neil85ae86

I just cut out my cat and put a cheap *** turbo muffler on my car and I guess it made for a pretty significant drop in back pressure since my car is now spiking to 12+ psi with probe/mx6 RHB5. After going for a pretty hard run for 15 minutes or so I get puffs of blue smoke during deceleration, especially noticeable under combined braking/deceleration as the rpm drops to idle ( I guess under maximum vaccuum). It doesn't do it during acceleration and the engine still feels strong, doesnt' make any new noises. The blue smoke seemed to drop after the car had been driven normally for a while and idled for a while. Anyone have any ideas? FYI, the crankcase is vented to atmosphere via a catch can. I don't think this turbo has ever seen these kind of boost levels, could this be an idicator that the seals are going? I haven't done a compression check yet, or pulled any of the intake plumbing to check for oil.

Neil

hotrex

valve stem seals

J-SMITH69

weak rings

shortyz

there have been a few people on here that have had that same thing, i remember one guy solved the problem by lowering his oil pressure to the turbo..


usually valve seals leak when the engine is cold, when the engine heats up the valve seal expands and seals up..

but it could be those 3 things that have been listed.

neil85ae86

I definitely agree that the valve seals should leak when it's cold, not just when the engine is hot after a hard run.

If it's rings it will hopefully show up on a compression test, I tested it last week and the numbers were great.

The more I think about it the more it makes sense to me that it's the turbo, at high rpm the oil pressure is at it's maximum so after a hard run it probably takes a while for the oil that get's pushed past the seals to make it to the intake. ...if it was the valve seals I would have thought that it would be almost instantaneous as oil pump pressure increased to the point where it was pushing oil past the sea, their is no blue smoke during acceleration.

I ran the car for a while last night and again no blue smoke. This is a fairly fresh JDM low mileage engine, and even though it's factory low compression, it compression tests higher than my higher compression NA engine, and probably has a stronger oil pump than my tired old motor, so could be a combination of things.

I'm going to check the plugs, do a compression test, and take the turbo to IC plumbing off to see if it's full of oil.

I'm using the factory IHI oil feed restrictor which is tiny, maybe 1 mm so I don't want to restrict it anymore. I have another turbo on the shelf.

Neil

neil85ae86

Ok, when I first started the car this morning their was some blue smoke, could have been residual left over from whatever happened yesterday. I warmed it up and did a compression test, 197-199 across. The plugs were all black from running too rich or possibly from oil contamination. I pulled the hose off the compressor outlet of the turbo, the outlet is clean and dry.

My drain is 13mm I.D. so it should be plenty big enough, maybe it's getting blocked by the oil in the pan during braking, but I didn't have that problem with the old engine, and it's the same pan, pick-up and baffle.

Maybe my rings and valve seals are on their way out, I wouldn't think so with good compression results, but maybe a leak-down test is needed. The old engine had much worse compression results, had 200k on the head, only about 30k on the block and used very little oil, nothing like this one.

Maybe oil is getting pushed through the turbine seal? Anyone know what color deposits I should be looking for on the turbine if oil is burning up on it?

Maybe maybe maybe.... ?

Neil

crxdan

I have the same problem on accleration. I would think that only during accleration thet oil woudl come out. Ill try lowering the oil PSI.

But i think if its decleration, i woudl instantly guess valve stem seals. The boost keeps the oil out at accel, while vacuum will suck in oil at decel.
Especially since this problem just started occuring when u swapped the engines.

shortyz

13mm, thats like 1/2 ID, thats not very big..

Cray91

drop a little change on a valve for your oil feed line, see if that helps. You could replace the seals on teh turbo ifyou think it could be that.

neil85ae86

13mm may not seem very big, but it's bigger than what this turbo had from the factory (10mm) and it has a nice straight run to the pan, the factory had about a 70 degree bend. It has the same size drain as a t-bird, I'm using t-bird drain fitting, which fits Earls #12 SS line. I didn't have a problem with this arrangement on the old block.

Yeah, I'm running out of ideas, it's probably the valve stem seals, I'm going to switch to some of that 'high mileage' oil that's supposed to cause the seals to swell, see if it helps. This engine did sit for alot of years so they could be dried and cracked. While it sat in my garage for a couple years I regularly poured oil across the valvetrain, and soaked the chambers, but I don't know how long it sat in transit and at the importers before I got my hands on it.

Neil