Were the oil control rings new during the rebuild?

 

No , unknown.. I assumed new ones were used .

 

As a newly "minted" lawyer you should know you "never "assume anything Frogman, hopefully you can get a second car as a "daily-driver" now that your on the fast-track, and have the time to devote to getting this issue sorted out on your RX7.

 

I drove 500 miles and It went from F ( 100% ) to just above L ( 10% ) .

I drained oil and switched to VR1.

I have a bad feeling Castrol changed it's GTX formulation since it smells different now . Sigh.

 

Careful with that Valvoline VR1. It has a high Zinc content and even the conventional stuff does not burn cleanly. It could make your problem even worse!

 

Well as if today the car no longer smells like burnt oil when i go past 5k rpm , I have a bad feeling GTX changed their formula . I have a old quart which smells like oil and the new quart smells like a tangy plastic .

This all started after a oil change . The only other change was going from a OEM filter to a STP gold one.

 

Check out the The Motor Oil Geek on YouTube https://www.youtube.com/@themotoroilgeek. He provides hard data of what is actually in motor oil. It also looks like he evaluated Castrol GTX. A comparison he has of Pennzoil and Quaker State synthetics is very interesting. Both of those brands are owned by Shell and both oils meet the same specs. How they get there chemically is interesting.

He recently tested Valvoline VR1 oil and determined that the formulation has been changed to meet new Direct Injection requirements. Is it a good or bad oil for a Rotary that isn't on 100% premix, I don't know. I use it because it is formulated for racing, widely available and affordable. I also premix 2cycle oil in to my fuel so I am not trying to burn it on purpose. In the distant past, A/B testing with Mobil One and Amsoil indicated that the VR1 handled heat better. Maybe a retest is worth doing in that regard. I am not seeing wear issues with using VR1, however.

 

The VR1 change was done 5 years ago IIRC in 2019 , the only major change was they eliminated calcium and jacked up potassium to compensate .

GTX has served me well for 7 years.

That being said the VR1 seems to be NOT burning , at least I can't smell it .

 

Your post mentioned you switched to using VR1 in you car and I just ran across a video that addressed a specific issue with using VR1 oil in a rotary engine Frogman. I'm not familiar with the guy doing the video however, he does seem to know his way around rotory engines. Check out the video link at the ten minute mark that discusses VR1 properties, it may, or may not be important. It may be "much ado about nothing" but knowing how this oil issue is consumming you it my be worth a few minutes of your time.

 

I fully Understand . At this point my goal is to REDUCE burn . If the burning lets up at this rate then GTX is going back in . If the VR1 reduces the burning then there is that.
I did allot of research and it turns out GTX doesn't hold it's weight very well when it gets hot or when it's new . VR1 is much more stable at all temps but tends to start losing its stability at the 3k mark. I added VR1 but the cat still has the 2 residual GTX quarts .

What bothers me Is aside from the rev at idle the car doesn't even smoke at start up or leave smoke plumes. Maybe a vac line isn't working properly and oil is being siphoned in .
I noticed that the front of my carb has oil on it , If any one has an idea why that is , it would be greatly appreciated .