With all the talk about pvc and blowing oil, etc. I remember that we used to hook breathers to the valve covers and hoses from them to Chevy retard valves welded in the header collectors.

Does anyone use this type of system anymore? Would it help the LSx PVC issues?

 

I bet this is only a race car option for the LS1 since it will be spewing oil vapor into the air. It does work, however, and as rpm increases the higher the vaccum pulled through the crankcase hence the tighter the rings will seal. IF I were to put this on an LS1 I would put the breathers at the FRONT of the valve covers to lessen the possiblity of sucking pure oil out the exhaust. I have heard that part of the "oil in the intake" problem with these cars is that upon hard aceleratrion oil tends to pool at the rear of the head/valve cover. Since the stock PCV system pulls from the rear of the valve cover pure oil gets into the PCV system instead of just vapor.

 

has anyone experimented with this on an ls1? i never heard of this before and it sounds very interesting!

 

I used to build engines for offroad racing(4 wheel drives) and we used them a lot. Engines would last a couple of seasons, and when torn down, the inerds looked absolutely great.

In some cases we had to put the crank seals in backwards, or dirt would get sucked in through the seals.

Personally, I don't like re-cycling engine air/oil back tothe TB, etc. and this system does create vacuum and a clean engine. I just haven't tried in on an LSx motor.

I've seen them at Jegs/Summit a year or so ago.

Edit: They still sell them

 

Anyone else?

 

I was thinking about doing this in my setup. Not quite sure yet. If I did, would it be wiser to do it before or after the turbo is the question..

 

Put the seal in backwards because dirt would get sucked in? There is no way that a header evac system will pull that much vacuum. It takes close to 25 inches to do that.

 

I've seen it, and read of others with the same thing, back in the 70's. It wasn't real common, but it has happened. I used toi have pictures, but that was before PC's

 

My boss is the inventor of that evac system, way back in the 60's. Dick Moroso was the first to copy and market the idea. They will pull up to about 4" of vacuum if they're designed and installed exactly right. That's not enough to much at all unfortunately. That's why the vacuum pump was invented (Moroso, Aerospace, GZ)

 

We have a EVAC system on the 74 Formula that my cousin drives. 476 cube big block. I would expect a tall version of the LS1 valve cover would help with a LS1 version EVAC.

 

I've seen more than 4" out of them, but in any case, any vacuum in the crankcase vs pressure is a good thing.

 

Agreed...

 

How about with a complete exhaust system?

Open headers worked fine and I have had some success with closed exhaust on other setups, but no experience with the LSx.

 

No way will it work with an exhaust system. It may pull a little, but ANY restrictions and it won't function. You'd be better off using an LS6 valley cover, and plugging the fresh air intake on the valve covers.

 

I thought about doing this, but then some issues came up when I thought about how I would drive the car on the road course and didnt think it would help much at all.

 

You've made yourself perfectly clear on this, and many including Moroso agree with you.

Then there is a whole other camp, including Mr. Gasket who think otherwise.

So who is your boss that invented this?

I've been looking at the GZ vacuum pump and some others as well. I may invest in a pump and fab the rest myself. Don't want to spend over $300 or $400, that's for sure.

 

You can put a filter inline with the pcv line, like an air compressor filter from Home Depot for about $20. The filter media is too fine though, so you can drill about 20 holes in the filter with your smallest drill bit. It captures the oil but leaves the vaccum intact in the crankcase. Of course you need a couple hose clamps, some hose barbs, and about 12 inches of rubber hose too.

 

Can you explain to me the reason behind drilling the holes? I have a filter on my car now, but no holes.

 

I found that my gas mileage would decline about 1+ mpg and then go back to normal after I replaced the filter. I realized that the filter would plug up after 2-3,000 miles. Then I drilled some holes so the filter wouldn''t plug up so soon.

The amount of oil being filtered out is the same, with or without the holes.

The decline in gas mileage also shows that the slight vacuum from the pcv is helpful. But I think the vacuum is so small that it helps mpg and power mostly in lower rpm ranges.

 

I have read elsewhere to replace the filter used in the water seperators for air compressors with steel wool. Have yet to do it but this oil out of the PCV is a real issue with my V6.