Evac

[Oldschool]

Have a SBC with Enderle injection with bug (Alky). I have a evac system running from my exhaust ( see picture) . My question is will this work good enough for this set up ? I know some recommend a vacuum pump, but the dollars are a little short with getting this set up. One guy told me this would help cut down on milky oil.

[THE FRENCHTOWN FLYER]

I do not think it will work as well as routing it to a collector where it would see a signal from all eight cylinders instead of two. It may have trouble keeping up with the positive pressure build-up in the crankcase. Having said that - its on the car; try it. It may work well enough to work well enough.

[dreracecar]

Never run that setup with a blower motor

[olddiggersrule]

I have always wondered about those evac systems even on gas carbed to the collectors? Doesn't the crankcase pressure need to have a breather on the inlet somewhere? I've seen two lines to the headers and no place for air to enter the system? Additionally why would breathing oil in front of the slicks be a good idea?

[ricardo1967]

I have always wondered about those evac systems even on gas carbed to the collectors? Doesn't the crankcase pressure need to have a breather on the inlet somewhere? I've seen two lines to the headers and no place for air to enter the system? Additionally why would breathing oil in front of the slicks be a good idea?

'Air' enters the system through piston rings and valve guides.

[Roger]

I see you already have an oil separator on the valve cover and a check valve at an angle on the pipe. Should work I think. The oil separator will keep any oil out of the exhaust so none gets on the slicks while the system at rpm should draw 5” of vacuum, at least according to the info attached from a boat performance site. Look towards the bottom of the page on the site for the info.

          http://www.performanceboats.com/gn7-dyno/52702-header-evac-zoomies.html

Putting a breather on the engine with a pan evac system would do no more than draw air through the engine and would create no vacuum. The vacuum is used to reduce power lost to windage and to reduce internal pressure due to cylinder pressure leakage past the rings.

You could disconnect the evac line from the oil separator and put a vacuum gauge in the line, fire up the engine in the pits, and see how much vacuum you can pull. The boat article said he was pulling 3” when he hit the throttle while still on the trailer.

Let us know how the system works out for you. As long as the oil separators are working properly, I would think it’s safe.

[dreracecar]

The only way to know if this system works is by using a vacuum gage and moniter during the run. Jenkins came up with this almost 50 years ago while working with low drag 2 ring pistons to keep them from "fluttering" by putting a little negative pressure in the crankcase, after that it took on a life of its own.
 as far as milky oil, switch to "Brad Penn" brand oil, it will not emulsify with the alc like many other brands do

[Oldschool]

I run Brad Penn oil and really appreciate everyone's input.