SetofAces Posted October 31, 2009 Report Share Posted October 31, 2009 (edited) I installed an NXS mbc a few days ago; apparently I wasn't getting enough vacuum to activate the wastegate, because I could hear it, or the bpv, or whatever, working when I chopped the throttle before installing the mbc, but not after I installed the controller. I thought this was kinda weird, but since I've been so busy with everything else, I let it slide . . . until yesterday, when I heard a loud sound coming from the front of the car while it was warming up after I gave the throttle a slight blip (I was trying to build oil pressure to get the timing chain tensioner to do its job; yes, I do know that revving a cold car isn't a great idea). Near as I can tell, that sound was my turbo breaking; now it has quite a bit of shaft play, so I took it off and tried replacing it with the turbo off of my spare motor. Unfortunately, I didn't think this one through all the way. The spare motor is an '86 non-intercooled motor, so the compressor housing points in the wrong direction to use the IC. I figured that I would just bypass the IC for now, until I can get a new turbo (may as well upgrade I suppose), but now it sounds crazily screwed up as soon as I start making boost. The only thing that makes sense to me (aside from a toasted turbo) is yet another vacuum leakk to the wastegate actuator (so it isn't working like it should). So I suppose I have 3 options: try and swap out the compressor housings (but I don't know how to do that; seems like it shouldn't be hard in theory but I'm having a difficult time getting the housing off of the blown turbo) or try and fix the vacuum lines/leaks (I like the idea of swapping the housings better); buy the ported big 16g that I can get locally for $230 (supposedly genuine MHI, supposedly <3 miles), will this bolt right up? Or option number three: upgrade my insurance (haha I don't even have insurance) to full coverage and torch the fu**er, then blame it on my ex. Or ninjas. Those dirty, evil, crafty swine; those ninjas. Or maybe I'm talking about my ex? I can't think straight anymore; my turbo aint spoolin no more so now my head is. Any ideas? Edited October 31, 2009 by SetofAces Link to comment Share on other sites More sharing options...
ragdoll_unlimited Posted October 31, 2009 Report Share Posted October 31, 2009 i have fully rebuilt replacement 12a turbos for sale for $175 shipped with core. Link to comment Share on other sites More sharing options...
SetofAces Posted October 31, 2009 Author Report Share Posted October 31, 2009 Will a big 16g bolt right up? I tried searching the forums, but the search here doesn't seem to work worth a damn . . . Link to comment Share on other sites More sharing options...
StarquestRescue Posted October 31, 2009 Report Share Posted October 31, 2009 Will a big 16g bolt right up? I tried searching the forums, but the search here doesn't seem to work worth a damn . . .Not if it is for a dsm. Dsm turbos reqire mods to use. Swap the housing first. That snap ring can be a pain. You may need to get a better snap ring tool. Some where on here are tips on how to use a dsm turbo. Link to comment Share on other sites More sharing options...
Indiana Posted October 31, 2009 Report Share Posted October 31, 2009 When you started up the motor, timing tensioner got its pressure and was doing its job before the exhaust was exiting the muffler. Someone rebuild the motor and leave the rubber stick out of that plunger cavity? Its will still move out you rev up the motor its not going anywhere. There is no "vacuum" on the wastegate actuator. Its boost pressure that pushes it open, meaning it pushes the arm OUT (because its a big spring inside that holds it pulled in) and when the boost is high enough to overcome the tension of that spring the arm extends and moves the wastegate flapper arm and swings the wastegate open. How did you hook that MBC up? If its just a typical MBC and you set it loose and you have no boost gauge (factory boost gauge is electrical fed from the ECU based off sensor readings mainly the MAF and is not at all accurate) then you may have had high boost that resulted in over spinning the turbo and if your oil was dirty, or it was ready to go then that it was did it. Link to comment Share on other sites More sharing options...
