Vacuum Pumps: Plumbing Arrangement

[skinny z]

I'm asking for a fellow racer who regularly thrashes his car at the dragstrip and autocross.
500+ HP 406 SBC. Nothing out of the ordinary.
The discussion has come up regarding incorporating a vacuum pump and how the plumbing is best arranged.
An electric pump is already in hand (I think scavenged off of a Ford in the junkyard).
Can anyone direct me to a layout? Or more than one layout if there's more than one way to go about it?
Thanks in advance.

[skinny z]

A look through ST yielded this:

001-acp-vacuum-pump-test.jpg

Looks straightforward enough.

[Dave B]

Screenshot_20240305-140158~2.png

Here is a perfect example of one that is pathetic. Line right on belt. Turn tank and get fitting away from belt. And raise filter as high as possible.

[brandonu]

Here's one a did a few weeks ago on a 408 Street BBC. I always try to pull from one valve cover, as high on it as I can and away from oil spray. I make a thin aluminum "bracket" to hang the can on that would get sandwiched behind the alternator or removed if the can will hang elsewhere. The bracket works well to hold it for dyno purposes.

[Dave B]

∆∆∆∆ I dont like them anywhere near the end of the rocker in the oil spray like you did yours. I dont even want mine in the valve cover period, but if i do its in front side not on top and near where rocker pivots at trunnion. Even with fitting blocked inside of valve cover, i still dont want mine there. i was at track awile back, guy was in big hurry between rounds setting lash. Cross threaded fitting from pump to vc.

[Dave B]

A look through ST yielded this:


001-acp-vacuum-pump-test.jpg


Looks straightforward enough.

i didnt even see vac pump ,just the 70 lb motor plate. Guys i build engines for have me taking 3 lbs off intake ,6 out of each head in mill. They would shit if i sent them a snow blade for a bobcat skid loader. i saw derby cars with less engine plate than that. lol

[prairiehotrodder]

i recently installed a product engineering vacuum pump on my BBC race engine. I bought it used with a few spare parts. I'm guessing the previous owner had a bad experience with it because it wasn't set up right. Mine mounts to the motorplate and uses a cog belt (not a v-belt) and i bought the crank mandrel pulley setup from jones racing. I pull from the top of drivers side valve cover and i have a vacuum port on the passenger side valve cover hooked to my AEM gage so i can data log the vacuum. I have a homemade bracket welded to the rad support that holds my breather tank which is just a cheap moroso unit. The whole system has worked very good for me and i don't have alot invested in it. I lost the pulley once because i didn't have a proper bolt holding it on, i bought a moroso pulley for it that was a much better design. i don't have a good picture.

Brian

DSC01578.JPG

[weedburner]

OP has an electric pump in hand, not a belt driven unit.

My journey started with a street/strip build that used low tension rings and went thru a lot of oil. Added the electric pump in an effort to improve oil consumption.

I used off the shelf circle track valve covers that came with fittings welded on for crossover breathers. I atached some hoses to those fittings an then ran those hoses to a homemade oil separator tank. An oulet hose from the separator tank then was plumbed to the electric pump inlet.



That initial setup fixed my oil consumption problem. Downside to the above setup was the pump running all the time, on 12v it drew enough amps to melt the solder out of the brush leads after extended use. I installed a ballast resistor to reduce voltage and the brushes were then happy but that reduced vacuum draw. Installed a switch so I could drive around town on low voltage, 12v at the track or when spraying. Here's the electric pump located behind the firewall...



From there, I installed a pcv valve in the top of the separator tank and also installed a header style evac check-valve on the electric pump's exhaust port. That allowed me to use the pcv valve as the primary vacuum source, only turn the electric pump on at the track. I log crankcase vacuum, and one time at the track I forgot to turn the electric pump on. To my surprise, the crankcase never went positive pressure, still had some pcv valve drawn vacuum in reserve at the end of the pass. Here's a graph showing the crankcase vacuum trace getting drawn down against WOT over time...



The next evolution of my system was to completely eliminate the electric pump and separator tank, use only the pcv valve as a vacuum source. I also installed the crossover breather setup, but installed check-valves inside the breathers which allowed the pcv to still draw a vacuum. Also moved the pcv valve to a location between the breathers...





That's my current system, works for me.

Grant

[skinny z]

The next evolution of my system was to completely eliminate the electric pump and separator tank, use only the pcv valve as a vacuum source. I also installed the crossover breather setup, but installed check-valves inside the breathers which allowed the pcv to still draw a vacuum. Also moved the pcv valve to a location between the breathers...

Now that's interesting.
What kind of vacuum can you see? What's the hose routing or more specifically, where does the PCV valve fit into all of this? This question is more for me as my friend is on the pump bandwagon. But pumpless has piqued my interest.

[weedburner]

It's a well sealed low-compression 355sbc, gapless rings, nitrous friendly cam (251/261 114lca).

In the beginning back in 2012 with no pcv valve, the electric pump pulled 4"Hg in the crankcase on 12v. With the ballast resistor dropping voltage to 9.5v, it only pulled 1"Hg. Draw is another issue, 12a @ 12v. The reason I originally added the pcv valve to the system was so I could turn off the electric pump for street driving to reduce the draw on my small alternator.

The pcv with no vacuum pump pulls 15"Hg in the crankcase @ 2500rpm down the highway, 10"Hg @ idle, and still has vacuum in reserve after making a WOT pass. Found out that I didn't need the electric pump, so I removed it. Added the check valve breathers in case there was a problem so the crankcase would not see positive pressure. Been this way for several years now with no problems. Inside of the breathers and the top of the check balls are dry, no sign of the check balls ever opening due to pressure.

My car has sort of a gasser vibe, with no front bumper it's screaming for a moon style tank up front. I'm not going to use the tank for fuel though, I'm going to move the check-valve breathers and pcv valve to the tank and use it as a catch tank which also adds volume to my crankcase. The idea is adding crankcase volume with a catch tank should make my pcv valve produced vacuum last longer @ WOT. Also moving the pcv to the catch tank should make it very unlikely that any oil could ever make it to the intake tract.

Grant

[JC565Ford]

many different ways to do it:

[skinny z]

many different ways to do it:

Can't open your pictures.

[skinny z]

Also moving the pcv to the catch tank should make it very unlikely that any oil could ever make it to the intake tract.

Moving the ventilation out of the intake is the driving factor behind my friends push for an alternative.
Somewhat similar to my own predicament several years with a well worn short lock allowing plenty of blow by. That's when I incorporated a separator between the PCV valve on the drivers side valve cover and the intake plenum. It helped ease the amount of oil and combustion residue getting in there. Fresh air in through a passenger side breather in typical fashion.

So my friend appears determined to eliminate that intake contamination so here we are at the vacuum pump installation.

[JC565Ford]

Can't open your pictures.

They are showing up on my end

[skinny z]

Hmm.

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