pcv valve

[james]

There can be harm running a PCV valve, if your engine is on the brink of detonation.  Oil mist is sucked into the intake tract with a PCV, and that makes the mixture more prone to detonation.  I never use PCV valves for that reason.  Also, use of the PCV valve does not automatically remove oil mist from the engine compartment, sometimes you will get mist out of the lone breather anyway.  A PCV valve will improve that situation in most cases, though.

A better,  albeit more complex solution to this issue, is to use a pan evac system, where the valve cover breathers are connected to tubes that run down to the header collectors.  In that case you don't have any crankcase openings to the engine compartment, so no oil mist, and no oil gets into the intake tract to encourage detonation.  Plus you get the added benefit of a few inches of crankcase vacuum.  I've had good luck running those systems on the street and at the track, but it's a lot more work to install.

I noticed a mist of oil in my 482 engine bay and a friend of mine at the car show recommende the following little number. http://mewagner.com/?p=444  Anyone know abou this?

[machoneman]

Pricey indeed and yes I've seen it before. Nice concept but for the $, much cheaper to experiment with a std. PCV valve and blocking the line (a chunk of plastic or aluminum rod) with a hole drilled in the plug, say a 1/4" hole. Idea is the same: control the level of vaccum the valve sees.

Or, just buy any maker's PCV valve for a '69-'70 Boss 302 engine as that valve has about the lowest spring pressure around. https://www.summitracing.com/parts/smp-v156/year/1970/make/ford/model/mustang/submodel/boss-302


'Course we just had a few posts on the pro/con use of a PCV valve very recently. If you have a a performance engine (worked over, hot, fill in your adjective) ideally you won't use a PCV valve at all and instead install a pan evacuation system to remove oil vapors.   

[390owner]

What would it do If I ran a hose from the vent to the air cleaner base. I have a chrome air cleaner and it has a spot for a hose to hook to. I think it is for the suction side but would it pull any air from the vent? Both vents caps are fogging when the engine is running just thought the air cleaner might keep it from fogging to much. I want to go with the exhaust set up but this if it works will be easy