crankcase evacuation [Archive] - Chevy Nova Forum

: crankcase evacuation


steed
31st-July-2012, 04:10 PM
hi all,

I have a question concerning my crankcase evacuation system.

the hoses and the oil breathers are extreme hot when engine is running. I'm wondering if exhaust gas is flowing in the wrong direction from the collector to the valve covers.

does anyone have an idea?

thank you very much in advance.

carl

The Big Al
31st-July-2012, 04:15 PM
It's a easy test!

wGrx2rvIxJ0

Real McCoy
31st-July-2012, 04:16 PM
Do you have the one way valves at the header collector? The are actually anti back fire valves from a air pumped smog motor but they only let air flow one way. You can remove a hose at the valve cover and feel if the collector is drawing air in also.

steed
31st-July-2012, 04:23 PM
thank you, I will check tomorrow. I've got the Moroso System with the check valves at the collector.

are your oil breathers and hoses appearing extreme hot when engine is running?

greets
carl

Real McCoy
31st-July-2012, 11:04 PM
I run a vacuum pump now but I don't remember the hoses being horribly hot when I ran the pan e vac stuff. Your sucking blow by out and if you don't have excessive amounts you're not moving that much air.

steed
1st-August-2012, 04:11 AM
I run a vacuum pump now but I don't remember the hoses being horribly hot when I ran the pan e vac stuff. Your sucking blow by out and if you don't have excessive amounts you're not moving that much air.

good morning,

the hoses and the oil breathers are hotter than the valve covers and you can't touch them at all.

I'm thinking about switching to a vacuum pump. is it possible for you to post some picture of the installation?

do you have changed something in the engine setup for that - other piston rings or so? does it make sense to use a vacuum pump on the street as well?

sorry the number of questions :-)

thanks in advance
carl

Nova67ss
1st-August-2012, 05:09 AM
Ive got an teory about this that vacu pan kit

I think they are fine with open headers on a racecar, but used with mufflers on streetcars, U got backpressure that pusch exhaust fumes backwards up to the breathers..Depending on mufflers U gona get some effekt though (straight thru type I guess)

Had that kit on a car and it worked "come ci come sa" so I switched that out and whent with orginal PCV instead..

71nova355
1st-August-2012, 06:01 AM
I was told not to use the "welded into the header collector" set up with an exhaust. There's companies making a pcv catch can system I think I'm going to try. I just don't like the idea of oil getting sucked into the intake and I can't run baffles even after having welded aluminum (tall/wide) covers made. After the afr stud girdles there very Lil room before my actual pcv valve.

The Big Al
1st-August-2012, 03:23 PM
They should be hot, your sucking crank case fums from inside the engine.

You should also have breathers on the covers so fresh air can come in. I did and it helped air flow.

For a normal street engine the better choice is a PCV system. I have the evac system because of the High RPM when drag racing.

As for as mufflers go, the systems works with mufflers. Mine always has.

I did make baffles that bolt to the stud girdle to block any oil splash.

Big discussion and argument a few years ago.

www.stevesnovasite.com/forums/showthread.php?t=76896


Al

steed
1st-August-2012, 03:54 PM
They should be hot, your sucking crank case fums from inside the engine.

You should also have breathers on the covers so fresh air can come in. I did and it helped air flow.

For a normal street engine the better choice is a PCV system. I have the evac system because of the High RPM when drag racing.

As for as mufflers go, the systems works with mufflers. Mine always has.

I did make baffles that bolt to the stud girdle to block any oil splash.

Big discussion and argument a few years ago.

www.stevesnovasite.com/forums/showthread.php?t=76896


Al

i checked the system today. the problem is, they don't suck but they pump hot exhaust gas in the valve cover at idle speed and at 4000rpm. the breathers are so hot, that I can't touch them at all.

the system is installed just the way you described it in the 2007 threat.

when I pull out a breather - idle speed increase from 1000rpm to 2500rpm and back when I install the system again.

I guess "something is rotten in the state of denmark". :confused:

it's not a normal street engine. red line is at 8.500 and it goes 10.39 on a prepared track but I drive it on the street from time to time.

what do you think about the vacuum pump solution?

greets
carl

sbc1320
1st-August-2012, 03:55 PM
I just don't like the idea of oil getting sucked into the intake and I can't run baffles even after having welded aluminum (tall/wide) covers made. After the afr stud girdles there very Lil room before my actual pcv valve.

I run a flat style baffle that came with my Ansen valve covers and I am running AFR heads with a Jomar stud girdle. No oil sucking thru my pcv valve.

