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baller. many thanks, sir.
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Originally Posted by JasonC SBB
(Post 574594)
Has anyone actually measured blowby flow and pressure? Examined the blowby routing in the cam cover baffles? I have.
With my old tired 2000 motor the pressure was too high - 20" water at mid RPMs. I opened the valve cover's baffles and added plastic kitchen scrubbers. I discovered that all the blowby passed through a tiny hole (3/16" IIRC) connecting one chamber to another. I enlarged this hole to a pair of 1/4" holes. This mod reduced the crankcase pressure to about 10". Before this mod I'd also discovered that the fittings and hoses to my home-made catch can was worth about 7" of pressure loss. Larger fittings helped a lot. The scrubbers reduced the rate at which my catch can filled up. The problem I was trying to solve was turbo seals weeping when the car was driven hard. The above mods reduced it a lot. Just for comparison, a stationary turbo diesel setup crankcase pressure spec is <5" water. IIRC aftermarket turbo manufacturers recommend <10". On my new 2001 motor I measured blowby FLOW and it was a bit over half of what a healthy motor shows. However at redline and full power the crankcase pressure is around 10-15" water. This motor has a stock valve cover. So the pressure is marginally high despite the tight ring seal. What this all tells me is that the tiny hole that separates 2 chambers in the baffling of the valve cover is too small for when you turbo the motor. Blowby is proportional to power production (and ring condition of course). If you double or triple the horsepower, it stands to reason the that said hole may need to be enlarged. If I now get weeping out of my turbo seals with my new motor at the track, I'm gonna do the same mod I did before. The reason turbos may weep with high crankcase pressure, is that this same crankcase pressure can cause the oil drain line to back up. If anyone wonders why some turbos don't weep with high crankcase pressure, perhaps it's due to variance in how the drain is routed. In my car, the drain hose has a very slight uphill portion where it passes under the a/c compressor. The stock breather baffles are kind of cool the way they work. It is designed to where oil condensation will pool up and with pressure pulses and in vacuum situations the liquid gets sucked back into the head while gas can escape. The baffles on the port that attaches to the PCV sort of suck for doing oil separation. And I think Oil will slosh into it especially during hard acceleration in a left hand uphill turn. I am pretty sure turn 5 and 6 at Laguna were causing oil to pump out that side and fill my catch can. My current plan is to enlarge the holes in the breather side baffles So it is equivalent to a -8 AN line and route it to a VTA catch can breather. What was the PCV port in the valve cover will be connected by a hose to the pan above the oil level. This line will be routed through a swirl pot/ oil separator of some sort wit an additional line hooked up to the VTA catch can breather as well. Probably use all -8 lines but with a -10 line down to the pan. Now I just need to figure out what will work for the swirl pot/oil separator to keep the liquid oil that splashes from the PCV port and the pan port from filling up my catch can breather. Bob |
Originally Posted by levnubhin
(Post 574625)
Update: It's been almost 2 weeks and everything is working perfectly. I think the biggest help is having that crank case vent.
Dam it now I am thinking I want to add that port in a 1.8 block. Just drill and tap it some how. I’m thinking that must work much better than going to the pan It is high enough it must non be getting too much oil slosh in it. It is also big like 5/8” so it should really keep pressure from building up in the crank case. Bob |
just got this http://www.summitracing.com/parts/SUM-120108/
i will give it a shot. |
I don't see why adding a vent to the block is better than a vent in the cam cover ... ?? Especially by modifying the existing baffles. The holes that connect the block airspace to the head airspace are huge.
EDIT:
Originally Posted by bbundy
I think what happens if you only vent the valve cover and vent it well, as in better than what you can get from a PCV system, is the pressure and gas flow from the bottom end generated from blow by has to go back up to the top of the head through the oil drain back passages if it gets too much it will impede the oil trying to drain back from the head to the pan and basically cause much of your oil to get stuck in the top of the head where it can slosh up into the upper vents or even possibly cause an oil starvation issue.
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Originally Posted by JasonC SBB
(Post 574698)
I don't see why adding a vent to the block is better than a vent in the cam cover ... ?? Especially by modifying the existing baffles. The holes that connect the block airspace to the head airspace are huge.
EDIT: I thought of that too but it seems a stretch. Because the pressure can't get from the crank case to the cam cover quick enough. You end up blowing out seals instead. __________________ Best Car Insurance | Auto Protection Today | FREE Trade-In Quote |
BTW a good motor will have a blowby cfm that is 1/50th of the hp output.
