thinking about blowby

[DeepRoots]

has anyone ever plumbed their crankcase into their vacuum pump?
Obviously you'd want to do it with appropriate baffles or from the timing cover.

Drew

 

[The Warden]

Hadn't heard of this idea before...just wondering, what would be the advantage to doing this?

 

[geonc]

OK Drew...make my head hurt this early

For one, if you do have excessive blow by = excessive crankcase press and that brings soot/carbon etc....to the vac pump, shortening it's life....

Secondly, you would be introducing negative pressure [vacuum] into a system that does not normally produce it, unlike a gas eng that relies on vac to draw in fuel.....

In therory it's a good idea and I'm not bashing or anything, but practical application I'm not so sure without some Rube Goldberg kinda engineering

This will be an interesting thread no doubt

 

[DeepRoots]

well last time I was at the track, I was talking to a fella with a 512 bbf, and he had a vac pump. I asked if it was for power brakes (figuring he had an aggressive cam), it was not.
It was strictly for removing crankcase pressure and shooting it into the exhaust.

So I spent some time googling it outta just curiousity, and I guess on most 400hp engines the lack of pressure for the rotating assembly to run through nets an extra 15hp or so.

So me just thinking, I've already got a 3/4inch pipe elbow welded to the timing cover that goes to the intake, running it to a vac pump wouldn't be a big deal.... plus we already have one handy.

So there,
drew

 

[SparkandFire]

Same logic as running a baffled block, eh?

Makes sense to me now...

 

[DeepRoots]

In theory it's a good idea and I'm not bashing or anything, but practical application I'm not so sure without some Rube Goldberg kinda engineering

a 5/8inch connection to a source of crankcase pressure, (I welded my 3/4inch to the plate that covers the IP bolts onto it's gear) Short piece of 5/8inch vac hose, and a 5/8inch T hardly qualifies as 'rube goldberg engineering'
I could have it assembled for $5, or I could root around the shop long enough and find the parts I need.

Even without excessive crankcase pressure, pull the dipstick on most of these trucks and it's obvious there is some pressure behind it all. Factor in a CDR valve shutting at high rpm and you've got a pressurized container the crankshaft, rods, and pistons are struggling to travel through.
On the other hand, if there was a filtered breather on a valve cover and an evac system pulling on the otherside, that pressurized vessel is replaced with a very faint breeze through the crankcase.
A pressurized vessel also tends to keep things suspended in the air better, hence things like windage trays are used to keep oil solids from slapping around in the engine.

This will be an interesting thread no doubt

Apparently not.

Ohh well back to reading threads like "I wanna put two powerstroke turbos on YO" and "I can spin my ancient 1200lb diesel 4,000rpms, so I gots me a hotrod!"

Drew

 

[TwoTone IDI]

i feel like it would depend on exactly how much you pull through

one thing i was always concerned with was on the piston... with a mechanically evacuated crankcase, extreme pressure on one side of the ring is met by suction on the other

even as the case may be on a normal, healthy engine there will be slight pressure to the crank side and extreme pressure to the combustion side, i feel like pressurizing both sides is the ideal situation

but that is just "feeling" engineering, not based in reality

 

[dyoung14]

a
Apparently not.

Ohh well back to reading threads like "I wanna put two powerstroke turbos on YO" and "I can spin my ancient 1200lb diesel 4,000rpms, so I gots me a hotrod!"

Drew

You know you can be a real butt head at times and i have never really understood why

 

[Dieselcrawler]

i had thought about putting the pipe adapter on the exhaust and plumping it to the exhaust, just like drag cars and the tubes running to the headers. on the header is a check valve, not allowing exhaust pressure to enter crankcase, but pulls vapors from crankcase.

like this

You must be registered for see images attach

 

[fury9]

with the right baffles and stuff why couldn't one just plumb it to the intake, the intake would have to be plumbed directly,somehow, for the maximum suction, not just a hose dumped in there. Or maybe it could even be plumbed to a turbo?? And I wonder, what would be the positives and negatives of having a negative vacuumed block?

 

[DeepRoots]

You know you can be a real butt head at times and i have never really understood why

That really is one of those great mysteries isn't it?
Wait about 12 years and ask again, but you'll already know.

to the original question.....

to quote:
Crankcase vacuum system
United States Patent 4257383
The crankcase vacuum greatly reduces oil migration around the piston rings and valve guides of the engine in order to reduce oil consumption, decrease contamination of the combustion chamber from oil leakage, and reduce detonation tendency. The crankcase vacuum also allows a reduction in oil ring tension which in turn reduces engine friction, resulting in a high power output and cooler running engine during operation thereof.

I suppose you *could* just run a pipe to the intake. But do to no restrictions we aren't really pulling a ton of vacuum... and a cdr closes at certain speeds.

Drew

 

[Fordsandguns]

OK Drew...make my head hurt this early

For one, if you do have excessive blow by = excessive crankcase press and that brings soot/carbon etc....to the vac pump, shortening it's life....

Why couldn't a second vac pump be used solely for the crankcase vent?
Maybe even an electric pump off a stroke?

 

[fury9]

Why couldn't a second vac pump be used solely for the crankcase vent?
Maybe even an electric pump off a stroke?

becay=use that would defeat the whole "purpose" of generating a higher power output? but back to the root post-Why don't you just try it and let us all know how great or terrible this excursion will be for you. Besides you need yet another reason to escape the wife to work on "the truck" lol hardy harrhar

 

[The Warden]

i had thought about putting the pipe adapter on the exhaust and plumping it to the exhaust, just like drag cars and the tubes running to the headers. on the header is a check valve, not allowing exhaust pressure to enter crankcase, but pulls vapors from crankcase.

like this

You must be registered for see images attach

One guy on here's done this with success...take a look at these threads:

http://oilburners.net/forums/showthread.php?t=8888

http://oilburners.net/forums/showthread.php?t=20605

I've got the Jegs kit to do the same; I just haven't run the hoses and whatnot...I'm planning to do this while my truck's out of service, whenever that gets started in earnest. I'm just running a road draft tube at the moment...

Drew, I see what you mean now...although it seems to me that, with the right venturi setup, you could achieve the same goal without using the vacuum pump. But, at the same time, your idea may work better...I'm honestly not sure. I say give it a shot and see what happens and FWIW I'm very curious about the outcome of this...

 

[Fordsandguns]

becay=use that would defeat the whole "purpose" of generating a higher power output? but back to the root post-Why don't you just try it and let us all know how great or terrible this excursion will be for you. Besides you need yet another reason to escape the wife to work on "the truck" lol hardy harrhar

Hence the suggestion of the electric pump. Granted I don't think that this will make an extra 15hp with our engines but you should make more than it takes to turn a vac pump or the extra draw on the alt. Plus if you route it into the exhaust you aren't having the mess in the intake or making the two back cylinders run hotter.