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#1051231 - 06/04/17 04:04 AM Re: Need input on crankcase evacuation remedies [Re: SSLance]  
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Haven't called Dave at MM yet, figured I needed to know what the new catch can system is doing before call was made.

So a test of what's going on in the crankcase is being done from cold start to hot idle over a 15 minute period. The MM can is disconnected from the engine. At the dirty side valve cover exit a hose runs to an improvised catch can. This is a 16 oz clear plastic water bottle with a 3/8" barb fitting epoxied 3" from the bottom. It is stuffed with two steel scrubbies for washing dishes, this mimic the material used in catch cans. The cap of the bottle is left off, this is the breather for the plastic can. Dirty air into the bottle, hopefully catch vapors and liquids, stinky air out the top. The clean air intake in the other valve cover is plugged with a vac/fuel pressure gauge. The dipstick tube is now adapted to input compressed air into the crankcase.

The procedure is apply 1 psi of air pressure to the dipstick tube. The gauge will show only a slight deflection, you feel the air pressure exiting the top of the plastic can. Do a cold startup, choke and all, idle engine until it's cycled the electric fans at 190, then run several minutes longer to hopefully get the oil up to 180 degrees. All the while doing a visual of the bottle and it's vent looking for, something? Have run this test twice and got, NADA. Sniffing the bottle vent tells you it's blow-by, doing the smoke test of the stream says the flow is slow and steady. But no water or oil in the bottle. At the minimum there should be something showing in the CLEAR plastic bottle.

Have run this test twice now, a few more times will happen. It takes about 1 minute to swap back and forth between the systems. Will run some hot tests also, go beat on the car and then do some hot hot idle testing. If an air pig was strapped into the pass seat a few WOT runs could be made at 1 psi to see what shows up in the plastic bottle.

At this point one thing stands out, how little blow-by this engine makes. With both dirty air and clean air ports wide open in the valve cover you see nothing at idle, yes it sticks, but that's expected. I've had a few SBC in my days, they all had something to show.
Possibly the end result of the catch can on this large displacement Q-jet SBC is the can won't be needing emptied very often. Disappointing because I wanted something to look at, bummer.

Once I figure out how much vac to apply at the new PVC, install the clean side restriction to maintain a few inches of vac at idle, I'll move on to something else. Opening the can drain periodically to see what's there should tell the story.
Bob

#1051252 - 06/05/17 03:51 AM Re: Need input on crankcase evacuation remedies [Re: SSLance]  
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Ran another cold start test yesterday, nothing. After reinstalling the MM can had the car car out yesterday and today, maybe 35 miles of just cruising around, the wife was with me. The engine does seem more responsive, this due to eliminating the large vac leak the stock PVC valve produced.

On the trip back to my shop this afternoon gave the engine a good workout. Parked it, hooked up the plastic catch can and blew 1 psi of air through the crankcase with the engine hot and idling. Got nothing in the can and if you caught the blow-by exiting the top of the bottle in the right light you could see a faint hint of blow-by. Ran it for several minutes, two cycles of both electric fans running On and Off, the second fan doesn't come on until about 195. So catching blow-by in the plastic can showed me nothing.

Next reinstalled the MM can. installed a gauge on the dipstick tube. Left the clean air wide open and got no vac on the dipstick tube.
Next plugged the clean side air port, 3 1/2" vac at the dipstick.
Next installed my restricted clean air fitting at the clean air intake. Currently a .048" hole. The vac reading at the dipstick tube slowly increased to 2", this on a hot engine idling at 750 and 13.9 A/F. Another vac gauge reading manifold vac reads a rock steady 16 1/2". So currently seeing 2" vac on the crankcase.

After letting the engine cool for a while opened the drain on the MM can, not surprised, nothing came out. Hmmm?

Got enough info now to have a talk with Dave at MM. Need to know what to expect if I increase his orifice size in the MM PCV valve. And If he will sell me another valve if I screw it up. I think with the engine build I'm working with a little more crankcase vac won't hurt anything. Shooting for 4" at the clean air intake. Will install a barb fitting in the restricted clean side to monitor PVC system vac. No big deal.
Bob

#1051434 - 06/12/17 09:11 PM Re: Need input on crankcase evacuation remedies [Re: SSLance]  
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Brief update.
A barb fitting to hook a vac gauge to the now restricted clean air side of the system is done. This allows monitoring of crankcase vac or pressure real time while driving. Will log a lot of miles this month, including a 200 mile round trip to Carlisle on the Pa Turnpike at 70+ mph. Won't have an opinion on what's going on with the recalibrated PVC system till the end of the month. Have made several trips over the years in this car running a tank full or more and checking mileage. Using the cruise, A/C on and some music almost 20 mpg is the norm. One of the suggested claims for a catch can system is increased fuel mileage. Don't think you would notice it doing around town driving. But because you don't have that large vac leak in the intake it may require less fuel at highway cruising. Remember I had to lean the idle A/F out when the catch can was installed, and cruise at 60 mph also needed to be leaned from 14.6 back to 15.0

Changed out the PCV valve grommet on the valve cover. The piece of crap Dorman HELP rubber grommet was swollen and very soft, just another junk product from them. The GM 14091870 grommets only come in a 5 pack, now I have a few spares. The clean side valve cover did have that GM grommet installed there for years, it was still good, but changed because I bought 5.

