LNF PCV Anti-coking drain back system
06-12-2014, 05:12 PM
#254
Have you changed the location of the AN fitting on the dipstick tube since I bought mine? If it was a couple inches lower and rotated a little more towards the front of the car, the hose would be able to clear the alternator.
If it has been moved, then I'd be interested in getting a new one. The smaller hose would obviously help with clearance as well.
If it has been moved, then I'd be interested in getting a new one. The smaller hose would obviously help with clearance as well.
06-12-2014, 09:46 PM
#255
Have you changed the location of the AN fitting on the dipstick tube since I bought mine? If it was a couple inches lower and rotated a little more towards the front of the car, the hose would be able to clear the alternator.
If it has been moved, then I'd be interested in getting a new one. The smaller hose would obviously help with clearance as well.
If it has been moved, then I'd be interested in getting a new one. The smaller hose would obviously help with clearance as well.
Last edited by Powell Race Parts; 06-12-2014 at 10:18 PM.
06-12-2014, 10:31 PM
#257
when you are done crank the car over ( oil changed of course) with plugs out to get rid of any dust and debris from walnuts...
torque wrench.
i leave the tob and the connector assembled just drop the four bolts....... I am going to take a tip from someone here and use the GM 88861802 or 88861803 solvent to loosen the crud after the first shot at blasting....
06-13-2014, 11:49 AM
#258
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These are my valves before and after. I used mostly the gm cleans chemical AND good old plain throttle body cleaner. I let my valves soak in it for about 20 minutes. And I swear the crud just came right off very easily with a tooth brush !! 
The walnut blast WAS NOT needede at all. Although I did hit them with the walnut for fun. They were already totally clean before. I didn't replace my PCV because my dealer didn't have one in stock. SO I just cleaned my old one up. When and if I do the job again. I don't think I will even use the wall nut blast again after seeing how clean they came without it. I literally could clean all four valves and have the car back together in a few hours. The longest part is waiting the 15-20 mins for the valves to just soak. Maybe next timew IF i do it again I might just try only a ten miute soak. 
After I was done saoking the valves I used my shop vac to suck up the chemical and the walnut blast after. I made a straw attachment out of fuel ine hose that worked perfectly. And then I used my air comperssor to blast any reamaning wall nut out after words with an air gun. It was fast , easy and very effective.
Before : ( I assume this is about avearge for an LNF with about 55,00 miles )
After : ( They look 100% better and my fuel milage has improved a fair amount, idles smoother. No real notice of any increased power though. Not that I ever lost any. )
The walnut blast WAS NOT needede at all. Although I did hit them with the walnut for fun. They were already totally clean before. I didn't replace my PCV because my dealer didn't have one in stock. SO I just cleaned my old one up. When and if I do the job again. I don't think I will even use the wall nut blast again after seeing how clean they came without it. I literally could clean all four valves and have the car back together in a few hours. The longest part is waiting the 15-20 mins for the valves to just soak. Maybe next timew IF i do it again I might just try only a ten miute soak. After I was done saoking the valves I used my shop vac to suck up the chemical and the walnut blast after. I made a straw attachment out of fuel ine hose that worked perfectly. And then I used my air comperssor to blast any reamaning wall nut out after words with an air gun. It was fast , easy and very effective. Before : ( I assume this is about avearge for an LNF with about 55,00 miles )
After : ( They look 100% better and my fuel milage has improved a fair amount, idles smoother. No real notice of any increased power though. Not that I ever lost any. )
06-13-2014, 07:25 PM
#259
nice work quicksilver. One draw back with letting the solvents soak, is that if it does leak past the valve seats it can potentially do frugly things to the ring lands. Not sure about it. I would use it sparlingly , not as a bird bath. If you didnt replace the PCV then its good you are skilled and experienced, you will be doing it again. Enjoy!
06-17-2014, 10:48 PM
#262
either the install is plumbed wrong or you have other issues with oil filling up in the seperator. The PCV cant take excessive blowby. If tis leaking at the vent its filling full of oil. either plumbing or blowby. So, what I do, after checking the plumbing routing and finding out about the tune etc , I do an engine health check with a compression and leak down test (If you have leak down of 25% or more its exessive blow by past the rings which are damaged; 150 compression across the board is normal for an LNF ) as well as a borescope of the valves to see their condition, and lately a replacement of the PCV valve in the IM as they are proving troublesome.