A 300 hp motor will have 6 cfm. That's not huge. I have a flow gauge and I can blow nearly 15 cfm with my lungs. I can't imagine that blocking the oil drainage given the head flow rate, and the size and # of holes in the head. Think about the tiny oil hole that supplies the head and the # and size of drains. |
Originally Posted by levnubhin
(Post 574708)
Because the pressure can't get from the crank case to the cam cover quick enough. You end up blowing out seals instead.
I happened to measure crankcase pressure 2 ways: by attaching a hose to the cam cover PCV hole, and by attaching the hose to the dipstick. Same pressure read. In both cases the blowby was flowing out the hotside cam cover vent. This says that the holes between the block and the head aren't restrictions to the flow. When I blow through the tiny hole in the baffles I mentioned, the resistance I feel is huge. |
Do you have pics of your baffles? stock and modded?
Both of mine have openings on them this size: http://i158.photobucket.com/albums/t...t/IMG_2061.jpg which is far larger than the vent exits at the cam cover. And there's at least that much area around each baffle when installed in the chamber. |
Originally Posted by JasonC SBB
(Post 574698)
I don't see why adding a vent to the block is better than a vent in the cam cover ... ?? Especially by modifying the existing baffles. The holes that connect the block airspace to the head airspace are huge.
EDIT: I thought of that too but it seems a stretch. Bob |
When I pour my Hawaiian Punch, I make sure to punch a vent hole.
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Originally Posted by m2cupcar
(Post 574739)
Do you have pics of your baffles? stock and modded?
http://pages.sbcglobal.net/jcuadra/c...er/stuffed.JPG I have to go find the pix of the hole. |
Originally Posted by devin mac
(Post 574641)
so, to summarize: you vented the blocked off port on the passenger rear of the block to a small'ish catch can, ported the two standard VC vents out to larger (-10AN equiv) openings, and ran both of those to a second, larger catch can. no internal mods (aside from porting out the vents) to the valve cover baffling or valve cover itself, correct?
I'm looking to get my car up and running again and i know i was struggling with some crankcase venting issues at 17psi when i put it away, so i want to get it right the first time, this time. |
In my 69 Buick, the big block is known to have oiling issues. The oil drains from the head to the block are too small from the factory. It's standard procedure to open these up larger. I wonder if our motors would benefit from the same treatment. Would it help the head oil drainage reducing the effect of the added blowby pressure?
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Originally Posted by cueball1
(Post 580775)
In my 69 Buick, the big block is known to have oiling issues. The oil drains from the head to the block are too small from the factory. It's standard procedure to open these up larger. I wonder if our motors would benefit from the same treatment. Would it help the head oil drainage reducing the effect of the added blowby pressure?
I am feeling not much steady state flow but there is defiantly pretty good pressure pulses even at idle. This is on a stock motor with good compression numbers but boosted. This goes back to my theory that pulsed flow even at low average pressure difference and flow rate contains so much more energy than steady state flow that it crates quite a different behavior in how it will push liquid around in a gaseous environment. I was going to hook the line to the side of the block it to an oil separator of some sort then to a VTA catch can but right now I just have it hooked directly to a VTA catch can. It seems to collect mostly water vapor so I think this location in the block works pretty good as a vent without getting much oil. Bob |
I stumbled on this pretty good document on blow-by and breather systems.
http://www.106rallye.co.uk/members/d...hersystems.pdf I still think I’m going to stay Vent to atmosphere but I plan to engineer the system well. I want to make a volume separator to fit in line before a Vent to atmosphere catch can. I think the big problem with the stock system is it just dosnt work well when you making several times the stock hp. Bob |
So would tapping the pan on a 99 engine not be a good idea? I have my engine out right now to reseal the oil pan so I was going to make a return for the catch can. I think thats how the MSM is setup from factory as well.
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Originally Posted by cryogenic
(Post 581566)
So would tapping the pan on a 99 engine not be a good idea? I have my engine out right now to reseal the oil pan so I was going to make a return for the catch can. I think thats how the MSM is setup from factory as well.
My experiance is there is a lot of oil slosh in the pan with hard cornering and braking. My port in the pan high and just below the alternator didn’t work so well. In some situations it would pump oil out. I assume it would slosh up covering the port and pressure pulses would give it enough momentum to shoot oil all the way up the hose. Maybe there is a better spot in the pan that would work I do not know. Interesting I found this site which sort of describes the breather system on an Escort RS or Sierra Cosworth. Again breather port up high on the block. I think the early 1.6l GTX in European rally trim came with a similar setup and it was cast in the block. http://www.wrc-cosworth.org/howto/br...separator.html Bob |
The pressure pulses in one end of the crankcase may be the pulsing from the nearest cylinder. Remember that air pumps back and forth between cyl 1&2 under the pistons because they alternate, and between 3&4. This is why it is recommended to enlarge the holes in the webbing in the block near the main bearing caps, between 1&2, and between 3&4. These holes are much smaller than the bore diameters.
