Major Oil Leak

[JBT]

Did you get a compression test? There are any number of seals front and rear that can cause external oil leaks. The oil in the cylinders could be caused by stuffed rings or stuffed valve seals.

It doesn't look very happy at all.

[Steampunk]

Novice1 had oil leakage here and there after the turbo install, but it was simply that the turbo's oil feed and return were not done up tight enough.

Check for oil under your pressure sender.

It's strange to have oil coming out of your cylinders unless JBT's scenario rings true.

Hopefully its relatively simple diagnosis in that the head-gasket has expired and thus oil is coming out of the galleries into the cylinders and out the block.

The oil is definitely not coming out of the cam cover gasket or CAS O-ring yeah?

[Steampunk]

Just another thought. Since you have the head off, have you considered a \"might as well do it at the same time\" scenario? ie. change valves, valve springs etc?

[Mr Morlock]

sasso- put me in the ltd knowledge class but perhaps a few observations. I would have thought a broken ring wouldn't effect all cylinders and stem seals might also be limited- you have a deluge of oil in all cylinders by the look of it.
Better of course to actually define the problem and you might save a lot of time by getting advice from one of the experienced MX5 motor rebuilders. Will be interested to know how you get on.

[fattima]

Did it start burning oil after fitting the turbo? Could be an oil seal in the turbo. As for the other leaks could be front crank seal, rocker cover? While you have the head it would be a good time to change the front seal.
Bit hard to do while you have the head off but clean the engine run it for a while and see where the leak is coming from.

[adamjp]

Have you looked at the inside of the inlet manifold? Is it oily?

From what you describe it seems that you may have inadvertently pressurised the crankcase which has exacerbated an existing oil issue. This could/would make the oil pass out wherever it can, but most importantly it will pass INTO the inlet manifold through the breather hoses. This would explain the mostly uniform coating of oil soot on the pistons/combustion chambers.

My 2c guess for you to look at.

[adamjp]

how do you pressurise the crankcase? is the breather hose that one on the top near the oil fill cap?

That and the PCV valve/pipe between the inlet manifold and the cam cover on the drivers side of the engine. If I remember correctly, you need a different PCV valve for positive pressure engines - anyone help here?

The vent pipe on the cam cover goes into the turbo intake. When I took off the intake pipe there was a small pool of oil sitting in front of the compressor. Perhaps its coming out of there and through the turbo into the intake. Aww that would mean my would intercooler is drenched inside.

If your crankcase is being pressurised, this would explain the oil soot and general unhappiness of your engine. That small pool of oil indicates that your turbo is not long for this world as it is being asked to compress oil/air. Apart from the mass of the oil hitting the rotating turbine blades (not a good thing), the oil may also be combusting when it is compressed in the oxygen rich environment. This is how turbine engines work - try sucking up kerosene (or oil) with a garden blower/vac and you will see what I mean.

If all of this is happening, your engine will be running very rich as much of your O2 will already be burnt before it gets to the intake manifold, let alone the combustion chamber. IMHO you should have an experienced turbo mechanic go over your turbo installation - it sounds sick.

[GS]

how do you pressurise the crankcase? is the breather hose that one on the top near the oil fill cap?

That and the PCV valve/pipe between the inlet manifold and the cam cover on the drivers side of the engine. If I remember correctly, you need a different PCV valve for positive pressure engines - anyone help here?

The vent pipe on the cam cover goes into the turbo intake. When I took off the intake pipe there was a small pool of oil sitting in front of the compressor. Perhaps its coming out of there and through the turbo into the intake. Aww that would mean my would intercooler is drenched inside.

If your crankcase is being pressurised, this would explain the oil soot and general unhappiness of your engine. That small pool of oil indicates that your turbo is not long for this world as it is being asked to compress oil/air. Apart from the mass of the oil hitting the rotating turbine blades (not a good thing), the oil may also be combusting when it is compressed in the oxygen rich environment. This is how turbine engines work - try sucking up kerosene (or oil) with a garden blower/vac and you will see what I mean.

