Changing oil after flooding the engine. Does everyone do this ??
 

I have flooded my rx7 twice since the most recent oil change, which was about 200 or so miles ago.

I was wondering why I read that you are suppose to change the oil after flooding it ?

Like for instance, what if you just did your oilchange , and it floods when you try starting it up ? It would be pretty stupid to have to change the oil again , when you just changed it (at least if u ask me).

I figure if you do your oil changes more often at about 1000-1500 miles, everything will be fine, you just dont want to flood many times or you probably will need to get an oil change (example : flooding it 10 or more times before you reach 1000 miles)

what? change your oil everytime you flood.......im not sure where you read that but I dont see why you would have to do that. Would suck if it was true cause most people on this board flood like every start up. Oil companies would be making another bil on rx7 owners alone. =P

i had a fb and a fc..and never flooded either one not even once!!

Well if you never flooded it youre one lucky guy, I remember even on my engines first startup it was flooding out on me alot until we finally got it started up.

Rotary engines I think are the worst when it comes to flooding issues, especially in cold weather.

I plan on getting some new spark plugs pretty soon , mine have about 2000 miles on them so I'm sure new ones will help prevent the car from flooding, maybe.

As far as changing the oil, if it is a minor flood, and it clears just fine by holding the throttle all the way open while cranking it is probably fine to not change the oil for a time or two.

But if it is a hard flood, something that won't clear without pulling fuses or spark plugs, or if you smell gas in the oil, then the oil should be changed.

That would probably be a waste of money. For performance applications every 10K miles is about right. Changing at 2K miles is probably a bit excessive even if you are using a CDI system.

THe exception to that would be if you are using the wrong temp or style plug

Well earlier today I had to pull the fuse to deflood the engine, but it was actually running before it got flooded. I didnt realize it was in gear and let off the clutch to put it in neutral, then it died from stalling into gear (not smart i know).

I tried to get it to start back up and took about 3 tries of letting it crank with the throttle open and it wouldnt start back up.

I removed the fuse to deflood and turned it over for about 5 seconds twice and then put the fuse back in to get it to start up, and it started right up.

I think my oil shouldnt need to be changed , do you ?

I am sure I may have been able to get it to start if i kept trying to crank it without removing the fuse, but wouldnt that be flooding it worse since youre cranking it more putting more fuel in there before it starts ?

I have only about 200 miles on my oil, I actually dont use the stock pcv valve I use an inline fuel filter connected to the oilfiller tube that has vacuum on the other side to pull all the gas/condensation etc out of there.

Youd be suprised how much gunk is in there right now after I flooded it twice since the oilchange , I'm pretty sure thats where alot of that gas that flooded the engine will go. I think I need to replace it with a new one soon, its getting pretty nasty looking inside and pretty full.

I think it's really a judgement call if your oil level is going up from flooding then you definatly need to change it asap but a little gas in the oil isnt' going to kill you.

I doubt my oil level is going up from gas, if it has its probably not even noticable

I'm not saying that if it's not going up you don't have to change it just giving an extreme example, that would be severe flooding but I also think changing you oil any time you flood is extreme in the other direction there isn't a general rule. Smell the oil, when you change the oil check to see if it's thinned out from the gas, if it has then you know you're letting it flood too many times before you change it.

Well this would only be the second time it has flooded since the oil change, this time it was a mistake on my part that caused it to flood, the last time the car was sitting for a little while and hadnt been started in a while , so it flooded when I tried to get it started initially.

even a hard flood one time wouldnt be enough to warrent changing the oil. maybe if you flood it over and over again. say 5-10 times in a week or 2, then yeah, it probably wouldnt hurt to step your oil change interval to maybe 1500 miles or so. Mine floods quite a bit and yes the oil smells like gas but it wont hurt anything too much unless you have like 4 quarts oil, 1 quart gas

Well I think mine should be fine then.

I plan on doin my oil changes at 1500 miles regardless , just because I plan on having this engine last me a while.

No, not if you are doing it correctly.

Again to de-flood a rotary engine (from a 12A to a modern Reni) you simply hold the throttle all the way open (without pumping the gas) and crank.