Last edited by Powell Race Parts; 06-17-2014 at 10:55 PM.
06-21-2014, 02:33 PM
#265
Senior Member
So, with this inherent problem, why are so many engines going DI? It doesn't make sense to me.
I was looking at new cars for the wife and absolutely loved the Regal GS. The fact that it's the same DI as the Cobalt makes me now look at other cars.
I was looking at new cars for the wife and absolutely loved the Regal GS. The fact that it's the same DI as the Cobalt makes me now look at other cars.
Last edited by SSlobalt; 06-21-2014 at 02:43 PM.
06-28-2014, 08:38 AM
#274
So I have been working with Alan Mcclure on the next step. Its very hard to produce parts and do research and work on cars etc. So Alan has been sharing the load with R&D esp. for LSJ-T variants.
We have concluded we need to induce more vacuum in the system. Why is vacuum important? All that oil and blow by vapor in the crankcase is getting flung around a lot. The outer edges of the crankshaft webs must be turning at 100 mph. Alan said to me tonight, imagine putting your hand out the window at a hundred miles per hour.
Imagine the poor piston at 6000 rpm; it is travelling up and down at the equvalent speed of about 30 miles per hour.
all that creates pressure in the crank case, and that pressure costs power. Oh and the piston accelleration speed increases as the square of the RPM. So does crank/rod bearing load .
We know from Wangspeeds comparisons, that he can drive for two weeks daily driving his turbo, ( a few hundred miles or more) and not collect more than 300 ml. of oil in the (non drain back) seperator. At the track he can collect 500 ml of oil in just twenty laps of racing, or say 50 miles.
so....if we can come up with a means to constantly maintain anout 15 inches of vacuum in the crankcase at all times, while continuing to seperate oil from the blow by gasses, then perhaps we can make more power ( sort of "free" power) and improve things like fuel economy, oil consumption, etc etc...and
no oil in the intake
on the track, racing, whereever.
that would be what we are working towards. In the meantime, with clean valves you can expect your LNF in normal dd work to maintain clean valves. Tune it, beat on it, track it, then its more difficult. Thats why v.3 of this system may well lead to some awesome results for racers.
We have concluded we need to induce more vacuum in the system. Why is vacuum important? All that oil and blow by vapor in the crankcase is getting flung around a lot. The outer edges of the crankshaft webs must be turning at 100 mph. Alan said to me tonight, imagine putting your hand out the window at a hundred miles per hour.
Imagine the poor piston at 6000 rpm; it is travelling up and down at the equvalent speed of about 30 miles per hour.
all that creates pressure in the crank case, and that pressure costs power. Oh and the piston accelleration speed increases as the square of the RPM. So does crank/rod bearing load .
We know from Wangspeeds comparisons, that he can drive for two weeks daily driving his turbo, ( a few hundred miles or more) and not collect more than 300 ml. of oil in the (non drain back) seperator. At the track he can collect 500 ml of oil in just twenty laps of racing, or say 50 miles.
so....if we can come up with a means to constantly maintain anout 15 inches of vacuum in the crankcase at all times, while continuing to seperate oil from the blow by gasses, then perhaps we can make more power ( sort of "free" power) and improve things like fuel economy, oil consumption, etc etc...and
no oil in the intake
on the track, racing, whereever.
that would be what we are working towards. In the meantime, with clean valves you can expect your LNF in normal dd work to maintain clean valves. Tune it, beat on it, track it, then its more difficult. Thats why v.3 of this system may well lead to some awesome results for racers.
Where is the vacuum pump going to go though?
06-28-2014, 02:42 PM
#275
Al already has one working. It's electric. Lsj is easy the LNf could use the kappa pump but it is not designed for continuous operation afaik and the plumbing we have not worked out yet. I am at v.3 currently. The theory is that the LNF PCV is one direction always under vacuum however delicate those levels maybe. But we have found otherwise. And I do t want to discuss plumbing here. For obvious reasons one we have not settled on a route and also I don't want to make it retarded simple to copy. Fortunately most folks who mod their cars run VTA and figure it rocks.