I thought about that afterwards. So much pressure would cause it pour into the crank case instead of vent out. You would need a good check valve. The way Chris did it seems like the way to go!

 

Napa and Pepboys told me they cant look up Crankcase Valve cover O-rings, weird.

Anyone have numbers or know what size they are? I cant really take mine off and drive to Napa...

 

Guzzle's got em!

Replacement O-rings for Diesel Engines

 

1.25" ID

1.5" OD is the size

1/8" width

 

Yup -- that's them. Mine were shot when I did my CCV -- they looked just like the pics above. I found a pair at Discount Autoparts. No problems since.

 

You guys rock

 

No matter how you plumb a CCV hose into the exhaust it's a bad thing to do. A check valve increases the crankcase pressure even more to overcome the restriction of the check valve plus the pressure in the tailpipe and the valve would quickly get clogged up with oil anyway and either stick closed or open or somewhere in between!

If you plumb a CCV hose into the exhaust without a check valve this is what I think happens....

Before you start the engine the pressure in the crankcase and the pressure in the tailpipe where the CCV hose is connected are both 0" H20 gauge. Then when you start the engine and let it idle there's only about 0.2" H20 gauge pressure in the crankcase due to the small amount of blow by gases past the rings at idle and about 10" to 30" H20 gauge pressure in the tailpipe where the CCV hose is connected.

This 10" to 30" H20 gauge pressure difference initially forces corrosive exhaust gases from the tailpipe back up the CCV hose and into the crankcase which subjects all the oil seals to the higher pressure in the tailpipe and contaminates the oil as well.

Then when you place the engine under load the higher amount of blow by gases will increase the crankcase pressure to a high enough value (about 30" H20 gauge or more) to force the blow by gases along with the backed up exhaust gases and some of the crankcase oil out into the tailpipe.

Then each time you let off the throttle the pressure in the crankcase due to the blow gases is reduced to a low enough level to once again allow some exhaust gases to back up into the crankcase and containment the oil some more, and this process is repeated each time you get on and off the throttle until you shut the engine off at which point I would expect to see plenty of oil in the tailpipe where the where the CCV hose is connected!

I instrumented my old F350 with a cockpit gauge that read from 0" to 10" H20 so I could measure the crankcase pressure to keep tabs on the CCV hose and on the engine's blow by in general especially when towing long steep grades at WOT. For a properly designed CCV mod that vents the CCV hose to the open atmosphere the amount of blow by from a healthy engine shouldn't cause more than a 4" H20 crankcase pressure when towing up a hill at WOT.

The following is just a sample of what's been posted on this subject...

CCV into exhaust.
https://www.ford-trucks.com/forums/7...o-exhaust.html

CCV mod into exhaust?
https://www.ford-trucks.com/forums/7...o-exhaust.html
CCV into exhaust is creating pressure
https://www.ford-trucks.com/forums/6...-pressure.html

 

Thanks again Gene for summing that up, can't get better reading than that.

 

I bought my dog house O-rings at the local hardware store super cheap. Not trying to take business away from guzzle, but if you are in a pinch and need them ASAP they are available at any good hardware store- mine were in the plumbing section somewhere.

 

I hear ya. I totally forgot about those o-rings until I got everything apart. Being impatient like I am, instead of ordering them from guzzle, I hit the local Home Depot five minutes away and continued on with the mod. If anyone is deciding to do the CCV mod, just plan ahead and assume that yours are shot.

 

When I do mine I will grab some from the fire company. We have a TON of O rings.

Anyone have a peice of 4" there not using?

 

Agreed, new O-rings are cheap insurance.

 

Wow good to see all the response to the CCV exhaust question. After thinking about it for a little bit I realized it was a bad idea. However, it is nice to know the science behind it. Thanks guys!!

 

Well here's some more light reading on the subject. I replied on another forum to this issue and that motivated me to try and explain it better as you can read below...

And Pocket knows all too well that I enjoy analyzing things and trying to explain why they do or don't work so among other things I'll try to explain why venting the crankcase to the exhaust can work for gassers but not for diesels.

