Clark455

As the title of the posts suggests, I was doing some tuning on my 442 over the weekend and thought of you guys running "lots of cam" with low vacuum. This may be old news to some?


M/E Wagner DF-17 Adjustable PCV Valve

I changed the mechanical advance curve and monkeyed around with the adjustable vacuum pot on the HEI distributor, upgraded from a 25cc accelerator pump to a 50cc with a different accelerator pump profile actuator cam, adjusted the rear throttle blades open just a hair more (4 corner adjustable idle circuit), and then it occurred to me that I should dig out the M/E Wagner adjustable PCV valve that I have. These mods cumulatively cured my off idle mild stumble and increased the drivability at low speeds very nicely - success! I had forgotten how much I liked this adjustable PCV valve, and how well it can be tuned to your specific needs. The individual control for the idle AND the cruise speeds really came in handy for creating a smoother overall run time experience. I add a PCV breather pipe to the base of my open element air cleaners so that the main air filter is all that is needed as opposed to running an independent separate breather in the valve cover - just an elbow coming out of the rear of the passenger side valve cover with a 3/4" ID silicone oil resistant hose connecting to the elbow installed into the base of the air cleaner - plenty of crankcase ventilation keeping the oil cleaner without actually sucking oil into the PCV system. When I nail it, I know that any possible fumes are going to be sucked straight into the carb while the PCV is shut during wide open throttle instead of just breathing out into the engine compartment. Some people have commented that "it doesn't smell like a hotrod" inside of my car, which makes me chuckle - nope, sorry, no exhaust leaks, no fuel smells, no oil vapors. Note that this PCV valve also works very well in boosted applications, as it conclusively and very positively closes 100% shut under boost, then returns back to normal operations once your foot is back out of it. No, it's not the best looking, but it sure works perfectly!

Click here to view the M/E Wagner website

Those that have one know how well it works. It's not cheap, well, because it's not made cheaply - very high precision item worth every penny.

Again, this may be old news to some as this has been around a while but thought of you guys while I was doing some tuning this weekend. The car runs WAY smoother now, almost as if it is fuel injected, and 60 foots like a champ now (not all from the PCV valve of course...)

Paul...

CANADIANOLDS

For those who want to keep the stock look, use the emptied out housing of your original PCV as the dummy one in the stock location and install the Wager hidden behind the carb.

70sgeek

I've been using one of these for the last 5 years - Easy to set up and infinitely adjustable to specific engine characteristics. Huge improvement over OEM-type valves.

oddball

Yup, it's a very nice part. It's a big help getting a smoother idle with a bigger cam.

SteveDB

This is pretty interesting. Their website has a lot of good info. I have been fighting oil leaks since getting my ride back on the road this year. Never had it this bad before. I hooked up a pressure sensor to the crankcase and it runs 2.5lbs of pressure at idle and up to 2.75 at moderate acceleration. I checked the new pcv valve I put in and it has no restriction either direction. Manifold vacuum at idle is 13.
here is the log.


I will order one of these and see what it does.
cheers Steve

Clark455

As the title suggests, I'm scratching my head over the positive crank case pressures you are reporting. Even without a PCV valve, with just a breather or two in the valve cover(s), I wouldn't expect to see positive crank case pressures. Where are you measuring? The sensor reading zero with the engine off? I haven't measured any of my builds, because temporarily blocking off the breather port on my engines actually induces a vacuum I can feel against my thumb, and hear it relax when I remove my thumb. The other thing that has me puzzled is your statement of no restriction in the PCV valve in either direction. There should be a definite difference between the direction of flow. I don't like the way they taste lol, but I always blow through them in both directions to see what I've got. I have been using the FRAM FV178, V178 in other brands, which yields a very high rate of flow in the "blow through test" in the inward direction, and just about no flow in the opposite direction. 2.5 PSI in the crank case will definitely induce oil seepage, so you should find a reduction if not complete stop to your oil leaks with the fully adjustable M/E Wagner PCV valve.

Do keep us posted. As mentioned, the high flow low cost FV178 PCV valve is what I have always used on most everything, but the Wagner is worth its weight in gold for me in the name of adjustment for drivability with a lumpier cam. My car was right there on the edge of the PCV valve flow range, dropping off at idle reducing my idle RPM's a bit too much in gear. The Wagner PCV valve allowed me to adjust it just right, to where I am only dropping off 200 RPM between neutral and drive at hot idle, whereas before it was dropping off almost 350 RPM, maybe even 375 with a looser 2600-2800 stall converter

Also, how many miles do you have on your build? Maybe your piston rings haven't fully seated yet? Today's modern rings seat in almost instantly, but maybe your build is acting up just a bit - it happens. All engines have a measure of piston ring blowby - the less the better, as this is essentially exhaust getting into your crank case, which of course brings carbon with it, which darkens up your oil quickly if this blowby is not properly sucked out by a well sorted positive crank case ventilation (PCV) system. So, bad enough to literally have a measurable amount of exhaust slipping past the piston rings into the lower end, as it brings abrasive carbon particulates with it, but building crank case pressure is definitely a strong factor in mysterious chronic oil leakage issues.

