PCV vs EVac

AveryMcLawhorn · 02-23-2021, 10:34 AM

Any suggestions for 283 SS motor. Trying to figure out which path to go.

bykr · 02-23-2021, 12:55 PM

Evac. I don't see why you 'd want to put blowby into the intake.

Mark Yacavone · 02-24-2021, 12:15 AM

Quote:

Originally Posted by bykr

Evac. I don't see why you 'd want to put blowby into the intake.

Crankcase vacuum.

Actually, you need both. One breather goes to back of carb. The other goes to a Y and to both collector probes.
Now you've got suction at all times, one way or the other.
If it really works good , you can turn the seals around on the crank ;-)

All you need then , is a crankcase vacuum port and a gauge. That gives you something else to look at in the lights :-)

bykr · 02-26-2021, 08:40 PM

Quote:

Originally Posted by Mark Yacavone

Crankcase vacuum.

Actually, you need both. One breather goes to back of carb. The other goes to a Y and to both collector probes.
Now you've got suction at all times, one way or the other.
If it really works good , you can turn the seals around on the crank ;-)

All you need then , is a crankcase vacuum port and a gauge. That gives you something else to look at in the lights :-)

So the increased crankcase vacuum ( better ring seal ?) offsets the intake charge dillution?

Dave Noll · 02-26-2021, 09:48 PM

For years I had a separator in the vacuum line between the carb and valve cover of my Cleveland. I've never had to drain any oil out of it.

Mark Yacavone · 02-26-2021, 10:12 PM

Quote:

Originally Posted by bykr

So the increased crankcase vacuum ( better ring seal ?) offsets the intake charge dillution?

It should anyway.
I'll take a controlled vacuum leak anyway I can, in a limited induction class...That goes for choke heat passages and hot idle compensators too ;-)

e vassar · 03-02-2021, 09:41 PM

So when I had my carburetor car...I had a idea to create as many vacum leaks as possible, and jet up to compensate, the engine would run like it had a bigger carb. I was told NO...they will check for that.

Mark Yacavone · 03-02-2021, 10:06 PM

Quote:

Originally Posted by e vassar

So when I had my carburetor car...I had a idea to create as many vacum leaks as possible, and jet up to compensate, the engine would run like it had a bigger carb. I was told NO...they will check for that.

Yes, intentional vacuum leaks are illegal.
What I mentioned come from the factory that way... ;-)

02-23-2021, 10:34 AM	#1
AveryMcLawhorn Junior Member Join Date: Nov 2020 Location: Snow Hill, NC Posts: 49 Likes: 62 Liked 80 Times in 19 Posts	PCV vs EVac Any suggestions for 283 SS motor. Trying to figure out which path to go.

02-23-2021, 12:55 PM	#2
bykr Member Join Date: Jan 2014 Location: SoCal Posts: 232 Likes: 274 Liked 167 Times in 81 Posts	Re: PCV vs EVac Evac. I don't see why you 'd want to put blowby into the intake. __________________ Tim Schmackpfeffer 762 SS

02-26-2021, 09:48 PM	#5
Dave Noll Senior Member Join Date: Nov 2007 Location: Div. 6, Eastern, WA Posts: 710 Likes: 2,676 Liked 240 Times in 112 Posts	Re: PCV vs EVac For years I had a separator in the vacuum line between the carb and valve cover of my Cleveland. I've never had to drain any oil out of it. __________________ Dave Noll, EF/S ,?/SA 6526

03-02-2021, 09:41 PM	#7
e vassar Member Join Date: Jul 2015 Posts: 382 Likes: 67 Liked 271 Times in 107 Posts	Re: PCV vs EVac So when I had my carburetor car...I had a idea to create as many vacum leaks as possible, and jet up to compensate, the engine would run like it had a bigger carb. I was told NO...they will check for that.