Spoke to Dave at MM last week, couldn't give me a definitive number on crankcase vac needed, but having just enough to keep a slight negative pressure at idle was suggested. So I'll play with slightly higher idle vac after I see some data oh what he would run, which is how the system is calibrated now.
Bob

#1051575 - 06/19/17 03:03 AM Re: Need input on crankcase evacuation remedies [Re: SSLance]  
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Another brief update.
A vac gauge now in the restricted clean air side, and a vac gauge monitoring engine vac. Idling 16" engine vac, about 1 1/2" on the PVC clean air side. A 4 mile trip around the block monitoring both gauges showed less than 1" at cruise or light accel, of course on high vac reading during deceleration that would climb very briefly to almost 2".

Back in the shop removed the PCV valve from the can, it's orifice was .199", so with a .048" restriction in the clean side 1 1/2" at idle.
Got out the number drills, opened up the valve to .205", now 3 1/2" at idle with a .048" restriction.
Next with the .205" valve install a .099" restriction, now 1" vac on the clean side.
Next opened up the valve to .209", with the .048" restriction now 4" vac on the clean side.
Next with the ,209" valve installed a .099" restriction, now 1 1/2".
Next with the opened up PVC valve orifice to .209" (.010" larger than stock) and a .059" restriction in the clean side 3 1/2" vac on the clean side.

So I increased the PVC valve orifice area by 10%, .199" to .209", and restriction area by 56%, .048" to .059". Just hard to imagine a .059" hole can flow enough clean air into the engine, but that's what I've been told.


That was the target I was shooting for, 3-4" at idle. Another test drive to see what the numbers are during various phases of driving will determine if I have gone to far. One thing I did notice was the A/F at idle got a little leaner after the final configuration was done. Something to think about, more tuning to follow. Removing the dipstick from the engine dropped crankcase vac to zero real quick. But putting your figure over the dipstick tube and it's right back at 3 1/2", and you can feel light suction on the tube. A good indicator of what's going on in the crankcase.
Bob

#1051703 - 06/23/17 05:34 AM Re: Need input on crankcase evacuation remedies [Re: SSLance]  
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Got the second clean air pipe powder coated on Tues, the last of the pieces to this puzzle. After having a vac hose barb welded into the first tube i made it was destroyed when I tried to wash the anodize off with Muriatic acid. Moral of that story is don't go eat diner while the alum tube get ate from the inside out. Also glass bead the tube, acid doesn't remove anodizing in some cases. although it did work on Aeroquip fittings, hmmm.

Dialed in the idle A/F at 13.9, 800 rpm and see a consistent 3 -3 1/2" of vac on the crankcase. Having R12 A/C and dual fans the engine was ran through a dozen circles while checking the tune, very happy at this point. Took a spin around the block and it shows the same vac under most conditions. When vac increases significantly under heavy decel, +20", crankcase vac will increase to 4 1/2", that was expected. That is probably good to add a little more purging for a carbed engine at that time, a lot of junk going past the rings under hard decel.

Hard to find somewhere to test WOT for a good distance, like a mile, around here anymore. To many people with cell phones these days. With this MM recirc can the cleaned positive pressure at WOT from the crankcase goes into a white filter in the air cleaner base. It's very easy to monitor what get dumped at that filter under WOT driving, I'll keep an eye on that. The old clean air side had the same filter, I would monitor that for how much oil was being pushed out there when it was the the positive crankcase pressure relief point. Over a period of several months there would be a very light oil mark on the filter, nothing drastic.

