pcv again.

[skata]

From what I heard from the guy that I bought mine off of it was ok to run it all the time, so I don't know on that part. I did completely disassemble mine and there wasnt much oil or anything in there. I had just rebuilt the top end of my motor and there is virtually no blow-by so the impellers were clean. I truthfully don't know why it overheated, other than the fact that I was using it to try and suck air and not to blow the air it like how it was designed for. So who knows, I am definately going to keep my eyes open for another pump because it worked great until it melted down.

well you have to keep in mind that the air/gasses coming out of the engine are real hot(160 degrees+). running the pump for awhile will eventually heat up the pump.
i'm wondering if you could put some kind of valve somewhere in-line before the pump that would allow fresh/colder air into the pump. this would help cool the pump and provide a little relief for it. maybe just put in a very small opening somewhere in-line that could only allow so much fresh air in to the pump. this might lower the suction a bit, but may prolong the life of the pump.
just an idea.

 

[Hu Ryde]

This is why I am looking into putting the pump on the other side of the valve cover to put the cool/fresh air into the motor, instead of pulling it out I am displacing it with the cool fresh air that the pump will provide. It will then exit where the current stock location of the pcv is now and be routed to the atmosphere via a tube running to a fender well or such. Of course the inlet of the pump will be filtered and the outlet of the pump will be routed to the driverside valve cover as stated above. See, I'm not as crazy as you thought huh?

 

[Sy769]

I see what you are saying. However pumping fresh air in means you are putting positive pressure in the crankcase. Yes fresh air gets in there but vacuum is what you want in the crankcase.

Yes you can push a wagon or you can pull it. I think in this case pulling the wagon is the best option even if it takes more R&D to accomplish your goals.

 

[skata]

has anyone heard of routing the crankcase gasses to the exhaust?
someone mentioned to me once that you could strategicaly position a small metal tube into your exhaust pipe and weld it so that the tube goes into to the pipe and bend so that it goes directly down the center inside the pipe. it might need something else done also. the theory is that as the exhaust passes around the little pipe, it will create a suction on it and pull the crankcase fumes into the exhaust. you can run a hose from the valve cover to the exhaust. i'm sure it could work, but it might need some r&d. the advantages are that the blow-by gasses go out the back of the truck and you wont need a pump. i have seen this principle work before with water. anybody seen this done before?

 

[canadian]

i've seen that before on one of those rail type drag cars (the one with the motor behind the driver). there's a braided line going from the valve cover down to a fitting on the header, and the pressure drop across the end of the hose pulls the fumes out of the motor.

you could probably weld a small tube into the dp at a 45* angle and run the line to the valve covers on the passenger side to create the suction.

 

[jwaller]

yes that would wok BUT our exhaust is pressureized BC IT"S TOO SMALL. have any of you ever put a pressure gauge in your exhaust ...no..well I have...and under full boost I see 20psi or more in my exhaust system depending on boost) and I only have ~3ft of open pipe behind my turbo!!!...so that idea won't work either.... it works for them BC they have a huge pipe with only 1 cylinder going through it and thus no pressure in the pipe and the exhaust rushing by the hole scavenges air from the crankcase.

 

[Hu Ryde]

I too thought about this, (bung in exhaust idea) and was going to do a similar check as you did john but never found the time. Thanks for posting the results, saves alot of people fom wasting time.

 

[canadian]

it works for them BC they have a huge pipe with only 1 cylinder going through it and thus no pressure in the pipe and the exhaust rushing by the hole scavenges air from the crankcase.

IIRC the fitting was in the collector at the end of the header, so wouldn't all cylinders be going through it? I'm confused now. On the topic of backpressure in the exhaust, that would mean that the pressure would go back up the line plumbed into the PCV system and would be trying to push air *into* the valve covers thus not allowing the crankcase vapours to escape right?

 

[Hu Ryde]

From what I get out of it, our turbo in line with the exh flow doesn't let our exhaust flow free enough to be able to do this.

 

[Ian Turgeon]

i sent an email to gavic to see what he's got to input on the subject. Hopefully he'll get it.

Im just tired of looking in my intake and seeing the oil passed by the pcv system everywhere. I'd like to eliminate the octane lowering oil, and non-oxygen gases from entering the intake. And it seems like the right thing to do at the same time is create a constant vacuum in the crankcase to improve ring sealing, and posibly find a few horses at the same time.

 

[Sy769]

I would think there are some oil/air seperators and some electric vac pumps that would work. You will probably need to put the pump downstream far enough so the air can cool before reaching the pump. Maybe back under the bed. Just off the top of my head I remember looking at a oil seperator for my old airplane that went in line with the crankcase vent to keep oil off the belly.

Here is a couple DIY seperators. Do a search and you should find more

http://www.y8s.com/celica/air-oil/

http://www.autospeed.com/A_0338/P_1/article.html

I think even without a pump these would help keep oil out of the intake tract.

 

[InvisiBill]

http://www.fbody.com/members/stevenmh/Firebird_HTML/pcv_mod.htm might have some helpful info too.

I do remember hearing on this board about someone using the exhaust to scavenge the vapors...

 

[jwaller]

like patrick posted it's not hard to make an oil seperator. the hard part is getting a good pump thats cheap. moroso has them but they are seveal hundred dollars. 350 and up I think. we need to find a air pump like possibly what steve gavic did, by using an old smog pump to sump air from a vale cover. the problem is that the GM bracket that would hold that pump is pre 92,91 stuff and would locate the pump under our AC compressor but that then gets in the way of our exhaust crossover and turbo. an electrical air pump is the best option BC of ease of mounting but the thing is finding a good one that lasts and can put the crankcase in 15" of vacume..

 

[Maverick87]

If you look back through Hot Rod mag. And found an article they did a test and gained about 10-15 hp by using a vac pump. The only thing was that the gains were seen at 6000 plus rpm.

 

[Hu Ryde]

Just some more info:

http://www.speeddemonmotorsports.com/Tech/articles/vacuumpump.html

http://www.mpbrakes.com/vacuumpump.htm

http://www.bludotinc.com/PartsCatalog/parts_catalog.htm

 

[ericguy320]

i have the same air pump off an 01 vette i thought about leaving the tb side pcv on the car and putting the pump ant the air box side and have the air pump come on only under boost so i wont burn the pump up besides the tb makes enough vacume at idle for the crankcase, and the only time you would need high crankcase vac is at high rpm or boost.