Well I'm running twin t-3's on a 350 silverado. I had installed a new cartridge on one side the other side was old an leaked. I assumed that the leaky side needed a new cartridge. Well today (I have only had it running three days) both side leaked so bad oil came out the exhaust! I have 10AN drains on both. They are not the best angle wise but I'm pretty sure that the turbos are getting fed with too much oil. The chevy makes over 60 PSI of oil pressure. So my plan is too add oil .04 restrictors. I'm also wondering if I'm pressurizing the crank through the PCV valve. Although I bought an NOS turbo coupe PCV valve it might be blowing by. Therefore I bought a one way valve to add into the PCV feed from the carb.
Any ideas? Opinions?

 

I'd start with addressing the crankcase venting before restricting turbos. Make sure you have plenty of venting, and try it without the pcv. What size feed lines? With proper drains and venting you should not have an issue with oil leakage, and imo should not run a restrictor on anything but a bb turbo unless its a last resort (should have asked... bb turbo's?).

 

no its not a bb turbo. its a plain jane turbo (actually two) from svo stangs. I had restrictors on my last car with the same turbos and it worked well. I will add the one way valve to the PCV valve. I did order the restrictors they were inexpensive thirty for the pair. I hoping the combination will fix the issue. The oil was literally dripping out the exhaust!!!!!!!!!

 

I know many have used restrictors with good results, its just not the way i'd go. Many oem turbo's (larger diesel equip, and trucks) run large feed lines (.5-.625) with 50-100+ psi without drain problems. The problem with restrictors imo is that you don't know when the turbo is starving for oil until it fails. Just my 2 cents though.

 

when my new cartridge started spewing oil I was pretty discouraged. the drains are 10 AN. they don't go straight down but they aren.t horrible, i just think the 4 an feeds are too much for it. the chinese t3 oil flanges have a restrictor but it is pretty dang big

 

Any pics? Is the new cartridge Chinese?

 

i have a build of the truck in the build board. it probably we is chinese im not sure. it was not leaking when first installed. i know my last build had 3an lines as well. also it doesnt smoke at idle only when u rev it when the oil psi increases

 

I missed that they're svo turbo's.

 

they are svo turbos but one has an ebay cartridge. I found it years ago and it sat in the garage untikl this build. There were others on this website that bought the and had luck. However being an ebay cartridge I assume it's hit or miss. I disconnected the PCV and blocked the vacuum and took it for a ride. Both turbos smoked badly. I wonder if the seals let blow by oil is it a slip by or do they blow out? If so I/m looking at two new cartridges. When I first drove it it smoked pretty badly when in boost. It then blew the carb hat gasket out and blow by decreased. After I added the felpro reenforced gasket blowby increased. I think this is b/c the turbos are now spooling. I just can't figurre why the oil blow by would increase with the spooling. the exhaust gas goes by either way so why would it leak more with more boost? Anyway the main issue is why is it leaking? Why would a new cartridge go? As I asked before if they leak does it mean they need rebuilds (gasket blow out)?

 

I'm not sure if I followed that last post, but if you're having ring seal issues, more boost is only going to further the blowby, and drain back issue.

 

The engine is brand new.  It never burned oil.  The problem is in the turbos.  If I had blow by b/c of too much pressure does that mean I destroyed the seals?  I/m wondering if  I need to rebuild both catridges

 

As mentioned address the PVC first. Turbos have their own restrictors already in the center section. It doesn't matter how large the feed is. I would never use restrictors.

Chances are your turbo seals are good just being overcome by crank case pressure. Once the PVC pressure is relieved the oil will go back to the pan not out of the center section. Keep in mind residual oil may take some time to get consumed or burn off...

 

I disconnected the PCV and took it for a ride. I thought the oil would take time to burn off as well. I tried to goose it on the way home and oil came out so bad the engine compargment filled with smoke. The oil was almost dripping out of the dang thing when i opened the hood. it also really wouldnt spool. it was kind of dead.

 

If it wont spool check for damaged turbos, or engine.

 

I'm aware of what it could be. It could always be a damaged engine. It is less common for an engine to run and idle well if it is blown enough that it spews oil out the exhaust. The turbo is another question. It seems as if the oil is pouring out of it without draining well. I have 10AN drains. The new side worked well without smoking for a few runs and 50 miles of driving. I have no idea why it ould give trouble all of a sudden. It did seem to coicide with the repair of the hat gasket. Before I replaced the gasket it didn't smoke that much

 

What kind of valve covers are you running? If you can, just run huge ass hoses from each VC overboard for now just to ensure you have sufficient crank venting. I battled the same thing for months. Turned out the cheapo parts store valve cover breather I was running was not breathing at all. Almost immediately after removing it, my smoking probelm stopped.

Also If you want to run a restrictor, just verify you're getting the minimum oil flow required by your turbo by pulling the drain and counting so many seconds while collecting the drain oil in a measuring device. I think my little t25 requires around 1ltr/min iirc. I think I've seen somewhere that t3's are just under 2ltr/min. Don't quote me and find out for sure before you start restricting. But if your motor is making 60+psi, who the hell knows how much volume they are seeing, but it could be too much. What size restrictors did you buy? I'd start by restricting it to 0.070"+, not .040". Unless that is, it still meets the flow requirements. Good luck

 

Do you have blow by without a PCV? I diconnected my PCV and had bigtime blowby. I know my venting stinks. I need a breather. I just didn't think a breather would cause the drainage issues

 

I have never ran a pcv with my current turbo setup. When I installed the turbo I simply popped a breather on the vc and ditched the pcv setup. I did all this just to get it going and decide what ventilation to do next. I ended up chasing my tail for a couple months trying to figure out my smoking problem. Turned out the crank case just needed to breath. The junk breather was just that, junk, didn't breath at all. What I'm saying is put a GOOD breather on your dipstick tube, fill cap, vc breather, and anything else you can think of, and clean all the residual oil out of the pipes and see if it continues smoking. If it does, than start investigating the turbos/oiling system. When oil comes out of a spinning turbo, its foamed up and trying to gravity feed back down a 5/8" hole. Just imagine blowing pressure back up the hole that oil foam is trying to fall down. It fucks everything up.

 

I will add breathers. I went out to check the truck today. The compressor side was full of oil. I wonder why this could happen? There also seems to be a ton of side to side movement. This was a brand new center section. What the hell could of happened to it? It definately had enough oil.

 

When I had my issues there was alot of oil on the compressor side