Wow I did not think they were that much !! I am glad the stock PCV valve I use works fine with my combo. Thanks , Ron

Email sent. Thanks again Gus.

I just bought one last week. My engine builder was somewhat skeptical, but it is going on my new motor. Andrew

I think I might just get a new billet base place with the ports in it or should I sacrifice an inch of air filter and put a spacer under the carb with a port in it. I'm running a 4" drop base filter now, or maybe just whack a hole in the hood and put the Max Wedge scoop on that I've had for a few years

Gus

Gus I will say because the Max Wedge scoop dips in the middle it dont give much more room as you can see. Ron

So i know how a pcv (positive crankcase ventilation) valve works in theory:
limited flow at high vacuum and greater flow as the throttle butterflys more fully open.

I know that as the rings and bores wear blowby gas increases and the pcv may need to changed to a higher flow device. I know that Ford makes a higher flow pcv valve for high mileage v8s.

I have read that somehow the 1994-1995 iron 8L V10 got by with no PCV mechanism, just a fixed sized hole.

I have read that a "Dry Sump" is a kinda pcv replacement... the vacuum pump sucks all the blowby gases away at all rpms and the crank/rods/piston undersides all move with less air to push out of the way. This saves more horsepower at high rpm than the vacuum pump consumes.

I have not thought through how a "big cam" with more than stock overlap affects pcv selection.
Big cam overlaps make idle vacuum lower. Big cams create "internal EGR" at idle making the idle rough and lopey.

What adjustment does it have that makes the custom PCV worth $127 ?

my one application will be a set of cross rams from a '60 300F, which had a road draft tube. the other will be a max wedge intake. i like the idea of an oil mist catch can. i think i'll try to fab one for both of these applications.

i crossed the part number that was the Mopar Performance valve and somehow i came up with an application for one of the 4 cylinder dodges from the 90s i think it was.
fram FV281

it was significantly lighter weight than the PCV valve what was on the car, which i imagine was a factory 318 magnum application. i haven't started it yet so it will be interesting to see if it makes any differences.
my motor has 13" vacuum at 850rpm idle in neutral.

360view, the ME Wagner valve has several adjustability features.

They also built a PCV dyno/flowbench of sorts to figure out the whole thing.

The instructions have a chart to determine a baseline setup using CID and idle vacuum.

Notice how AndyF's valve has one screw backed way out? Thats to cover super low vacuum situations. $127 is a major chunk of change, but the valve is rebuildable and will always work for whatever combo you build.


Incidentally, I checked crankcase vac on my Dakota and it is 7" at idle.

got my invoice today.

You are confusing a crankcase evacuation system with a dry sump oiling system. Change the name in the above from "dry sump" to "crankcase evacuation system".

Me too!

I have had a MEWagner valve on my motor for about a month, which equates to just a few drives. I first heard of it here on Moparts and decided to give it a try. I would recommend reading their website, but here are some thoughts for consideration.

PCV system is to remove combustion by-products from the crankcase. These by-products can be deterimental to the oil and parts in the crankcase. By-products in the crankcase results from blowby (ie imperfect ring seal - it can never be perfect). Blowby is a function of both the quality of the ring seating but also the size of the ring area. Larger bore motors and higher compression will naturally have more blow-by volume, assuming equivalent ring seating to other motors. This is why ring technology gets so much focus.

In the old days, venting the crankcase was done by draft tubes, which used the positive pressure in the crankcase to force the vapors out. Obviously not real good for emissions and it left oily deposit on road surface. Positive crankcase pressure may increase likelihood of oil seepage at seals and gaskets and slightly increases the work load on the motor. The PCV system pulled those vapors back into the combustion process via a controlled vacuum leak (ie the PCV valve) which creates a negative pressure in the crankcase under some circumstances. Manufacturers tune the PCV to the motor characteristics.

Motors which have an overbore, higher compression, and performance cams can result in the factory PCV valve not being a good match. In my case I have a 400/470 stroker which has a 4.375" bore, the compression is a good 2 points higher and the extra displacement does not completely cover up the overlap presented by the cam. Vacuum at idle is much less than a factory motor (10" Hg in gear in my case before the swap). The PCV valve closes at low vacuum, and a modified motor may put the PCV valve in a reduced flow area at idle, particularly when transitioning from park into drive. Cam is also a bit lumpy which causes vacuum fluctuations. Put it all together and the "controlled vacuum leak" is now a "fluctuating vacuum leak", which can make the idle itself less stable and less smooth.

Big bore motors will also need more crankcase venting under normal highway driving, and extra PCV flow can be helpful.

The ME Wagner valve has two adjustments: one for when the low flow channel opens, and one for when the higher flow channel opens (total flow is sum of both channels). I have been able to move my low flow channel opening point to below typical in-gear idle conditions and have picked up a solid 1" or so of vacuum in gear after the initial tuning (better idle vacuum with a better controlled vacuum leak). I don't have power brakes but for some folks this could be a benefit. High flow adds in at cruising conditions. Like all PCV, valve will close at WOT; vacuum pump or evac systems have an advantage here.

Of course the benefit of this setup will vary on a case-by-case basis. I suspect there is more benefit to automatic cars and stroker motors. I will be curious to hear of other's results.

Thank you for that explanation of the two channels and their adjustments.

Yep that is the one. Here are some pictures.

Andy, did you use the same grommet with or breather on the other side's VC or something else?

Thanks,

Steve

Duh, the cheapest and easiest way is to plug it. It's just an emission thing anyway. How many on here have a pcv on there race car?

Most race cars dont run a PCV valve because they are at wide open throttle most of the time and the PCV valve dont work at wide open throttle as it will be closed. But I run a PCV valve on my street car as I prefer to run one and help purge any blowby from the crankcase and keep any pressure from building in the crankcase. I just run a stock type PCV and it works good at idle and part throttle. Ron

Ron,

Do you run a nipple breather on the driver's side? Where does that hose route to?

This is the best pic I have of it. The PCV hose goes to the large vacum nipple on the carb base. My power brake booster hose goes to a nipple on my Indy dual plane intake. And yes I do use a nipple breather on the drivers valve cover. The hose just goes down by the frame as I did not want any oil to maybe spit out onto the valve cover when I race it since the PCV dont work at full throttle. So I use that hose to run any spitting oil when I race under the frame but it does not spit any oil as the hose is still dry. Its open of course so the PCV system pulls air through the crankcase. Ron