I think my stock turbo is blown...

F

float_6969

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2003.5 MSP Blue #2450, 1995 Nissan 240sx, 1996 Mazda Miata
So my oil consumption is really high. Like a half a quart every gas tank. Plugs aren't fouled, and no oil leaks. Smokes bad when you first start it up, especially when it's cold (like sitting overnight). Due to the clean plugs, I don't think it's burning it in the combustion chamber, which means it's either the exhaust side valve stems or the turbo. I don't think it's the valve stems due to the fact that it wouldn't be going through oil as quickly as it is.

So if I'm right, where do I find a new center section? I'm not interested in upgrading the turbo, as I'll never want to make more than 200hp. This is the DD and I don't want to get to crazy with it.

If I can buy just the center section, can I replace it without having to remove the manifold and turbo?

If I do have to remove the manifold, I want to replace things that require the same things to be removed. The stock manifold is cracked in 2 places, but doesn't seem to be leaking. Is it going to leak eventually, or do the cracks seem to stay the same? They've been there since I bought the car and haven't changed.

Does the stock "S" pipe need replaced for the power levels I'm looking at? What about the "J" pipe?

Any other things I should do while I'm in there?
 
the C.H.R.A is what i assume you are talking about. i think the easiest way is to just take the mani and the turbo off. i dont really see how you would have the room down there to take the scrolls off and put a new C.H.R.A on.
 
I kinda figured that was the case. It's pretty tight for space down in there.

Any input on the manifold, S and J pipes?
 
im sure you could get away with using them. just open up the exhaust a little more. and a tune obviously.
 
Hmm, don't know anything about it, and I can't find much about it either. How would that compare in spool to the stock turbo? I don't want it to have any more lag than stock.
 
if you take off your intake and intercooler pipe is there oil in the compressor housing?
 
I'll check that this weekend, but if it was burning that much oil, the plugs would look fouled. I think it's leaking on the exhaust side though.
 
If it was you'd probably be blowing black smoke while driving. I don't think your cats will absorb that much oil, if you even have cats on your car.
 
1/2 qt of oil is a lot to be going through for one tank. Maybe if valve seals piston rings and turbo seals were gone but sounds more like a major leak than a seal
 
I know it's smoking while driving, as after I noticed the high oil consumption, I had my wife watch the exhaust as I pulled away.

I just checked the oil and it's down another 1/3-1/2 of a qt. It's been 4 days, and if i had to guess, the car has been driven maybe 50 miles. So that actually means it's way more than a 1/2 of a quart per tank. If it's the oil seals on the turbo, then it would leak more at higher revs, and since I've put most of those miles on, it's seen 6K quite a few times in those 50 miles. I have about 2 hrs of highway driving to do today. I'm going to fill it back up before I leave, and then check it after I get back and see what it's done.

I don't think it's leaking externally, as there are no spot on the driveway. I checked for oil outside of the block everywhere I could see, and except for the valve cover BARELY seeping, it's dry. I can't see the back side of the block under the intake manifold though. I'm going to check that today.

I also pulled the hot pipe off. It was way cleaner in there than I expected it to be. I couldn't actually see any oil at all, but when I wiped my finger on the inside, it came off a LITTLE dirty/oily. I don't have a catch can, so my guess is it's just normal blow by. Nothing that would account for quarts of oil anyway.

Gonna do a compression test today as well and see how it turns out. I was going to look through the FSM to see if I could find the compression specs, but if anyone knows them off the top of their head, that would be helpful.
 
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i did it not long ago.. pretty sure its 160-165psi with a 5%allowed tolerance between each cyl..

i wish my shop didnt have my manual still, got it from mazda, its their shop book.. like 800 pages
 
Just paying someone to do a head gasket parts and labor is $600 ish a real turbo from garret is closer to $1,000
 
So I checked a bunch of things yesterday. First thing is the plugs. They're basically new (maybe 1K miles on them). They all looked perfect, except for the #2 cylinder. It looked oily. My heart sank. I thought for sure I had a cracked ringland or something. So I check the compression to verify. 190psi, all within 2psi!!! That's EXCEPTIONAL for a motor with 100K miles on it. And I think that's higher than it should be, which is confusing. So I look down in all the cylinders and sure enough, the top of the #2 piston is actually wet with oil. Valve cover gasket is fine and didn't drop oil down in when I removed the plug. So I'm thinking HG or PCV system. Obviously the PCV system is the easiest to check. I pulled the PCV valve and it's VERY oily inside, as well as the tubes for the PCV system. I also thought there was standing oil in the valve cover. I was wrong, it was just the way it's built, but I replaced the valve cover gasket, just to be safe. I also replaced the PCV valve. It seemed ok, but it can't hurt. Another thing I noticed was the top of the pistons were REALLY carbon'd up. Probably from the stupid rich stock tune. So I Seafoamed the motor, added some to the oil, and put a whole pint in the gas tank. Then I filled the engine back up with oil, drove about 150 miles, 75% highway 25% city, and checked the oil.... I didn't loose a drop!

I'm really confused by some aspects of this. I'm assuming that the issues was with the PCV valve but how can the PCV system move THAT MUCH oil into the motor. Secondly, why would it only be the #2 cylinder when the PCV system feeds all cylinders equally? If it's not the PCV system, the only other things I did were to replace the valve cover gasket. I checked the gasket thoroughly and the original gasket wasn't really leaking. Maybe just barely seeping. Could it have been the Seafoam? If so, what? The only thing I could come up with was that maybe the #2 cylinder had a stuck ring? I know the car sat a lot when my father in law had it, but not enough to get a ring stuck. I'm thinking about going out and beating on it today to see if high revs causes the issue.

Also, someone mentioned a HG. Could it fail in such a way that it would dump oil into the #2 cylinder only at high revs and not leak any coolant whatsoever? It hasn't used a drop of coolant the 2 months I've owned it, and my father in law said he's never had to add any either.
 
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Not sure what you mean. I warmed the car up to NOT, removed the fuel pump relay and let the car die, then cranked it over a few times to relieve all the fuel pressure. Then I removed the coil packs and plugs, installed the compression tester, had my wife put the throttle to the floor and crank it until my compression tester stopped showing more pressure building.
 
I have good news!!!! No more oil consumption. We've easily run through a tank of gas and haven't lost a drop of oil.

Musta been the PCV valve. I'm still amazed that it could move that much oil, but I'm not going to complain either. An $8 PCV valve is WAY better than any of the other options, LOL.
 
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