Pulling in oil heavy through PCV Valve
#1855800
06/24/15 11:06 AM
06/24/15 11:06 AM
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Joined: Aug 2005
Posts: 4,799 ILL
MLR426
OP
master
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OP
master
Joined: Aug 2005
Posts: 4,799
ILL
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Stock 440-6 barrel restoration engine, the PCV Valve is pulling in oil after rebuild wetting inside intake and fouling plugs. Engine holding 18 steady vacuum and I have done a compression check and find all cylinders at 165 psi. There is stock valve covers on the engine with baffle so there is no direct oil being splashed on the valve. I'm at a loss any ideas ? Engine ran on dyno with no pcv and of course ran awesome, rings sealed right up and made 410hp 470 torque.
Thanks MLR426
Last edited by MLR426; 06/24/15 11:12 AM.
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Re: Pulling in oil heavy through PCV Valve
[Re: MLR426]
#1855825
06/24/15 12:08 PM
06/24/15 12:08 PM
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Joined: Oct 2003
Posts: 7,506 Az
Crizila
master
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master
Joined: Oct 2003
Posts: 7,506
Az
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Crankcase should be running a slight vacuum at idle? Using the correct PCV valve? with Mr P. Sounds like it just isn't baffled well enough.
Fastest 300
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Re: Pulling in oil heavy through PCV Valve
[Re: MLR426]
#1855905
06/24/15 01:59 PM
06/24/15 01:59 PM
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Joined: Aug 2003
Posts: 43,157 Bend,OR USA
Cab_Burge
I Win
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I Win
Joined: Aug 2003
Posts: 43,157
Bend,OR USA
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Stock 440-6 barrel restoration engine, the PCV Valve is pulling in oil after rebuild wetting inside intake and fouling plugs. Engine holding 18 steady vacuum and I have done a compression check and find all cylinders at 165 psi. There is stock valve covers on the engine with baffle so there is no direct oil being splashed on the valve. I'm at a loss any ideas ? Engine ran on dyno with no pcv and of course ran awesome, rings sealed right up and made 410hp 470 torque.
Thanks MLR426 Are you sure that the oil is coming into the motor from the PCV or is it possible that the oil is sucking into the intake from the lifter valley pan? I've seen a lot of rebuilt motors, especially cast iron six pak motors, suck oil into the motor from the lifter valleys from a bad seal on the intake valley pans To test this remove the PCV from the valve cover and remove the hose from the intake or carb, you could leave the PCV sit outside the valve cover with a rag wrap around the bottom of the PCV to keep debris and dirt from sucing into the motor also and leave it hook up to keep the vacume the same I have taped a rag over the PCV hole in the rocker arm cover to see if crankcase pressure is blowing oil out of the valve covers to test issues like this also Lots of gremlins in these motors, dang it If you try this test drive the car long enough to suck all the oil out of the intake, if it doesn't dry up in 100 miles of street driving the valley pan may be your problem I now set the intake manifolds on the motors without the valley pans and use a feeler gauge to check the manifold to head fitment on all four corners at the top and bottom of each corner, I write it down on the intake corners for future reference I've seen some that have .015 on the bottom of one corner and have .007 at the top of that corner, I've also seen .000 on one corner with .025 on the bottom on the same corner I shoot for having the manifold cut to fit the motors with .002 max at the bottom and no more than .005 on the top so the valley pans will be pinched in tight at the bottom I also will use the thin intake gaskets to help seal up the intake from sucking oil into the motor IHTHs Let us know what you do and find
Last edited by Cab_Burge; 06/24/15 02:01 PM.
Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)
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Re: Pulling in oil heavy through PCV Valve
[Re: perfmachst]
#1855919
06/24/15 02:26 PM
06/24/15 02:26 PM
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Joined: Jul 2013
Posts: 1,272 Northern Calyfornua
Sxrxrnr
pro stock
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pro stock
Joined: Jul 2013
Posts: 1,272
Northern Calyfornua
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Complete agreement. Had identical issue on newly built 512 ci six pac fouling plugs badly which began some 800 miles after build. Thought might be pcv too. Vented it to atmosphere, no improvement. Pulled intake, all ports on intake manifold and head slathered with oil. Replaced turkey pan,,,could not add additional fiber gaskets as geometry too far off to get bolts started. Used silicone sealer liberally on turkey pan. Still had plug fouling. Very odd, no smoke from exhaust,,suspect fouling plugs so badly that they were not firing, hence no smoke.
Suspected significant head and intake incompat.
Replaced heads with Edelbrock Performers. Problem resolved perfectly. Using turkey pan only.
Valve guides of replaced iron heads upon inspection after removal were perfect.
Close inspection of intake turkey pan gasket, heads and intake each time after removal, never did demonstrate how the oil was being allowed to suck into ports. I now somewhat believe there was a very poor fit of intake to heads, silicon was sealing this gap temporarily, then it would 'tear' and allow oil to suck in. This phenomenon of the silicon tearing in the middle leaving no trace on postmortem
Imagine silicon between your forefinger and thumb. Pull them apart, the silicon tearing in the middle, leaving no evidence on either the thumb or finger.
In error I responded to incorrect post. This post should have been in response to Cal-Burge post on leaking intake/head geometry.
Last edited by Sxrxrnr; 06/24/15 02:32 PM.
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Re: Pulling in oil heavy through PCV Valve
[Re: MLR426]
#1856343
06/25/15 01:02 AM
06/25/15 01:02 AM
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Joined: Jan 2003
Posts: 1,758 Windsor, ON, Canada
Diplomat360
top fuel
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top fuel
Joined: Jan 2003
Posts: 1,758
Windsor, ON, Canada
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What valve seals are you running?
I used the Teflon PC seals originally on a brand new rebuild...kept on chasing strange oil-consumption issues showing up as oil residue in the intake runners, fouled plugs and occasional blue puff out the exhaust...went to the standard "go-to" place, that being manifold head port alignment, didn't find anything there.
Eventually I noticed the tell-tale oil accumulation over the valve head (after the engine shut-down and oil dripped down past the teflon seals and down the valve guide). Went to CompCams #529-16 Viton seals...problems gone...intake runners nice & clear, no more blue puffs of smoke, valve heads are staying clean.
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Re: Pulling in oil heavy through PCV Valve
[Re: MLR426]
#1856451
06/25/15 09:32 AM
06/25/15 09:32 AM
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Joined: Aug 2005
Posts: 4,799 ILL
MLR426
OP
master
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OP
master
Joined: Aug 2005
Posts: 4,799
ILL
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Intake is sealed good it is totally coming in through the Pcv valve. Trying to get customer to change out Pcv. This engine holds steady vacuum at 18 and doesn't waver stays steady. It also has 165 psi compression on all cylinders. Trying to get guy to change valve and change plugs.
Martin
Last edited by MLR426; 06/25/15 11:50 AM.
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Re: Pulling in oil heavy through PCV Valve
[Re: MLR426]
#1857052
06/25/15 10:12 PM
06/25/15 10:12 PM
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Joined: Sep 2010
Posts: 170 renton , washington
perfmachst
member
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member
Joined: Sep 2010
Posts: 170
renton , washington
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I see what your talking about cab with free flowing Pcv the one on the car is not restrictive. So what gives here ? Before rebuild no oil being pulled in now I have oil being pulled in through the same Pcv. I know engine holds 18 vacuum don't know what it had before. I found a newer style Pcv that is definitely restrictive. Night and day difference.
Mlr426
the reason I asked about gapless rings , is you have to restrict the the pcv valve when using gapless rings. they pull a lot of vacuum!!! total seal wants a dowel in line , with a .060 hole in it. otherwise , it will suck oil out of engine!!
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