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View Full Version : Exhaust evac system, where to put the filter?



86Shelby
03-20-2007, 03:40 PM
I'm seriously considering putting an exhaust driven evac system on my R/T but and having difficulty deciding where to put the vent filter. I do not want some big dorky filter that doubles as the oil fill cap.:yuck: I've been considering replacing one of the plugs at the end of the cam bore, but installing it backwards to allow extra room for a baffle. Or possibly just add it to the end of the rear valve cover with a weld-on tube. Anyone have any ideas they'd like to throw out?

Turbodave
03-20-2007, 05:00 PM
Could the filter be put inline and tee'd into the breather box under th intake?

Lotashelbys
03-20-2007, 06:31 PM
I would just drill and tap BOTH valve covers on the drivers side with like a 3/8" NPT and screw hose barbs in them and run it to a pretty little catch tank in your facorite location:thumb:

mcsvt
03-20-2007, 07:18 PM
I would just drill and tap BOTH valve covers on the drivers side with like a 3/8" NPT and screw hose barbs in them and run it to a pretty little catch tank in your facorite location:thumb:

That's pretty much what is done on the SMP car last I saw it.

johnl
03-20-2007, 08:13 PM
Is there ANY question about how well the oil drains back?

If there is, then a crankcase connection would eliminate any chance of oil flooding the "rocker box," using horsepower by tangling with the valve train, allowing/causing the valve guide seals to fail during vacuum, and least of all causing the VC to seep oil.

TurboJerry
03-21-2007, 03:28 AM
The oil will have a hard time draining back with crankcase venting at the VC's. That's why Lotus didn't allow PCV there. (why it's on the block) Maybe ok for a racecar, but a street car might have starvation problems.

86Shelby
03-21-2007, 09:15 AM
Could the filter be put inline and tee'd into the breather box under th intake?

I was thinking of using the breather box as a catch can of sorts to help seperate the oil before it went through the pipe to the exhaust. I think that would help keep the engine bay looking cleaner w/o having a catch can sitting somewhere; most are too large for my taste.

I'd also like to try to stay away from a stock-style setup with the vent placed in between the evac source and the engine.

I'd really like to use the head as the area where the vent/filter is to help in getting oil back to the pan. The vacuum source si going to be going to the factory spot on the center drainback in the block.

Jackson- I absolutely will not be cutting my front valve cover. I have FAR too much work into that.:nod:

johnl
03-21-2007, 09:35 PM
Exhaust evac can create a LOT of vacuum. If the take off is the VC, then you have a lot of air coming up the drain back passages - preventing oil from getting back to the crankcase.

Because exhaust evac is so effective, you want a regulated and filtered breather (see Jegs or where ever - they sell 'em) to relieve some of the vacuum while still maintaining negative pressure - just not too much.

It is best if this regulated filtered breather is on a VC and if the inlet for your evac is on the block. That way the air pulled by the evac through the regulated breather HELPS the oil drain back from the cam box(es) to the crankcase.