[DeTomaso] Crankcase Ventilation, and Open Valve Cover Vents

[cengles at cox.net]

Dear Chris, 

This "expert" says that the last engine I built with just breathers because "why would would you want to burn nasty oil vapors instead of high octane plus air?" sounded plausible. It seemed to have more steam and oil mist from the breathers than I cared for. 
I recently did an online review of basic PCV information and I am now convinced that a PCV valve arrangement for the current engine build is a benefit. It will have one. 

Regarding a PCV in a supercharged engine, there is a forum for supercharged Pontiac Grand Ams ( I think ). They had an extensive debate, argument, discussion about the advantages and disadvantages of a PCV in a supercharged Pontiac engine. More than one person confirmed that with the PCV removed there was much more oil mist in the engine bay. The reported solution was a catch can for the oil. There seemed to be a great absence of any hard evidence for actual engine benefit in the non-PVC engines. All in all, I thought the bottom line was there was no harm to the PVC in a supercharged or normally aspirated engine. 

Warmest regards, Chuck Engles


---- Chris Difani <cdifani at pacbell.net> wrote:
>Guys:
>
>And once again I come to THE panel of experts, to ask for their collective wisdom....
>
>
>..... and if that isn't a scary thought, I don't know what one is!
>
>
>Okay, now for my actual question.
>
>Since my Pantera L is a 1973, I don't need to worry about smog equipment, smog inspections, or any of that stuff... even if I am in California. HOWEVER, I'm wondering if there is an actual benefit to using a PCV valve, or any of the other "mild" versions of smog control that is found on our older engines.
>
>In my particular case, with a 2003 Ford Modular engine that's supercharged, and all electronically controlled, I _can_ plumb the engine with all the original style valve cover vent plumbing. But I don't want to, and the only way I'll do it is if there's a really good reason to do so, a "better performance" reason. Right now I'm seriously contemplating installing a pair of valve cover vents, and that's it. Nothing else.
>
>The original system had a "controlled" vent on one valve cover, and the other valve cover connected to the lower intake plenum (below the supercharger) via an AN8 size hose routed thru an air-oil separator. If they didn't have the air-oil separator, the intake plenum would accumulate a small oil slick over time... and extreme use.
>
>And just for general information, and to carry on this valve cover thread, my oil drain back holes consist of four holes in each head, that are 5/8" in diameter. They're straight thru to the crank case. Since this is an overhead cam engine, I have no lifter holes, or valley holes. My only drain back capacity are the four passages in each head.
>
>Thanks,
>
>Chris
>
>Chris Difani
>'73 L #5829 "LITNNG"
>The Electric Pantera
>Sacramento, CA
>Email: cdifani at pacbell.net
>