The last thing I did to the system was drain the can, got maybe a teaspoon of water out of it. Doing a 200+ mile round trip this weekend to Carlisle, most of it will be 72 mph, will be able to dial in the cruise A/F, 15.0. It takes about 2 minutes to tweak it on a Q-jet. With A/C on, CD cranking, and cruise set at 72 looking for 20 mpg with the 4.11s. Of course when i get back I'll be draining the can again, hopefully it catches something that would have went down the intake runners.
Bob

#1051829 - 06/27/17 05:01 AM Re: Need input on crankcase evacuation remedies [Re: SSLance]  
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Did the 205 mile round trip to Carlisle Chevy Nationals on Sat. Got a late start in the morning, roads were wet, most of the drive is turnpike but it was dry. The A/C cranking up and back, cruise set at 74, managed a little over 21 mpg, not bad for a 427 sbc with 4:11 gears. A/F running 14.7 at that speed, at 60 was 15.0 so I didn't tweak it, most of my local highway mph is about 60 around home.
Can I say the catch can with it's new PVC system helped mileage, maybe. Only an occasional time or two when I wasted some gas to quickly pass a truck, other than that drove sanely. The Allman Brothers, Live at the Fillmore East is still a good cruising CD.

Curiosity had me open the drain on the can when the car was sitting back in the shop on Sun, NADA.

Will be playing with the tune of the new system the rest of the year to try and determine how much vac and fresh air to supply the crankcase. It seems there is no simple answer to that and no good info either, will have to figure that out by trial and error.
Bob

#1051839 - 06/27/17 02:07 PM Re: Need input on crankcase evacuation remedies [Re: SSLance]  
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I personally think not gathering much in the catch can shows that the system is working as designed by keeping positive crankcase pressure from ever happening. When the crankcase goes positive, that's when things get wonky and the air gets contaminated quickly (mainly with oil).

You have that cured for sure...

Regarding cleaning condensation out of crankcase, eh...it's an added plus I guess, but I'm betting the little bit you are getting out of there is going right by the can and into the air cleaner again to be expelled.

I haven't even looked at my can since my first track day with it...guess I should pull the plug on it and see what comes out.


Lance
1985 Monte Carlo SS Street Car
#1051863 - 06/28/17 04:32 AM Re: Need input on crankcase evacuation remedies [Re: SSLance]  
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When this catch can post got started you got me thinking about how I would benefit from doing a can. After a lot of looking for good info I could see the big benefactors are the forced air engines, the cars that run high rpm on and off the throttle, and direct injected engines. Your car running extended track time falls into that group. For me my old PVC system was adequate, not spending a lot of time at WOT, the clean air side never pushed much oil out that side. Good valve cover baffles helped that.

It was the other benefits to a good can that got me thinking, claims of better mileage, hp increase, less oil going into the intake manifold, less pushing of oil past seals that got me thinking. But again I think all those are pluses for forced induction, due to not ingesting oil via the stock PVC system. So being a need to know type replacing the 60 year old design system with something better became the Spring project for the car. Also it was more fun than pulling the T56 and installing a new clutch which is what I should have done.

One of the benefits of the MM PVC can is his "proprietary" PVC valve. After talking to Dave about the orifice/flow I decided to take the valve out of the can and disassemble it. After a few attempts to remove the barb fitting and filter off the back of it the decision was made not to destroy the valve trying, there may be red Locktite to prevent disassemble, "proprietary". The barb fitting in the MM PVC is used as the orifice, it was a .199"opening. Dave indicates the range of orifice size is .203" to ,234" depending on how much engine vac is available at idle, less vac a bigger hole.

For me being able to tune the PVC system so it doesn't have the big vacuum leak under the carb is the plus. Being able to control how much fresh air is induced into the right valve cover and being able to meter the flow on the left side at the new PVC reduces that big leak in the intake. Have reaped rewards because of less vac loss, better idle, more responsive off idle, and maybe even mpg.

Not surprisingly there is very little info on catch cans on carbed engines. In the old days a breather on each valve cover took care of venting the crankcase, a shop rag was used to maintain it, With the advent of the PVC system in the mid 60's the factories, mandated by the Feds, burned the blowby by dumping it down the intake. Not much has changed from that basic system on most engine even today. Adding a can that can meter the flow, clean it and relieve crankcase pressure after cleaning it just seems like an improvement to a 60 year old design.

When I expect to see something in the can is during the colder/damp months. My car is driven all 12 months for pleasure in the NE, 2K miles or so, weather permitting. Condensation I would think. Oil, not thinking there will be much in the can.

On a Qjet a 3/8" tube in the center of the throttle plate is the PVC vac source, where it dumps the blowby on the bottom of the main wells will tell how much oil was being removed by the old system. Next time the Qjet is off will spit clean that area, use that as a indicator to can efficiency.
Bob

#1051990 - 07/04/17 03:41 AM Re: Need input on crankcase evacuation remedies [Re: SSLance]  
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WHAT, another update!!!

Spent way to much time on this project. The past week did a lot of reading, searching for flow info necessary for a PCV system to work properly. Generally speaking the factory systems do a good job at metering the flow for the engine conditions, idle, cruise and ok at WOT. This I kinda knew from the get-go. If the correct valve is in the stock or even modded engine and the stock flow path is maintained purging the crankcase is accomplished.

