Also, I was thinking: What if a small hole was drilled into the exhaust pipe, say about 1 foot past one collector. A 1/4" diameter metal line is bent and put in the hole and then turned so it points rearward inside the exhaust pipe. Then welded in place. So the exhaust gasses going by it will cause a vacuum on that metal line and draw air from it. Just like a drinking straw. That line can then be attached to a rubber line that attaches to the valley cover port or a valve cover port, which will draw crankscase gasses.
Would just have to do a test to see if it creates enough suction. If it does, a PCV valve could also be put in line if desired.

Or...a venturi. Its can me mounted low, maybe right in front of the air dam to catch air while moving. That can be attached to a line and also draw air from the crankcase that way.

BUT...a simple electric pusher air pump to push fresh air into the crankcase continually through the valley cover port and let it escape through the valve cover port vents...I think is the best.

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One of my brothers has a 1st gen 383/procharger setup, and has exactly what you describe (the venturii) in one of his collectors. I believe it's a commercial setup that incorporates a valve of some sort (PCV like) in the event of a backfire. As we live 1500 miles apart it's not something I can run over and look at.

I was curious, did you ever do the needle valve thing?

If you want to do the oil analysis thing, go here: http://polarislabs1.com/

The way it works is you send them I think $20. You'll get a sample bottle and a mailer. You'll need a little hand pump (Harbor Freight has a couple). As the method of pulling the sample can have a significant impact on the results, ya gotta be careful and do it right. If you want, PM me and I'll give you directions.

 

No....I just tighten or loosen one of my clamps and it squeezes or loosens its grip on the hose....making more or less air able to flow through. It works great for now.

I'll look into that oil analysis, I'll try to do it this coming week. I'm kind of curious too.

I looked at their site...there's a ton of things they can test for. What should I have tested?


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In a normal diesel analysis, they look at the oil's additive package, wear metals, fuel dilution, any signs of anti-freeze, viscosity and the TBN (a dropping TBN, or Total Base Number, indicates acid buildup). When you fill out the form provided, you'll have to indicate the engine, oil type, mileage, mileage on the oil and so on. Those things will dictate the 'normal analysis' parameters. When you put the oil type down, be as specific as you can. Like Mobil 1, 5w-30 full synthetic or whatever you have in there.

When you get the results, you'll get a print out showing all the parameters I mentioned plus the chemist's recommendation as to what you should do. Over time, these reports will give you a very good idea of what is going on inside the engine. What the chemist says about the condition of the oil is 100% definitive, assuming you've done your part when taking the sample. How you draw the sample is as important as the sample itself, as doing it wrong will skew the results...sometimes severely.

 

Thats cool.

PM the directions how to get the oil out properly. Thanks.

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Curious to what classes and what tracks they run at?

At the very least drag only motors have a scavange evac system in the header colletors to pull vac, and anyone thats serious has a belt driven vac pump.....especially the Alky motors due to the amount of moisture the alchol introduces to the crankcase. Next time your at a sanctioned )NHRA/IHRA) race walk around the pits and look at the dragster motors and how they evac. You will see that any w/a vac pump run a relief valve on the opposite valve cover because if you pul any more than 14-15" of vac you start to pull oil off the wrist pins & rod journals.

The reason I ask about all these friends drag racing high HP v8's you claim run no vac source for evac is I have run a pro team for 7 years and we run most every sanctioned track in the Eastern US and have yet to see a high HP dragster or door car w/out evac so I'm curious to what class they race and where.

The oil analysis will show the acid build up....and no, it takes a year or two before you would see any substantial damage to your internal engine parts.....but an easy way is after 6 mnths or so of runninng like you describe pull a valve cover and look and the corrosion from the vapors on your rocker arms. This is the first place it is visable.

More of my background? My team holds several local, divisonal, National, & World championships in Super Pro, Super Comp, Quickrod, Top Dragster, and non-electronics.....I am also a graduate of the Reher Morrision Racing engine building school and have been an engine builder for over 35 years. Take a little time & read David Reher's tech tips......a world of information: http://www.rehermorrison.com/blog/?cat=3

Bottom line is, w/out a proper evac system you WILL sustain long term engine damage. It may take a few years to notice, but I build motors 6 days a week when not racing and se the results first hand.

