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Old 06-02-2006, 05:22 PM   #1
The Edge
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Location: Vaughan MS
Default Electric Pump Crankcase Evacuation System

Has anyone used one of these? I don't want to run a belt driven pump, to keep things simple. I'm guessing I would use a pump similar to GM PN 12568241 with a small collection tank between the line coming from the valve covers and the line to the pump.
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Old 06-02-2006, 06:05 PM   #2
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Location: Little Rock AR

Never used one of those but why not keep the stock setup? It only works when you have some manifold vacuum so it is automaticaly disabled at WOT. No evacuation when running hard so it can't hurt performance.

If it works, why fix it?

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Old 06-02-2006, 06:46 PM   #3
The Edge
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sorry should have explained further....have no PVC system at this time and carb has no vaccume. Engine is 469BB with approx 630 hp. Only breathers on the valve covers.
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Old 06-03-2006, 05:37 AM   #4
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Location: Dallas County Texas
Default Had *TOO* good luck with header suction evac system

I had a problem with occassional leaks from everywhere when running long and hard at 5000+ on my 413.

These are simple tubes, about 1" diameter, welded into the secondary collector or exhaust collector jsut after any O2 sensors/exh gas temp pyros, etc.

A large heater hose attaches from them to the valve covers - and they NEED to be extended!!! As engine RPM increases, the vacuum produced is tremendous (don't ask my hand how it knows...) - and it's free, like turbo charging energy...well...recovering what you've already paid for at least.

They have a one way valve to prevent a backfire from reaching oil.

I need to block mine a little as they create SUCH a vacuum they are pulling oil up the extended baffled tube ont he valve covers and causing a leak THERE (and at the highest RPM a visible oil smoke.!

Cheap, effective, no moving parts - hell of a thing!

Moroso makes them as well as others.
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Old 06-03-2006, 06:26 AM   #5
Bob Onit
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Originally Posted by The Edge
have no PVC system at this time
Actually PCV is very important for a clean engine
I think I can dig up the articles I read about this if you would like to see them.
Honestly, PCV is much more than both banks just breathing..you need that valve.
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Old 06-03-2006, 12:50 PM   #6
The Edge
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Member Since: Aug 2000
Location: Vaughan MS

I've resolved that I do need it as well. I am just looking for parts that someone has used, including electric pump, as I don't want to weld into the exhaust collector. I can handle an electric setup in my garage and know that the vaccume pressure will be consistent as opposed to the trial and error associated with the pan evac method. The main question is which electric pump to use based on how many inches Hg it will pull. I'm having a hard time finding out this info. Here's what a couple of people have mentioned, but I have no info on it:

GM PART # 12568241
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Old 06-05-2006, 03:53 AM   #7
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Default I know the SSBC auxillary vacuum pump is insufficient for this

When I upgraded to this temporary mid-level engine (or it's immediate predecessor) I was worried the much larger cam would deprive my terrible brakes of even more boost, so I replaced the gas evap cannister, long since disconnected by a previous owner, with a vacuum reservoir of about the same dimension and bought one of the $250ish vacuum pumps from SSBC to run to it - which I mounted in the nose cone.

It turned out both cams I've used, while having decent lift and duration, have little overlap and it wasn't needed. I therefore routed it into one of the valve cover ports in a similar manner to the PCV system.

Both combined were insufficient to remove considerable crankcase pressure developed by a higher cylinder pressure higher performance engine with nitrous pistons and the requisite somewhat looser rings for longevity.

I believe that vac pump pulled about 10A...so 120 watts or, at most, 1/6th hp (more like 1/10-1/8 if it was really efficient.) I think this is just way too little air being moved to overcome blowby on a higher powered engine at sustained higher RPM.

I believe this is why the 3- and 4-vaned mechanical vac pumps were developed as they can access so much more power and are automatically weighted to engine RPM. I know creating a significant vacuum in the crankcase, in addition to removing all volatiles (especially water - not just gasoline), really helps to seat the rings and greatly reduce loss of power from air resistance below the pistons (which is proportional to RPM and the diameter of the pistons - bad in a big inch big block or a high revving small block.)

I was going to install one, after about the fifth oil pan gasket or valve cover gasket or distributor gasket leaked while being pushed out from the excess crankcase pressure, when someone suggested the header venturi system. It was a lot easier to install (and cheaper) and so I gave it a whirl and have been pleased with it, except for the vacuum is too much at times and pulls oil up to where it can leak after shutdown. (I will shortly put a restrictor in the tubes or more baffles in the valve cover riser pipes to stop this silliness...)

Whenever I finally build the real engine that started this absurd project a half decade ago, I will use the biggest, baddest 4-vaned mechanical vacuum pump out there at the time(and a dry sump oiling system, since I'll have that "free" extra vacuum source to work with....)

If I could find the silly thing, I'd sell you the SSBC vacuum pump for cheap...if.....I..... could.....find.......it....

BTW, the SSBC one is..."amusingly...quaintly....invigorati ngly!" loud. You may really want to test whatever one you get if possible (if you have a nice and quiet car...which I do not.) This thing sounded like a mini aircompressor..which..is...exactly...wha t..it...is... I could usually hear it over the headers, over the (previous) mechanical fan, even over the TCI Rattler harmonic balancer at shutdown. We're not talking gear drive noisy...but...well..."significant"

Last edited by WayneLBurnham; 06-05-2006 at 04:00 AM.
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Old 06-05-2006, 03:53 AM
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