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  #16 (permalink)  
Old 06-01-2013, 03:52 AM
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That is using your noodle.
Which PCV valves have the lighter tension spring?
Is there any differences in the pindle shape? (flow)
This should be added to the Wiki.

aisr...Thanks for the great post.

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Last edited by F-BIRD'88; 06-01-2013 at 03:58 AM.
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Old 06-03-2013, 09:02 AM
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NAPA# 2-9229 (the body of the valve is stamped 2088) GM 4/6/8 cyl '85-'95
Spring free height is .775"
95 grams compressed .300"

NAPA# 2-9333 (the body of the valve is stamped 2221) Ford 5.0 & 460 '87-2002
Spring free height is .800"
110 grams compressed .300"

NAPA# 2-9210 (the body of the valve is stamped 2072, pictured in previous post) GM 262/350/454 '80's thru the '90's
Spring free height is .775"
117 grams compressed .300"

There are different pintel shapes and tapers.
All the above have the same dia holes in the internal "washer" that the pintle slides into.
2221 and 2072 use the same pintle with 4 cutouts in the large "nailhead" end and a short taper.
2088 has a pintle that looks like a sawed off nail, no cutouts in the nailhead and a very gradual large dia taper where it slides into the "washer".

I also have two other valves in hand, they were special order from my local store. I didn't get them until after i had made my valve, so i have not bothered to cut them apart yet. They are...
NAPA# 2-9230 (stamped V187) '80-'87 Chevette
NAPA# 2-9246 (stamped 2108) '74-'79 350/400/454

All the above valves share the same 3/4" body diameter where they plug into the rubber grommet, and have the same plastic elbow pushed onto the top.

Last edited by aisr; 06-03-2013 at 09:31 AM.
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Old 06-03-2013, 11:13 AM
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Great info on the different PCV valves.
The Chevette PCV valve sounds promising. How much engine manifold vacuum @ idle is needed to keep that chevette PCV valve in the idle/low flow position?

Any vacuum info on the others? (idle vacuum required to keep the pindle in the idle position)

Could test on a running engine with a vacuum gauge inline on the PCV hose. Just vary the applied vacuum and watch the pindle in the PCV.
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Old 06-03-2013, 02:14 PM
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It might take me a few days to get to it, but i will see what i can come up with for a vac test.
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Old 06-03-2013, 03:24 PM
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Quote:
Originally Posted by aisr View Post
NAPA# 2-9229 (the body of the valve is stamped 2088) GM 4/6/8 cyl '85-'95
Spring free height is .775"
95 grams compressed .300"

NAPA# 2-9333 (the body of the valve is stamped 2221) Ford 5.0 & 460 '87-2002
Spring free height is .800"
110 grams compressed .300"

NAPA# 2-9210 (the body of the valve is stamped 2072, pictured in previous post) GM 262/350/454 '80's thru the '90's
Spring free height is .775"
117 grams compressed .300"

There are different pintel shapes and tapers.
All the above have the same dia holes in the internal "washer" that the pintle slides into.
2221 and 2072 use the same pintle with 4 cutouts in the large "nailhead" end and a short taper.
2088 has a pintle that looks like a sawed off nail, no cutouts in the nailhead and a very gradual large dia taper where it slides into the "washer".

I also have two other valves in hand, they were special order from my local store. I didn't get them until after i had made my valve, so i have not bothered to cut them apart yet. They are...
NAPA# 2-9230 (stamped V187) '80-'87 Chevette
NAPA# 2-9246 (stamped 2108) '74-'79 350/400/454

All the above valves share the same 3/4" body diameter where they plug into the rubber grommet, and have the same plastic elbow pushed onto the top.
Wow! All this info should definitely be wiki'd!

So what is the goal of building your custom valve? Should it stay closed at idle and open up and some % of max vacuum?

I was unaware that there was a spring in the valve. My pintle opens if I turn the valve upside down.
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Old 06-03-2013, 10:15 PM
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Quote:
Originally Posted by Silver Surfer View Post
Wow! All this info should definitely be wiki'd!

So what is the goal of building your custom valve? Should it stay closed at idle and open up and some % of max vacuum?

I was unaware that there was a spring in the valve. My pintle opens if I turn the valve upside down.
That is the open high flow position. Seen when the engine is at or close to WOT.

Apply vacuum to see the pindle move to the idle position (low flow)
Much like a metering rod (up rich/down lean {idle /cruise})

The PCV valve must stay in the idle position @ idle.
Big cams with low idle vacuum throw off a stock V8 PCV valve, creating a lean idle.
A vacuum leak.
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Old 06-04-2013, 08:18 AM
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Oil Contamination

Hey Silver Surfer, I'm also dealing with some oil contamination in my Camaro engine. I bought the same filter separator as yours from HF. Haven't installed it yet, but I wanted to point out that the auto drain valve feature can be reversed. Pull the valve out of the reservoir and put the spring on the outside with the c-clip as a retainer. I did a bench test on it with a vacuum pump and it seals good.