 

OK fair enough you well schooled in race engines and have the credentials to prove it. So back to the question how do I keep the oil OUT of my intake? The catch can (Rev Extreme) simply enough does not work (for me). I am game to try anything a graduate of the Reher Morrision Racing engine building school will suggest. I will also pass this info along to many of my friends. I am all ears....

 

Can you send me pics of how the can was set-up? If plumbed correctly, and the oil is coming into the intake from the PCV then the can will catch all but a very small amount (no can can catch 100%). It is also possible if you have an early design (over 8 months old) that the perforated dispersion tube may have come loose so the vapors are going in the top and right out the outlet instead of down the tube and dispersed to condense to droplets that are trapped...just send it back & they will repair & update it free). There are several other ways for oil mist to enter the intake manifold, the PCV system is the most common with the fresh air make up source (the fitting on the top rear of your throttle body) being the second most common. To eliminate that you need to cap the TB fitting and run a valve cover breather (installed as far from the crankcase vent as possible...ideally you want to pull filtered fresh air in one valve cover & evac it out the other or the LS6/LS2 style valley cover is sencond best) Then if it is excess crankcase pressure pushing oil vapor/mist out faster than the PCV can evac it you will see it pushed back through the line from the pass valve cover front to the TB and it is ingested from there. The 3rd point of ingestion is from reversion. This of course needs at least one piston/ring/bore/valveguide or seal issue that is allowing oil to be pulled into that one or more intake port and at high RPM's the reversion pulse will "push" that oil throughout the entire intake manifold. It will appear to have entered from the vac fitting that the PCV system uses but is really from one of the cylinders (reversion is a whole different process that is not widely understood but do a Google search and you can actually find some super high speed video of engines on dyno's where at high RPM's...9-10-12K plus the reversion cloud of A/F mixture is actually rising out of the intake runners or carb on a non fuel injected motor). To test for that just place a clean clear fuel filter inline between the catch can outlet (the side fitting on the RevX can) and the vac fitting. If it gets oil on the can side, oil is coming through the can. If it first appears on the intake vacuum side, then it is reversion so you have a deeper issue. On the LS motors we pull apart it is usually # 7 ringland broken between the compression & middle ring, or the land itself broke off at the top. We also find the top ringland pinched or crushed down on the top ring (comp. ring) and metal transfer along the piston side has caused the oil & scraper ring to stick allowing oil & blow-by. Also, try this: at idle (vac is at it's greatest when at idle or when the throttle blade closes from high RPM's) remove the oil fill cap and hold your hand over it. Does it pull a slight suction? If so, all is good with most of the system and I doubt you have a damaged piston/ring/bore. But if there is ANY pressure pushing back you have a deeper issue and that is the cause of the oil problem.

Now on big cam/stroker builds a can inline on the dirty side, and a can inline from the fresh air source may be needed (the bigger the bore & longer the stroke, the more crankcase pressure is built up) If it is forced induction, then you have a whole new process to deal with......and that is the PCV system works proerly when at idle & non-boost, but when you start making boost you have switched from the intake manifold being negative atmosphere to a pressurized component and the PCV system is rendered useless and pressure escapes wherever it can. The solution then is to have oneway check valves inline so the vacuum need for proper evacuation comes from in front of the compressor (head unit) through a line run to the air filter.

This is getting a bit long and I hope all can follow this, but if not ask me specific questions for clarification so this helps all. I'll go over every type of solution and the pros & cons of each....and remeber, this problem is NOT just in the GM LS based engines, but is an issue with ALL modern closed systems. We just tear into our cars where as the Mercedes or Lincoln owner never even realizes there is an issue.

