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I have a 416 ls3 that is consuming about 1 quart every 600-800 miles which seems abnormal even for a stroker. The engine has about 10k miles on it. I currently have a catch can installed and have confirmed the routing multiple times. The catch can gets about 3-4 tablespoons of oil a month. However, I have noticed that my intake floor is coated with oil and I believe this is the reason for my oil consumption, but what can I do beyond the catch can to stop oil from getting into my intake? I did a compression test on 2 cylinders to see if the engine has bad rings and it was fine, about 210 psi in both cylinders but I will do the rest of the cylinders this weekend. I've seen people using two catch cans, breathers, vacuum pumps etc, what would be a good solution for my engine?
Im betting the oil is getting through the clean line of the PCV system, its the line that runs from the valve cover to the throttle body, its supposed to allow air into the crankcase but at times oil vapor can come back up.
If thats the case you can either run an additional catch can on that line or you can run a one-way check valve on that line that lets air only into the crankcase and not back out, and then run a breather with a one-way check valve letting air out but not in, that will relive the pressure that was causing the oil to come back up the clean line in the first place.
Im betting the oil is getting through the clean line of the PCV system, its the line that runs from the valve cover to the throttle body, its supposed to allow air into the crankcase but at times oil vapor can come back up.
If thats the case you can either run an additional catch can on that line or you can run a one-way check valve on that line that lets air only into the crankcase and not back out, and then run a breather with a one-way check valve letting air out but not in, that will relive the pressure that was causing the oil to come back up the clean line in the first place.
I dont know what your particular issue is or how your PCV system is set up. But i do know that having manifold vacuum on the crankcase helps rings seal, and it should be inline with a separator / breather. Fresh air should come in on the opposing bank post MAF.
I dont know what your particular issue is or how your PCV system is set up. But i do know that having manifold vacuum on the crankcase helps rings seal, and it should be inline with a separator / breather. Fresh air should come in on the opposing bank post MAF.
It does, he is on the stock system and the clean line is for bringing air into the crank.
Im betting the oil is getting through the clean line of the PCV system, its the line that runs from the valve cover to the throttle body, its supposed to allow air into the crankcase but at times oil vapor can come back up.
If thats the case you can either run an additional catch can on that line or you can run a one-way check valve on that line that lets air only into the crankcase and not back out, and then run a breather with a one-way check valve letting air out but not in, that will relive the pressure that was causing the oil to come back up the clean line in the first place.
That's not true, there is no CLEAN LINE. The forward line acts as a air intake at part throttle, at WOT that same line is used as a relief line for crank case pressure. If you block it off with a one way valve something else will suffer from high pressure. You might try adding a catch can to the "CLEAN LINE" side, but it must be full flow or you will not vent enough crankcase pressure at WOT.
Last edited by RockinWs6; Apr 17, 2017 at 08:27 PM.
That's not true, there is no CLEAN LINE. The forward line acts as a air intake at part throttle, at WOT that same line is used as a relief line for crank case pressure. If you block it off with a one way valve something else will suffer from high pressure. You might try adding a catch can to the "CLEAN LINE" side, but it must be full flow or you will not vent enough crankcase pressure at WOT.
That's the name of the line...
And that is what the breather (with a check valve in it only letting air out) is for. That way oil doesnt go back up the clean line into the intake, the pressure is vented out the breather.
Oh I see it just dumps the high pressure out instead of feeding it back into the intake. I misunderstood and though it blocked everything. You realize either way that is measured air? Not sure how that enters in the equation but I suspect dumping it like that would make it run a tad richer. But dumping the oil that's in that air has to make a hell of a mess? Doesn't matter it is a good idea from a performance stand point.
Last edited by RockinWs6; Apr 20, 2017 at 12:20 AM.
if it is dry try a better catch can or look to your valve seals or piston rings for improvement, as pcv is only 1 of 3 ways to get oil into the intake
if it is wet then try for a better catch can that can handle more crankcase flow
if you are connecting the can to the valley plate either you need to have a valley plate with the built in pcv or you need to have a pcv in-line. check your part numbers
A properly built stroker with a 4 inch stroke crank won't use anymore oil than a good stock LS1 in my experience. Smokers get a bad reputation for oil consumption due to marginal engine builders. My 91 RS has a 383 LS1 and the oil level barely changes on the dip stick between the 3,000 mile oil changes. No adds are required. The oil level is checked at every gas fill up.
My 99TA did suck down a quart of oil every 600 miles for a while. This car got me in the habit of checking oil level in everything I drive at fill you time. The PCV hoses were all split and cracked. The oil consumption drop to 1qt every 1000 to 1500 miles. Sometimes if a rocker stand bolt that goes into the head doesn't have sealant oil can get where it shouldn't.
When the TA got new valve seals the oil consumption dropped from 1 quart per 1000 to 1500 miles to half a quart every 4000 miles. The TA sucked down oil like a fat kid does a double cheese burger and milkshake. The root cause was the valve seals needed to be replaced.
I hope the extra catch can will take care of the issue. Best wishes to getting the issue resolved.
I capped off the TB line from the passenger side valve cover to the TB, and added a GM vented oil cap that I modded to open under any pressure. So far, the car has not consumed a quart in nearly 1000 miles, so there was definitely oil getting into the intake.
Mine was so bad if I pulled the no1 and no2 plugs I could see they were much darker than the ones further back. What was gm thinking with that stock setup? Even the rockers are way to close to the vacuum port and the shield for the port is junk.
I capped off the TB line from the passenger side valve cover to the TB, and added a GM vented oil cap that I modded to open under any pressure. So far, the car has not consumed a quart in nearly 1000 miles, so there was definitely oil getting into the intake.
Make sure your engine can get fresh air into the crank case. Thats why I suggested a 1-way check valve that lets air in but doesn't let air/oil back into the intake.
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Help me solve my oil consumption! 
