eriksseven

iTrader: (6)

I'm working on a customers s4 Turbo II... It's a fresh rebuild with less than two hours of run-time. I did not do the rebuild. Apparently there was issues with heavy and repeated flooding after the rebuild--and it was basically running like crap or not running at all. Allegedly the stock ECU cas was running a Walbro 255 and 750cc primary and secondaries--so flooding would not be out of the question.

I received the car and did a nearly entire engine-bay rehaul because it was very poorly put together. However, before I started the car, I checked the oil level. The oil level was VERY high, and was dripping off the dip-stick. The oil smelled strongly of fuel.

Anyways, after getting the car running--it was unable to hold an idle, and would choke out if taken about 2k RPM's. It smoked heavily out the exhaust the entire time I had it running (30 minutes altogether). Not questioning the $3500 engine-rebuild, I went forward and spent several days checking and replacing everything possibly related to fuel-delivery or control. The injectors were put back to stock 550cc's BTW. Everything seemed good--however no matter what was replaced, the TII was still running very, very poorly while continuing to smoke.

I decided to inspect and replace the oil, and I discovered that it was diluted with gasoline to the point of having consistency like Dr. Pepper. This is 20W-50 with less than two hours of run-time... I talked to the mechanic who did the rebuild and he was certain that the early-on, repeat flooding was causing the blow-by. His position was that *of course* diluted oil would squeeze past the oil-seals. My question to him was how gasoline got into the oil in the first place...

Am I dealing with potentially bad oil-control rings, or is it possible that the oil was dilluted due to the heavy and repeat flooding?

He did not list oil-seal inserts on the $3500 receipt, nor did he replace the oil-control rings springs with new ones. He said he had oil-seal inserts "at the shop" that he used in the engine-build, and that he reused the oil-control rings springs.

Imput?

RotaMan99

Well I have heard numorous times that flooding is common with fresh rebuilds untill all the seals have been set.

What color is the smoke out the exhaust? The oil control rings sound a bit suspicious but I have never rebuilt an engine. Although I have spare internal parts in my barn.

Do you know if he reused the Oil Side Seals?

RX7Tuner.

The oil control ring springs don't usually wear out. They can, however, easily be installed incorrectly. If the right ring isn't matched with the correct side of the rotor AND facing the right direction AND the groove of the spring not seated correctly, it can fail. It is also a pain to get the oil control rings seated properly in the rotor. It's very easy to pinch the o-ring. Even in a flooded car, gas should not be leaking past the oil conrtol rings if they were installed properly. Not to jump the gun. but I bet you're looking at tearing into the engine. I'm sure others will have other suggestions before you crack it open.

Good Luck,

Brian

eriksseven

iTrader: (6)

This is what I was thinking... I've dealt with severe flooding in many different Rx7's, but never once noticed dilluted oil from blow-by. Then again, the customers uncle mentioned something about "gas-in-the-oil from flooding", as if it were general automotive knowledge?

The complete theory is this:

The car ran OK after the rebuild, but was only ran for maybe 30-45 minutes in the next several days, before the stock 550cc fuel-injectors were replaced with new 750cc injectors. This was because according to the original owner, two of the injectors were "bad"... The new owner, thinking that "performance" injectors would be a good idea (lol), attempted to run the car with the 4x750cc injectors, a Walbro 255 fuel-pump and the stock ECU. Now, according to the theory, the owner then proceeded to repeatedly flood the crap out of his car, which (fill in the blank) led to fuel bypassing the side-seals and oil-seals, thereby dilluting the oil to the consistency of Dr. Pepper... The final portion of the theory is this:

Now that the oil is sooo thin, it is able to easily bypass the oil-control ring seals and make it's way into the combustion chamber--where it coats, chokes and floods the engine to the point that spark and combustion and nearly impossible, hence the constant smoke and poor running condition.

The car will not rev past 2k-3k RPM's before choking out, and will only run between 1k-2k RPM's (very rough at that).

eriksseven

iTrader: (6)

So I did some searching, and according to respectable sources (Icemark, Iceblue etc.) it appears that flooding will by nature causes fuel to push past the side-seals/oil-seals... I guess that answers my question about flooding and blow-by... I would still like confirmation though.

Anyways, that just leaves the second part of the theory:

Will extremely thin and dilluted oil be able to push BACK into the combustion chambers to the point of killing spark and combustion while the engine is running?

Carzy Driver

what shop charges $3500 for a rebuild and only replaces half the seals?

that's the problem, old oil control ring seals and springs is letting the Dr. Pepper seep pass the seals. where the side seals replaced with new seals? maybe the builder clearanced them to much. the engine is burning that mix and has basically been made into a rolling smokebomb. how fouled up are the plugs?

eriksseven

iTrader: (6)

Well, just to be fair, the oil-control rings were replaced--as were the oil-seal inserts (allegedly). The oil-control rings springs were reused. The side-seals were also replaced--which does allow the option for them being clearanced too much I suppose.

The new leading plugs have about 25 minutes of run-time and are BLACK. The 02 sensor is black as well.

And again, I appreciate any and all imput.

Thanks,

micah

My engine at 150k miles wasn't eating much fuel past the oil seals, but WAS gobbling fuel into my oil.... Maybe not as quickly as you describe... but pretty quick. I would also have to assume that new oil control rings would have to seat into used irons..... correct? a little blow-by is to be expected at first. Did he test the oil control ring springs PRIOR to re-using them? I have no problem with reusing them, but atleast check them against the FSM... If the engine previously overheated, the springs could be flattened.. just like apex seal springs do.

RETed

Yes, too much fuel will get past the oil control rings and down into the oil pan.

If the oil control rings are "bad" or install incorrectly, it will usually cause the engine to smoke (oil) excessively.

Get rid of the old oil and put in some new oil.
If you run into the same problem after getting the car to run better after the oil change, something else is amiss (internally).


-Ted