Having some PCV system issues and looking at THIS:

http://mewagner.com/?p=444

Choking on the price, but maybe we can get something together with these guys.

https://www.stevesnovasite.com/threa...le-pcv.666423/

 

Any benefit to an engine running say 7-8 inches of vaccum?

 

Yes, proper crankcase pressure helps the piston rings seal and improves engine health and power output. Also allows for use of lighter tension piston rings. I think it's common to target about 14-17 psi vacuum (crankcase) when pushing the engine hard, such as road racing. Takes a vacuum pump to achieve those levels.

I've been thinking about adding a GZ Motorsports pump to my engine. It's EXPENSIVE though and I haven't been able to bring myself to do it.

 

In my case, I have a young 383 TPI/FIRST that is getting a fair amount of oil in the top plenum. I just added SS mesh to the PCV baffle and a oil catch can- looking to add the valve and perhaps fix the problem at the source rather than deal with symptoms. I don't know whether it's just the way the PCV is or maybe a poor break in.

 

I've forgotten how the old school stuff works.

The PCV has a check valve that only opens when plenum is in vacuum, right? So wouldn't oil film in the manifold just be a problem with poor baffle design inside the valve cover? At WOT I'm guessing you have a breather on the opposite valve cover?

 

http://mewagner.com/?page_id=1927



Expensive....but other than a catch can- may go a long way in dealing with oil in the plenum on a 383.



http://67-72chevytrucks.com/vboard/s...d.php?t=787630



If I can get another five interested in a purchase- it would be a substantial savings.

 

In *general*, unless you are running a significant amount of forced induction, large amounts of oil in the plenum would be due to poor ring seal (blow-by) in the crankcase. I find that oil catch cans, air-oil-separators, and the like are typically a crutch for poor engine assembly - often too aggressive with honing (which, ideally you shouldn't do at all). Typically people bottle brush hone the crap out of the cylinders, throw in new rings, and send it. This usually results in the rings overheating and losing their tension. And then...... BLOW BY.

With this adjustable PCV valve..... what is your plan exactly? It's designed to help with idle vacuum on engines with cams that are already low and are causing a stock valve to be in "cruise" mode at idle - thus generating a large vacuum leak at idle. If you have blow-by problems generating too much crankcase pressure that's pushing oil into the plenum this is not occurring at idle. This is under load when your crankcase pressure is at it's highest. I don't see how this valve is going to improve venting and stop oil from being pushed through it under load.

I don't see how a tunable PCV valve is going to help. Best thing to do is solve the blow-by (mechanical) problem. Second best would be to just atmospheric vent the engine and change the oil more often to avoid fouling. Catch cans and all that mess is just that - a MESS. But in *general* we don't have to atmospheric vent or dramatically alter the PCV system of *most* engines till we are past 25 psi of forced induction. 30+ psi and we start having trouble usually - blowing dip-sticks out of the tubes, and lots of oil being pushed into the vent system. But none of that should apply to a simple 383 NA. Go fix the source of your blow-by.

GD

 

I won't disagree with you, but as a starting point it is a lot cheaper to try the valve, the engine isn't coming out as the catch can is doing the tasked job. Also if a factory pcv doesn't match the application- this may help.

 

I can see the potential benefits of the adjustable valve with respect to idle quality and so forth. But if the factory nipple/valve/hose can't flow enough to prevent oil being shoved up through into the plenum then I don't think this is going to solve that situation at all.

GD

 

OK, I contacted Wagner to try to jump into another group buy nothing going on right now- they seem to be very flexible to deal with- I have a few feelers out on other sites. Email Barbara and give her my email to get started on a head count.

http://mewagner.com/?page_id=1927

davefarr1967@gmail.com

Dave,
Sorry, no group buys at the present time. You only need six so do some posting or ask around. We will let you know if any group buys take place in the near future.

Barbara Wagner

Customer Service
M/E Wagner Performance Products
barbara.wagner@mewagner.com
www.mewagner.com
570-899-4544

 

Ah, my friend, please allow me to add some detail...

PCV applied via vacuum pump (belt driven) or electronically (electric pump perhaps) or exhaust driven... those can increase power because the energy that drives the pcv suction doesn't come from the piston's pressure drop. I think you understand that well but didn't mention the other side of the coin....

that is, PCV applied via the pressure drop of a piston at WOT (like factory pcv) comes from the post air filter tract, which directly affects the pressure of the intake manifold.
In other words, intake driven pcv doesn't 'work' unless the air filter is slightly restrictive, which of course subtracts some percentage of power (4 to 8%? ish) to gain the benefits of PCV (improved ring seal and all of that)

Next, the vacuum in the crankcase in wet sump application pulls against the oil pump (or so I have heard). It is common in wet sump to target approx 3psi of vacuum, maybe 4 or 5psi (around 6 to 8" of Mercury for example). The factory target is around 3"Hg (1.5psi of pressure drop) in factory wet sump.


Also, Atmospheric pressure at sea level is 14.5psi and you cannot achieve the vacuum of space here on Earth (0psi) so its impossible to get anymore than 14.4~psi of vacuum in any container on Earth if you start at 14.5psi... In other words, if your starting pressure is 12psi (high on a mountain) you couldn't achieve 12psi of vacuum in any container because that give you the vacuum of space (0psi absolute).

One of the most common mistakes I see is people using a very free flowing air filter on an engine. This essentially eliminates the pressure drop behind the filter (good for power) which eliminates the WOT pcv system, which facilitates oil blowing out of every seal and orifice over time... thus oil begins to collect and smear and drip and sticky dirty mess begins to appear after say 10 to 20k miles.... it takes some time but it happens. The right way to run an intake driven pcv system is to use an air filter which provides the desired pressure drop (factory target of 3" Hg or 1.5psi at WOT) which will help keep oil inside the engine and pressure off the seals at the cost of power.

To put another way, the intake air filter system is integral to the pcv and oil systems, they need to work together.

 

Dave,

Please have the interested parties e-mail their order to me and mention Daves2020 Group Buy to receive the discount. When I receive 6 orders I will send each party their invoices through PayPal which they can pay for with any credit card. Thank for your getting your group buy together.

Barbara Wagner

Customer Service
M/E Wagner Performance Products
570-899-4544
www.mewagner.com

 

I need to keep doing research on my current brand-new engine situation, but if it comes to it, I might be interested in this group purchase. undecided now, but following along with this thread

 

https://www.chevelles.com/forums/13-...l#post11246124

 

I haven't seen anything regarding what the group purchase price would be. (I may have missed at the Chevrolet site).
Any idea?

 

Discount Information

• 25% discount off of all DF-17 Dual Flow PCV Valve purchases ($96.75 discounted price)
• Free shipping on US orders, non-US customers pay standard shipping (non-US shipping rates are already discounted)
• No discount on inline adaptors or other accessories
• Group must order a total of 6 or more DF-17 Dual Flow PCV Valves to qualify for discount (buyers may purchase more than one valve each)

 

Thanks for the info.

 

We have reached the purchase threshold, I've asked Wagner to hold group buy open for another week.

 

Hi Dave,

I’ve sent your PayPal invoice. The group buy will be available until March 31. This will give others a fair amount of time to respond. Thank you for organizing this group buy.

Barbara Wagner

Customer Service

M/E Wagner Performance Products

570-899-4544

www.mewagner.com