SetofAces Posted October 31, 2009 Author Report Share Posted October 31, 2009 When you started up the motor, timing tensioner got its pressure and was doing its job before the exhaust was exiting the muffler. Someone rebuild the motor and leave the rubber stick out of that plunger cavity? Its will still move out you rev up the motor its not going anywhere. There is no "vacuum" on the wastegate actuator. Its boost pressure that pushes it open, meaning it pushes the arm OUT (because its a big spring inside that holds it pulled in) and when the boost is high enough to overcome the tension of that spring the arm extends and moves the wastegate flapper arm and swings the wastegate open. How did you hook that MBC up? If its just a typical MBC and you set it loose and you have no boost gauge (factory boost gauge is electrical fed from the ECU based off sensor readings mainly the MAF and is not at all accurate) then you may have had high boost that resulted in over spinning the turbo and if your oil was dirty, or it was ready to go then that it was did it. The timing chain rattles until I start to see the oil pressure gauge move up; usually after I start driving or rev the motor a few times. I have a manual boost gauge hooked up. The MBC was hooked up to the port on the wastegate actuator, and to the fitting on the intake tube going into the TB (where the wastegate line was originally connected. I assumed that the line was leaking somewhere, as I couldn't hear the BPV/wastegate/whatever activating whenever I chopped the throttle/shifted/etc. Link to comment Share on other sites More sharing options...
dstar88 Posted October 31, 2009 Report Share Posted October 31, 2009 you can reclock that compressor housing from the non i/c 12a that you have, you know.. all you need are some snap ring pliers to take the snap ring off that hold the compressor housing in place. then turn the housing the the point to where it will mate up with the stock i/c hoses. once you find the correct spot you want it at. just put the snap ring back on and your done. or you can switch compressor housings from the 12a that you messed up somehow just by doing the same thing.. Daniel Link to comment Share on other sites More sharing options...
Edde Posted October 31, 2009 Report Share Posted October 31, 2009 Those chains can't make noise for more than about 2 seconds - maybe 3 - on startup or there are other troubles IMO. Better make sure there really is oil pressure on this car. Maybe I'm reading it wrong. Then go over everything - look and feel how these turbos spin by hand - gently. There will be a half cup of plastic and metal shards in the oil pan if the chains have never been changed. Any of that gets in the oil to your turbo and it's bearings are gone. They cannot wait unless you don't drive it. More than the chains it's the guides that get worn badly. The wastegate operation is different from any bypass valve or blowoff. You will not hear the wastegate opening, it just bleeds off excess boost to the exhaust when you're boosting to the max. Anytime I'm not sure I drain some oil and inspect it carefully. Unfortunately you may not get a sample of the bigger chunks in the oil pan doing this but if there is metal, there is metal. Link to comment Share on other sites More sharing options...
Indiana Posted October 31, 2009 Report Share Posted October 31, 2009 I don't know what a timing chain sounds like when it rattles but there are other things that can rattle. Oil pressure is low? That motor have balance shafts in it still? You may have bearings making noise or valve train? Link to comment Share on other sites More sharing options...
Tim_C. Posted October 31, 2009 Report Share Posted October 31, 2009 Yeah, there are chain and oiling issues. You need to get it running without noise before doing anything else. There is most likely chain guide material all through the oiling system that you really can't get rid of without rebuilding the engine and cleaning all of it out. You could replace the cam timing chain, get rid of the balance shafts, new guides and even a new pump and still not have good enough pressure to the head. It certainly needs these parts and work at a minimum, but I suspect that won't be enough and that a rebuild may be in order. Then you could keep the shafts if you want, but I prefer to remove them. Link to comment Share on other sites More sharing options...
SetofAces Posted October 31, 2009 Author Report Share Posted October 31, 2009 Yeah, there are chain and oiling issues. You need to get it running without noise before doing anything else. There is most likely chain guide material all through the oiling system that you really can't get rid of without rebuilding the engine and cleaning all of it out. You could replace the cam timing chain, get rid of the balance shafts, new guides and even a new pump and still not have good enough pressure to the head. It certainly needs these parts and work at a minimum, but I suspect that won't be enough and that a rebuild may be in order. Then you could keep the shafts if you want, but I prefer to remove them. If the gauge is to be trusted, then my oil pressure is fine; it took me changing the oil multiple times after buying the car to flush most of the crud out, but now it reads where it's supposed to. I have a spare motor; I'm going to check out the bottom end (head and manifold's cracked) and if it's in good shape then I'll eliminate the jet valves, and perhaps have some porting and a valve job done on the head that's on the car now, perhaps install OS SS valves while I'm at it. I'm hoping to do this without even re-ringing the sapre motor, but we'll see; for the moment, however, I just need something to get around in. Link to comment Share on other sites More sharing options...
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