Never pump the gas, simply hold it all the way open.

See this maximizes the MOP output and air input.

Unless its like mine, thats too far gone. Then you have to pull the fuse. Or just throw in a cutoff switch like me. Gotta love worn out rotary

So then no matter what if you keep doing this the engine will start up , even if it may take 5-10 minutes or so maybe more.

What if youre impatient like I am and dont feel like waiting 5-10 minutes or however long it takes and would just rather take out the fuse and deflood it that way if youre having some bad luck unflooding it

Is this the bad decision to make ?

I ask because I heard its bad for the bearings in the engine to take out the fuse and deflood with the fuse out because the bearings get more stress, is that true ?

I would 2ndly think its bad because you said if you have to deflood the car by taking out the fuse it means the car was worsely flooded and requires an oil change sooner because of this , although I plan on changing my oil every 1000-1500 miles anyways.

I try to change my oil sooner because my speedometer is inoperable at the time so I cant really get an exact mileage of when to change it.

No, you should not crank a car for 5 or 10 minutes. A flood should clear in 15-20 seconds at the most.

The exception to that would be (of course) a motor that was not in mechanically sound condition.

Too many people pull the fuse, thinking that is the correct way, but that can in some cases (such as S5 and S6 motors)pulling the fuse can cause increased wear and further issues related to that.

Again, holding the throttle (accell pedal) all the way down, allows a maximum amount of both air and oil in. Oil helps the apex seals seal again, while the maximum amount of air helps flush out the combustion chambers.

Well my motor only has 2000 miles on the rebuild from rotaryresurrection.com so I would think the motor is in good condition (100+ compression on all faces i would hope).

I also have my 5/6 ports sleeves/rods all removed on my car , could that cause it flood on startup more often ?

Could it also cause the car to be harder to start or make it not start at all when it when it does get flooded ? Then that would mean you would need to to take out the fuse to deflood it, if you cant get it to start up just cranking it.

change it when you smell gas in the oil

because of the design, the excess gas doesnt leak to the oil pan like piston engine.

gas sinks to bottom and goes nowhere - they have to travel up, to the oil control rings, get thru 2 of them, to the e-shaft before it could get to the oil pan.

ona piston engine, when it floods, all it needs to do it have gravity pull it down and go to oil pan


gravity exists in rotary engine.


so no, u dont need to change oil after flooding - only when u smell it in oil - and by that time, u shoudl change it anyways for the sake of common sense

Well in my case it only flooded twice , so shouldnt all the stuff get burned out after being driven if it doesnt get flooded again.

actually rebuilt engine without new housings or lapped plates will have very low compression initially, and take some time (1-5000 miles) to build to acceptable compression.

In those cases I recommend a fuel cut off switch, until the motor is fully broken in and you are seeing 120+ compression.

Well I dont usually have much problems with it ever flooding, its only a very once in a while thing.

I didnt know it could that long to build full compression , I drive my car basically like its broken in. I've redlined it several times and i take it past 4k quite a bit (because my 5/6 ports removed i get crappy acceleration below 4k).

But anyways, according to what you say my car may not have full compression until its finally reached 5000 miles, so with low compression it may cause it to flood more often basically, right. (since compression is big part of what makes thing engine start , and without it or without enough the car will not start)

just depends on how worn the parts are that were used in the rebuild on how long it takes to fully break in.

nd if you are having flooding issues, it would appear that it is not fully broken in or you have leaking injectors

Maybe its not fully broken in yet ?? I dont know how bad the housings were and i dont know if the injectors are leaky but i did have them all cleaned/flowtested about 2000 miles ago.

Im just going to do my best to make sure i dont flood it.

My rebuild is also using atkins apex seals dont they help to break in the motor faster than all the other seals (at least I thought).


The only 2 times it flooded like i said before

1- after it sat for about 1-2 weeks without being started

2- the car was just just started (cold start), and i made it stall out letting off the clutch in gear

Ive never really had many problems with it not starting, its not something that happens often. Its flooded on me twice in the past 6 months (ive just had bad luck recently)