Now that a "proprietary" valve is being used in the MM can I needed numbers to try and set it up. A search found guesstimate flow ratings for small orifices when a set amount of vacuum is applied to the opening. This info allows a better guess on what size the clean air restriction should be.
From various technical places on the web the 1"-2" vacuum on the clean side seems to be the number at idle. Dave implies the same thing, very slight vac at idle. Blowby gases at at there lowest, you just need to have clean air to replace it.

Number from the orifice flow tables which may apply here. Currently have three orifice I'm testing with, .060", .090", and .120".
Orifice size -------------2" vacuum ----------4" vacuum
1/16" (.060") -----------.300 cfm---------------.420 cfm
(.090") -------------------?-------------------------?
1/8" (.120") ------------1.20 cfm -------------1.68 cfm
Couldn't find cfm numbers for the .090" but we can guess at that.

Have tested the .060" and .090", this evening made the .120" restrictor to be tested later.
With the .060 at idle 3 1/2"- 4" vac at a point 2" downstream of the restrictor on the clean side intake. This would indicate that flow would be somewhere in the neighborhood of .420 cfm. The author of the flow table states orifice shape has a lot to do with flow and it would fair to assume flow is actually about 2/3 of theoretical. So a guess of .300 cfm would be close.

Next the .090". At idle 2 1/2 - 3" vac, so larger orifice produces lower vac. Nothing on the flow table for that size but would think somewhere around a corrected
,600 cfm. Still much less than one cubic foot of fresh air per minute.

Will try the .120" when the epoxy dries. Suspect it to be in the 1 - 1 1/2" range so looking at less than 1 cfm. Doesn't sound like much but it seems from indications I've read it should be enough.
They do sell an electronic manometer to measure the cfm flow, I own three analog manometers, to much trouble to install one on the clean air tube now.

Couple points of interest. As more fresh air is pulled into the new PCV system the effect on A/F ratios is effected. Will be interesting to see how much the idle A/F changes with different orifices. From a .060" to the .090" about .1 A/F leaner. Would think the .120 will go leaner yet. One of the goals of this project was to decrease the vac lose, so just having the right amount of clean air into the crankcase is the goal.

The other interesting thing about the MM can is at WOT it's PVC valve goes closed, on the top of the can is the valve that goes open to either dump the cleaned blowby to the atmosphere, or as I've done, dump it back into the air cleaner via a 1/2" hose. With that hose disconnected from the air cleaner, engine idling, the .060" orifice installed, there is some measurable vac on this hose This is due to the almost 4" CC vac at the clean air, and the rubber disc that is the valve in the top of the can leaking vac. I pulled the top of the can apart and checked the simple rubber disc that sits in there, but, it's a simple piece of rubber that gets sucked against a fairly large hole.
With the .090" orifice installed the the vac at that hose is reduced almost to zero, hmm. Testing the .120" should be interesting, expecting no vac there.

One other litmus test is the dipstick tube test. With the engine idling pull the dipstick, place a thin strip of paper over the hole, a good indicator of vac in the crankcase.

Hopefully soon I'll get this all sorted out, then I'll call Dave again and discuss my findings. Really would like to put this project to bed.
Bob

#1051999 - 07/04/17 03:41 PM Re: Need input on crankcase evacuation remedies [Re: SSLance]  
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Me too!!! laugh J\K

I pulled the breather off the top of my can and couldn't feel with my hand any vacuum on the can with the engine at warm idle, so I put a piece of tissue paper over the top hole and saw that there was just enough vacuum to pull the paper toward the can. That was good enough for me!!

You are like me in a lot of ways Bob, once you dig your teeth into something, you don't give up until desired results are reached. I just think it's cool that this can and valve setup gives you the tools you need to dial this in exactly to your specs.

Happy 4th buddy! Keep up the good work...


Lance
1985 Monte Carlo SS Street Car
#1052000 - 07/04/17 03:54 PM Re: Need input on crankcase evacuation remedies [Re: SSLance]  
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Wow this one is really got you up against the wall Bob. If you need it I can send you one of my electronic manometers so you can accurately measure the negative pressure. Mine has many settings in all units so you can even measure the CFM. I have two of them so you could take your time with it and send it back when you're ready. But I will tell you the electronic units are very sensitive and do bounce around quiet a bit. So when I take readings I use the high and low and use an average of the two. This tool is a very useful and has helped me quiet a bit on every car. You can even measure differential pressures too on both ends + & -.

Send me a PM and I can ship it out next week when I'm back from Germany.

Ron.

Last edited by 1 Slow SS; 07/04/17 04:04 PM.