Both the Bernoulli effect and the Venturi effect have been cited as reasons why hooking a CCV hose to a special fitting in the tailpipe will cause a lower than atmospheric pressure in the crankcase. At first glance this seems like a reasonable assumption because the Bernoulli effect states that... "as the speed of a moving fluid increases the pressure within the fluid decreases and the fluid can be either a liquid or a gas"!

Well the exhaust gas flows through the tailpipe at a considerable speed so the Bernoulli effect says the pressure within the exhaust gas is lower than if wasn't moving at all and that as the exhaust gas speed increases the pressure within the exhaust gas gets even lower, but the key here is how much lower and lower than what reference? In order to vent the crankcase the pressure within the exhaust gas has to be lower than atmospheric pressure!

I'll try to explain the Bernoulli effect and the Venturi effect in terms of the air flowing through a stock CCV tube and into the turbo inlet, and in terms of the exhaust gas flowing through a tailpipe and out into the atmosphere. Even though these are similar situations they're different enough that venting the crankcase to a stock CCV tube causes a lower than atmospheric pressure in the crankcase whereas venting the crankcase into the tailpipe causes a higher than atmospheric pressure in the crankcase.

When a 70 F room temperature mass of air is stationary all of the air molecules are in random thermal motion with a random velocity of Vr=920 mph and the air molecules exert a static pressure of Ps=14.7 psi by bouncing off of everything they come into contact with. This Ps=14.7 psi is due to their Vr=920 mph random velocity.

Now if this mass of air is flowing with a directed velocity of Vd=60 mph then all the molecules are moving along a given direction at Vd=60 mph and they exert a dynamic impact pressure Pd on any object they encounter. If you put your hand out the window at 60 mph with the palm facing forward perpendicular to the air flow your hand feels a dynamic impact pressure of Pd =0.0627 psi=1.735" H20!

That probably seems like a surprisingly low pressure for 60 mph but if your hand measures 5"x7" there's a {(5)(7)(0.0627)}=2.2 lb force pushing it backwards and if your arm is 3 feet long that's a 6.6 lb-ft TQ trying to rotate your shoulder!

The point of this is that stationary air only exerts a static pressure Ps whereas moving air exerts both a dynamic impact pressure Pd and a static pressure Ps and the increase in Pd comes at the expense of a decrease in Ps! In addition to their directed velocity Vd the molecules in moving air are also buzzing around in a random way with a random velocity Vr that's just slightly lower than the previous Vr=920 mph when the air was stationary.

This slight lowering of the random velocity Vr in moving air is necessary to maintain the total Kinetic ENERGY KE=1/2mVr^2+1/2mVd^2 in the moving air mass at the same valve as the KE=1/2mVr^2 in the stationary air mass. This slightly lower Vr causes a slightly lower Ps which is the Physics explanation of the Bernoulli effect that the static pressure within a mass of moving air is lower than the static pressure in a mass of stationary air containing the same total Kinetic ENERGY.

Bernoulli's Principle says that the total pressure Pt in an air mass which is due to its total Kinetic ENERGY is given by Pt=Ps+Pd and that as the air moves faster the Pd gets higher the and Ps gets lower so as to maintain the Pt constant.

You can estimate Pd from... Pd={(Vd/Vr)^2}{Ps}={(60/920)^2}{14.7}=0.06252=1.730" H20, and the exact equation for Pd is... Pd={(AD)(MPH^2)}/{155.62} Inches H20 where AD is the Air Density lb/ft^3. At 70 F and 14.7 psi the AD=0.075 lb/ft^3 so the Pd at 60 mph is Pd={(AD)(MPH^2)}/{155.62}={(0.075)(60^2)}/{155.62}=1.735" H20=0.0627 psi. For stationary air Pt=Ps=14.7 psi and this is the same Pt for the moving air so the new Ps=Pt-Pd=14.7-0.0627=14.6373 psi, and the difference in the static pressure within the moving air relative to the static pressure within the stationary air is Pd=0.0627 psi=1.735" H20.