I also wanted to address the water in the oil. You will NOT fill your crankcase up in short order with just breathers. What happens is each time your engine reaches operating temp the unburnt fuel, water vapor, combustion by-products will gass or "flash-off" as vapor. But only the excess crankcase pressure being relieved through the breather will carry any of that out....and without a proper evac system, a good amount remains in the crankcase and recondenses back to droplets that coat the internal engine parts as your motor cools down and it contaminates the oil. Every time you heat cycle you are adding more contamination and it is not very visable to just "look" at your oil....you need a proffesional analysis to see just what is accumulating in your oil and how it is breaking down its ability to protect...but the corrosion from the sulferic acid is also very damaging over time (I'll try to post up some pics of parts showing just this in the near future). Just pull the dipstick on a diesel 20 miles after an oil change...it already "looks" black & dirty, but is still new and providing the proper protection. Sight is deceiving. Oil might look pretty clean but an analysis report will show destructive levels of contaminants.

I'll add more after some more questions come in.

 

 

Use the best- http://www.dysonanalysis.com

It will take some time and multiple samples to see the affects.

 

If your blowby levels (CFM I guess?) exceeds the amount of CFM the intake can pull out of the crankcase thru the PCV system you will have pressure correct?

 

Yes, that is spot on. I would suspect a restricted LS6 valley cover vent or a excess blowby issue. Cap the valley cover and pull the crankcase from the drivers side rear valve cover fitting.....

 

Is this the mechanism of excessive oil consumption in the early LS1s with the ring-flutter issue at high rpms? (REF #01-06-01-023A)

My 99 has burned some oil from day 1 and it has increased every time I increased the stall. Oil gets black fast. Different heads/cams didn't really change it much, just higher stall. The entire intake manifold has an even film of oil inside and the intake ports of the heads are stained with it, same amount each one. Now with my 4200 stall I burn a qt of Mobil1 every ~300 mi. I tried the "orificed" PCV which did nothing. I had an AMW catch can on the dirty side years ago which caught a small fraction of the total. Did the LS6 valley conversion, no change. This has been the single most frustrating PITA with this car.

 

blackstone labs also tests oil too...

 

One of the major issues on modified engines is the 2.5mm fixed orifice GM started installing in '04 valley covers. This restriction coupled with the restricted oil separation chamber on the valley cover do not allow the crankcase to evacuate properly. I've been performing some testing on a restricted valley cover to find a fix to this but I'm not ready to publish anything.

 

This is EXACTLY what I had suspected. I did PM T Lewis and explained that I had excess pressure at idle. I have the LS2(2005) valley cover ran into the can and then to the intake. Fresh air thru the TB. At idle if I removed the oilcap I had excess pressure. If I simply capped the valley and routed the vaccume line to the passenger valve cover and replaced the oilcap when I pulled the plug from the drivers side cover it sucked my finger in something ridiculous. I'd like to try removing the valley cover and opening that port up underneath removing the orifice altogether. I'd still have the PCV built into the can that would be run in that portion of the circuit anyway. Just wondering how much the vaccume readings changing with a now much freer flowing crank draw would throw off my SD tune.

 

The oil gets dirty looking fast because the blowby past the rings has alot of carbon in it. My 99 ls1 used about 1 qt every 500miles and the oil got dirty looking very fast, intake was also full of oil. It was a ring sealing problem, my 02 uses no oil and the intake is completely clean and the oil stays clean looking between changes. So you would have to consider when the intake is oily and the oil gets black quickly after changes you need to fix the real problem. THE RINGS or the cylinder leakage under pressure.

 

LS6427 you can idiot this and moron that.......you know everything and engineers know nothing.....LOL

 

One thing I was wondering here. On a car with a vaccume pump setup thats is ideal. Lets say it pulls enough vaccume that the relief valve does not get triggered. Where does the fresh air source come from that evacutes/replaces these harmfull gasses out of the crankcase?

 

Yes, the early LS1's have a very high percentage of ring flutter due to the lower tension.....only fix for that is a re-ring. I have to agree that the vented valley cover orfice is a n issue especially after a motor has been apart. Debris can clog it up and then it is even more restricted. I like to pull from the rear of the drivers side valve cover, and have the fresh air enter the pass side frnt. This allows very little restriction and a very complete "flush path" through the crankcase.

If it does not pull enough vacuum to open the relief valve then it is either pulling it past seals or the blow-by is to excessive and you need to check rings/piston/bore. Try the routing I recomended and post the results......that may be your fix.