1986 Monte Carlo SS LS3 build almost running. NOT.....LOL
I will rebuild the car and up the bar a bit,Speed tech, frame work and a bigger LSX.
#1052008 - 07/04/17 07:26 PM Re: Need input on crankcase evacuation remedies [Re: SSLance]  
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Having been out of work for a year now, some call it retirement, the "every day is Sat" thing, I find there is to much time now to resolve the mysteries of the world. Like why do I hook the ball off the first couple tees, why does my 4.3L eat caps and rotors, why do i still need to go to the bank for cash, and the damn can thing. Eventually something else will take priority, like gutting the kitchen, and I'll either back burner the can or, put it to rest.

Thanks for the offer Ron! At this point I'll decline, the only thing i would ask would be a copy of the setup necessary to use it. What i have installed now is very versatile, can easily go back to stock in minutes, two good ports to measure vac, and changing up the clean side orifice can be done while running.
For now the guessing game of tuning the flow with crankcase vac readings is the route I'm on, and the rest of the Summer to do it, remember, I'm retired.
Bob

#1052268 - 07/14/17 06:24 AM Re: Need input on crankcase evacuation remedies [Re: SSLance]  
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Had some time tonight, ran a few tests on different orifice combos.
First was the can installed, .209" orifice in the can's PCV valve, .120" clean side restriction, no air cleaner.
780 idle, 13.9-14.0 A/F, 16 1/2" idle vac, 2" vac on the PCV system. Engine is hot and electric fans have cycled. This combo was run for the past two weeks.
During these tests the idle speed and idle mixture screws weren't adjusted to optimize speed or A/F,


Second setup tested was the what I ran before the can install. A Delco 2072 valve, and a non restricted (.625") clean air side. basically a stock L69 PCV system.
850 idle, 13.8-13.9 A/F, 16 1/2" idle vac, 0" vac measured at the clean air inlet. The .625" wouldn't allow vacuum to build in the crankcase but was pulling a lot of air through the system.

Third test was interesting. Same setup as above, stock PCV valve but with a .120" restriction in the clean air.
875 idle, 13.4- 13.6 A/F, 16 1/2' idle vac, 3 to 3 1/2" vac in the clean side.

Fourth test was back to the can setup to make sure things have remained the same, except entire air cleaner is on the engine. The cold air package on the air cleaner has two 4" ducts that pull cold air from the airbox ahead of the condenser, this effects A/F at idle slightly,
800 idle, 14.0-14.2 A/F, 16 1/2", 2" on clean side

What did i learn. The stockish PCV system flow a lot of air at idle through the crankcase but wouldn't pull a vacuum due to the huge, .625", clean air inlet. When I would restrict the stock system with a .120" orifice immediately had 3+" on the clean side and idle A/F got richer and idle speed went up a little. This tells me the stock PCV valve orifice at idle is larger than what is in the can's valve.

The setup i will run for the next couple weeks will be the .209" in the can valve with the .120" clean side restriction. After that will next open up the can's valve another 10% in area to .219", this should increase system vac into the 3" range with the .120" clean side.
The goal is to have enough crankcase vac to evaluate at idle and cruise, and to reduce the amount of vac loss the engine has via the system. Somewhere there is a happy medium.
Bob

#1052279 - 07/14/17 03:51 PM Re: Need input on crankcase evacuation remedies [Re: SSLance]  
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I just inspected Barney for the first time since Midwest Muscle Car and found just a bit of oil had escaped the pass side breather. Remember I flogged it hard there with LOTS of WOT time.

I sent Dave a message to see what I can adjust to allow more pressure to escape thru the can instead of the incoming air side during WOT. I'm guessing he is going to have me open his valve up a bit or put a bigger line from driver side breather to can. We'll see.

Still nowhere near as bad as it was last year, but can still be tweaked to be better for sure.


Lance
1985 Monte Carlo SS Street Car
#1052280 - 07/14/17 07:45 PM Re: Need input on crankcase evacuation remedies [Re: SSLance]  
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I just had my machinist friend open up the fitting on the driver side valve cover barb from 0.220 to .270. That's the most I can get out of it.

If that turns out to be not enough I'll drill the breather out and re-tap for a larger fitting to go there, that's the choke point on the dirty side.


Lance
1985 Monte Carlo SS Street Car
#1052297 - 07/15/17 04:35 AM Re: Need input on crankcase evacuation remedies [Re: SSLance]  
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The dirty side on my setup is 1/2" from the valve cover to the can. Had Dave install a 3/8" barb in the dirty side when he shipped it. I bought a 1/2" barb elsewhere and went 1/2" right from the start, thought bigger is better for that dirty line. You have the filter on top of the can. Out of the top a 120 degree 1/2" barb, 1/2" hose run to a filter in the air cleaner housing. We're both using the same carb port and a 3/8" hose to the MM PCV valve in the can.

