The Mighty 258 > Emissions/Vacuum Systems

PCV Modification/Upgrade

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ammachine390:
My 258 always seemed to have too much blowby, it would blow the oily fumes into the air cleaner. This would cause the air filter to get all oily and dirty, and eventually there would be oil puddles in the air cleaner.  One solution is to use the Envalve, but that costs $58. My solution was to take the normal pcv valve, and cut the very bottom of it off, and remove the valve components on the inside. This keeps a constant vacuum on the crankcase. I then took an and old air injection check valve and put it on the breather line so that the crankcase holds the vacuum, but if there is a time when the vacuum drops too low, it will still be able to vent the pressure. So far it's been working, the air filter has been staying clean, and my acceleration has improved.  Also, thanks to JayRamb who provided with some answers about his experience with the envalve.

Here's a pic of the check valve setup.

68AMXGOPAC:
Interesting - good idea - and such. What was Jayramb's prognosis of the N-valve ??I had been considering one. Now I wonder if I have a air system check valve around.......... thanks.

ammachine390:
AFAIK, JayRamb was very satisfied with the Envalve. I think the check valve might be leaking some vacuum, but it's very minimal (almost like a regular pcv valve would pull fresh air in) but I might take it off and see it how it works without the valve and just have the system totally sealed.  When the crankcase is totally sealed, and the engine is idling pulling about 21 inches of vacuum, the crankcase would hold a steady 8 inches, even while accelerating the engine. I never got the crankcase close to presurized, so I think the check valve may be unnecessary, I put it on as a "just in case" while testing. So far, it looks like it has never had to vent.

shaggimo:
Nice alternative cheap solution! I run two pcv valves in my I6's (er, well, ok, in Eaglegirls 258, and my 4.0, lol), hers and mine had some excess pressure too, some problem has ceased.

ammachine390:
Here's a pic of how I cut the pcv valve to allow constant flow.

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