Real McCoy
1st-August-2012, 10:47 PM
i checked the system today. the problem is, they don't suck but they pump hot exhaust gas in the valve cover at idle speed and at 4000rpm. the breathers are so hot, that I can't touch them at all.

the system is installed just the way you described it in the 2007 threat.

when I pull out a breather - idle speed increase from 1000rpm to 2500rpm and back when I install the system again.

I guess "something is rotten in the state of denmark". :confused:

it's not a normal street engine. red line is at 8.500 and it goes 10.39 on a prepared track but I drive it on the street from time to time.

what do you think about the vacuum pump solution?

greets
carl

If the anti back fire valves are working properly air can not blow back into the motor. Sounds like the one way valves have failed. Maybe check those.

boosted
2nd-August-2012, 05:29 AM
i tried useing that type of pan evac system years ago and the class i ran in we have to run mufflers they worked ok with the dyno max straight thru bullet mufflers but not wity the flow master 2 or 3 chamber mufflers.
so i ended up putting a vaccumm pump on it and never looked back

steed
2nd-August-2012, 10:48 AM
i tried useing that type of pan evac system years ago and the class i ran in we have to run mufflers they worked ok with the dyno max straight thru bullet mufflers but not wity the flow master 2 or 3 chamber mufflers.
so i ended up putting a vaccumm pump on it and never looked back

ok, I have alternator, power steering and electrical wp. do you have a pic of the installation on a sbc? I'm wondering how I can handle 3 v-belts.

greets
carl

boosted
2nd-August-2012, 11:05 AM
ok, I have alternator, power steering and electrical wp. do you have a pic of the installation on a sbc? I'm wondering how I can handle 3 v-belts.

greets
carl

i'll have to see if i have any pics. i run alternator,belt drive fuel pump and vaccumm pump and elec h2o pump. i use a mandrel belt drive system so i can move my bet drive item around and then space the pulleys on the mandrel driv as needed

CarreraGuy
2nd-August-2012, 11:10 AM
This is ancient hisotry, but on the original Durango Deuce rallly car (2002-2005), Mike Goble installed a smog pump to extract gases from the pan (creating negative pressure under the pistons), so the engine would run a little faster. The system required the use of a vented, oil catch-bottle, and a valve to dump the contents of the bottle back into the oiling system after a few speed runs. We also use a Accusump.

71nova355
2nd-August-2012, 04:42 PM
I run a flat style baffle that came with my Ansen valve covers and I am running AFR heads with a Jomar stud girdle. No oil sucking thru my pcv valve.

How much were those valve covers? I saved money and bought my set from a place (whites performance in fl) they were only 60, they said I could have bought a 300 dollar set or they would build me what they build for there boat motors. Extra tall n wide, lol, well I needed the width cause of the Canfield heads and scorpion rockers I'm using. They were actually hitting the old valve covers the way the rockers are offset. With the girdles on there's only 3/8" between the tallest covers I've seen or have. I realize obviously someone could build taller ones but, come on. They had barrels in them but I had to tear them at the spot weld. Maybe your stud girdle is thinner idk. But a short pcv valve tests damn near right on top of the girdle. I've even tried the baffled grommets but there too deep. Anyway, good for you!

steed
14th-August-2012, 02:03 PM
good evening. i have checked the check valves on the collector and found out that they are burned out.

http://img31.imageshack.us/img31/3757/14082012073.jpg (http://imageshack.us/photo/my-images/31/14082012073.jpg/)

BUT: this is the first problem. I found out, that there is a heavy vacuum under the valve covers as I pulled out the evac breathers and the engine is running. the vacuum is increasing when rev up.

I've never heard that there can be a vacuum under the valve covers. :eek:

When I pull the breathers out of the valve covers, the idle speed increase from 1200 to 2000rpm and when I put my hands on the holes of the valve covers, the idle speed decrease back to 1200rpm.

Does anyone has an idea what can effect this?

greets
carl

sbc1320
14th-August-2012, 03:26 PM
How much were those valve covers?

I think I bid $160 on them and won them off of Ebay.

71nova355
15th-August-2012, 01:59 PM
Also after about 1000 miles my ten dollar a quart oil starts turning from barely visible to black. About that time I replace the pcv valve and start planning my oil change. Its never been aloud to get to bad. Last night tho using a GPS deal I ran a quarter after adjusting my accelerator pump linkage to the closest hole to the intake and ran an 11.08 122mph. Now, that's not a track time just using my phone so I don't expect it to be right on but when my secondaries snap open its on! Its been running so good lately, but last night the weather went cold and she drives so much better then . Sry guys just rambling.