Going 1/2" on the dirty side would maybe help with dumping more WOT blowby out the top of the can instead of the clean air side.
My thinking is Dave is going to tell you to go smaller on your clean air restriction. And also make sure there is good baffling in the valve cover. to keep oil away from the clean side port. Restricting the clean side should make the path for the blowby at WOT to go out the larger valve cover opening which is the dirty side.

To measure crankcase vac all you need is a 4"piece of 3/8" rubber hose, a fitting to adapt 3/8" ID hose to a smaller vacuum hose and a vac gauge. Pull the dipstick, stick the 3/8" hose over the dipstick tube, true crankcase vac readings at idle, or cruise if you want to take the vac gauge for a ride. You have that Locar dipstick, adapt to it.
You will most likely have 0 crankcase vac at idle with your setup. If you haven't touched the orifice in the MM valve, .199", the only way to get a minimal amount of vac in the crankcase is to restrict the clean side to .060". Dave says run "minimal", 1-2", I've read 2 or 3, one of my vac gauges has a PVC range marked on it, 3-5" normal. I'm shooting for 2" with 3" tops and trying to do that with the smallest amount of fresh air necessary to keep the crankcase purged.
Being the vac source is the intake plenum reducing the amount of flow through the PCV system is a good thing.
Bob

#1052299 - 07/15/17 04:50 AM Re: Need input on crankcase evacuation remedies [Re: SSLance]  
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Member

Joined: Jan 2000
Posts: 3,714
Pottstown, Pa
By the way I have a 90 degree 1/2" fitting that will go into a 3/4" PCV valve grommet. You're welcome to it. Would make changing to 1/2" dirty side a little easier. I'll send you a pic.

Also I bought that 1/2" barb fitting for the dirty side of the can here. Excellent quality, made in CA, fast ship, small specially shop with the odd fittings he produces. It's hard to find good fittings elsewhere that ain't made in China.

http://www.ebay.com/itm/10-O-Ring-Boss-to-1-2-Hose-Barb-Adapter-AN-Fitting-ORB-/271387339975?hash=item3f2ff22cc7:g:zpQAAOxy4dNS~APr

Bob

#1053027 - 08/21/17 02:49 PM Re: Need input on crankcase evacuation remedies [Re: SSLance]  
Joined: Jan 2000
Posts: 3,714
mmc427ss Offline
15+ Year
mmc427ss  Offline
15+ Year
Member

Joined: Jan 2000
Posts: 3,714
Pottstown, Pa
Update after about 1 month with no changes to the can system. Have had the vac gauge on the clean side of the system several times to monitor the vac at idle and while out for a joy ride/cruise. I think I'd like to see more consistent vac in the 2-3" range while cruising. May open the MM PVC valve orifice up another .010" and see what changes. The only problem with that is there is no going back to a smaller orifice once you enlarge it. Currently running a .120" restriction in the clean side, but that can be changed to whatever I want there.

Have resisted opening the can drain to see what has been collected, trying to get at least another 500 miles on the can before looking. I feel once the cold weather gets here with more cold weather starts more condensation will collect in the can. One of these days will pull the carb and clean the intake and underside of the carb where the old PCV dumped. Then in the Spring will check those areas to see if they stayed clean. If the can is doing it's job there should be no oil deposits there.

The engine has about 15K miles on it now and when it was switched to Mobil 1 10-30 at about 1000 miles it started seeping oil at the front and rear crank seals. Nothing serious, just annoying. After a days running I would see a small patch of oil dripped on the floor under those ares. What I've noticed is less oil being dropped. With the old stock PCV system with unlimited clean air supply, 11/16" opening, there would be no measurable vac at idle due to the huge clean air supply. With now having the restricted clean air and a measurable vac on the crankcase it may be reducing the seepage at the seals.

Due to what seems like an every Fri storm I haven't had the car to the track for 1/4 mile blasts this year, yet. Weather is looking good for this Fri, intention is to get 6 passes on the car before Maple Grove stops T&T Fridays for the year. Was hoping to get to the track 4 times this season, at this point the number is 0. Previously would monitor WOT blowby by how much oil was on the clean side filter. The ring seal and blowby is still very good and really don't expect much in the can even with numerous passes. There is now a filter on the can's WOT port to keep an eye on what is dumped there, I would expect nothing there. Unfortunately in this area of PA you can't go anywhere and make 4 gear passes on the public roads anymore, not like when I was a kid and you could do it back on the roads between the farm fields. Times have changed!
Bob

