Valve cover breather experiment. Interesting results.
12-13-2016, 11:20 AM
#43
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This post is about the passenger side breather / throttle body hookup, but in order to give the proper context, I'm sharing extra info about my recent experiences.
I've owned 3 LT1s over the past 16 years or so. The first two, even though I did performance mods I left the emission systems intact.
Let me preface the next paragraph by saying I knew what I was getting into, but I know these cars like the palm of my hand and can disassemble/reassemble them in my sleep. Plus I have two new vehicles for daily driver type stuff, so I was in no rush.
The one I have now has really low mileage for a '95, but I got it cheap because I bought it from some kid who had butchered some stuff under the hood and then got upset when the car ran like crap. For example, he tried removing the EGR and AIR pump, and then realized the computer was throwing codes, so he put the modules back on but left their hoses all unhooked and cut up. Jammed spark plugs in them to (unsuccessfully) try to get them to stop spewing exhaust into the engine compartment. Bunch of other issues too, like to make electrical connections he'd strip the ends of both wires and then tie them together like you'd tie drawstrings on your pants, then slap a thin layer of electrical tape over them. He WELDED the exhaust manifolds to the heads, which took over 10 hours and a trip to my father-in-law's machine shop to undo and repair properly. Bunch of stuff, I could go on for hours. I ended up spending ~80 hours tearing apart everything I could in the interior, the engine compartment (broke it down as much as I could without actually pulling the engine out), the chassis, etc. and cleaning / rewiring / replacing/ reassembling.
I finished the AIR / EGR removal properly, including using TunerCat to disable the computer codes.
After doing all of this, it ran near-perfect, but there was still some idling issues / random misfires, and the exhaust smelled like oil / sometimes had a puff of blue smoke. Compression check passed though. I have the DataMaster software and am experienced with it, but it didn't really tell me much about this particular problem. All new parts on the car including sensors, and everything read fine in DataMaster.
I then remembered that when taking apart and cleaning the intake manifold, it was coated in oil more than usual. I just assumed no one had ever taken it apart and cleaned it before. Turns out that for whatever reason, this hose we're talking about that goes from the passenger valve cover into the side of the throttle body was sucking up way more oil than it should. I still don't know why, and I had never experienced this bad of a breather issue with my other two LT1s. But I removed the hose, put a vacuum cap on the throttle body, and installed a Moroso breather/filter assembly on the valve cover (which took some fabrication and ingenuity).
Doing so resolved all my remaining issues. Now I have a clean idle, no weird misfires, no oil smell or puffs of smoke coming out of my exhaust. The car runs slightly leaner (though still on the rich side as they prefer to do) and the throttle is more responsive. The last thing I think about in one of these vehicles is gas mileage, but nothing stands out to me when compared with the other two I owned (i.e. I'm not randomly sucking gas twice as fast or anything like that)
I'm not saying it's a great idea for everyone. If I wasn't having the problems I mentioned above, I would have left well enough alone.
But it worked great in my situation, and now she's running like she just rolled out of the factory in '95!
Performance mods to come next autumn/winter, but first order of business was just to save it from the abusive previous owner and restore it to 98%+ peak operating condition so I can enjoy it all next spring/summer before tearing it all down again. Lulz.
I've owned 3 LT1s over the past 16 years or so. The first two, even though I did performance mods I left the emission systems intact.
Let me preface the next paragraph by saying I knew what I was getting into, but I know these cars like the palm of my hand and can disassemble/reassemble them in my sleep. Plus I have two new vehicles for daily driver type stuff, so I was in no rush.
The one I have now has really low mileage for a '95, but I got it cheap because I bought it from some kid who had butchered some stuff under the hood and then got upset when the car ran like crap. For example, he tried removing the EGR and AIR pump, and then realized the computer was throwing codes, so he put the modules back on but left their hoses all unhooked and cut up. Jammed spark plugs in them to (unsuccessfully) try to get them to stop spewing exhaust into the engine compartment. Bunch of other issues too, like to make electrical connections he'd strip the ends of both wires and then tie them together like you'd tie drawstrings on your pants, then slap a thin layer of electrical tape over them. He WELDED the exhaust manifolds to the heads, which took over 10 hours and a trip to my father-in-law's machine shop to undo and repair properly. Bunch of stuff, I could go on for hours. I ended up spending ~80 hours tearing apart everything I could in the interior, the engine compartment (broke it down as much as I could without actually pulling the engine out), the chassis, etc. and cleaning / rewiring / replacing/ reassembling.
I finished the AIR / EGR removal properly, including using TunerCat to disable the computer codes.
After doing all of this, it ran near-perfect, but there was still some idling issues / random misfires, and the exhaust smelled like oil / sometimes had a puff of blue smoke. Compression check passed though. I have the DataMaster software and am experienced with it, but it didn't really tell me much about this particular problem. All new parts on the car including sensors, and everything read fine in DataMaster.
I then remembered that when taking apart and cleaning the intake manifold, it was coated in oil more than usual. I just assumed no one had ever taken it apart and cleaned it before. Turns out that for whatever reason, this hose we're talking about that goes from the passenger valve cover into the side of the throttle body was sucking up way more oil than it should. I still don't know why, and I had never experienced this bad of a breather issue with my other two LT1s. But I removed the hose, put a vacuum cap on the throttle body, and installed a Moroso breather/filter assembly on the valve cover (which took some fabrication and ingenuity).
Doing so resolved all my remaining issues. Now I have a clean idle, no weird misfires, no oil smell or puffs of smoke coming out of my exhaust. The car runs slightly leaner (though still on the rich side as they prefer to do) and the throttle is more responsive. The last thing I think about in one of these vehicles is gas mileage, but nothing stands out to me when compared with the other two I owned (i.e. I'm not randomly sucking gas twice as fast or anything like that)
I'm not saying it's a great idea for everyone. If I wasn't having the problems I mentioned above, I would have left well enough alone.
But it worked great in my situation, and now she's running like she just rolled out of the factory in '95!
Performance mods to come next autumn/winter, but first order of business was just to save it from the abusive previous owner and restore it to 98%+ peak operating condition so I can enjoy it all next spring/summer before tearing it all down again. Lulz.
12-22-2016, 06:33 PM
#44
11 Second Club
I have a breather in each valve cover and it works perfect..
