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Another PCV thread. N/A Carb w/ fox covers

2K views 24 replies 8 participants last post by  bgjohnson 
#1 · (Edited)
I've had my low-po N/A 357 assembled and between the fenders without break-in since Oct. and can't decide on a means of crankcase evac. This will be my DD.

The obvious answer is to use the carb covers that are on it. But I like to make things difficult. :evil:

I'm determined to equip the fox VCs. Can I use a single screw-in breather?

My understanding is that the move to PCV was based primarily on emission control, but also aids in contaminant removal from the oil. I plan to change the oil @ 3k mi. Will driving this interval without PCV be detrimental enough to accelerate wear to the engine?
 
#2 ·
I've had my low-po N/A 357 assembled and between the fenders without break-in since Oct. and can't decide on a means of crankcase evac. This will be my DD.

The obvious answer is to use the carb covers that are on it. But I like to make things difficult. :evil:

I'm determined to equip the fox VCs. Can I eliminate the PCV and use a single screw-in breather?

My understanding is that the move to PCV was based primarily on emission control, but also aids in contaminant removal from the oil. I plan to change the oil @ 3k mi. Will driving this interval without PCV be detrimental enough to accelerate wear to the engine?
I ended up making a breather tube that fits tight in the PCV valve opening and No breathers in the valve cover
Works just fun..Got the idea from the guys at Trickflow

as long as your Not Boosted then it works great

wont pass smog.......lol

1952
 
#3 ·
Right on. I saw your thread when I was searching, but I have an AirGap.

To clarify the question, I am asking if anyone has experience with running a single breather, with no PCV and it's effect on the oil compared to having a pcv system.

Reason for causing all the trouble is that I despise an oily carbon soaked intake, but will deal if the oil life suffers. I swear I'm neurotic about this ####.
 
#5 ·
Did some more searching and I'm convinced I was barking up the wrong tree.

OK I'm gonna poke a hole, conjure a baffle, grommet up a PCV valve and use a oil separator to block oil from dirtying my intake.

JB WELD here I come!!!:salute:
 
#6 ·
if its a carbed 351, and you want fox efi valve covers, why not just run 2 passenger side ones with breathers?

you need 1pcv and 1 breather OR 2 breathers

lonnie 1952- time will tell, go beat on it and watch the dipstick pop up and spray your headers, then one day, you'll beat on it and suddenly pick up 25hp, then you'll realize you have an oil leak, once you lean on it, the pressure will find its way out
 
#7 ·
I'm testing a system, I designed, using parts I had in the shop.
Took a remote oil filter assembly,and modified it with a long tube,that almost goes to the bottom of an oil filter,like FL-1A.
Mounted the unit upside down,across from valve cover,but slightly higher than valve cover. Plumbed it so the intake vac. pulls from center tube feed,thru filter medium and from PCV valve on valve cover,which has a baffle.
So far it is working great,as no oil has entered the top of the inside tube.
Oil seems to collect at bottom of PCV hose entry,into the filter adapter.
If it ever eventually soaks up to the top of the filter area,you simply throw away and replace with a low cost filter.
Testing air flow,it allows free flow of air from the crankcase,seems to be little restriction. Time will tell,how well it works.
 
#9 ·
Unless you remote mount a vented catch can ( the preferred option if you want to go without pcv ) then your choice is breather - which deposits the oily mess ON TOP OF THE ENGINE WHERE EVERYONE CAN SEE IT - or PCV. If your engine is nice and tight, and you have the pcv source trapped/screened the way you should, it shouldn't pick up too much oil. I run my pcv line to a catch can and then to the intake -- inside of the intake is nice and clean AND I have a functioning pcv valve.
 
#10 ·
Some guys were using an electric vac. pump, F6ZE-9A486-DC, as an alternative PCV setup,instead of sucking the PCV into the engine.
Does this still work,long term, on the street? Does it provide enough air flow for the system?
 
#11 ·
I'll post some pic's of mine later this evening when I got off of work , as it's not the ordinary means of venting. I'm running a super victor and I tapped two 7/8" holes in the rear of the intake manifold valley. I fab. a baffle from aluminum sheet metal packed it with stainless steel mesh which I mounted on the bottom of the manifold inside the motor. I ran two hose from the intake to a homemade catch can with a large k&n filter which is vented to atmosphere.