Also, for others interested, I recently replaced the LQ4 6.0L engine in my wifes truck. The brand new crate engine from GM comes with a fixed orifice in the valve cover. The paperwork says to throw the original PCV valve away and connect the hose to the nipple. It appears they are finding the correct size orifice for the engine vacuum and are no longer using a valve. Got me to thinking that perhaps a small inline needle valve to adjust crankcase vacuum flow might be the ticket. Not too much to cause a major leak, just enough to evacuate the crankcase. Nolan
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Old 06-04-2013, 10:20 AM
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My goal was to eliminate my electric vacuum pump's constant 12amp draw. This car is street/strip and has a sbc with a thin low tension ring package. Without crankcase vacuum, it would go thru a qt of 5W-20 Mobile 1 in less than 250mi. My original intention was to make a custom pcv and sealed system to get the vacuum i was looking for, but i ended up just using an off the shelf pcv with the added adjustment screw, basically just using it as a variable orfice.

With the current sealed pcv system, it now draws 8"Hg in the crankcase while driving down the hiway. Now the electric vac pump only has to come on for the n2o.

8.26:1 357 sbc, .650" solid roller on 114 LSA, -10SP Brodix heads (298cfm), 625 Carter carb, and a 200shot of n2o. Now this combo would seem to suck on paper, but it runs in the 5's on the 1/8mi on 87 octane and gets slightly better than 20mpg down the hiway. This car gets better mileage than my Astrovan
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Old 06-04-2013, 10:51 AM
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Here's some pics showing what was done to turn the valve into an adjustable orifice...



The screw is 1" long. I just drilled a hole slightly smaller than the thread diameter, and the screw made it's own threads in the plastic elbow.



Try to make the threads straight in the plastic, so that the tip of the screw comes out centered on the pcv valve's pintle.

I mounted my modified pcv valve in the top of my oil separator, away from the valvecover.
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Old 06-04-2013, 12:58 PM
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Quote:
Originally Posted by OLNOLAN View Post
It appears they are finding the correct size orifice for the engine vacuum and are no longer using a valve.
Good food for thought. The PCV valve also acts as a one way device, so if you are running forced induction, the valve keeps pressure from entering the crank case. It also serves to prevent backfire byproducts from entering the crank case as well (I would assume this would also be important to hot rodders who tend to use cams that cause a lot of reversion by more valve overlap and a late closing intake valve).
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Old 06-12-2013, 07:24 AM
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I'm adding my pcv oil results to the thread for reference:

My 383 stoker has less than 8000 miles. 9.7:1, aluminum valve covers with internal pcv baffles. Pcv is rear pass side, breather for pcv is drivers side front (at least this is how I have it connected).

I have a catch can that collects about a table spoon in 50 miles. Never measured it though, I just drain it.

If the pcv valve is correct you'll hear it almost whistle at idle (removed from the valve cover). It's sounds similar to a vacuum leak, a hiss.

My in gear idle is about 10hg vacuum or less.

I've used 3 different catch cans and had 2 that caused restricted pcv flow. They had barb connectors that were less than 1/4" openings inside and it affected my idle. I had to make my own with 3/8" ports and baffles inside and seemingly no restriction. Without some sort of baffle inside the catch can the engine will suck up some oil so the volume of oil in the catch can is lower than one with baffles.

My old stock 305 had only on foam filter in the air cleaner where the pcv connected up in to. Anyone with an oem carb intake from the 80s knows how oily that filter gets. Ideally you'd want the oil trapped and drained but oem allowed some to burn.
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Old 07-10-2013, 12:52 AM
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someone asked if a teaspoon in 50 miles was ok....

according to GM.. a quart every 500 miles is 'acceptable' oil consumption (for the older engines, not sure if this has changed with the LS-series)
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Old 07-10-2013, 03:53 PM
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Quote:
Originally Posted by kc8oye View Post
someone asked if a teaspoon in 50 miles was ok....

according to GM.. a quart every 500 miles is 'acceptable' oil consumption (for the older engines, not sure if this has changed with the LS-series)
WOW so that is 6qts of oil in a 3,000 mile drain interval? I am going to have to call BS on that (no offense).
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Old 07-11-2013, 09:45 AM
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Read the owners manual of your car. It's all there.

I'll take a look at my '98 and see if it's still there or if they changed it.
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Old 07-11-2013, 12:08 PM
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A SBC holds 5 qts, so if you go through 6 qts every 3,000 miles you'd never have to change the oil...just keep toppping it off (just like a Harley)
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