Extreme Oil Consumption
Thread Starter
Staging Lane
Joined: Aug 2010
Posts: 69
Likes: 0
From: NC
Extreme Oil Consumption Ok I've got a 408 that I had built by a professional. Just broke in and tuned made 487/473 during the tune. For the first month or so of only weekend driving it it exhibited no problems at all. I changed the oil again recently from the high zinc oil to a standard 10w-30 with out all the zinc.
Since then I have noticed extreme oil consumption. Enough that I can actually start the car up and put my hand by the exhaust and watch it pepper my hand with raw oil.
I currently have all the pcv ports connected to the intake. I've seen some posts about a catch can solving the issues so I installed one but since then havent drove the car enough to see is its made a difference.
For reference a 40-50 mile Saturday cruise can consume 1/2-3/4 of a quart. Seems extreme to me to be the pcv system.
The setup is
408
ls6 intake
246/248 cam
3" single exit exhaust with a Y
Since then I have noticed extreme oil consumption. Enough that I can actually start the car up and put my hand by the exhaust and watch it pepper my hand with raw oil.
I currently have all the pcv ports connected to the intake. I've seen some posts about a catch can solving the issues so I installed one but since then havent drove the car enough to see is its made a difference.
For reference a 40-50 mile Saturday cruise can consume 1/2-3/4 of a quart. Seems extreme to me to be the pcv system.
The setup is
408
ls6 intake
246/248 cam
3" single exit exhaust with a Y
Thread Starter
Staging Lane
Joined: Aug 2010
Posts: 69
Likes: 0
From: NC
One of the pictures is with the intake off. There is a good bit of oil under the intake(picture). I'm not sure if its enough to foul the plugs like this(picture). There's also a picture with the catch can installed.
I ran a compression test on the engine and got 170 across the board other than on cylinder 5 which got 210 the first time I ran it, (ran the others) came back to it and it made 190, and then 185.
That makes me think oil on top of the piston is causing the compression to go up on #5 but as it clears is going back to normal.
The starter doesnt make as much oil pressure as the engine running so I'm either at PCV system and catch can, Head Gasket, or bad ring on #5 but that wouldnt explain why they all have oil them.
I ran a compression test on the engine and got 170 across the board other than on cylinder 5 which got 210 the first time I ran it, (ran the others) came back to it and it made 190, and then 185.
That makes me think oil on top of the piston is causing the compression to go up on #5 but as it clears is going back to normal.
The starter doesnt make as much oil pressure as the engine running so I'm either at PCV system and catch can, Head Gasket, or bad ring on #5 but that wouldnt explain why they all have oil them.
Thread Starter
Staging Lane
Joined: Aug 2010
Posts: 69
Likes: 0
From: NC
He used total seal rings and considering its not that much of a top end cam I dont think that was the case. I did notice a good bit of oil build up on top of all of the intake valves when I removed the intake. I'm leaning towards catch can now because I dont see how all of the stem seals could be bad.
12 Second Club
Joined: Sep 2005
Posts: 4,273
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From: Bucks County, Pa.
I'm using the Moroso universal air oil separator now, but if I had to do it over again, there are better ones out there, in my opinion, like some of the ones the Coyote and Mopar peeps use. 
I currently have all the pcv ports connected to the intake
ideally you want slightly negative pressure in the crankcase being caused by the intake manifold vacuum to scavenge crankcase vapors. you don't want more than 1 psi of vacuum otherwise you risk various problems such as outside air pushing past crank front/rear seals and various other places. and too much pressure would cause oil leaks. the oem setup is one valve cover breather having line going to air filter lid behind air filter for intake air, other is through pcv valve to meter suction connected behind throttle plate.
as a test which is free and would not hurt anything provided you account for any mess, is disconnect the pcv system and vent both valve covers to atmosphere with suitable filter to prevent oil from going everywhere. a cheap way is to use some clear fram fuel filters then you could plumb some clear 3/8" clear pvc from depot to the intake way upstream, this way you can see if oil is really being pushed and then easily see oil coated in the air filter box. this would easily/quickly tell you if it's a pcv problem or something else especially if you're getting your hand peppered with oil out the tailpipe.
