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-   -   Oil control rings are bad (https://www.rx7club.com/2nd-generation-specific-1986-1992-17/oil-control-rings-bad-953878/)

rxmiles 05-11-11 04:48 PM

Oil control rings are bad
 
My car has a little over 130 k miles on it, and it smokes like a burning Chrismas tree, at high rpms, I nkow its either the oil control rings or tue coolant seals, but what Im asking is: can I just replace the oil rings or do I need to replace anything else.? The engine runs excellent and seems to ha e good compression, I don't have the money to buy a full rebuilt kit, and I'm saving to buy a tII, I want myn
N/a so I can learn ton rebuild these engines.

nycgps 05-11-11 05:36 PM

short answer : you can

long answer : do you want to take all the work to take the engine out and take it apart and just replace the o-rings and coolant seals and other related seals ? yes it can be done but is it worth it. you gotta think about that part.

Len-Len 05-11-11 05:46 PM

No, probably won't need a full rebuild kit. Get the FSM from the fAQ section, tear it down, and see what it needs. If its either a coolant seal or oil control ring failure, it usually won't need too much shit. Is the smoke white or black?

RotaryEvolution 05-11-11 05:51 PM

no offense to the above but disregard them.

with 130k miles you will need new apex seals, oil control seals, front and rear main seals and a full engine gasket kit. that is the BARE MINIMUM you will be expecting to need which totals at about $450.

if you can't afford that along with a rebuild video (~$20 additional) then plan to sell the car. that is the blunt truth to what you should be expecting. with 130k miles the rotor housings will also be marginal unless the engine has been premixed for many of those miles.

that all assumes you are lucky enough to have good condition belts, hoses and clutch. not to mention vacuum lines and fuel lines...

so the real answer to your question is "no" unless you were only referring to a master rebuild kit, which yes is overkill for most applications.

at high RPMs it is your oil seals failing, the best advice i can offer is use thicker oil(4 quarts of 20W-50 motor oil and 1 small bottle of STP engine treatment) and make sure to warm up the car fully before getting on the throttle if you can't afford to fix it and don't want to sell it.

Len-Len 05-11-11 10:44 PM

Well if Karack says it needs a full rebuild, then it needs a full rebuild. He knows these engines better than anyone on this forum IMO.
But I will say that my previous FC had a coolant seal failure at 100k and the only things I replaced were the soft seals. That engine ran strong for the remaining year I owned the car, hell it may still be running. Definitely wasn't the right way to do it but it worked for me.

RotaryEvolution 05-12-11 11:03 AM

ignoring the apex seal wear isn't a good idea and will cost more than simply neglecting them with a basic soft seal kit. it can easily turn into costing a rotor and housing, new seals anyways plus a whole new soft seal kit and install gaskets plus whatever breaks during removal/reinstallation. the stock 3 piece seals have a tendency to drop out of the seal slot when worn much beyond 150k or less with hard miles, which his motor is fast approaching.

if he has a garage full of spare engine parts then sure, spare rotors and housings all cleaned up and ready to go it's no big loss short of the $200 minimum for reseal kit plus $50 for oil filter, oil and coolant.

basically what i'm saying is it is going to cost more than he thinks it will AND doing it too cheaply will just wind up being him throwing his money in the toilet to buy a few months from an engine that just smokes because he can't keep his foot out of it? he really shouldn't be attempting to keep the car then if he can't afford to fix it right and i am one of the most reasonable rotary rebuilders around.. unlike the many who will push new rotor housings on you with each rebuild.

RotaryRocket88 05-12-11 11:53 AM

Exactly. If you're going to tear an engine down, you might as well do a full rebuild so you're not taking it apart again down the road.

j9fd3s 05-12-11 11:59 AM

i have noticed the smoker engines tend to come apart and have the housings looking really nice, so usually it is a less expensive rebuild than if it broke an apex seal and there is carnage in there.

@130k, you need to replace/eliminate the thermal pellet too, it fails, and then it doesn't get oil spray into the rotors, and it cooks the oil seals, FC's do it a lot, back when there were a lot of em around

StevenL5975 05-12-11 12:08 PM

Full ack to Karack.

Plus you will always find something broken while your are in which needs to be changed/repaired or whatever.

I am currently doing a S5 T2 rebuild for a friend. The only thing I can say: "Do it right or do it twice"
Even if this is my first rotary rebuild that statement is the rule to live by.
I learned that too.

Another thing which seems often to be ignored: Do the rebuild before the engine blows. People tend to drive them knowing they need repairs until they blow it up and then
whining about replacing half of their engine.

Carzy Driver 05-12-11 02:07 PM

I'm with Karack on this, why go through the whole rebuilding process to replace 8 soft seals and just use the old worn hard seals. Mow some lawns, shovel driveways or work the corners for a complete rebuild kit.

RotaryEvolution 05-12-11 02:13 PM


Originally Posted by j9fd3s (Post 10617635)
i have noticed the smoker engines tend to come apart and have the housings looking really nice, so usually it is a less expensive rebuild than if it broke an apex seal and there is carnage in there.

@130k, you need to replace/eliminate the thermal pellet too, it fails, and then it doesn't get oil spray into the rotors, and it cooks the oil seals, FC's do it a lot, back when there were a lot of em around

they generally do get more lubrication which causes less wear, but eventually the carbon buildup will stick the seals to the point where one day the car will free spin with no compression due to stuck seals or eat a seal due to the seals getting stuck while running and getting crunched in the exhaust port taper while trying to compress with the engine running.

at least do a periodic steam cleaning of the engine internals to attempt to dislodge all the carbon that is being built up due to the bad oil seals.

j9fd3s 05-12-11 04:01 PM


Originally Posted by Karack (Post 10617909)
they generally do get more lubrication which causes less wear, but eventually the carbon buildup will stick the seals to the point where one day the car will free spin with no compression due to stuck seals or eat a seal due to the seals getting stuck while running and getting crunched in the exhaust port taper while trying to compress with the engine running.

at least do a periodic steam cleaning of the engine internals to attempt to dislodge all the carbon that is being built up due to the bad oil seals.

yeah true the oil does cause a lot of carbon buildup, but if it smokes really bad you aren't going to be driving it too long.


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