How much discharge is normal to see coming out of the ccv tube?

When I say discharge... I mean the gasses floating off in the air.

 

I think it varies. But as long as it is a steady stream and not puffing you should be good. I get a pretty good cloud coming out.

 

Mine is very visible coming out, in fact people look at it and say, 'your truck is smoking'

I just say I know, and dont go into a long diatribe about what it does.

 

Mine's the same as the two above. It looks like a tiny exhaust hose (which I guess it essentially is) running under the truck.

 

Temperatures and oil types will affect how much "visible" smoke you see out of the CCV, but the visible smoke is not an indicator of the actual amount of blowby.

 

how can I measure the blowby?

 

Like this:



Make sure the cap doesn't physically blow off.

(Man, I'm getting a lot of usage out of this simple vid!! )

 

Great visual tool, Joe. Thanks.

 

I've read that Ford has some sort of "CFM gauge" for measuring the blow by CFM but I've not seen any pass/fail CFM spec numbers for blow by CFM. Considering that blow by occurs on 3 out of the 4 strokes my "guess" is that the blow by CFM might be 10 CFM or higher at WOT full load and that's assuming a 1% leakage past the rings.

Ford has a crankcase pressure test that's used as a quick way to diagnosis excessive blow by and if the engine fails this crankcase pressure test the engine is considered to be in such bad condition that a compression test would be a waste of money and Ford recommends a rebuilt engine be installed.

What I've read about this Ford crankcase pressure test is that the stock CCV is sealed off completely at both the doghouse and CCV coupler ends and the engine is run at WOT in neutral for 30 seconds with a special oil cap installed which has a small vent in it to allow blow by to pressurize the crankcase and the resulting crankcase pressure to bleed off at a calibrated rate. When done in this manner the Ford spec for an acceptable amount of blow by is a maximum crankcase pressure of less than 4.0" H2O which is less than 0.145 psi.

On another forum a Ford tech posted that... "My Ford 2000 7.3L Powerstroke Diesel Powertrain Control/Emissions Diagnosis Manual, page 4A-54 says anything less than 4" H2O, at WOT under no load, is OK. The test is performed by sealing off the breather and putting an orifice restrictor adapter in place of the oil filler cap. The engine is run WOT for 30 seconds and if less than 4" H2O the engine is ok. The restrictor has a small hole so they can backup pressure and vent it at a calibrated rate. I do not know how small the hole in the restrictor is. Any Techs have access to a crankcase orifice restrictor tool 014-00743 that can measure the restrictor hole for us?"

Here's some pictures of how I instrumented my old F350 to measure the crankcase pressure so I could keep tabs on the CCV hose and on the blow by in general especially when towing long steep grades at WOT. Basically you install a fitting for a 1/4" ID plastic hose on the oil filler neck and run the hose to a 10" H2O gauge in the cockpit. In the picture below the gauge on the left which reads from 0" to 10" H2O...



...was connected to the hose going to the oil filler tube in this picture...



With my CCV design I had a crankcase pressure of 0.7" H20 at idle and 3.0" H20 at WOT full load which indicates that my rings were sealing well. A new engine exhibits about a x4 increase in crankcase pressure from idle to WOT full load.

Using a gauge with a 10" H2O scale allows for some needle bounce which you'll get under some load conditions and for increased readings due to engine wear. An older engine nearing the end of its service life exhibits higher crankcase pressures at all throttle positions and about a x8 increase in crankcase pressure from idle to WOT full load.

A crankcase pressure gauge is a good way of monitoring the general health status of your engine. In addition to monitoring your CCV performance you can... 1) monitor the wear/failure of the piston rings, 2) monitor the wear/failure of the turbo bearing seal which prevents hot exhaust gas from entering the crankcase via the oil drain hole, and 3) detect head gasket leaks that allow combustion pressure to leak through oil drain holes into the crankcase.

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