If all of this is happening, your engine will be running very rich as much of your O2 will already be burnt before it gets to the intake manifold, let alone the combustion chamber. IMHO you should have an experienced turbo mechanic go over your turbo installation - it sounds sick.

Yep, from what ive read the standard MX5 PCV valve has a habit of crapping itself with positive vacuum. A popular option is to upgrade to the PCV valve from a 323 turbo. Apparently this will withstand a mild boost level, but the guys running 10-12+ psi are still looking for a better option. Do a seach for "PCV" on miataturbo.net for some more info. Sounds like you've got an existing pre-boost issue anyway, but the PCV valve may be amplifying the problem.

ps. Just found a thread of one related story:

http://www.miataturbo.net/forum/showthread.php?t=9920

[manga_blue]

Heya.

For a while now my engine has been eating oil and alot of it seems to be ending up on the bottom of the gearbox. Firstly I found it to be all down the left side of the engine, when I took off the exhaust manifold it looked like the rear left was leaking

Maybe you might have a few different leaks as well. The very first one you mentioned describes pretty well what happens you get when a rear crankshaft oil seal failure. Positive pressure in the crankcase would make that worse.

I'm definitely not saying this is all your problem, it might be one of several.

[Mr Morlock]

Sasso- you need to give yourself a buffer somehow- borrow another car, hire a bomb or get someone to drop you off to work. Is it practical to actually bypass/ remove the turbo to assist in fault diagnosis? The comp check would tell you something. IS crankcase pressure measurable? Ultimately you might have to pay a pro to do it for you.
You have detailed all the things that happened and a sequence- if you do take it to a pro that will be useful in nailing it. As someone else already said you may have more than one root cause.

[NMX516]

It seems to have gone from bad to worse. Changed the head gasket now the car doesn't even start. Got 3 hours sleep trying to fix my car to get to work the next day.

Ok something else that might help the diagnosis. On occasion, I would be driving down the street from my house going wherever, I'll get to the end of the street, say a minute later. I stop to turn left, the engine would stall, I try to restart it but it makes a really strange whining sound instead of cranking over nicely, and it doesn't start. I usually have to activate the flood clear (full throttle) to get it to start.

Now with the new gasket on, its doing it all the time, the whining noise, It occasionally kicks, but more worryingly it makes all sorts of popping noises out of both the intake and exhast.
Any ideas?

How did you set the cam timing when you put the head back on??

Sounds to me like the cam timing is way out. Did you mark it all up before you removed the head, and then put it back on with the cams and bottom pulley at exactly the same position as before you pulled it all apart?

[Ajay]

AEM is a brand of intake system.

Glad your car is almost running good again!..

Cheers
Ajay

[adamjp]

Dude, I thought I kinda covered what oil in the inlet means.....

Even if you are running an exceptionally wild camshaft, your forced induction setup would make it practically impossible for any charge to revert BACK to the inlet manifold from the combustion chamber.

To go over this all again. from what you have said, you are probably pressurising your crankcase due to a faulty PCV valve. This is exacerbating existing oil leaks and is forcing oil into your inlet system between the air filter and the turbo.

This diagnosis makes more sense than a possible reversion from the combustion chamber to the inlet manifold. It is also the more expensive diagnosis of the two. I'll wager that your inlet tubing, including your intercooler, are also lined with a nice oil finish.

[Fatty]

there is a very simple, easy test to check the pcv valve. take it out and blow thru it. you should be able to blow thru it from the engine side, but not the intake side. if you can blow thru it both ways, then it needs replacing.

probably worthwhile doing this test just to rule it out 100%.

[fattima]

Have you done a compression test? If not do a dry and a wet test to get an idea if rings are shot. Details here
http://www.geocities.com/dsmgrrrl/FAQs/compression.htm