Darrin
 
#12 ·
Here's a couple of pics. In the last photo on the pass. side you can see the 2 hoses from the intake going to the catch can. Just under the rad. hose is the k&n filter thats on top of the catch can. The valve covers stay nice & clean, the motor vents nicely and no oily lines or breathers to mess with when check lash adjustments.

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#13 ·
Thanks for the replies on such a beat to death topic.

I was lurking around http://bobistheoilguy.com for an empirical answer to my oil quality question, and found significant evidence that as long as the blowby has an unrestricted exit from the crankcase, it has no appreciable effect to the oil.

http://www.bobistheoilguy.com/forums/ubbthreads.php?ubb=showflat&Number=1635814&page=3

Like Mr. Yount has stated here, there are many factors to influence crankcase evac. setups. Concerns are intake deposits, oil spewing on my new stuff, and smelling like a gas station. I think I can kill all this noise by dumping to the exhaust. I may use the O2 bung and let it dump on the converter, thus becoming the worst air-polluting abomination in the greater Columbus area.:D

No catch can to monitor, no fumes to smell, no oily mess. Just simple catalyst failure.
 
#15 · (Edited)
Thanks for props on the car. And yes those hoses are big 3/4" i.d. I used two lines too asure not pressure in the motor along with good oil control in the pan. Just like you, I didn't want any oil from a pvc system messing up my nicely ported manifold or oily breathers. I've been on the fence about running a vac. pump and so far my system has worked very good.
Exhaust evac aren't very efficent @ low rpm's. For a drag car it will work fine but a street driven or daily driver is not desirable. If you decide to go this route besure to use one way check valves at the headders. A unrestricted atomsphere venting system based around a catch can would be much better for a non-drag car compaired to a evac setup.
 
#16 ·
you need to mount those check valves at a 45degree angle, just like the picture in the instructions that come with the kit.

like was said, those work really well on an open header race car, but street driving and restrictive mufflers, its not such a good idea(ive done it)
 
#17 ·
Examined several manufacturer's sites, on http://www.moroso.com it specifically notes: "*NOTE: Cannot be be used on cars w/ mufflers".

Compare it to this jive... http://www.youtube.com/watch?v=wGrx2rvIxJ0

My questions all lead to the efficiency of the system with mufflers. Will it keep up @ sustained 6000R?
The more I read, the more I get conflicting information. Damn internet...
 
#19 ·
The circle track guy's just run a taller stand pipe on the valve cover and they use those copper looking brillo pads that are used in the kitchen for scrubing dish packed inside and a traditional breather on top. The brillo pad will knockout the oil mist/vapor out of the air.
For cheap I would go with a catchcan type atmosphere vent otherwise a belt driven vacuum pump set-up with the type of useage the motor would be seeing, If drag racing the headder evac or Belt driven Vacuum system. I don't know if you've been around any cars using a headder evac or atmosphere venting but if you live in an area with higher humidity there will be milky oil in the valve covers every time you run the valve lashes. You'll need to do oil changes more frequently
 
#20 ·
For simplicity, tap the back of both valve covers for the 3/4 fittings. Run them both to a catch can on the passenger side strut tower.

If you desire a slight pull on the system, run a tube from top of catch can to the air filter, PRE-CARB. The air filter will create a slight draw through effect at higher RPMs, and a little at idle, but not enough to dirty the intake.
 
#21 ·
For simplicity, tap the back of both valve covers for the 3/4 fittings. Run them both to a catch can on the passenger side strut tower.
If you desire a slight pull on the system, run a tube from top of catch can to the air filter, PRE-CARB. The air filter will create a slight draw through effect at higher RPMs, and a little at idle, but not enough to dirty the intake.
i really like this idea !!!!!!!

but.............might you have some PICS !?!?
 
#22 ·
I do not. Check out

theturboforums.com, and look it up. There are a ton of diagrams people have made. Even one guy that CNC'd a catch can with a built in oneway valve as part of the can.
 
#25 ·
Yep, you can keep the filter on top of the catch can and run a separate line to the air cleaner. Or run a large tube to the air cleaner without the filter on top of the catch can.

Works great for boost and n/a applications.
 
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