#1053059 - 08/24/17 04:22 AM Re: Need input on crankcase evacuation remedies [Re: SSLance]  
Joined: Jan 2000
Posts: 3,714
mmc427ss Offline
15+ Year
mmc427ss  Offline
15+ Year
Member

Joined: Jan 2000
Posts: 3,714
Pottstown, Pa
Well as things go had some free time Tues afternoon and pulled the carb. Cleaned it externally, the venturi, and the throttle plate of any traces of blowby or that lousy E10. Also cleaned the plenum and as far down the runner as possible. There was really no sign of oil in the throttle plate area where the PCV dumps the junk, fuel discoloration yes. The manifold is a Weiand single plane so it's easy to clean the plenum and runners. Now when that area is checked again, in say Dec, it will have only catch can history there.

Tues evening made a trip around the block to watch vac readings, was seeing about 1" idle and cruising, deceleration when engine vac is high less than 1 1/2". So did the math, removed the MM PCV valve and opened up the MM PCV orifice 4%, from ,209" to .213". It was late in the evening, drizzling, so only got to check idle PCV vac at the clean side, was now reading 1 1/2", up about 1/2", the idle A/F was a little leaner at 14.0 - 14.1 up .1 to .2, idle speed increased about 50. In the next day or so will do a 10 mile jaunt, trim the idle A/F a tad richer. The 60 mph A/F was previously dead on 15.0, will be interesting to see if that also needs richened a little.

Initial thinking was to run the least amount of PCV vac to keep the crankcase happy under normal driving, 2"-3". And at the same time to reduce the amount of vac lost to that system. Sneaking up on that combo, don't want to overshoot the goal.
What bothers me the most is the stock system had an unlimited amount of clean air through the 11/16" supply tube. Currently running a .120" orifice instead, which flows about one cfm at 2" vac, compare that to how much air you can pull through a much larger supply at virtually zero vac, it would gulp much more air being unrestricted. Tonight didn't have time to do more testing on the new setup.

Fri at Maple Grove will be running the car at their T&T. Bolted the Hoosier QTP on and made seven 30' burns on them to clean off the rust. Good thing, they were a little thumpy at first from sitting since last Fall.
Bob

#1053103 - 08/27/17 06:28 PM Re: Need input on crankcase evacuation remedies [Re: SSLance]  
Joined: Jan 2000
Posts: 3,714
mmc427ss Offline
15+ Year
mmc427ss  Offline
15+ Year
Member

Joined: Jan 2000
Posts: 3,714
Pottstown, Pa
Well the trip to Maple Grove was a bust. First time I've paid 20 bucks to go to a car show where all the cars had slicks. The timing system was non functional, 4 cars made a pass at 6 pm, that was it for the night, no timing. I sat at the front of lane 5 from 5:30 until 9:00 pm when they cancelled the T&T. They blamed it on a lightning strike from a storm on Tues. Wouldn't you think someone would have tested the system hours before the T&T? They blamed it on fiber optics failure, I blame it on their lackadaisical attitude toward the little guys. They had a big track rental scheduled for Sat/Sun, the FF Live, http://ogs1320.com/ff-live/ Have seen no news on whether that happened Sat. Gotta love the Grove, NOT!

Had the vac gauge on the PCV system for the trip to the Grove, removed it at tech. Seeing 1 to 1 1/2" vac for the trip with someone riding shotgun to monitor it. Thinking about going to the next step up in drills, from a #3, .213" to a 7/32", .2188". That's an additional 5% increase over the .213". Would be about a 20% increase in orifice area over what came originally from M&M which was .199". Will stay with the .120" clean air restriction.
Bob

#1053724 - 10/02/17 02:22 AM Re: Need input on crankcase evacuation remedies [Re: SSLance]  
Joined: Jan 2000
Posts: 3,714
mmc427ss Offline
15+ Year
mmc427ss  Offline
15+ Year
Member

Joined: Jan 2000
Posts: 3,714
Pottstown, Pa
In the past month put some miles on the car including a second trip to Maple Grove, 3 lousy passes, and a trip for the Magna Buick track rental at Cecil County. Where do you see 50 GN, a hand full of GNX, Turbo T, and '70 GSX all in one spot. Also made 5 not so good passes there, best of 12.49 @ 112.6. A year ago ran 12 teens at Cecil, I'm pretty sure it's the driver, the car pulls hard in high gear.

So now with about 1000 miles on the can, a handful of WOT passes at the track and some playing on the street it was time to see what's in the can. A couple times before opening the can's drain showed nothing was collected. Yesterday was the same result. So I removed the can, took it completely apart. Very little oil, none in the bottom, the coalescing medium had a very light film on oil on it. The most oily area was the can's insert that directs flow. Where the dirty air comes into the can, and then is pulled downward around the perimeter into the medium was wet. Manifold vac is then pulled through the center of that insert, via the PCV valve, this purges the medium. The PCV chamber in the insert and the inlet area of the PCV valve weren't what you call wet, but indicated oil being there.

