misery motorsports

just a question for you LS guru's
I have a 2005 ls2 408 stroker big custom grind cam .650 lift with ls3 cnc ported heads, decked 11.1 compression victor jr intake, quickfuel race Q850 carb !! it boot scoots and boogies but just like before I had it built its blowing oil out of the valve cover breather's !! is there some setup or something i'm missing? I know Ls engines build a lot of crankcase pressure especially stroker motor's do I need a vaccum pump or something to pull the vaccum rather then just a clear hose and breather/filter?

Pop N Wood

iTrader: (1)

Seems like a pretty common complaint for guys trying to run simple breathers on the valve covers.

If you don't want to run a PCV, and your motor may overwhelm one of them anyway, then you can try some type of vented catch can. This will at least keep the mess out of your engine bay. i think 3pedals had a thread recently of a cheap one that he found.

The other option I have always found interesting is this Moroso evacuation unit. Uses exhaust flow to draw a vac instead of a vac pump.

http://www.jegs.com/i/Moroso/710/25900/10002/-1

newschool72

iTrader: (12)

I think it was Doug G that had the thread, Pop. But anyway, if its a street engine , don't run the Moroso unit. At part throttle the back pressure from the exhaust can send pulses of spent fumes back into the crank case. If its a race only setup with very free flowing exhaust, the system is suppose to work fairly well. Like Pop said, the vented catch can should work better than the straight vent in the cover. It will at least give the oil a place to "fall out" of the crankcase pressure before it escapes onto your headers.

fast89stang

iTrader: (2)

I have the header evac. Picked up a tenth with it, pulls awesome vac, and i have bullet mufflers.

newschool72

iTrader: (12)

That's interesting that you picked up a 10th with the evac system. Did you have a PCV setup before the evac deal? Or was it just from less resistance on the back side of the pistons? I saw an article on a hot 408 SBC build and they picked up close to 20 HP with a better windage pan and the pump style crank case evac system. It was a pretty radical build that turned up into the 7K range with a big solid roller. If I remember right it made around 650ish HP.

fast89stang

iTrader: (2)

I just had the system vented before. It never puked oil, I just knew i have always picked up switching to it on my other combos. I dont know how it works at wot, but at idle, it will suck a dollar bill up to the oil fill hole and if you rev it slightly, it will try and suck it in the engine. I dont think its as good as a vac pump, but works and is lots cheaper. OH and btw, it never smokes on the big end. I have the cheapo ebay fab'd valve covers and we put the ports in for the hose, and welded in our own baffles.

TXsilverado

iTrader: (18)

you have a breather on each valve cover? mine is set up in a more factory style. breather on passenger valve cover and a vacuum line to the intake from the drivers side valve cover...or in my case, a vacuum line from the LS6 valley cover.

Luke_Siebert

With the proper hone, rings, and piston design, this should not be an issue. Have you done a leak down test?

fast89stang

iTrader: (2)

I have no breather. Just a fitting welded to valve cover with a baffle inside.

Doug G

Yes, I had similar issue and added a breather to the oil fill cap, then found a cheapie baffled breather (un-tested yet) that I ran both PCV lines to, to "free vent" (no vacuum).
Oiled down track fist pass before any breather due to it pushing oil dip stick.
Next time at the track....no oil down or cloud with just oil cap breather.
Added the catch can for extra precaution
This was on a fresh built LY6.