Original Breather vs PCV?
#1
Burning Brakes
Thread Starter
Original Breather vs PCV?
I have my 64 327 300hp engine down and wonder should I stay the original oil breather system or block it off and convert to a PCV system? Are there any pros and cons?
#3
Race Director
All 64's came with a PCV system. The pcv was mounted inline in a hose that ran from the oil fill tube to the carb base.
In place of the road draft tube used in 62 and earlier the 64 had a vent tube that ran forward toward the rear of air cleaner base. The vent tube was connected to the air cleaner base with a short (about 2" long) hose.
In place of the road draft tube used in 62 and earlier the 64 had a vent tube that ran forward toward the rear of air cleaner base. The vent tube was connected to the air cleaner base with a short (about 2" long) hose.
#4
Burning Brakes
Yep and the 63 has a vent in the back of the block (beside the distributor) with a tube running to the PCV which is screwed in the base of the carb. It gets its intake through a hose that runs from the air cleaner to the oil fill tube.
Cheers,
Bob
Cheers,
Bob
#5
Team Owner
Member Since: Mar 2003
Location: Greenville, Indiana
Posts: 26,118
Received 1,843 Likes
on
1,398 Posts
Some engines in that era used a PCV valve and some used a simple restrictor fitting to draw crankacase vapors out of the crankcase. I don't think it's clear what type of system the OP has here.
Whatever it is, it would be best to have a closed system to atmosphere and not use a vented oil fill cap, for example.
Whatever it is, it would be best to have a closed system to atmosphere and not use a vented oil fill cap, for example.
#6
Safety Car
#7
Drifting
Great website.I have a LT1 in my 65.I have the pcv in the left(passenger side) valve cover and a breather/oil fill on the right(drivers side).Some say this is incorrect.That i need the pcv in the right valve cover and the vent in the left valve cover going to the air cleaner base.Does it matter which side is which?Im getting rid of incorrect things little at a time.
Thx,Mark
Last edited by VetteRed1965; 03-29-2009 at 07:10 PM.
#8
Race Director
Member Since: Mar 2001
Location: Mustang OK
Posts: 13,845
Received 3,766 Likes
on
1,669 Posts
2023 C1 of the Year Finalist - Modified
2015 C1 of the Year Finalist
Regarding the crankcase ventilation system on 67-earlier Small Blocks, there have been numerous methods which used the oil filler tube and the hole in the rear of the block.
Of course, the first system was a breather cap in the oil filler tube with a road draft tube in the rear of the block which vented to the atmosphere below the car. The road draft tube was in use on ALLLLLLLLLLLLLLLLLL engines up through 62------------EXCEPT in Calif. In 1962, Calif delivery cars got a PCV setup. Beginning in 63, all engines for US delivery had SOME KIND OF PCV setup, again, using the oil filler tube and the hole in the rear of the block (there were multiple variations, depending on application, ie big car, Vette, truck, Nova, etc). Personally, I really hated to see that rear hold go away, because the holes for crankcase venting in the valve covers was really a detraction to a nicely detailed engine!
I don't care what engine/car a person has, a SB with the 67-earlier Corvette script valve covers is as good as it gets--------------and why ruin them with holes!!!!!!!!!!
Check George's link if your engine plans are for a later "no-hole" Small Block installation (for example a SB400 with script valve covers ).
Tom Parsons
Last edited by DZAUTO; 03-29-2009 at 10:15 AM.
#9
Safety Car
Yo Black Magic,
Great website.I have a LT1 in my 65.I have the pvc in the left(passenger side) valve cover and a breather/oil fill on the right(drivers side).Some say this is incorrect.That i need the pvc in the right valve cover and the vent in the left valve cover going to the air cleaner base.Does it matter which side is which?Im getting rid of incorrect things little at a time.
Thx,Mark
Great website.I have a LT1 in my 65.I have the pvc in the left(passenger side) valve cover and a breather/oil fill on the right(drivers side).Some say this is incorrect.That i need the pvc in the right valve cover and the vent in the left valve cover going to the air cleaner base.Does it matter which side is which?Im getting rid of incorrect things little at a time.
Thx,Mark
I think either will work BUT most PCV valves are on the right side (passengers) due to engine torque and oil splash.
George
#10
Race Director
If you have oil splash getting into the PCV valve you have too much oil in the engine. Also, torque has no impact on the PCV. It vents fumes, not oil
#11
Team Owner
Member Since: Mar 2003
Location: Greenville, Indiana
Posts: 26,118
Received 1,843 Likes
on
1,398 Posts
I read here once that a guy claimed his PCV valve being on the right hand side picked up oil because the rotation of the crank threw the oil up in the right side of the head. Don't know that I believe that though.
Most SBC PCV's I'm familiar with are in the left valve cover and the clean air breather intake is in the right side.
Most SBC PCV's I'm familiar with are in the left valve cover and the clean air breather intake is in the right side.
#12
Burning Brakes
Thread Starter
I will get some pics tomorrow to post. I looked all over the intake and carb and can't find a PCV valve. Someone must have removed the valve and just replaced it with a straight run of hose. As Sherlock would say "Something is amiss here".
#13
I'm sure the crankshaft won't be throwing oil up to the rocker covers.
#14
Race Director
Member Since: Mar 2001
Location: Mustang OK
Posts: 13,845
Received 3,766 Likes
on
1,669 Posts
2023 C1 of the Year Finalist - Modified
2015 C1 of the Year Finalist
#15
Team Owner
Member Since: Mar 2003
Location: Greenville, Indiana
Posts: 26,118
Received 1,843 Likes
on
1,398 Posts
#16
Team Owner
Member Since: Mar 2003
Location: Greenville, Indiana
Posts: 26,118
Received 1,843 Likes
on
1,398 Posts
If you have a hose going from the bottom of the carb or the intake manifold to anywhere in the crankcase to draw fumes, pull the hose and see if the fitting it slides onto has a small hole in it. Maybe .015-.020. If you have that, that metered orfice is taking the place of the PCV valve.
#17
Instructor
Member Since: Mar 2007
Location: Champaign Illinois
Posts: 200
Likes: 0
Received 0 Likes
on
0 Posts
Yes there is no PCV valve in a 64 327 with 300HP! It is difficult to believe that this car does not have a PCV! The people that rebuilt the engine asked where the PCV valve was and I had to explain that there was a short transition from ropad draft tube to the 63-64 system to the PVC system!
#18
Drifting
#19
Drifting
Yes there is no PCV valve in a 64 327 with 300HP! It is difficult to believe that this car does not have a PCV! The people that rebuilt the engine asked where the PCV valve was and I had to explain that there was a short transition from ropad draft tube to the 63-64 system to the PVC system!
csteve, i have to agree that there is a fuzzie period around 63-64 when the road draft tube was replaced by the PCV system...
EDIT: HOKIE, definately go with a PCV system, there are many advantages.
Last edited by mechron; 03-30-2009 at 03:15 AM.
#20
Team Owner
Member Since: Mar 2003
Location: Greenville, Indiana
Posts: 26,118
Received 1,843 Likes
on
1,398 Posts
By the way, how do you know for a fact that's not true?