Let us know how it goes. My strategy of using a high flow PCV valve along with a breather pipe being brought into the inside of my open element air cleaner is keeping my oil very clean, and while not measured, is likely applying an ever so slight vacuum to the crankcase even at wide open throttle (as the breather pipe inside of the inside of air filter has got to be applying an ever so slight suction, as air filters do impose an ever so slight restriction to air flow) (creating an ever so slight vacuum inside of the air filter where my breather pipe from the other valve cover is plumbed to). I have never seen any oily residue out of the breather pipe port on the inside of the air cleaner housing, but it wouldn't surprise me if I ever did see at least a little as I flog my engines stupid hard. For every 50 miles I put on the car, it is wound to 6 grand wide open at least twice to a full 100+ MPH (!) *BUT* my oiling systems are set up for road race conditions, Milodon windage trays, 8 quart oil pans, Melling high volume oil pumps with the higher pressure spring installed (and additionally preloaded .200"), 11 quarts total of Valvoline VR1 Synthetic 20W50, twin remote FRAM HP1 racing oil filters, and a large 10" x 12" double pass oil cooler running AN-10 lines throughout. On cooler days, I have to let the car warm up at very least 10 minutes just idling out in the driveway, then drive mellow below 2500 RPM's until the oil pressure gauge comes down from being pegged at max. Once the oil pressure drops enough to come off the pegged position, then I know I can start in on it, usually within 5-8 miles of run time. I don't like hopping straight onto the freeway sitting at 3 grand cruise RPM at 80 MPH before I see the gauge come down from it's pegged position, as I picture the strain put on the distributor and cam drive gears while the oil is still thick...

Paul

fleming442

The rings haven't seated yet. I wouldn't worry about it for a while, just run open breathers to not suck oil.

Clark455

The suggestion of just running some breathers by Fleming is old school dragstrip thinking. Yes, it has some validity to it as this will prevent positive crank case pressures building up (as it will all push out of the breathers instead of building positive crank case pressure), BUT I strongly disagree, especially if this is a street driven car. Why? The soot, basically exhaust carbon particulates, that are getting past the piston rings are poisoning the oil. I'd rather suck some oil vapors through the PCV system to keep the crank case evacuated clean of all the exhaust fumes getting down in there. Think about it - literally exhaust particulates mixing in with the oil - uh, um, no way would I allow that. Besides turning the oil jet black, it also breaks down the lubricity of the oil dramatically. Most certainly not going to argue about it but feel very strongly against just running a breather in each valve cover. If it's pushing that much blowby, it's going to get oily around the breathers and stink up the engine compartment, possibly stinking up the passenger compartment too - yuck, no thanks. If it is indeed piston ring blowby, the rings will seat before all too long anyway providing they were all installed right side up. If there is an excessively loose piston ring end gap, or anything else going on of this nature, I'd still want the PCV system to suck it all up instead of having it accumulate in the crank case and then venting it all out of breathers into the engine compartment.

My .02 cents - well, I suppose 10 cents now with inflation.

Paul

Bernhard

Have you monitored the Crankcase vacuum through the rpm range ?They claim that it pulls vacuum almost through the entire rpm range.

SteveDB

Traveling for business this week so sorry short reply.
The rings are still seating on a new build.
Sensor is mounted in fuel pump block plate.
Wagner valve on order, will be easy to do back to back before snow flies.

thanks, steve

Clark455

Studying the AEM readings SteveDB posted actually has me a little puzzled, as you can see that he ran through the gears watching the red RPM line, yet the crankcase pressure reading is relatively flat line. Run through a gear, then the load changing against the next gear, and the next yet no particular movement in the crankcase pressure reading? If it's a manual trans, then letting off the gas, shifting, and reapplying load OR an auto trans running up and down the RPM range is still changing the load factor during gear changes which I would expect to correlate to larger fluctuations in the crankcase pressure readings based upon the varying RPM X load. Staying flatline on crankcase pressure like it's showing doesn't seem to jive. If the sensor is mounted in the fuel pump block off plate, I wonder if it is reacting to oil whip from the timing chain, though that would vary with engine RPM changes too. Timing chain oil whip against the sensor may also explain why the readings are so jagged, but that could just be electrical noise. Hmmm, looking at it again, there does seem to be a frequency change correlating to RPM, which may indeed be registering oil whip from the timing chain. A manual downshift would draw a vacuum inside of the cylinders, which would reverse / stop the blowby temporarily, also placing maximum vacuum against the PCV system - would be interesting to see what the readings may show in that scenario.

Things that make you go hmmm....

Paul

SteveDB

I’m confused too but that’s why I am trying to learn more and use data to quantify.
you make a good point on sensor calibration. I will start next log with car not running and then start it. I built the engine years ago and then it sat while the rest of the car was built from frame up as I suffered from extreme project creep.

so the engine is older tech / thought process with sealed power pistons, traditional wide ring pack and a zero gap second ring.
I also had carb issues and washed the cylinder walls pretty bad. It does seem to be sealing up now though.

yes it is a 4 speed car.

the sensor is a good AEM sensor in their stainless steel line of pressure sensors so the logger recognizes it and automatically pulled up the scale but I will double check that too this weekend when I get home.
thanks all for the input,
Steve

SteveDB

So its a sensor calibration issue. the pressure inside is basically atmospheric or 0 PSI.
I will continue to learn to run the data system and then post again when the ME Wagner valve arrives.
Good discussion, thanks all.