In the cam box, there would be less of that pulsing. |
AFAIK the WRC Escort Cosworths had a venturi device connected to the turbo and the crankcase then venting into the exhaust pipe. Under load the turbo blows into the venturi device thus creating vacuum in the crank case. The goal is to create vacuum in the crankcase and the turbo cars can achieve it without a separate mechanical pump - just use the turbo to do the work.
Most likely the current WRC cars use similar systems
Originally Posted by bbundy
(Post 581571)
I think The MSM runs the return below the oil level all the way to the bottom to make sure it is submerged in oil. Works good as a return but not so much as a vent I would think.
My experiance is there is a lot of oil slosh in the pan with hard cornering and braking. My port in the pan high and just below the alternator didn’t work so well. In some situations it would pump oil out. I assume it would slosh up covering the port and pressure pulses would give it enough momentum to shoot oil all the way up the hose. Maybe there is a better spot in the pan that would work I do not know. Interesting I found this site which sort of describes the breather system on an Escort RS or Sierra Cosworth. Again breather port up high on the block. I think the early 1.6l GTX in European rally trim came with a similar setup and it was cast in the block. http://www.wrc-cosworth.org/howto/br...separator.html Bob |
1 Attachment(s)
Here is the diagram from some manual
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Originally Posted by JasonC SBB
(Post 574594)
I opened the valve cover's baffles and added plastic kitchen scrubbers.
Btw did you remember to drill small holes in the baffle covers so the accumulated oil can drain back out of the baffled area? |
When I opened em up some time later the plastic scrubbers looked fine. <shrug>
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Ι ordered yesterday a CUSCO oil catch can, that I found in very good price...I read in many forums different opinions about the cans...other say it is better to have some material inside the can to catch oil and fumes better, others say that the difference in temperature or speed of fumes when entering the can do the job....
As from what I was informed, this can opens from top, do you think it is a good idea to put some metal wool inside for better filtering? Isn't there the posibilitty some little metal particle from the wool to be sucked somewhere and cause a problem? (I will also use a one way valve between the can and the intake) The can is this one http://64.19.142.11/www.nipponpower....93-1-large.jpg |
4 Attachment(s)
Originally Posted by JasonC SBB
(Post 574594)
I opened the valve cover's baffles and added plastic kitchen scrubbers.
After I put the plastic scrubbers my catch cans started filling at a much, much higher rate. Seems like the scrubbers help the oil moving, climbing up and getting out of the vent ports. In like 30 miles of cruising I had to empty the PCV side catch can because it started filling that fast. I just opened the valve cover to see what happened inside and one can really see how the oil started travelling on the scrubbers ... Here is my valve cover: https://www.miataturbo.net/attachmen...5&d=1281307655 Here it is with the scrubbers installed: https://www.miataturbo.net/attachmen...6&d=1281307720 And this is after 30 miles of cruising and one autocross: https://www.miataturbo.net/attachmen...7&d=1281308001 Here is the other side (top side, when cover is on the engine) of the scrubbers: https://www.miataturbo.net/attachmen...8&d=1281308096 Before putting the scrubbers in, my catch cans filled at a really slow rate. I had to empty after months of driving. Very strange .... :| |
I'm next on this deal, calling ARTech...
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Just throwing this out there because I'm about to buy a catch can. (Artech, if you have a solution let us know) I have the square valve cover with port at the rear of the head. I don't have a catch can and no filter attached. I've boosted to 20psi and I have no blow by out of this orifice. I'm surprised that I don't, but it may be worth the switch to a different valve cover. I think it is a protege valve cover.
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Originally Posted by djp0623
(Post 638208)
Just throwing this out there because I'm about to buy a catch can. (Artech, if you have a solution let us know) I have the square valve cover with port at the rear of the head. I don't have a catch can and no filter attached. I've boosted to 20psi and I have no blow by out of this orifice. I'm surprised that I don't, but it may be worth the switch to a different valve cover. I think it is a protege valve cover.
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Anybody have any new info/feedback on using the port under the alternator on the 1.6 as a block vent? Suggestions for guys with 1.8s? I currently have the stock PCV system still intact, and the driver's side port open VTA, but I'm only running 12ish psi. Should I just drill and tap a bigger fitting into the PCV side of the valve cover and the same for the driver's side and run 2 lines to a catch can? 2nd fittings in the oil pan for an oil return/vent for the bottom end seems to possibly cause oil backing up in the catch can drain line correct?
