93 sc400 blowing smoke out of pcv and elbow

[Erik Sawyer]

hey guys, I have a 93 sc400 that is supercharged. I’m a mechanic so I get some smoke coming from here is normal, but this is an extreme amount of smoke. Oil leaks out of cold air intake when I shut it off. I have to add a quart of oil every 50 miles or so. I have seen many threads on this topic but I think this is an extreme situation. The only thing I can think is the rings are shot and sc is dumping boost into crankcase. But then I read these motors are indestructible. Any ideas would be greatly appreciated. Thanks fellas!

 

[Zuffen]

How long have you been running the Supercharger?

What sort/brand of Supercharger?

What pressure does it run?

A picture or two would help.

 

[Erik Sawyer]

How long have you been running the Supercharger?

What sort/brand of Supercharger?

What pressure does it run?

A picture or two would help.

 

[Erik Sawyer]

Not sure what brand of supercharger it is, or what psi it is running. I bought the car with it on it. I have owned 2 sc400’s prior to this one. I can’t dowload pictures on here for some reason, says file to large. I’m beginning to think I have a cracked ring or a hole in a piston. Car runs rough until I hit 2k then it smoothes right out. I swapped over my fuel pump, headers, cat back exhaust, injectors and rail from my old car. Car flies when it’s right, now it’s hard to keep it running.

 

[Zuffen]

If I was in your situation I'd do a compression check to see which cylinder or cylinders was down on compression.

The spark plugs will also tell you which cylinder is burning oil.

A cheap borescope would allow you to have a look in each cylinder without lifting the head.

I think you may find it easier and cheaper to source another long block and swap your accessories onto it.

 

[Erik Sawyer]

I have another motor out of my other sc. is it really difficult to put pistons and rings in these motors? I’ve done motor work on Chevrolet’s mostly. I have read that these engines are impossible to work on. I planned on rebuilding this motor this winter but if they are that hard I might leave it alone.

 

[Frank Clark]

I have another motor out of my other sc. is it really difficult to put pistons and rings in these motors? I’ve done motor work on Chevrolet’s mostly. I have read that these engines are impossible to work on. I planned on rebuilding this motor this winter but if they are that hard I might leave it alone.

That simply is not true. We have (or have had) race cars with SBC Chevys, LS1, LS7 and 2GR and 1UZs. The 1UZ obviously has DOHC/Timing belt and MORE valves, but other than that is not any worse than the others.

The current engine in my avatar car (OK the engine is out this week, but...), is a VVTi 1UZ. It has aftermarket Rods/Pistons/ARP Head and Main Studs/etc, along with a monster turbo...

I've also been into the non-VVTi engine and it's slightly less complicated than the VVTi, but the short block is the same for all practical purposes.

Aftermarket parts availability is another matter of coarse.

An engine with excessive blow by probably needs a hone/rings AT MINIMUM. And of course you could need head work and what not.

So it's probably CHEAPER to get a low mileage JDM engine (I pay $695/engine) and install that. New intake gaskets (to swap your SC on), fresh water pump, timing belt, tensioner, idler, serpentine belt, oil filter and you should be good to go. Less than $1000 all in. Non-VVTi are getting harder to find, but I've seen the Dallas area JDM guys with some in stock. Every imported JDM engine I've opened up has shown no significant amount of wear. Of course YMMV.

If you are looking for a bit stronger engine, Eagle Rods/Ross Pistons along with a bore/hone would make for a much stronger engine. But your engine probably needs the heads freshened at this point as well. Add in fresh gaskets, bearings, head bolts (not reusable), water pump, timing belt etc. So that's probably $2500+ in parts and machine shop labor (perhaps a good bit more).

The JDM engine is a much cheaper 'fix' if that is what you are after. But don't think the 1UZ is a bear to work on.

 

[Zuffen]

I rebuilt my supercharged 1UZ a few years ago and I'm not a trained mechanic and it all went together without any dramas.

The rebuild parts cost in Australia was about the same as buying 6 JDM used engines so I ended up selling the engine and replacing it with a stock JDM engine and it's going well.

I wouldn't rebuild another simply because of the cost factor.

 

[Frank Clark]

[QUOTE="...have to add a quart of oil every 50 miles or so....[/QUOTE]

I missed that part first time around. I would not rebuild that. Even if I wanted to do internal upgrades, I’d buy a JDM engine to start from.

A quart/50 miles could very well mean you also have lots of gas and carbon in the oil. Bearings could be trashed. Heads could be trashed (cams do not have replaceable bearings).