[Healeys] crank case ventilation

Bob Spidell bspidell at comcast.net
Wed Mar 17 06:51:35 MST 2010


In this case, 'closed' doesn't mean 'sealed.'  It means the system is 
continuous, with an intake--the filter--and an output--the PCV valve 
into the manifold.  That's how OEM PCV systems work (see: 
*http://tinyurl.com/yajrlzb )*.  To truly breathe, you need an inlet 
vent (the 'V' in PCV is for 'ventilation').  Ever try pouring gas from a 
can without opening the vent hole?   Pulling a significant vacuum means 
you're not circulating the gases--the intent of a PCV system.  

This setup does work well as is, however (I have it on my BJ8).


bs



Alan Bromfield wrote:
> FWIW the PCV fitting as described is definitely a truly closed system.
> The vacuum can definitely be felt when you open the oil filler cap or
> lift the dipstick off the sealing washer. Also when air is admitted in
> that way, engine revs increase slightly as the air gets drawn into the
> crankcase or rocker box and then imto the inlet manifold.
>
> I am surprised that this mod hasn't been adopted more widely. It is a
> major contribution to solving oil incontinence in our 'mature'
> engines.
>
> On 17 March 2010 13:21, Bob Spidell <bspidell at comcast.net> wrote:
>   
>> That type/size filter is usually used on a PCV-fitted car as an intake
>> filter on a valve cover.
>> One possible problem with the PCV retrofit on a Healey is the PCV valve is
>> usually fitted to draw gases through the 'T' fitting on the valve cover.  An
>> exactly correct PCV installation would have the T fitting removed and
>> something like this on the valve cover so air would be drawn in through the
>> valve cover and gases--including blowby and air from inside the valve cover
>> that gets pulled down the pushrod holes--to be sucked into the intake
>> manifold (i.e. a truly closed system).
>>
>> I've considered this for my car but haven't tried it.
>>
>>
>> bs
>>
>>     
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Bob Spidell           San Jose, CA            bspidell at comcast.net

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