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Cspence has the vent port plumbed to his catch can. Check his build thread for pictures and details. PO installed it, but I don't think he's had any issues.
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Originally Posted by curly
(Post 638382)
Cspence has the vent port plumbed to his catch can. Check his build thread for pictures and details. PO installed it, but I don't think he's had any issues.
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I put the port on the block to a catch can and once I did that nothing ever came out of the valve cover vents.
__________________ Best Car Insurance | Auto Protection Today | FREE Trade-In Quote |
Originally Posted by levnubhin
(Post 638439)
I put the port on the block to a catch can and once I did that nothing ever came out of the valve cover vents.
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This is going to sound dumb, but here it goes.....:facepalm:
After reading the thread i haven't found the main reason for doing all of this venting other than preventing excessive blowby out of the valve cover and possibly blowing out seals. Is this it, or am I missing something. Would someone break it down for me. I am now concerned because I don't get anything out of the valve cover, and I haven't blown any seals. Am I just lucky? Not making enough power? If it ain't broke don't fix it? Combination of 1.8 , 99 worked head, different valve cover, and 323 PCV just happens to work, etc etc |
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I have a baffle there.
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Originally Posted by jtothawhat
(Post 638470)
I have a baffle there.
http://ecx.images-amazon.com/images/I/3147NYF4SVL.jpg |
Yeah I was going to put one on the other side and opted out because it was hard because the manifold is so close to that opening that I don't even think a AN fitting would clear. Hopefully this does the job, and if I ever can get the car running I will keep you posted. This is obviously better than PVC valve so we'll see.
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My catch-can set-up was a failure:
http://i51.tinypic.com/dhd381.jpg With extreme left cornering around 1.3 G's I'm shooting oil through the passenger side line and filling up the can, I blame this on the oil feed being too close to the baffle port. I'm going to run one side only and see what it does, maybe two ports on that side if I need too. I think the secret is to keep the baffle orifice close to the center of the cover so oil can wash around the sides and not go into the ports, and keep it away from the front and rear. After looking at this: https://www.miataturbo.net/attachmen...7&d=1281308001 I think that hard cornering, with acceleration is what made the oil come out. hmmm... |
hmmm ... you're making me rethink my set up - fortunately I haven't bought/fabricated anything yet.
Did you add any filters/'scrubbers' to try to slow the sloshing? I was going to mount my catch can to the front of the cam cover since my thermostat housing is gonzo and I've got the space there. I planned on mounting the catch can (a 2"x6" extrusion with internal baffles, 2 10 an lines on top and a port on the opposing side post baffle/filter to draw a vacuum) up higher than the cam cover ports so the oil would have to at least travel 'up hill'. It seems a lot of the set ups on here are lack a 'torturous path' - something which has solved many fluid ingress issues. I suppose if oil gets in the line and blow-by pressurizes the line then a torturous path doesn't do no good. In for updates before I waste time/$. FYI on your october post - Earls makes black hard coated tight 90's. I ordered mine from anplumbing.com. They're a pretty good vendor. -Zach |
Originally Posted by hustler
(Post 660145)
After looking at this:
I think I made pictures - will have to find those and post later. P.S. Another thing is to make sure the baffle covers are well sealed with some gasket maker but I assume most already know that. |
Nevermind, levinubbhjin posted this stuff already.
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So, as I was lying in bed last night waiting to come down from Saturday night's meth binge, I thought of a quick and easy test to see if one's valve cover is ventilated enough.
Wrap your lips around one of the hoses that leads into your VC and blow hard. Feel if there is resistance and you can also check to see if there is a lot of air coming out the other port in your VC. A more scientific way to do this could be to use a bike pump or air compressor on one side with a pressure gauge on the other. Anyways, the mouth test might quickly show if the ports or the baffled passages just do not flow enough air. I haven't done this yet on my stock VC w/ stock ports but I will try it and report back. |
I am now running the passenger side port plugged and one -10 line from the drive's-side location with success at the track. I'm getting cappuccino in the can bust still blowing a minute amount of oil through the filter, not enough to add oil though. I will put steel-wool in the can and see what happens. It looks like I'm done working on it though.
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So you don't have anything in your can? No baffle, no stuffing to capture the oil vapor?
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Originally Posted by m2cupcar
(Post 665549)
So you don't have anything in your can? No baffle, no stuffing to capture the oil vapor?
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on boost (11psi on a stock 1.6 engine), I'll have the oil catch can filling up mighty fast and it overflows (Carbing 0.6l oil tank).
