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Author
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Topic: Clear smoke when shifting & PCV valve
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Pierre
Gearhead Posts: 541
From: Near Paris, France
Registered: Apr 2002
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posted 05-21-2002 10:06 AM
   
When shifting around 5000+ RPM a small puff of Grey smoke comes out of the left exhaust (yesterday was my first time following my own car !).
Context: 302, with new edelbrock 2.02/1.60 valves, new Head gasket Fel Pro top quality.
I am thinking of two possibilities: Worn rings on one cylinder on the left bank(unlikely since the bottom engine was recently rebuilt) Or My PCV valve was covered with oil (I did read some of the recent topics on this issue). My Valve cover are Edelbrock with baffles but the PCV valve seat agains the bottom of the baffle ! . That PCV valve enters the intake (Performer RPM 302 model)on the left bank and gets directly in cylinder number 8 out on the left bank....... Could this be my problem ?
Is this normal for the PCV valve to seat against the baffle ?
Can I just plug both ends and get rid of it ? Thanks in advance
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jkilroy
Gearhead Posts: 1808
From: Vicksburg, MS
Registered: Dec 99
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posted 05-21-2002 10:31 AM
Is the plug in number 8 all gunked up?------------------
Jay Kilroy
68' Fastback GT 390
"No such thing as a cam thats too big"
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Pierre
Gearhead Posts: 541
From: Near Paris, France
Registered: Apr 2002
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posted 05-21-2002 10:45 AM
Haven't checked that but last time I did they were grey (normal). The heads+plugs only have a few hundred miles; to young to show any sign probably.
On my previous heads though, there was no sign of oil burning but(PCV valve was seating in the same spot) my intake valves were covered with a thick black rubbery deposit on the left side (on the stem side).
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mustangboy
Gearhead Posts: 773
From: Ont, Canada
Registered: Mar 2002
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posted 05-21-2002 06:53 PM
Grey-black smoke is usually a sign of a rich mixture,are you sure its not carb related?I admit its weird its only on one side but I've seen it before.
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SteveLaRiviere
Administrator Posts: 42139
From: Saco, Maine
Registered: May 99
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posted 05-21-2002 08:21 PM
Couple of things. First, a puff of smoke during a high vacuum condition such as letting off to shift tells you oil is being drawn through the valve guides indicating excessive valve stem/valve guide clearance or worn/ineffective valve seals. Worn rings cause the engine to burn oil when the engine is under load. The PVC valve will not work blocked, so you need to find a shorter PCV or taller PCV grommet. Having it block could be the cause of your oil burning if it's allowing excessive crankcase pressure to build. Always use a PCV valve; it's a cheap pan evacuation system, and the oil fumes it draws in extends valve seat life. ------------------
'70 Mustang Mach 1 M code 351C 4V/FMX/3.25 open
'72 Mustang Sprint Coupe 351C 4V/FMX/4.30 Trac Lok
'94 F-150 XL 5.8L/E4OD/3.55 Limited Slip
MCA Member # 47773 "Doubt is not a pleasant condition, but certainty is absurd."
- Voltaire
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Calcat
Journeyman Posts: 75
From: Los Angeles, CA
Registered: Feb 2002
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posted 05-22-2002 03:30 AM
it would'nt hurt to route the PCV valve straight into the carb so the reccirculated fumes, which are carrying a small amount of oil, are distributed evenly through the cylinders.
If you are running PC seals on the intakes, you might want to check that they are all seated properly and have not risen up.
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Pierre
Gearhead Posts: 541
From: Near Paris, France
Registered: Apr 2002
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posted 05-22-2002 06:12 AM
Heads being new, I am going to rule-out the valve wear option at this time . I am going to raise the position of the PCV valve and connect it to the back of the carb intead of the intake and see what happens.
I'll also check the correct symetry of A/F ratio in the carb just in case.
I'll keep you posted as usual (and thanks again !)
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Hell_Fish
Gearhead Posts: 860
From: Austin, TX.
Registered: May 2002
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posted 05-22-2002 02:11 PM
Mr gasket sells a twist on breather that you use a chevy PCV valve with. Its a nice looking set-up.------------------
Dustin C
56 F-100
Mech. for wifes 69 Mustang coupe
65 Plymouth Barracuda
70 Dodge Swinger
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