PCV valve on flatty
Thread Starter
|
Posting Guru
Joined: Sep 2004
Posts: 1,616
Likes: 3
From: Sapulpa OK
PCV valve on flatty
I tried to tune my new rebuilt flathead that I had installed a PCV valve underneath the manifold. I couldn't get to idle very well and I figured the PCV valve I used was too large. It was for a Chrysler V8 and I suppose it flowed too much. I bought a smaller one,sized for a Chevy V6, about 193 cu. in. I had to redesign the works to accommodate the newer valve and this is what I came up with.
The billet connector pipe is only drilled on the bottom half thereby blocking off the road draft tube. I will leave the road draft tube in place for looks.
I should have it back together tomorrow. I'll post the results then.
I hope the picture shows up.
The billet connector pipe is only drilled on the bottom half thereby blocking off the road draft tube. I will leave the road draft tube in place for looks.
I should have it back together tomorrow. I'll post the results then.
I hope the picture shows up.
Fleet Owner
Joined: Jul 2004
Posts: 27,290
Likes: 1,055
From: NM
Not sure exactly how that works, Steve. Is the 3/8" Tee blocked on the top side? Or does it connect to the manifold? I suspect the smaller tube is actually where the gases flow? Or is that a balance tube?
Some PCV valves have to be mounted vertically to work correctly, not sure if that's the case with this one.
If this is your first fire-up on the flatty, don't jump to any conclusions. Mine has changed dramatically after the first couple hours run time, as the rope packings fit themselves to the crank, the rings seat, etc. I've had to change the mixture screws 3 or 4 times as it beds in. Idle speed went up 300 RPM after the first hour, with no other changes! Don't forget to re-torque the heads, too, at the first re-torque the bolts were down around 40 ft-lbs.
Some PCV valves have to be mounted vertically to work correctly, not sure if that's the case with this one.
If this is your first fire-up on the flatty, don't jump to any conclusions. Mine has changed dramatically after the first couple hours run time, as the rope packings fit themselves to the crank, the rings seat, etc. I've had to change the mixture screws 3 or 4 times as it beds in. Idle speed went up 300 RPM after the first hour, with no other changes! Don't forget to re-torque the heads, too, at the first re-torque the bolts were down around 40 ft-lbs.
Thread Starter
|
Posting Guru
Joined: Sep 2004
Posts: 1,616
Likes: 3
From: Sapulpa OK
I am feeding vapors into two intake runners. I thought that the original port on the carb would see vacuum from all eight cylinders so I reasoned tapping both runners would approximate flow from all eight cylinders. We will see.
Just got it all back together today and will try to run it tomorrow.
Just got it all back together today and will try to run it tomorrow.
Thread Starter
|
Posting Guru
Joined: Sep 2004
Posts: 1,616
Likes: 3
From: Sapulpa OK
Looks like this will work. I got it running this morning and dialed everything in and it was able to idle relatively smooth considering the cam. It varies between 750 & 800 RPM. It accelerates smartly too and starts immediately.
Now back to the bodywork. Ugh!
Now back to the bodywork. Ugh!
Thread
Thread Starter
Forum
Replies
Last Post