I've got a hose connecting the crankcase breather on the (US) Driver side of the cam cover and a hose to the breather on the lower block, just slightly below the right of the oil filter. These 2 are connected by a T-connector to 1 inlet of the oil catch, with the other vented to air. My PCV valve is still plumbed back to intake. Any suggestions to prevent excessive oil loss? |
The lower port on the intake side of the block also fills my catch can up. I am going to try a new set up though where that will become the return for the catch can since the valve cover ports don't blow any oil out.
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Originally Posted by tyson87
(Post 666420)
The lower port on the intake side of the block also fills my catch can up. I am going to try a new set up though where that will become the return for the catch can since the valve cover ports don't blow any oil out.
I'm thinking whether I should use a separate oil catch can for the lower breather tube. I once connected the PCV breather and Crankcase breather on the valvecover by a t joint to my oil catch can. when I did this, i got oil spill pretty bad. After plugging the PCV back to intake and the crankcase side to the oil catch, i never ever had to empty my oil catch can... |
Originally Posted by tyson87
(Post 666420)
The lower port on the intake side of the block also fills my catch can up. I am going to try a new set up though where that will become the return for the catch can since the valve cover ports don't blow any oil out.
I’m considering venting both sides of the valve cover and the block and adding a drain back line to the bottom of the pan below the oil level. Bob |
On Matt Andrews' car were were filling-up the catch can through the oil pan "return" port at Big Willow.
What is this "breather port on the lower part of the block"? My car seems to be fine with it's current set-up so I'm not going to touch it unless a problem develops on one of the tracks with a huge sweeper where I stand on the loud pedal. |
Originally Posted by hustler
(Post 666567)
On Matt Andrews' car were were filling-up the catch can through the oil pan "return" port at Big Willow.
What is this "breather port on the lower part of the block"? __________________ Best Car Insurance | Auto Protection Today | FREE Trade-In Quote |
1 Attachment(s)
Originally Posted by hustler
(Post 666567)
On Matt Andrews' car were were filling-up the catch can through the oil pan "return" port at Big Willow.
What is this "breather port on the lower part of the block"? My car seems to be fine with it's current set-up so I'm not going to touch it unless a problem develops on one of the tracks with a huge sweeper where I stand on the loud pedal. On my 1.8l block I drilled a hole in it at the same location taped in a -10 AN to 1/2" pipe port and JB-Welded it in place. It gets a lot less oil coming out than a port than the one I had placed in the pan placed in the front of the pan above the oil level. The line I had going to the pan would create a huge mess after hard braking and high revs. I think if you have a return it needs to stay fully submerged below the oil level in the sump to keep it from puking oil back up. The 323 GTX’s that had the block breather port also had a similar ~5/8” metal tube cast into the oil pan at the bottom of the sump for a return I assume. I also assume they had an oil separator catch can in versions of the car without PCV systems that properly vented the crank case to atmosphere and yet kept all the oil in the engine. Pic below shows both the block brether port and the return port on a 323 GTX. Both are unused on a car sold with a PCV system instead of a breather system. Bob |
I've thought about tapping that and adding a line with a 1-way valve there.
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Originally Posted by hustler
(Post 666593)
I've thought about tapping that and adding a line with a 1-way valve there.
Bob |
Originally Posted by hustler
(Post 666593)
I've thought about tapping that and adding a line with a 1-way valve there.
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Originally Posted by bbundy
(Post 666611)
With a 1 way valve it either wouldn’t behave as a breather or it wouldn’t behave as a drain back take your pick.
Bob |
Originally Posted by hustler
(Post 666614)
I'll take the drain back. At some point that port will be submerged on a left-corner and it will push oil up the hose. I think this is where BMW L6's and Honda motors get a break considering their slant...a port at the top of the pan on the slant.
Bob |
Originally Posted by bbundy
(Post 666502)
I think the vent on the side of the block needs to stay a vent. A return from the catch can need to return below the oil level in the sump. The 323 GTX's blocks that had the vent already in the side of the block also came with an oil pan that had a metal pipe sticking out of it for a return at the very bottom of the pan. In countries where PCV systems were mandated they didn’t use the vent or the return and just put a cap on them. Sometime in the 80’s everything went to PCV systems eliminating traditional crank case venting systems.
I’m considering venting both sides of the valve cover and the block and adding a drain back line to the bottom of the pan below the oil level. Bob If this is the case, can I just tap the 'outlet' port on my oil catch can, ie, the one currently venting to air, to the turbo oil return line to the sump?Or am i missing something? |
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