So I learned how easy it is to remove the can from the car, inspect the internals of the can, and that I'm collecting zero water or other sticky liquids, and either my engine has very little blowby or the can is not doing a good job at collecting oil.
I did notice that there is no oil on the rubber disc check valve in the top of the can. This check valve is to redirect WOT crankcase pressure when the PCV valve is closed during WOT, some cans will have a filter attached to this port and dump the "exhaust" to the atmosphere. On my setup a 1/2" hose runs to the air cleaner housing and into a white fiber filter to dump WOT pressures into the housing. There is another filter duplicated on the other side of the air cleaner used for the PCV clean air supply. The filters being white easily show any oil deposited there. Both showed marginal oil when check. So some oil mist is coming from the crankcase. What does that tell me, I'll be monitoring them for awhile.

This month will run the car again at Cecil to see if an old guy that doesn't want to hurt the car can get it down the track, hopefully make a lot of passes. Later is an autox with two drivers, should be 8 minutes of cranking the engine in 2nd gear. Another 500 miles hopefully before the good days for a drive become less. I'll pull the top of the can again to check the medium, and remove the carb to inspect the area where the PCV dumps into the manifold for oil.

I would really like to think this engine has little blowby, but almost 10 years of vigorous driving and 17K miles tells me otherwise. Idling hot with the valve covers venting to the atmosphere actually shows little blowby. My 1969 307 back in the day with 200K, that had blowby.
A few weeks ago #2 plug was removed, this was always the one that showed signs of oil down the guides. It actually looked good, but I think the new seals installed with the beehive springs a few years ago have more to do with that, nothing to do with the can.

Just thought I should update this. A work in progress because an inquiring mind needs to know.
Bob

#1053728 - 10/02/17 12:42 PM Re: Need input on crankcase evacuation remedies [Re: mmc427ss]  
Joined: Sep 2007
Posts: 3,035
1 Slow SS Offline
Member
1 Slow SS  Offline
Member

Joined: Sep 2007
Posts: 3,035
Small town USA
Bob,

Leak down test tells you exactly what you have in % on each cylinder.


1986 Monte Carlo SS LS3 build almost running. NOT.....LOL
I will rebuild the car and up the bar a bit,Speed tech, frame work and a bigger LSX.
#1053730 - 10/02/17 01:36 PM Re: Need input on crankcase evacuation remedies [Re: SSLance]  
Joined: Dec 2007
Posts: 5,479
SSLance Offline
Member
SSLance  Offline
Member

Joined: Dec 2007
Posts: 5,479
Smithville, MO
I wonder if having the can right over your header is drying the moisture out of it? My can is up in front of the header panel no where near any direct engine heat and I always get at least a little bit of gassy or oily smelling water out of it. Yours may be collecting water but drying it out before you empty the can...


Lance
1985 Monte Carlo SS Street Car
#1053732 - 10/02/17 02:19 PM Re: Need input on crankcase evacuation remedies [Re: SSLance]  
Joined: Jan 2000
Posts: 3,714
mmc427ss Offline
15+ Year
mmc427ss  Offline
15+ Year
Member

Joined: Jan 2000
Posts: 3,714
Pottstown, Pa
Yes I know that but have been reluctant to do a leak down test. Mostly because less than expected results would drive me into a new stage of the build that is VERY expensive, an engine refresh and adding the other 100 hp. It would take a lottery win and a divorce to make that happen. My estimate is over 4K including a new clutch. The other factor is car down time. Have owned this car for over 25 years, total build downtime for all the various mods is less than 3 months.over that 25 years. I lose interest when things take to long. One friend's 69 Camaro took 1 1/2 years in the body shop for paint, another friend's Monte has been apart for over 8 years, having mine apart for the Winter months or longer doesn't interest me. Also being retired now it's a little more difficult to pull rabbits out of the hat. and hide them from the wife.
Bob

#1053735 - 10/02/17 08:46 PM Re: Need input on crankcase evacuation remedies [Re: mmc427ss]  
Joined: Sep 2007
Posts: 3,035
1 Slow SS Offline
Member
1 Slow SS  Offline
Member

Joined: Sep 2007
Posts: 3,035
Small town USA
So just googling facts and writting posts is the future then huh? Sorry to hear Bob,


1986 Monte Carlo SS LS3 build almost running. NOT.....LOL
I will rebuild the car and up the bar a bit,Speed tech, frame work and a bigger LSX.
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