In order to get a better feel for the relatively low pressures we're dealing with here consider that the pressure inside a 9” latex balloon is approximately 30" H20 higher than atmospheric pressure and that the typical human can exhale a maximum pressure that's about 40" H20 higher than atmospheric pressure!

The pic below is a model for the stock CCV tube. The static pressure within the mass of stationary air outside the air filter is P3=14.7 psi. Assume a tube diameter D1=4" with an air flow of 460 cfm which works out to a V1=60 mph. Now P1 is the static pressure within the mass of moving air and as before P3-P1=Pd=0.0627 psi=1.735" H20, and this lowering of the static pressure in the moving air by 1.735" H20 is the Bernoulli effect!

Downstream the tube narrows from a diameter D1 to D2 so that the cross sectional area reduces from A1 to A2 which increases the flow velocity to V2={(A1/A2)}{V1} and since the Pd~(V2/V1)^2 this means that P2~(A1/A2)^2 so P2 is given by P2={(A1/A2)^2}{P1}. Since (A1/A2)=(D1/D2)^2 the P2={(D1/D2)^4}{P1}.

If D2=3.5" then P2={(D1/D2)^4}{P1}={(4.0/3.5)^4}{1.735}=2.96" H20. Having P1 less than P3 and P2 less than P3 are both examples of the Bernoulli effect, and having P2 less than P1 is an example of the Venturi effect. According to Racor hooking a CCV hose to P2 and getting a 3" H20 "vacuum" would be just right for venting a crankcase, but as we'll see life isn't quite that simple!



The pic below is of my stock CCV tube and notice that the narrowed down Venturi section in it has a scoop that's pointing back into the incoming air flow! The reason for the scoop is to cancel the Inches H20 restriction of the air filter versus cfm flow. If you just hooked a CCV hose to P2 you'd be getting a 3" H20 pressure drop due to the Bernoulli effect plus up to an 18" H20 pressure drop due to the restriction of the air filter and a 21" H20 "vacuum" is way too much to safely apply to a crankcase.

I took measurements of my stock CCV while towing and it does a very good job of regulating the negative pressure applied to the crankcase to between -2" H20 and -7" H20 maximum at WOT full load. If it wasn't for blowing my turbo boot twice I'd never have considered doing a CCV mod to begin with!



Look at the first pic again and imagine that it's now a tailpipe with the turbo end vented to the P3=14.7 psi atmosphere pressure and exhaust gas being forced to flow into the air filter end under a pressure that's about 30" H20 higher than P3. Now the few inches of H20 pressure reduction within the exhaust gas due to the Bernoulli effect is relative to the exhaust inlet pressure which is 30" H20 above 14.7 psi so you wind up applying a 25" H20 or so pressure to the crankcase.

Here's how I think the device below works in a gasser that's set up with header pipes which are combined into a collector pipe.

6002 - Mr. Gasket Crankcase Evacuation System
Mr. Gasket :: Instruction Sheets

Click on 6002 to see a copy of the installation instructions...
http://www.mr-gasket.com/pdf/6002.pdf

Note the step #5 in the installation instructions above regarding the placement of the angled tube in the collector as is shown below. Those directions are very explicit concerning where the angled tube must be placed and how far it should extend into the collector pipe for various diameter collectors. Evidently someone's done some measurements and determined that the tube needs to be inserted about 40% of the collector radius. These directions also say to install a one-way check valve in each angled tube!

I think each of the header pipes is like a shotgun barrel and that each exhaust stroke is like a shotgun blast into the collector, and each blast produces a very intense pressure pulse that's of short duration and each pressure pulse is followed by a trailing low pressure tail that's of considerably longer duration and below atmospheric pressure. The angled tube is positioned to intercept these negative pressure tails and the check valve is to insure that the high pressure pulses don't enter the crankcase.

In a diesel with a turbo the exhaust manifold smoothes out the individual exhaust pulses so that they all run together and become an even flow at a more constant pressure. Then compared to the gasser the residual spent exhaust following the turbo essentially trickles down the tailpipe to where people install their CCV angled tubes.